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LI B HAR.Y
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546
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1944/45-^46^7
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I N 0 R a A N IC SEMINAR
1944-1945
TABLE OF CONTENTS
Page
THE COORDINATION NUMBER OF COPPER IN THE POLYETHYLENE-
AMMONIUM CHLOROCUPROATES 1
Hans Jonas sen
IONIZATION IN METHANOL 5
W. E< Morrell
SPECTROPHCTOMETRIC ESTIMATION OF CERTAIN RARE EARTH
ELEMENTS 6
Therald Moeller
DIAGRAM OF THE CORROSION PROCESS 7
Clifford R. Keizer
OXIDATION STATES OF COBALT AND NICKEL 8
John C. Bailar. Jr,
THE BASICITY CHARACTERISTICS OF SCANDIUM, YTTRIUM, AND
THE RARE EARTH ELEMENTS 12
Therald Moeller
CTHE OXIDATION-REDUCTION POTENTIALS OF VANADIUM 19
H. A. Lai tin en v
THE HONORABLE ROBERT BOYLE 23
Virginia Bartow
COORDINATION COMPOUNDS OF BORON TRI FLUORIDE 25
Donald R. Martin
ALUMINUM PHOSPHIDE 33
T. G. Kloae
PREPARATION OF POTASSIUM CHLORDPLATINITE 33
Janes V. Quagliano
AMPHIPROTIC SUBSTANCES 34
Elizabeth W. Peel
MOLECULAR COMPOUNDS BETWEEN AMINES AND SULFUR DIOXIDE.
COMMENTS ON JANDER' S THEORY OF IONIC REACTIONS IN LIQUID
SULFUR DIOXIDE 35
A* L. Oppegard
THE STRUCTURE OF ORTHONITRIC -ACID 35a
Hans B, Jonassen
REACTIONS BETWEEN SOLIDS 36
Nancy Downs
Table of Contents (continued)
Page
INORGANIC CATALYSIS; INDUCED REACTION, PRECIPITATION,
AND 'SOLUTION 40
F. W. Cagle, Jr.
THE BORON HYDRIDES 43
Margaret Kramer
A SURVEY OF INORGANIC NITRIDES; PROPERTIES, PREPARATION,
AND REACTIONS 48
Lawrence J. Edwards
HYDRIDES OF ALUMINUM iiND GALLIUM 51
Therald Moeller
REPORT ON THE "INDUSTRIAL AND ELECTROCHEMICAL CONFERENCE"
HELD IN CHICAGO, JANUARY 19, 1945. 52
John C. Bailar, Jr.
ADDITION COMPOUNDS OF THE ALKALI METALS AND THEIR
STRUCTURES 53
Hans Jonassen
ADSORPTION AND SURFACE IONIZATION ON TUNGSTEN 57
Clifford R# Keizer
THE STRUCTURE OF LIQUIDS 62
W« E. Morrell
"INORGANIC BENZENE" 65
T. G. Klose
BEHAVIOR OF METALS IN NITRIC ACID 69
Clifford R. Keizer
REMOVAL OF OXYGEN FROM COMMERCIAL TANK NITROGEN.
SENSITIVE METHODS FOR ANALYSIS OF OXYGEN IN GASES. 70
H. A. Laitinen
A NEW PERIODIC TABLE 71
Donald R. Martin
COORDINATION COMPLEXES OF DIPYRIDYL AND RELATED SUBSTANCES 72
F. W. Cagle, Jr.
PHOSPHONITRILIC CHLORIDES AND "INORGANIC RUBBER" 76
L. J. Edwards
THE HALIDES OF SILICON 79
Margaret Kracer
Table of Contents (continued)
Page
SYNTHETIC OPTICAL CRYSTALS 84
A, L, Oppegard
SOLVENT EFFECT OF LITHIUM NITRATE ON ZINC ACETATE IN
ACETIC ACID 85
Nancy Downs
COMPARISON OF THE AMMINES OF COBALT AND COPPER 85
J« V. Quagliano
COMPLEX COMPOUNDS OF PHENYLBIGUANIDE-p- SULFONIC ACID 86
Margaret Kramer
THE DETERMINATION OF CRYSTAL STRUCTURE 87
Kf J. Pipenberg
SIR HUMPHRY DAVY 91
Virginia Bartow
THE HALOGENOIDS OR "PSEUDO-HALOGENS" 95
Nancy Downs
THE COORDINATION NUMBER 0? COPPER IN THE
FOLYETHYLENE-^IIHONIUM CHLOFiOCUPRQATES
Hans Jonassen October 24, 1944
Coordination numbers from one to six have been reported for the
coordination of chloride ions to the centrrl copcer ion in the oresence
of excess chloride ions,
In the study of absorption spectra of copoer chloride solutions,
Getman (1) reported in 1922 that in solutions containing copper end
chloride ions the displacement of the region of maximum transmit ten cy
toward longer wave-length with increasing chloride ion concentration
was due to the displacement of the eouilibrium:
Cu(H20)4+3 + 4C1- <--===> CuCll2 + 4H30
Spacu and Murgulescu (2) reached similar conclusions from spectro-
photometries studies of the system. They postulated the formation of
both CUCI4 and CuCl3 complexes in such solutions, Babko(3) obtained
data wmcn indicated the presence of the following chlorocuproates in
such solutions: CuCl+, CuCl3~, CuCl4=. 3hagwat (4) ascribed the
inapplicability of Beer' s Law to copeer chloride solutions to the
presence of such complex Ions as CuCl+, CuCl3-, CuCl4=% as well as the
CU ion itself, Moeller (5), applying a modification of Job* s method
o- continuous variation to a solution of copper containing excess
chloride ions, obtained data which seemed to Drove definitely the
presence of CuCl4 ions in the solution, but his data do not preclude
the existence of any other chlorocuproates. All the data cited above
seem to indicate that the colors of the CuCl4= and CuCl3~ are yellow
rather than blue.
Similar complexes also have been prepared in the crystalline state.
Topsoe (7) reported the preparation of yellow chlorocuproates of
methylamine, dimethylamine and trimethylamine. In 1906, Grossman and
Schuecfc (8) prepared the tetrachlorocuoroate of ethylenes lacin.-. The
series of chlorocuproates of organic substitued monoamines was extended
by Remy and Laves (9), Dehn (10), Michaelenko (11), and Amiel (12, 13).
The cnlorocuproates isolated by these authors contained CuCl3-, CuCl4=
complexes. The structures assigned to these indicated mononuclear
complex ions, giving copper and coordination numbers of three, four,
and five respectively. '
m In 1956 Dubsky rnd Vrgenhofer (14) postulated a new theorv. They
maintained tnrt all chlorocuproates prepared up to that time were really
hexachlorocuproates of polynuclear structure containing two or more
cnloride bridges. They prepared a series of hexachlorocuproates to
jupstantiate their theory. Two of the compounds prepared" by them with
tne structures which they postulated are given below,
1. Tetra.-anilinium hexachloro-diaouo- /& -dichlorodicoDoer dihydrate
H20
, \ ^ CI . H30
(C6riB NI-fc.H)* Cuv^ ^Cu ,2H20
; / ^ ci^" ^ci3
(01)3
_ 2 -
2. Diquinolinium tetrachlorotetraaquo-/A-dichlorodicopper
dihydrate-:
(ouinp H )a
(H30)3
Ola
Cu
,. CI
(H30)3
Cu
\
Cl:
.2H30
Experimental
The research project started as an investigation of the complexes
formed between copper r.nd the straight chrin polyethylene bases of the
Hofmann series: diethylenetriamine, triethylenetetramine, and
tetraethylenepentomine. The complexes formed between an r.queous solu-
tion of copper sulfate rnd the rmines could not be pfrecipitf ted by the
addition" of an organic solvent nor by evaporation* SimiL?r results
were obtained with aqueous solutions of copper chloride; but when CuCl3o
2H20 was dissolved in methanol rnd the amine was rdded to this solution
a precipitate was formed* The first precipitate formed had a yellow
color, but upon stirring -nd further addition of rmine the solution
solidified forming a green meal, After filtering, the green meal shewed
the presence of several solid phases: a yellowish green phase, a deep
green phase, and a deep blue phrse on the top lryer. The blue phase
of the' top layer seemed to be a hydrrtion product of the other two
phases. Excess amine was added to part of the precipitate and it dis-
solved forming a deep blue solution. Concentrated hydrochloric acid
was added to the remainder P.nd a yellow precipitate wps formed which
was very soluble in water but which could be reprecipitated by the
addition of an equal amount of concentrated hydrochloric acid. All the
polyethylene amines gave similrr yellow precipitates when prepared in
a similar fashion.
Analysis showed that the following empirical formulre c-^uld be
assigned to the compounds:
1. The diethylenetriamine comolex:
2. The triethylenetctranine comole
NHa03H4NH<5aH4NHa.3HCl.CuCla'
NH3C3H4NHC3H4NHC3H4NH3. 4HC1(
CuCl,
No rersonrble empiricrl formula could be calculated f^r the
tetraethylenepentamine complex with copper ion.
The first member of this series, the ethylenediamine complex, which
had been obtained previously by Grossman and Schueck (8), wrs also
prepared in order to compare its physicrl and chemical properties with
those of the higher members of this series. Analysis snowed it to have
the following composition: NH3C3H4NH3»2HCl.CuCl3
Discussion of Results:
Microscopic
dien(diethylenet
were translucent
configurations;
formed ill-defin
on the corners r-
freezing point 1
lin aqueous solut
by the following
investigation showed that the en(ethylenediamine ),
riamine), rnd the trien(triethylenetetrrmine ) complexes
, showed birefringency, and had well defined crystalline
whereas the tetren(tetraethylenepentc°minc ) complex
ed opaque crystal clusters with only slight birefringency
f the crystals. Molecular weight determinations by
owering snowed thrt the complexes dissociated completely
ions. This total dissociation was further substantiated
facts:
- 3 _
sllver chloride Pw££tS " ^ " W8 nccess^ ** Ooagulrte the
the hydro t eel cop er icnT °hlorooupror.tce are the sane Kg those of
All of these facts seem then to point to the following conclusions:
2* Con^lotS1-^^^3?-01^6 MmPletely in aqueous solutions.
' ?£*?•£?! dissociation cm only bo explained if it is Pssumed
attract1on:m?leXOS lB th* Wli* *** "* *!«** Vlfflgle .
F 3* oonflcu^^^„at1tr°tt,,n °nly mononuclear chloro comolex
, 2?2t g tl0M would seem reasonable.
"* to Savenancc°'rSrn???rgUrr.UOn ?G oentrol 00W« ion seems
tetrochl^Si"te!°ofnnvffo0r ^.f^*^ ethylenedian^onium
ftentoohloiopi^tX'tf' °L I f r tne dietnylenetriamoanium
l hexrchlorocu"roate!' ** °* "* f°r ^lethylenetetrammonium
I 5* theyecrnebee ^tfL^faf ^ °ora?le*e^ in ^us solution
In the solid Jr*l\i L f s^Cn only ln the S0Hd state; and
tlvelyr^SigLSI t^°\^^rcno%l^J:ti10Wing fUCt-6 h^ *« tenta-
1. En complex: en,Ha j Cu ^j
[px Cl)
2. Dien complex: dlen.H3 j Cl Cu !
L?1 enj
« * < , i^oi ci!
o. Iric-n complex. trlen.K4 Cl Cu Cl
Lei ci|
BIBLIOGRAPHY
(1) Get men; J. Phvs. Chen. 26, 217-246 (1922)
(2) Bprou and Kurgulescu; Zeit. Phys. Chen. A 17D, 70-80 (1934)
(3) Babko; Univ. etat de Kiev, Bull. Sci., Rec. chim. 4, 81-100, (1939)
(4) Hbagwat; J. Ind. Chem. Sec., 17, 53-59, (1940).
(5) Hoeller; J. Phys. Chem., 48,111-119, (1944)
(6) Job; ^nn, chlm. , 10, 9, 113-203, (1928)
(?) Topsoe; Dansk Viclens., 17, (1882)
(8) Grossman and Schueck; Zeit. a.norg, Chem.,, 50, l~$p, (1906)
(9) Remy and Laves; Ber. , 66B, 401-407, (1933)
ilO) Dehn; J. Am, Chem. S*c. , 48, 275-277, (1926)
ill) Hichaelenkc; J. Russ, Phys, Chem. Soc., 61, 2253-2567, (1929)
12) Amiel; Compt, rend., 201, 964-966, (1935)
13) Amiel; Compt. rend., 2018 1383-1385, (1935)
14) Dubsky and Wa.genhofer; Z, anorg, allg. Chem., 230, U^lSg, (1937)
15) *mielj Compt. rend., 208, 1113-1115, (1938)
- 5 -
ROLL CALL
October 24, 1944
Ionization in Methanol . W. E. Morrell
By colorimetric (indicator) and conduc time trie methods, G-uss
and Kolthoff . (J.A.C.S., 66, 1484-88 (1944)) studied the behavior of
SO 2 in methanolc They conclude that CK3-0-S-0-K (of. H-0-S-O-H)
0 0
is formed, and that its dissociation constant in methanol is 3 x 10"*7
CH3OH + S02 = CH30S0aH = CH3OS08- + CH3OH3+
aCH30'SQg" 'aCH30H3+ = KA = 3 x 1Q-7
S03
(The constant for the corresponding dissociation in water is 2 x 10~8t )
The authors state, that they find no indication of S02 acting
as a "Lewis" acid with their indicator, thymol blue.
The addition of small quantities of water to methanol solutions
of S02 results in the transfer of protons f ran methanol ium ions to
water, the water acting as a Bronsted "base".
Kanning, Byrne and Bobalek (J.A.C.S. , 66, 1700-03 (1944)) (cf.
ibid,, 65, 1111-16 (1943)) studied the conductivity of sulfuric
acid in methanol, and from their data' calculated the dissociation
constant of sulfuric acid in methanol. They report the following
values:
t, ° C. K
20 0.027
25 0.024
30 0.024
35 0.018
Although they list two significant figures in the vrlues of
the constant at various temperatures, the authors state that the
techniques employed can yield only orders of magnitude.
The authors conclude that sulfuric acid in methanol exhibits
properties of a strong univalent electrolyte*
'•••:!-. "'■:■.> -;--* •
<■•-. <\ '.. *•.■>
.... .v •!? s. '.: -■;•
«,~.»-;
s.:i*C:/;iJ +
i :-•-■•
v-t. -«*••.--■•
" a
-. :. v
Soeotrophotometric Estimation of Certain Rare Enrth Elements
i j i r K - - — ^m — i ■-■■ I ■ " ■» ■ ■ » ■ «*■ ■ i- ■■■. ■■ »■— i - m ■■■ ■«! i ■ ■ ■ ■-
The raid Mo e Her
Aqueous solutions of salts of many of the rare earth elements
are characterized not only by their very definite absorption spectra
but also by the sharpness and Intensities of many of the absorption
bands in both the visible and infra rod reglonsc A comprehensive
spectrophotometry examination of aoueous solutions of the nitrates
of most of the rare earth elements (including yttrium) in the
spectral range 350 to 100 mu has been published by Rodden (1,2).
Inasmuch as the positions or the absorption bands differ among the
various elements and inasmuch as most of the systems obey the Beers
relation fairly well, a quantitative method of estimating one
material in the presence of others is available. This is particu-
larly true for the determination of a colored substance in the
presence of a colorless one such as lanthanum, gadolinium, terbium,
yttrium , ytterbium (in the visible), and lutecium, since solutions
of the nitrates of these elements show no absorption,, The determ-
ination of colored components in the presence of each other is
easily done if all others exhibit 100* transmit tancy at the wave
length where one absorbs or if corrections are made by determining
the absorptions of all others as pure substances at that desired
wave length.
Applications. — Rodden (1, 2) lists a number of analyses of
mixtures, especially of the cerium earths. In brief, the method
consists in reducing cerium-free oxides with hydrogen (to convert
Pr-eOn to Fra03) and examining a nitrate solution at 402 mu (Sm),
44S mu(Pr), and 521 mu (Nd). A slight correction for the inter-
ference of Sm with the Pr analysis Is then made and lanthanum Is ob-
tained by difference. This method has been successfully applied In
this laboratory through use of 3-eneral Electric Recording Spectro-
photometer (-3),
Among the yttrium earths, the chief utility aopears to lie in
a quantitative following of a fractionation procedure or in the
estimation of a colored component in the presence of yttrium. In
this laboratory, the ferrocyanide separation of yttrium from
erbium (4,5) and the sulfate fractionation of the yttrium earths
(4) have been followed, and quantitative analyses of erbium,
thulium, and ytterbium samples have been made with excellent and
rapidly attainable results.
The effects of certain anions upon these absorption spectra
appear to be very pronounced (6); so a standard procedure is necessary,
References;
1. Rodden, C. J. ; J. Research Nat?.. Bur. Stds. 26, 557 (1941).
2. Rodden, C. J.: J, Research Natl. Bur. Stds. 28, 265 (1942).
3. Moeller, T. : Research notes,
4. Kremers, H. E. : Ph. D, Thesis, University of Illinois (1944).
5. Moeller, T. , and Kremers, H. E. : J. Am, Chem. Soc. 66, 307 (1944).
6. Edwards, L. J.: 3. S. Thesis, University of Illinois (1944).
- 7 ~
Pi ap ram of the Corrosion Process
Clifford R. Keizer
1. Ionization of the metal: He > He+ + e
2. Passage of metal ions rlong flaws on surfrce nf metal into solu-
tion or of ions in solution in the reverse direction-*
3. Removal of metal ions from the surface of the mode by their
diffusion into the body of the solution,
4. Motion of the ions in solution mnder the influence of the electric
poles,
6» Diffusion of hydrated hydrogen ions (H30+) toward cathode.
6. Dehydration of H30+.
7. Process of neutralization of hydrogen ions H+ + e~ > H
8. "Malization" of hydrogen atoms 2H > H2
9.' Diffusion of the hydrogen molecules toward the cathode,
10, Formation of hydrogen bubbles and their release at the surface of
the cathode,
11, Passage of oxygen from the air to the electrolyte.
12, Passage of oxygen through the solution by convection.
13, Diffusion of oxygen along the electrolyte layer adjoining the
cathode.
14» Reduction of oxygen at the surface of the cathode forming 0H~
02 + 4e"~ + 2H20 > 40H~
15. Diffusion of OH- ions from the cathode.
16* Process of reduction of oxygen to hydrogen peroxide
02 + 2e~ + 2H4* -> H202
17. Process of further reduction of hydrogen peroxide to QH"
K202 + 2e- -> 20H-
18. Diffusion of reduced H202 (60fT) from the cathode,
19. Flow of electrons in the metal.
/>
vo
r>
u
| 8
<r
— * J ire c* tor* or
ftr 6 c ' 'pr\
^-.-^ -» <xirt c' 'O in of no''Or>
of ton-i ^ ehchon^
dtr*cf,on of nro**to* °f
Reference: J$e&r^ p*,ho** &7 d.ff^^*
N. D, Thomashow, Journ, Gen. Chem. (U.S.S.R. ) 12, 585 (1942) *w
: # ." • .. - - -i- V-- .v ".- •'.- . .' •-. i. •*. ^ j ■•• •* ■■■
. ». r -:"*-•'
•fj - • T
T "•' ;-s
-.--; • •",— . -,
hw Oi ?:-=- :X:;^^/; ^:T: \^\
. „• j
wf
-' •"
>
J
**.
V"i„* <Sk\
-■
\ -* ¥
*- r
: • -..•.-...- :'
ft
- S -
OXIDATION STATES OF COBALT AND NICKEL
John C, Bailar, Jr.. November 7, 1944
I « Introduction
A, Methods of Determining Oxidation State
1. Analysis of Compounds, This is misleading unless the
structure of the compound is known. Thus, Ni02.xH20
exists in two forms — dioxide and peroxide. The former
is black, and contains tetravalent nickel; the latter is
green, and contains divalent nickel. It is obtained by
the action of H202 on Ni++ , and liberates H202 when
treated with acids. It has never been obtained pure,
the Ni:0 ratio varying from 1:1.49 to 1:1.98. (l) CoS2
and NiSs d.o not contain tetravalent metal, but have oeen
shown magnetically to contain divalent metal. (?) They
are analagous to pyrite. (3)
2, Properties of the ion in Question — most cobaltic and
nickelic compounds are oxidizing agents.
3, Isomorphism with compounds of known oxidation state.
4. Physical methods, such as magnetic susceptibility.
I. Zero-velent and negative valent metals.
A. The carbonyls, nitrosyls and carbonyl hydrides. If we assume
tnat trie electrons in Ni(CO)4 belong to the CO molecules, Ni is
zero/alent. If the electrons are partially controlled by the
metal, Ni has a negative valence.
Blanchard (4) assumes that in dimeric carbonyls the metal is
negative. He believes that an electron is transferred from
• n tnn\ S ln SUCh cornP°unds as Co(C0)3N0, and from H to Co in
B. Cyanides.
Burgess (5) reduced K2Ni(CN)4 with potassium in liquid ammonia,
and obtained K^NifCN)* as yellow crystals,
I. Monovalent Metals.
A. NigQ has been reported, but probably does not exist. X-ray
diagrams indicate only the existence of mixtures of NiO and
(14),
B. KaNi(CN)4 is reduced by many reducing agents to K2Ni(CN),
Alkali metal amalgams are probably best'- (6, 7,8 ) but zinc,
t^l^i r?T ?;U?an be used- Electrolytic methods are also
suitable. K2Ni(CN)3 readily absorbs 02 from the air, and in
tne absence of air, liberates hydrogen from water. In the
^rn°^o q6XSnSS KCN' howe^> it ^Y be preserved for several
cays. (,oa,8c,9;
4K2Ni(CN)3 + 2H20 3K3Ni(CN)4 + Ni + ?.KOH + H2
d«S T0X1^atl°^educticn Potential has been measured by Grube
and Lieder (10) and by Tedeschi (ll). E° = 0.8^ volts It
^^eB f ^H &Cr*°j4. E^lW an5 ^(^ quantitatively. It
fauces Ag+, Hg+*, Pb++, Bi^++ , As+3 to metal. (6)
b. Acidification of solutions of K2Ni(CN)3 ppts. NiCN, which can
- SVfSi?801^641 in KCN t0 S'ive the original material. (6)
D. KjfcilCN; a absorbs CO, supposedly giving K2 [ Ni(CN)3C0 (l?.).
It also absorbs C2H2(1^; NO* (13)? Manchot bllfeves tnat
^ t5-^-^-1^'3 > b-vC+^— and Samuel say that the NO is
reduced to NHs0H and the Ni+1 is oxidized to Ni+3
B. Reduction of Ni++ by a. mixture of NaNO? and Na3S03 gives two
products, whioh are said to be KN'(S03H) ( S03Ni ).nK30 and Ni(OH).
(15) These results seem doubtful.
F. Manchot and his coworkers have prepared many nitrosyl salts,
which they claim contain univalent Fe, Co, and Ni. In an
atmosphere of NO, cobalt salts react with K3S303 to give
K3 Co (NO )3(S303)3 . The corresponding nickel salt is
K3 Ni(NO)(S3P3)3 (16). Mercaptans can be used instead of
tniosulfates (17). The existence of univalent metal in these
compounds has been denied by Carabi (18) and by Ormont (19).
IV. Trivalent Metals
A. Many cobalt ammines, cyanides and nitro compounds contain
tripositive cobalt.
B. Cobaltic fluoride is readily obtained by the action of
fluorine on cobalt salts; has been suggested as a fluorinatinc
agent. a
C. Oxidizing agents in alkaline media convert Co++ to Co(OH)3.
_ Even air will produce this change to some extent (21), In
acid solution it is a powerful oxidizing agent.
D. Cebaltic sulfate can be prepared electrolytically and is a
_ valuable oxidizing agent in organic reactions (22). Cobalt
alum is well known (36).
E. Many attempts have been made to prepare Ni6l3 (23). Some of
these gave red solna. which liberate 0,2-0.3 of an atom of
"active" oxygen per nickel atom.
F. Ni303.xH30 is doubtful. Alkaline oxidizing agents give precipi-
tates of varying composition, with ratios of Ni:0 varying from
1:1.1 to 1:1.9. X-ray data show that these materials are NiO
or mixtures of NiO and NiOa (24,25), Ott and Cairns, however,
Delleve Ni303 to be a true compound (31), At lower temperature,
NiO absorbs oxygen readily (25).
This material is the oxidizing agent in the Edison storage
cell. While it is fairly stable when wet, it loses oxygen slowly
■ in*.b°llins water (2?)* T&natar (28) believed it to be a oeroxide
but tnis is probably incorrect (29).
G. Schall and coworkers (23a, 30) orepared Ni(C3H303)3 and Co(C3H303)
by electrolysis of solutions of the diacetates in glacial acetic
acid. The Ni+a compound is deep green and the Co*3 com-oound
apple green. They are decomposed by water, This work is rather
doubtful, as the authors did not get consistent results,
n, Oxime compounds. Nickel formoxime in alkaline alcohol solu-
tions absorb oxygen from the air to give a deeo brown solution.
A nickelic complex may, be crystallized from the solution (32).
.-- NHg\
Benzamidoxime forms \CeH5C N j Ni (33).
v NO / 3
V. Tetravalent metals.
A. Nickel dioxide almost certainly exists, although it has never
oeen obtained pure. Preparations having as much as 1,9 atoms of
oxygen per nickel atom can be -orepared (34.35), It is a strong
oxidizing agent, converting chlorides to chlorine, sulfites to
aitnionate, ammonia to nitrogen.
B. Cobalt dioxide has been reported from oxidation of Co++ in
alkaline media (37),
C. If an alkaline solution containing Ni is heated with a strong
oxidizing agent and dimethylglyoxime, no ppt. forms, but a deep
red solution. From this solution, a comoound of tetravalent
nickel can be crystallized (38). It is said to be (DH)3NiO,
- 10 -
C. (continued)
If a solution of it is acidified in the oresence of KI, two
equivalents of I3 are liberated,
D. Polynuclear cobalt ammines, Werner prepared many polynuclear
ammines containing peroxo bridges. Analysis indicated that
some of these comoounds contained both tervalent and tetra-
valent cobalt. (39) Examples are f(NH3 )5Co03Co (KH3 )5 (NQ3)5
.NH3 . u-
and (NH3)4Cc Co(NH3)5 I X4 , Upon heating with H3804,
v03 '" J
such salts are decomposed to mononuclear ammines, with the
liberation of gaseous oxygen. The ammount of oxygen liberated
indicates one tetravalent cobalt atom. Titration with arsenit
leads to the same conclusion (40),
The magnetic susceptibility of these compounds confirms the
fact that the ion contains an unpaired electron ('40,41) so
the assumotion of tetravalent cobalt is confirmed.
- 11 -
BIBLIOGRAPHY
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Harol&son and Klemm, Z. anorg. allgem, Chen. 225, 409 (1935
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THE BASICITY CHARACTERISTICS OF SCANDIUM,
YTTRIUM, AND THE RARE EARTH
ELEMENTS
Therald Moeller November 14, 1944
Introduction
While the term "basicity", as applied to the metallic elements in
general, apparently, covers all phenomena from the ease with which the
free elements lose electrons to the extent to which oxygen containing
salts of these elements are decomposed thermally, such phenomena are
all manifestations of relative tendencies to lose or gain electrons an
are thus reducible to acid-base characteristics in the G-, N. Lewis
sense©
Scandium, yttrium, and particularly the rare earth elements are
generally recognized as yielding the most basic oxides of all the tri-
valent metals except actinium (11, 21, 69, 71, 73, 93, 99). As evi-
dences of these relatively high basicities, one may cite the ease with
which even the strongly ignited oxides dissolve in acids (69, 71, 73),
react with ammonium salts both in solution and at elevated tempera-
tures (43, 88), and absorb atmospheric carbon dioxide (69, 71, 73),
Parallel evidences of high basicities are noted in the slight, though
measurable, hydrolysis of aqueous salt solutions (10, 17, 18, 19, 57,
59, 60, 63, 70, 71, 73, 78, 92, 97) containing weakly basic anions,
the comparatively high water solubilities and precipitation pH values
of the hydrous oxides and hydroxides (16, 20, 21, 24, 63, 66, 74, 81,
90, 94, 96), the relatively high temperatures required for the
decompositions of oxygen-containing salts (102, 103, 104), and the
low ionization potentials of the free elements (89),
Significant basicity differences, especially between scandium and
yttrium, yttrium and lanthanum, and lanthanum and lutecium, are
apparent. Because of the excellent agreement between theoretically
predicted basicity variations and those observed and because of the
dependence of many separatlonal procedures upon such basicity differ-
ences, a detailed examination of these phenomena is profitable*
Establishment of Relative Basicities
A, Theo rr t i cal^onsi'd srriTions,
Since the relative attractions for electrons are dependent
upon atomic and ionic sizes (99), basicity predictions can be
based upon size considerations» Atomic and molecular volumes for
most of the elements and many of their compounds have been reportc
(6, 12, 13, 15, 44, 45, 46, 56, 62, 98), Data in Table I indicate
the expected increase g from scandium through yttrium to lanthanum,-
The decrease between lanthanum and lutecium (the lanthanide con-
'traction) is ascribable to the increased nuclear charges and the
simultaneous filling of the 4f orbitals. Paralleling atomic and"
molecular size variations fire vrvrirt?.ons in the i^dii of the . t ri-
val snt ions, 'che empirical and calculated values for which are
listed. Basic:', i\v decreases should parallel size decreases. The
combined effect;: of cation charge and size are given by the ionic
potentials of ''art 1 edge (35), and the relation between size and
Ionization potential is apparent,
Sise and crnarge-sise considerations would predict lower
basicities fcr ncberi^ls in a -^4 oxidation state and higher
basicities for these In a -5-2 state c The reported amphoterism of
Ce02 (26,93), :^yCx-: (;4)3 and Tb*0v{4) and the ease of hydrolysis
of Ce(lV) salts (S,2£f55,93) confirm the lowered basicities of
high valent materials! XI though amohoterism has been reported
for La203 (3), this is doubtful (1Q5),
.
' .. ... ,4*- : •<
■
. ■■ -
■■ : "
- 13 -
B. Experimental Establishment of Relative Basicities
1. Order of Precipitation by Alkalies, From a mixture of rare
earth salts in solution, soluble alkalies will precipitate
the least basic materials first. Scandium has thus been
shown to be the weakest base, and basicity decreases from
lanthanum down through lutecium (11, 71, 73, 92, 93).
Yttrium, however, appears to be as highly basic as the
cenium earths, a position which may be ascribable to a
concentration effect (96). Early work showed gadolinium
to be more basic than samarium (5, 8, 30), but more careful
procedures have reversed this order (47).
2. Precipitation and Dissolution of Hydrous Oxides and Hydr-
oxides, Solubility studies (24, 39 , 64 ) and electrometric
measurements upon alkali titrations (16, 20, 21, 66, 74, 81,
90, 94) have indicated decreasing basicities in the series
lanthanum to lutecium, with yttrium occupying a place close
to holmium and scandium following lutecium. Comparisons of
solubility product constants, assuming the precipitation of
hydrous hydroxides (54, 101), have lead to an order of com-
parative basicities paralleling an order of comparative
ionic radii (39, 74). (See Table I)
3. Hydrolysis Studies. The hydrolysis of rare earth salt
solutions has been measured by determination of conductivi-
ties (10, 17, 18, 57, 70). by measurement of hydrogen ion
concentration (10, 60, 78;, by determination of free acid
through extraction (97), and by the effects of the liber-
ated hydrogen ion upon the hydrolysis of esters (17, 18,
70), the inversion of sucrose (18), and the reduction of
iodate with iodide (59). In addition the evolution of
carbon dioxide from hydrolyzed carbonates has been measured
(19). Precipitation of basic salts, for example nitrites,
has been investigated (53, 92).
4» Thermal Decompositions to Basic Salts or Oxides. Measure-
ment of the decomposition temperatures of the anhydrous
sulfates (102, 103, 104) has shown that decomposition
temperature rises with increasing basicity of the element
concerned* Such basicity series do not agree too well
with those arrived at by other means.
5. Thermo-Chemical Inve st igaut ions . The heat of reaction of the
trivalent oxide with hydrochloric acid has been found to
increase In the series samarium, neodymium, praseodymium,
lanthanum (72).
6. Electrode Potentials. Although no direct relation exists
between basicity and electrode potential, Hcyrovsky (49)
ha.B derived an expression relating basicity, electrode
potential, and cation mass. The only measurements approaching
electrode potentials are the polarographic data of Noddack
and Brukl (80), but although these authors point out a
basicity relation, it appears that a portion of their data
represents reduction of the hydrogen ion (50, 64) and
application of their figures to the Hcyrovsky relation is
impractical. The approximate potentials listed by Latimer
(68) Indicate lanthanum to be the most basic and scandium
the least.
I ■
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- 14 -
C# Summary
basicity to decrease in the order La cJ^Tf'c"Undi?ate
E«. M. Tb, Dy, Y, Ho, toT^Xb,^, to, UlxR1. "*' ^ S^
II. Separations Based upon Basicity Differences
of 1=Pf?oe<aui>es of this^ypTTiave' been most successful
fractionation 2?% ^f^' and SOandl™ "^ " »S
„IaS 5 onati°n °f the yttrium sub-group. Although anv
3Sss?S.s«m smjspss' at
1. Precipitation bx Alkaline Materials. The caustic alkalies
10, 8, 16, 30), ammonia (5. 8, 33, 42 52 sp a7 qi «
magnesia (76 91) rare earth oxides (ioo),' cranio Iksll'
(48, 58) oxides and carbonates (78), and urel?41 q f! w
S'S^E S'S^S'^ffiSa? c16 P? V"^ -alilflnd
. ammonium J&V fSLl?f hlve"^^1 Kg"8 °ati°nS °r
excellent results, ;*M&<&&£- £1^^^
3' JWP^fcSW^gSHfeatf1^ empl?yed by Kriiss
mercury oath o^.'£ gS2 SJlSSISSl^ V^37
65, 77, 91), the least baQlo materlalg separat{n^ f^s?f~37'
4- ©ajHJPsa&figgf^fe ^ough not wide^
42, 75) J ° Deen used wlt^ some success (26,
5* SeSoIfS gSufe^ff fe°-.rf"f°"ta1n1n, Salts.
28* £f Is 40 I58eP4f W^ °f f! yttrlum earths fll, 27,
at'controlied temSiJta^.- "f™1 ^composition of sulfates
ea temperatures has not proved effective (102).
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77. Neckers, J. W. , with Kremers, H. C. : J. Am Chem. Soc. 50, 950 (1928)
78. Neish, A. C., and Burns, J. W. : Can, Chem. Met. 5, 69 TT921)
79. Nilson, L. F.: Ber. 12, 554 (1879)
80. Noddack, W. , and Brukl, A,; Angew, Chem. 50, 362 (1937)
81. Oka, Y. : J. Chem. Soc. Japan 59, 971 (193&T
82. Prandtl, W. : Z. anorg. allgem. Chem. 143t 277 (1925)
83. Prandtl, W. : Z. anorg, allgem. Chem. 209, 13 (1932)
84. Prandtl, W. : and Huttner, K. : Z. anorg. allgem„ Chem. 136, 289
(1924)
85. Prandtl, W. , and Losch, J.: Z. anorg, allgem. Chem. 122, 159 (1922)-
127, 209 (1923) '.
86. Prandtl, W, , and RaucheHberger, J..: Ber. 53, 043 (1920)
87. Prandtl, W. , and Rauchenberger, J.: Z. anorg. allgem Chem. 120,
120 (1922); 122, 311 (1922); 129, 176- (1923)- "
88. Reed, J, B. , Hopkins. B S. , and "Audrieth, L4 F. : J. Am. Chem.
Soc. 57, 1159 (1935)
I
\~-
09. Rolla, L. , and Piccardi, G„ : Phil. Hag. tviij , 7, 206 (1929)
90. Sadolin, E„ : Z0 anorg. allgem, Chen. 160, 133 (1927)
91 . Se Iwo o d , P . W, : J , Am , Che m. So c , 55_, 4U00 (1933)
92. Sherwood, G, R», and Hopkins 5 S. : J, Am. Chen. Soc. 5_5, 3117
f ' CK r'~ \
93. Spencer, J„ F. : "The Metals of the Rare Earths", Longmans, G-reen
arid Von, London. (1919)
94. Sterba-Bdhm, J. S, , and Kelichar. M, : Collection Czechoslov, Chem.
Ccmmuni oat ions 7_> &7* 131 (1935)
95. Trombe, F. r Compt. rend6 215, 559 (1942)
96. Trombe, M.: Compt, rend. 216, 08G (1945)
97. Vesterberg, K. A.: Svensk Kern. Tldskrift 29, 101 (1917)
98. von Hevesy, G. : Z8 anorg. allgem. Chem. 147, 217 (1925); 150,
60 (1925)
99. von Hevesy, G-. : "Die seltenen Erden vom Standpunkte des Atombaues",
Verlag von Julius So ringer, Berlin (1927)
100. von Welsbach, A0 • Monatsh. 5, 500' (1004)
101. Weiser. H0 B. , and Killigan, W. 0.: J. Phys. Chema 42, 673 (1930)
102. Willard, H. KB, and Fowler, R." D, : J. Am Chem* Soc„ 54, 496 (1932)
103. Wohler. L. , and Flick, K. : 3er. 67B, 1679 (1934)
104. Wohler', L. , and Griinzweig, M. : 3er, 46, 1726 (1913)
105. Zambonini, F. , and Carobbi, G-. : Gazz. Chim. ital. 54, 46 (1924)
• :■'. . . ''
L
, •- ».- -
j. - - , ■ •
- 19 -
THE OXIDATION-REDUCTION POTENTIALS OF VANADIUM
H. A. Laitlnen November 21, 1944
I0 Introduction.
re^ctSn^or0^'," T°Uld be ai™ntaSeoae to write two electrode
■ tSore1" be'linit^T^ a°ld S°luti0n« The^llcu^ion wxl?^
abovl in aoid so?ut?on to *%measure?ent of the three couples noted
the couple V ^ f°n\Tt ?*** rtimation of th* potential of
F V, V fr0m heat and entr0py |jata#
I. The vanadium (IV) _ vanadium (V) couple
Bottcher (,) glve evidence^r !"&&£ react'lonr6^ ^
V02+ + 8H* + e- ^===* V0++ + HS0 (l)
of tn^surementl? '£gJ£ SSS"^^?*?1^1-1,!*? -liability
junction potentially measuring the cell' ° ellninated the "*"
Pt. V02+(Cl) + VO++(C2) + HC1(C3), HC1(C3), Hg8Cl3) Hg (2)
Srt5"S2 elec?roaeVreaec?ioVrCUUm t0 «* *«**UW,t* M HV03,
9V03 + 3H+ + 3e- ^---± V0++ + 2H30
tSneU«ent"vr^n? van4i,l„0( V'°B ^J*0'* H+C1 ?nd HC1°* ^^ that
Car.-enter Ufnade re^niLPrSeu- S'S V°2 or lts equivalent V(OH)4+.
rM7.H^ hi 7 neasureaents which confirmed the hPlf-cell
samfbasis^ Md re0aloulat^ the data of Coryell^nd Yosf on the
Keepingec3E7c;Fa3°constant8) EL"??*1?}*1** to zero concentration
calLe! elec^roie gave S°"= SqO°^|,f0r *he wteatial <* the
' The Vp"?fUm,Hn) " vanadium (IV) couple.
Kutter (1) measured the E.M.F. of the cell
Pt VOS04 + V3(S04)3 + H8S04(0.25M), H3S04 (0.25M), HgaS04, H*
v n$)\?*n vr^^^r^ im- vary^e *** > <*
AhCgg A+e bac 4J^«]X%Sed 33 vlTfoTt^TrlactU
+ H20 r-=^ V0++ + PH+ + 2e~ (4)
} ■ 3 ;; ■
:■•' ""'
•. -
"
- ■ ■
5 "•
r 2C -
whereas G-erke (7) computes
l/2(V0)aS04 + l/2S04= ===== VOS04 + e~, E° = -0,30 volt (5)
Foerster and Bottcher (2) measured a similar cell with V(III)
and V(IV) concentrations kept equal. The total V concentration
and Ha SO 4 concentration were varied but the latter was not kept
equal on the two sides of the cell. Hence, a liquid juction
potential was included. Latimer (8) gives E° = -0.314 volt with a
reference to Foerster and Bottcher,
The best measurements are those of Jones and Colvin (9) who
measured the E.M.F. of a series of cells
Pt, V0S04(C4) + l/2Va(S04)3(C3) + HaS04(C1), H8SCU(CX),
Hg2S04, Hg
1. keeping Cx constant, varying C4/C3,
2. keeping C4/C3 = 1, varying Cx from 1 to 0.02
The results were calculated by
1. extrapolating E.M. Fr to zero vanadium concentration, at each
acid concentration,
2, extrapolating to zero concentration of vanadium and acid' (zero
ionic strength) using the Debye-Huckel theory as a guide.
The result is that E° = -0,537 volt at 25°,
IV, The vanadium (II) - vanadium (ill) couple.
The history of the investigation of the vanadous-vanadic
couple parallels closely that of the vanadic-vanadyl couple. The
earliest study was that of Rutter (13) who measured the EJJdF. of
the cell
Ft, 1/2V3( 304)3 + V.8Q4 + H3S04(0.25M), H3SO4 (0.25M), Hg2S04,Hg
and found a value of E° = +0.210 volt.
Foerster and Bottcher (2) also made some similar measurements.
They found that variable potentials were obtained when using
platinum electrodes owing to the evolution of hydrogen but that if
mercury electrode is used, the difficulty is eliminated. This
"mixed potential" behavior of electrodes has been described in
other cases (10, .11). However, Foerster and Bottcher failed to
remove the liquid junction potential,
Jones and Colvin (12) measured the E.M.F. of the cell
Hg, 1/2V2(S04)3(C3) + VS04(C8) + HaaMCi), HgSO^Ci), Hg8S04,
Hg.
and calculated the results in much the same way as explained above
for the vanadic-vanadyl couple. They found that E° = +0.255 volt
at 25°.
.*. ^, ." -/
. ... . _- VF»\ ?■
- 21 ~
V.. The vanadium - vanadium (II) couple
The potential of this couple has never been measured, and the
measurement in aqueous solution appears to be impossible.. In acid
solution, the metal would rapidly react with hydrogen, if its
behavior were reversible. Actually, it does not give reversible
electrode behavior either in acid or alkaline solution.
Latimer (8) estimates from, the free energy of formation of
vanadous oxide and the free energy of solution of the oxide in
acid, a value of E° = Ca. 1.8 volts. From the heat of hydration
of vanadous oxide and the solubility of vanadous hydroxide, a
value of E° = Ca 1*2 volts is estimated. A final estimate of
1.5 + 0<3 volt is given. No source of the data is indicated,
except for the heat of formation dats which were listed by Eichowsky
and Rossini (14).
The following sample calculation will serve to illustrate the
estimation of the electrode potential in cases where experimental
data are scanty.
Given that the heat of formation of V303 is -195 kcal. (14,15)
and estimating the entropy of V303 to be twice that of MnO (16)
which is 14,4 cal./deg. mole, the free energy of formation of V303
is -185 kcrl.y compared with Latimer*s(8) value of 182 kcal.
To estimate the free energy of the reaction
V303 + 4H* -> 2V*"1" + 2H30 (6)
we will first find the heat of reaction between MnO and HC1 or
KN03. The heats of formation of MnCl3 (aq ) (17), MnO (S) (18) and
HC1 (aq) (19) are respectively 128.7, 96.5 and 39.7 kcrl./mole.,
giving a heat of reaction of .-47.2 kcal* Using Mn(N03)3(aq) (17)
and HNO3 (aq) (14), the heats of formation are 147.8 and 49.2 oal,
giving a heat of reaction of -47,1 kcal, for the reaction.
MnO + 2H+ -> Mn++ + H80
Apparently, no entropy data exist for Mn++, but for the
analagous reaction of FeO to give Fe++, the entropy of H+ is zero
by convention, that of Fe++ is -25.9 (20), that of H20 is 16,75
(21,22) and that of FeO is 14.2 cal,/mole deg* (16). The entropy
change is -23,4, Assuming for the V803 reaction an entropy change
of twice this amount, the free energy change of reaction (6) becomes
80 kcal. Subtracting the free energy of formation of two moles of
water we have
2V + 03 -> V303 AF° = -185
V303 + 4H+ -> 2V++ + 2H30 AF° = - 80
2H30 > gHg + Qs AF° a 113
2V + 4H* -> 2V4"1* + 2H3 AF° = -152 kcal.
The standard potential is calculated from the equation
E° = -&F°/nF = 152/4 x 23.06 = 1.7 volts.
- 22 -
BIBLIOGRAPHY
1. T. F. Rutter, Z. r.norg. Chem. 52, 377 (1907)
2. F. Foerster and F. Bottcher, Z7 physik. chen. 151A, 321 (1930)
5. C. D. Coryell and D^ M. Yost, J. Am, Chen. Soc, 55, 1909 (1933)
4*. J. E. Carpenter, J. Am. Chem. Soc,. 56, 1847 (19347
5. J. Meyer and M. Aulioh, Z. _anorg. allgera. Chem. 194, 282 (1930)
6. R. Abegg, F. Auerbaoh and R, Luther, "Messungen elektromotorisohe
Krafte galvanische Ketten", W. Knrpp, Hrlle, 1911 p, 204.
7. "International Critical Tables", Vol. VI, 332 (1929)
8. W* M. Latimer, "Oxidation Potentials", Prentice-Hall, New York,
1938, p. 243
9. Grinnell Jones and J. H. Colvin, J. Am. Chem. Soc. 66, 1563 (1944)
I. H. Kolthoff and C. S. Miller, J. Am. Chem. Soc. 62, 2171 (1940 )
H, A. Laitinen, J. Am. Chem. Soc. 64, 1133 (1942)
G-rinnell Jones and J. H. Colvin, J, Am. Chem. Soc. 66, 1573 (1944)
T. F. Rutter, Z. anorg Chem. 52, 373 (1907)
F. R, Bichowsky and F. D. Rossini, "Thermo chemistry of the
Chemical Substances", Reinhold, New York. 1936.
W. G-. Hixter, Am J. Sci. (4) 34, 141 (1932)
K. K. Kelley, U. S. Bur. of Mines Bull., No. 394 (1935)
H.P.J. J. Thomsen, "Thermochemische Untersuchungen", Barth,
Leipzig, (1882-6)
W. A. Roth, Z. angew. Chem. 42, 981 (1929)
F, D. Rossini, Bur. Standards J. Research 6, 791 (1931)
W.. M, Latimer, K. S. Pitzer and W. V. Smith, J. Am. Chem. Soc.
60, 1829 (1938)
W.~Y. Giauque and J. % Stout, J. Am. Chem. Socr 58, 1144 (1936)
W. F. G-iauque and R. C. Archibald, J. Am. Chem. Soc. 59, 531
(1937)
/
%-
- 23 -
THE HONORABLE ROBERT BOYLE
Virginia Bartow November 28, 1944
I. Youth 1626-1644
1. Born, Lismore, Ireland, a fourteenth child, January 25,
1826*
20 Mother, Katherine Fenton, daughter of Sir Geeffrey Fenton,
Secretary of StPte for Ireland.
3. Father, Richard Boyle, the G-reat Earl of Cork, Lord Justice
of Ireland — Elizabethan, Protestant, Royalist — "the
richest man in G-reat Britain and the most influential in
I re land" 0
4« Family, eleven brothers and sisters completely involved in
the court, the society and political struggles of the
periodo
5. Training
a. Foster parents — Irish peasants
b. Eton — tutor under Sir Henry Wottan, cousin of
Francis Bacon
c. Geneva — tutor a strict Calvinist.
d. Italian travels — Florence at end of the life of
Galelio.
II, Period of study and apprenticeship 1644-1660
10 English Civil War. Parlimentary Rule
2e Politics — a cavalier — sympathy with the Commonwealth.
3. Abode — Stallbridge Manor
a. Gentleman farmer
bft Experimentalist and Philosopher
c, Alchemist
4. London — with Lady Ranelagh, Katherine Boyle, a Parli-
mentarisn.
a. The "Invisible College", Wallis, Willis, Wren, Barlow,
Hooke, Evelyn.
b. Milton
5* Oxford, study of natural science — the Purge — Bodleian
Library.
6. Publications of importance
"Occasional Reflections"
"Seraphic Love"
"Some Considerations concerning the Style of the Holy
Bible"
"The Martyrdom of Theodora and Didymus"
II. Period of Productivity 1660-1670
1. Restoration
2. The Plague and The Fire
3. The Royal Society
4. Publications
1660 "The Soring of the Air"
1661 "The Skeptical Chc-mist"
Numerous Scientific Papers on Color, Cold, Corpuscular
Theory, etc*
■•• : i V-- '-"?o:.1'-,r
-
> , : ■ 1
~>>
X MF
4. 1 ,. * ~
J. •' - :
?.: . " ,
■ ■> .«. ..
•■-. 4 -
I ; .,'..
- 24 -
IV. Last Years 1670-1691
1. Abode — London on Pall Mall — 111 health
24 Religious views — leader of Anglican Church, the "via media"
between Romanism and Protestantism
3. Positions offered and rejected.
a. Peerage by Charles II
b. High Place in the church upon taking holy orders,
c. Presidency of the Royal Society
d. Provost of Eton
4* Positions held
a. Governorship for the Society for the Propagation of
the Gospel in New England
b# Membership on the Company of the Royal Mines
c. Director of the East India Company
d. Oxford, Doctor of Physic
5. Achievements
a. "Father of Chemistry"
. 1. An Historian
2, Founder of rnalytical chemistry
3, Clear enunciation of the idea of chemical elements
4, Proof air needed for combustion
b. Discoverer with Hooke of the Ideal Gas Law
c. Supersederof scholasticism of Aristotle and medieval
philosophy of Paracelsus with Baconian induction or
the "New Philosophy".
d. Purpose — "To consecrate his scientific labors for a
.witness to G-od* s creation and governance
of the universe."
6. Death — London, at Lady Ranelagh* s December 30, 1691.
a, Boyle Lectureship
b. "Not sure science is good for world,"
BIBLIOGRAPHY
Books
Townshend. Dorothea, "The Life and Letters of the G-reat Earl of
Cork", Duckworth. and Company, London, 1904,
Masson, Flora, "Robert Boyle", Constable and Company, London, 1914.
More, Louis Trenchard, "The Life and Works of the Honorable Rob.ert
Boyle", Oxford University Press, Mew Ygrk, New York, 1944.
Shaw, Peter, "The Philosophical 'forks of th<i Honorable Robert Boyle,
'Esq*"', W. and J. Innys, London, 1725.
Essays
Thorpe, Sir Edward, "Essays in Historical Chemistry", Macmillan
Company Ltd, , London 1931, Chapter I.
Ramsay, Sir William, "Essays Biographical anil Chemical", Archibald,
Constable and Company, Ltd.., London 1908, p. 19-309
Tilden, Sir William A, "Famous Chemists, the Men and Their Work",
George Routledgc- and Sons,. Ltd., London, 1931, Chapter I9
■ •:
. */~l
■ -H;v-^-'
''i-Ar V--" ! . .-
. - .,- ; p.prv-
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-• -
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'■ ■ ' - -
¥
- 25 *.
COORDINATION COMPOUNDS OF 30R0N TRIFLUORIDE
Donald Ray Martin December 5, 1944
■ Although boron trifluoride was dlsoovered over one-hundred and
tnirty years ago (35), knowledge of the many coordination compounds,
wnicn it is capable of forming, is comparatively recent. On the
basis of the electronic structure of boron trifluoride, the boron
atom should be a good acceptor of electrons and boron trifluoride
should form many coordination compounds by the following mechanism:
H
H
N
• *
H
: r :
• * • *
3 ;p ;
: f ;
h : f ;
• »
-> h : n ; b i f ;
h : f ;
thP nllLt % ^?5Sr of\8U?h compounds is astonishingly great while
the number of different atoms, which have been found to donate to the
boron atom, is surprisingly small.
These addition compounds will be discussed according; to the
groups in the Periodic Table of which the donor atom is a member,
fo9-1?0 °*J i£gon has been found by Booth and Willson (15) to form
See Table!/1011 C°mp0Unds with BF* at low temperatures under pressure,
?r,°Wps *Xn 'vlb As ™ould be expected from the fact that they
are pux«r> none or the members of these groups have been reported
as donors to the boron atom of 3F3# p
in
Grroui
whicTT
IV- Although no coordination compounds have been isolated
is a member of Group IV, it has been
Pfcfbon atom, in olefin compounds, is the donor to
postulated that the
S^°Sn ?t0® of ^^condensation and polymerization reaction; in
wnicn ->F3 is -the catalyst (11 ) (33) (36) (52) (55) (56) (77),
..^fj^J bee£ rp°r^elt? b? un^active toward CH4, closed chain
compounds, e*g# CeH6 and CO (33).
hi** ^aKSe an5 ™°bbe (47) reP°^ed ft reaction between a saturated
hydrocarbon and DF3 in which tertiary butyl boron fluoride was formed.
,,ta&orQjtP V» Nitrogen: The nitrogen atom in Its compounds forms
quite a rew coordination compounds with DF3; These may be of the type:
(2iU^f\* fVT3/ \fl am?°^a WteVWCQ), trimethyl amine (17)
acetomlcS (lef^ii^1"6/^ ^W1 amine (46)' ^hylamine (46),
In In t$fA ,Va aniline (50)(79) 84 ), dimethylaniline (17)(69) 84
aniline1 6* "L^Y*?^^*6*?' "onosodiua- and monopoia slum,
oxine (A ) k ?o?vG ^nllilnv lQ1)> P7a?inobenzolo acid (03), acetophenone
(16)° pipekdlne fllf nyl ket°Xime (41>> P^dine (21)(87J quinoiine
2N.3F3> where N is ammonia (27) (34) (79)
3N„BF3 where N is ammonia (27) (79)
S'?2£3 w£ere S is Pyrldine (16) and brucine
R5N^3f3Wwhere V?-b8xa^thyleReteir5minfi ,(r
is hexamethylenetetramine (91
50)
N80 is unreaotive with 3FB at low temperatures- (13) >
.... ■■;■]'■'. ■ ,. :.
. ■ . •■■■.■ ...».• .- ,■ . •.■...' •
i • •..-•*•■• '
«
i
• • •■"
'•
•v. . ' ' ,
i •■:• '
•
:• . . \fi Sjoqra >*1 , * ewe r;v
. .,. j ■ rift?®}- l$::.dhd%i
T:-.:': ■■■- — • -- r ,? St
: i -■• . • ... v -'• • ••'-•"■; ■■'.■■■ -'l V- r2Cr..-f> .v 'It; il i t'
. .. />■ ■'■.'■'.•' ... ; .-. "■? .- .-ft •■
' ' -•"'
« -
? «»■•** } (, .. , , 1. 1'-,^ ,» p.-.\'::'\i'\
- 26 -
Phosphorus. Only phosphine has been reported to donate to 3F$,
forming the compounds H3F.BF3 (89) and H3P.2BF3 (10)(G9).
Group VI, Oxygen- Inorganic, Oxygen In Inorganic compounds
seems to be a better donor when it is not attached to another atom
by a double bond,. The types of compounds reported are:
HQH.BFa (63)(6G)(86); H30.3F3, 2Cl0 H1R0 and K2O.BFa.C4H8C2 (63)(68)
2H0H,BF3 (2 ) (3 ) (4 )t9) (33) (35) (51) (60) (63) (68) (92); dihydroxyf luo-
boric acid H20.BF2.0H (48); 2H20.BF3.2CloHia0 and 2H2C.BF3. C4He02(63)(68)
BF3
3H0H.BF3 (59)
MOH.BF3 where M = Na or K (38), Ca, HaF03 or H3P209 (45)
MQ»BF3 where M = Ca (29), 3202 (5)(00), P204 (37) (40)
ils0e4BF3 where M « alkali metal or NH4 (85)
K2S04.BF3 where M = Nr, K, Tl, (Cs.2BF3) (6)(7)
Na8P04.3BF3, K3P04.3BF3, Na4P207.4BF3, K4Pa07.4BF, (6)
NaOCH3.BF3, K0CH3feBF3 (68), Kg(0CK3.BF3 )8 (75)
P0F3.BF3 (14); P0C13, S03C12 do not react (22)
See table IIIa
Oxygen-organic, As early as 1878 Landolph (56) reported that
BF3 combines "equivalent for equivalent ' with aldehydes, ketones
and carbonyls." Gasselln (33) in 1894 observed that the presence of
oxygen in an organic molecule Is a favorable condition for coordination
with BF3. As will be shown below, an oxygen attached by a double
bond does not coordinate with BF3 as easily as an oxygen atom
attached to two other atoms by single bonds.
Alcohols^ Two series of compounds have been reported as formed
by BF3 ?nd alcohols. They are;
ROH.BF* where R m CH3 (33)(75 ) (38), C2H5 (16)(33), JUCJTi (29)
glycol (33) (68), C6H5 (82).
2R0H.BF3 where R = CH3, C3Kb, n-C3H7, sec-C3H7, n-C4H, (63)(68)
CH2C1CH3, CC13CH3 (68), C6HSCH2 (24)(68), C6H8 (33) (68)
Meerwein and Pannwitz (68) concluded that the stability of BF3-
alcohol complexes is decreased if a polar or easily polarisable group,
e.g. CH»C1, CCI3, or C6H5, is in the immediate proximity of the
hydroxyl group. See Table IV,
Aldehydes. Very few coordination compounds of BF3 with alde-
hyde s"Tiavebee"n reported.
RCH0,BF3 where R = CH3, (CK3)3C, C13C (20)
Valenic and benzyl aldehydes have been reported to react eouiva-
lent for equivalent with BF3 (52) (55 ) (56)..
Ketones. Only acetone (33) and benzoyl acetone (69) have been
reported to form one to one coordination compounds with BF3. BF3 has
been reported to react with acetone (20 )(33)(50 ) (56 )\'&7), methyl
nonyl ketone, camphor (52) (53) (56) and benzoyl acetone (73).
;
»' i •"-'". *
: .
_.
,
1
1
] • , ■ ' ■>
■ .C 3 ;
• ' '. ■ < *a
''■;
* 1
.. .
:
»
'. ■ 1*1
im ■ *>$ ■
' '"'■ • '' \5' "J ',•■:':■■ ■.•'>*•,., 'f
' idqm *•■'■",.:■■■ « , * & I'S . ;
»e on er;.-
'■••■•• .. tfj , ..-fee*.
, \bq i \> ■ *w • : -. *•' .;• '
^ r v ■
,0* • • ■ • r »-
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'- ;' '■'>■' '- ■•':' • ' i.1' .- . -
. • • ■ . , , '■'
•• ■■■..-».-
r
i ■
) 3H
- 27 -
Acids. Analogous to the alcohol compounds, we find two series
of acid compounds with BF3, namely:
RCOOK.BF3 where R = H (68), CH9 (43)(62)(63 )(68 ), C3H5 (l6)(68)
tvJVvtimBB3 wnere a - n \oa)f uri3 ^oawhwmoo/, o8na udmoi
n-C3H7 (68). HgCCH = CH (68), COOH (68), C00H(CII)2 (68), COOH(CHa);
(68), C6HB (16)(68), C6H5CH8 (68)
2RC00H.BF3 where R - H (68), CH3 (16) (44) (63 ) (64 ) (68 ) CK2C1 (16)
(63)(68), CaH5 (68), n-C3H7 (68), i--C3H7 (69), H3CCH = CH (68),
Meerwein and Pannwitz draw the same conclusion about the stability
of acid-BF3 compounds that they did about alcohol-BF3 compounds,
€roxall, Sowa, and Nieuwland conclude that there is a greater tendency
for BF3 to coordinate with the carboxy or carbalkoxy groups than with
the phenolic group (25). See Table V.
Ethers. The ether compounds with BF3 are fairly well known. Those
that have been reported are one to one compounds with methyl (18)(19)
(3l)(53)(38)(57a), ethyl (3l)(33 ) (57a )(74)(90 ) , methyl ethyl (57a)(65)
methyl i-propy> {68), methyl amyl (67), n-propyl (65), i-propyl (18)
(74), i-propyl phenyl (74), amyl (74), i-amyl (74), dibenzyl (74),
ethyl benzyl (74), ethyl phenyl (16)(67), methyl phenyl (16)(67)
ethers. Attempts with diphenyl ether have failed (16) (67). See Table
VI.
BF3.2(n-C3H7 )20 has been reported by Keerwein and Pannwitz (68).
Other miscellaneous compounds of the ether type are C4H8O.BF3 (18)
and the betaines produced by the reaction of BF3 complexes with
ethylene oxide or epichlorohydrin (65).
Acid anhydrides. BF3#0(CH3CO )3 was reported in the same month
in 1931 by Bowlus and Nieuwland (15) and by Morgan and Taylor (71).
Two years later Keerwein (63) refuted their work and said the com-
pound was [(CH3C0)2CHC0330.BF3f Similarly, he reported propionic, n-
butyric, and i-butyric anhydrides to form compounds of the type
(RC0CHRC0)30.3BF3. Later with i-butyric anhydride he reported
[i-C3H7C0.C(CH3)3.C0330.3BF3, and with chloracetic and phenylacetic
anhydrides, molecular compounds (69). With succinic, benzoic, and
phthalic anhydrides Bowlus and Nieuwland (16) obtained no reaction,
however BF3.0(H3CCO)3 has since been reported (67).
Esters. Esters have been found to form stable coordination
compounds with BF3. The Notre Dame workers, studying the mechanism
of the alkylation of benzene using 3F3 as a. catalyst, have postulated
the formation of an intermediate complex of sn ester with BF3 (26)
(61). As a result, many BF3-ester compounds have been postulated,
but comparatively few isolated. Those isolated and reported are:
CH3.OCOR.BF3 where R = H (71). CH3 (16)(71). CHsOH (72), CfiH5(72).
C2H5.0C0R.BF3 where R= H (l6)(7l), CH3 (l6)(7l), C3HS (16).
C3H7OCOCH3.BF3 (16)
The following compounds absorbed one mole of BF3 to form viscous
liquids or crystalline compounds but existance of molecular compounds
was not established: ethyl chloroacetate, ethyl trichloroacetate, ethyl
benzoate, diethyl oxalate, diethyl raalona-te, diglycol acetate, phenyl
acetate (16) and p-tolyl acetate (41)
i
'
:
5
,j ,Cj
••:
.0 £^-
3
S
-
■
.
.
.■ -
■
.
j'
- 28 -
Sulfur- ifio rfcanic : Sulfur In compounds such as H80 (37), S02
(13), BQ> * ( 1.4 y . nai teen found to be a donor to the boron atom
of BF3 foiviiig one to one molecular compounds* See Table III.
However, lU sompourids such as S0C12 {22) ard PSF3 (14) the sulfur
atom did no"; donnts
teMfc VjtX , Fluorine,. Booth and Ca rt e r ( 12 ) s ugg e st tha t BF 3 is
associated aT~a pressure around 10 atmospheres, which could only come
about by BF3F £u 5F3. Berzelius (8) passed BF3 into water and
produced fluoboric acid, which can be written HF.BF3. Landolph re-
ported "hydroboric fluoride" which can be written BF3.3HF (54^ .. More
recently EF3.2HF has been reported (42).
Compounds of the type MFi.BFj and HF2.2BF3 where M = Fe or Co
have been reported (58), 2CaF3.BF3 has also been isolated (39).
The alkali metrl fluorides form compounds MF.BF3 (28)
Other miscellaneous compounds are N0F.3F3 and CH3C0+BF4-. The
chlorofluo rides of methane have limited miscibility in BF3.
Chlorine A du Pont patent (29) claims that organic coordination
compounds with BF3 are released from the BF3 by the addition of a halide
of Na, Zn, Al, Cu, Pb, Fe, or Sn. The inorganic halide coordinates
with the BF3 and thus releases the organic compound. NaCl was an
example cited.
KC1 and CH3 do no"c react with 3F3 (13') (38).
Group VIII. No compounds with elements in this group as donors
have been reported.
Summary. The elements which in their compounds are donors to
the boron atom of 3F3 are in a small area, of the non-metallic part
of the Periodic Table, thus
C N 0 F
P S CI A.
i?5 3
.
' -a
' v : -
"
'
, :
'
.■r -r.i •**
.
I. ,
- >;9 -
TABLE
COMTOUN.O
KELtfING POINT
°C
-126.6
DCILING- POINT
REFERS
ICE
I
A.5F-,
15
**2¥F.:
•127.3
/-.3B1 .
- U 3. 3
1 ' '2T3TT'
i B O.bi
-126; 3
A.83F,"
-128. 4
A.I6BF3
-129. 0
II
NH3rDF3
180
46
CgH5WH3.Br 3
89
46
(C3HrJ2NH.3F3
160'
46
(Csri5 ;3N.3F3
C6H5)(CH3C0)Hn,.BF3
29*5
80 3
46
133
84
(C6HG)T(CH3CO)C^N#BF
3 114
84
Ce^b CH: NCgas • --'3
135-45
81
G6HB(CNOH)CH3.BF3
107-13
41
C8H5N.BF3
45
3' JO
2187
KCN.BF3
40
76
CH3CN,BF3
87
1^-752
16
III
oxygen:
5.4-6
63
68,
2ri20 . BF 3
4.3-5
58.5-601#2* 464
,.s-5 53
58'
B4.H3.Ofe.fi -40 BF3
128-30
(decono. )
'68
C4 H^< s fe . >JH*.0 . BF • .
142
53
68
2ClnH180.H20.B^3
71-3-
63
2CloH180.2Hs0.3F3
59. 5-61
63
68
Sulfur
H2S4BF3
-137*0
37
S02„BF3
- 96,0
.13
SOF2.BF3
-140m8
14
IV
CH3OH.BF3
-19.4
75
C2H5OH_.BF3
-19"
16
(CH2OH)2.BF3
40-4
63,
68
Dialooholates
2CH3OH.BF3
58, 94
63,
68
2C2H50K.BF3
604; 51-215
63,
68
2C3H^0H,BF3
562
63,
68
2C4H OH.BF3
64, 5-70 3
63,
68
2CH2C1CH20H.BF3
592_2# 5
63,
68
2CCl3CH2OH,BF3
40-2
63
V
HCOOH.BF3
-20-1
68
CH3COOH,BF3
-25-4
59X3; 62xl
62, e
58,69
C3H5C00H.3F3
-28-9
38
n-C3H7COOH.BF3
-29-30
68
CK3CH:CHCOOH.BF3
-55-5
68
C6HBC00H.BF3
+d0-1.5(de
comp )
(98 crude
)
16,
68
C6H5CH2C00H.EF3
+56-9(deco
tip)
58
!
■
.
- to -
CABLK
COMPOUND
MEL71KG ?0B
°C
J?
.Dv./
ILIKG POINT
°C
refers ce
V
2HC00R„Bj\
43-4lx
68
(oont
. J2CHcCC3H.EFa
53-
-43.# : 14074e;
16, 68
ec»jifiCoofl.PFii
(0
-60 Cj3:62-31
v 15. 68
''xl' 3
68
2i-C,h7>jrh03r •
6 3-
•TO 16
69
2CH3CK:CH0OOH,I"3F3
CI.
— ' *i 5
68
(C00H)2.3F3
(CHC00H)2tBF3
57-8(deconp»
)
68
75-82
68
(CH2COOH)2..BF3
84-4(decomp.
)
68
VI
(CHa)3O.BF3
-10-4
126-8
18,31/38
57a
(C2H5)2O.SF3
(i-C3H7)sO.BP3
-50-2; -60. 4
123-5 . 7
13, 57a
68
18
(CH3)(C3H5)0.3F3
-98
127
57a
CH3) CgH^JO^BFa
(CH3)(C6H5)O.BF3
-41'
54. 3-5io
67
-1^-3
37
VII
C2H502CCH.BF3
102748
16
CH302CCH3, BF3
60
IIO73.V
16
CH302CCH20H.3F3
60 3
72
C2H5C2CCH3 . BF3
26
11973q
16
C3H702CCI-i3,Br-
I2674 3
16
csh5o2cch34bf3
40-55
72
p-CH3.C6H402CCH3.BF3
146-50
41
C2H5O2CC2K50BF3
33
II674 7
16
BIBLIOGRAPHY
•o •
unem,
1, Balz and Zinser>c Z, anorg. all
2. Basarow, Ber., 7, 023 (1874)
3. , Bull. sbc. chim., L^ 21, 290 (1874)
221, 225-48 (1935)
( Compt. rend., 78, 1690-1700 (1874)
r>aumgarten end Bruns, Ber., 723 , 1753 (1939)
i and Hennig, ibid, 723, 1743 (1939)
-__ and Muller, ibid, 693, 2688-90 (1936)
Berzellus, Pogg. Ann,, 2," 113 (1G24.)
9. : , ibid, 58, 50v5 (1643)
10. Bess on, Compt. rencl., 110, 80 (1890')
H# Booth, H. S. , Private Communication.
12.
13*
14.
13.
17*
18.
19..
20*
81*
and Carter, J. Phys. Chem*, 36, 1359 (1932)
-, and Martin, D. R. , J. Am.- Chem. Soc., 64, 2198-2205
(1942)
s and Walkup , J. R*., ibid, 65, 2334-39 (1943)
^___# and Will son, K. S. , ibid, 57. 2273-80 (1935)
Bowlus and Nieuwland, ibid, 53,. 3835 (1931)
Bright, J„ R. and Fernelius, W.. C.r ibid, 65, 735-6 (1943)
3ra«} H„ C, and Adams, ibid, 34, 2559 (1942)
, — and Adams, R„ K. , ibid, 6g>, 2253-4 (1943)
— t Schlesinger rnd Burg, ibid, 61, 673 (1939)
Wj 1 rnd Cardon,. ibid, 64, 325 (1942)
-
■-
,' ' ■ r
!■•<*■'?
,:■■•- .v--.
,
■
■■
•
*?
■
.
..
i ».
^ . - f ■
.. ■ ; . - .. .-./
..
j ■
.. * 1
3#S':.V
.
. •.-.:.
r »
.• ' .'.'
is
■
f- ' • - - «
-*•* ■ ;Di . ... ,•- •• • .
■J • r-< ; . • ■ - .. •
Li* . ,' • : . ■■-
: .
■\ 4
- 31 -
22. Burg, A. B. and Ross, M. K. , ibid, 65, 1637-8 (1943)
o?" 7~~~: ?nd Sister Agnes A. Green, ibid., 65, 1838-41 (1943)
24. Cannizzaro, Ann., 92, 113 (1854) —
25. Croxall, Sowa, and Nieuwland,' J, Am, Chem. Soo., 56, 2054 (1934)
%%* - ;•' -rru *Sd : — * J» 9rg- chem., 2, 253 {1937)
27. Davy. J„ . Phil0 Trans., £02, 352 (18X2)
28. de Boer and van Liempt, Rec, Trav. Chim., 46, 124 (1927)
# nn,oU Pont de Nemours . and co., Inc., Brit, 486, 887, June 13,
1930 0
30.Gasselin, Bull, coc.jshlm, , <g)7. T 17-18 (1892)
3°
c
, w \ ibid., (5)7 . 209 (18925
• — , ibidc, (5)9' . 401 (1892)
;33. . Ann. chim, phys., (7J,5 , 5 (1894)
34. Gay Lubsac, Gilbert Anc, 36, 6 (1810 )
\** n~~\ I 1 fTnJ Menard, Recherches physico-chimlques. 2, 36 (1811)
56. Gerhart and Hull, (to Standard Oil US. of Indiana) U,S."1> 148, 115
! Feb. 21, 1939; French823, 270 Jan. 18, 1953, ~' '
-57. German, A. F. 0, and Booth, H. S. , J. Phys. Chem.;. 30, 369 (1926)
,58. and Cleveland, M, , Sci., 53, 582 (lSSi) '
E* n""7 T"T and Torrey, &. G-> ibid, 54, 16 (1921)
,t0. Goring, Helen W. , "Reactions of Boron TrifTuoride", M. S, Thesis
Western Reserve University, Cleveland, Ohio (1927)
o T5rui?lti:> **• s- Thesis, Western Reserve University, Cleveland, Ohio.
|L2. Hantzsch, Ber. , 63, 1789 (1930) •
3. Hardtman Tietze, and Schepss, (to' I. G, Farbenindustrie A. G. )
Ger. 551, 513 October 18, 1927*
:4. Hinton and Nieuwland, J. Am, Chem. Soc, 54, 2017 (1932)
:5. I. G, Farbenindustrie A, G, , Brlt« 451, 353 Aug. 4, 1936,
:6. Kraus and Brown, J. Am. Chem, 'Soc, 51, 2690 (1929)
:7. Krause and Knobbe, Berf, 6&B. 2112 U931)
q# £*?Sfn' A°Wa> ??d Nieuwland J. Am. Chem. Soc, 59, 965 (1937)
:9> Kuhggn'(^-)0h^ P^s., i3}2, 116 (1841); Liebigts. Ann, \ 39,
0. Landolph, Ber„, 12, 1578 (1879)
1. . , ibid.,T2, 15G3 (1879)
2. } Compt. rend,, 85, 39 (1877)
3» : , ibid, 86, 539 TI078)
4. — , ibid, 86, 601 (1378)
5. f ibid, SS, 671 (1878)
6. $ ibid, Sg, 1463 (1878)
7, ------ , ibid, 89, 173 (1879)
7a. Laubengayer and Finlay, J. Am. Chem. Soc,, 65, 884-9 (1943)
u. long, k. E. , M. S. Thesis, Western Reserve UnTversity (1927)
9. ncAlevy (to E. I. du Pont de Nemours and Company, Inc.,) U. S. 2,
135, 454, November 1, 1938. ' , °\ l
' ^ m V^w^a^' ^d'MoC^ker, P. A., J, Am. 'Chem.
Soc, 66, 1263-4 (1944)
1. HcKe'nna and Sowa, ibid., 59, 1204 (1937)
2. Meerwein, Ann., 455, 227jtT927)
5. , Bcr#, 566.. 411 (1993) ,
*' ~ 7Tq^^ S^2ber?, G2S* 3eforder. ges.' Naturw. Marburg, 64, 119
(1930); Chem. Zentr. , 2, 1962 (1930) ^
1547833U939^erS> G°ld' Pfeil, and W1Uf*r8* J* P«*^ Chem,,
— o< —
66. , Hinz. Hofmann, Kronig and Pfeil, ibid., 147, 257 (1937)
67. . and Maier-Huser, ibid. 134, 51 (1932)
68. , and PannWitz, ibid, 141, 1£3 (1934)
69*. and Vossen, ibid, 141, 149 (1934)
70. Mixter, Am. Chem. J., 2, 163 (1&80)
71. Morgan and Taylor, J. Boo. Chem, Ind. , 50, G59 (1931)
72. and , J. Chem. Soc, , (1932), 1497
73. and Tunstall, ibid., 125, 1963"Tl924)
74. 0» Connor and Sowa, J. Am. Chem. Soc,, 60, 125 (1938)
75. O'Leary and Wenzke, ibid., 55, 2117 (1933)
76. Pattein, Compt. rend., 113, C5 (1091)
77. Price and Ciskowski, J.Tn, Chem. Soc, 60, 2499 (1930)
70. * and Meiater, ibid., 61, 1595 (1935T"
79, Rideal, 3er. , 22, 992 (18C97
00. Ruff, Braida, Bret Schneider, lienzel and Plant, Z. anorg. allgem.
Chem., 206, 59 (1932)
81. Snyder, Kornberg, and Romig, J. Am. Chem. Soc., 61. 3556 (1939)
82. Sowa, Hinton and Nleuwland, ibid., 55, 3402 (1933;
83. and Nleuwland, ibid., 50, 271TT936)
84. Sugden, S. and Waloff, II., J. Chem. Soc, (1932), 1492
05, Swinehart (to Harshaw Chemical Company) U.S. 29 140, 514 February
28, 1939; U.S. 2, 196, 907 April 9, 1940.
06, Thomas, Anzilotti, and Hennibn, Ind. Enc Chem., 32,. 400 (1940)
07, van der Meulen and Heller, J. Am. Chem. Soc., 54, 4404 (1932)
00* Vaughn, Bowlua, and Nleuwland, Proc. Indiana Acad. Sci., 40,
203-6 (193?-)
09. Wiberg and Heubaum, Z. anorg. allgem. Chem., 225, 270 (1935)
90. and Mathing, Ber., 70S, 690-7 (1937)
91. Burg, n. :\ rnd Hr.rtin, L. L. , 3g Am, Chem. Soc., 65, 1635-7
(1943) ... ■■ -
9r, 'ICiin?:cnber£ rnd KeWlorf, R. . cr-v, chip.., 54, 959 (1935)
3
. .. • ' • • -: ■• . - .-■ '■-■ v. ; . , \v
• ■ -;■• • : v
,
•j«
•
•
^
I
.. • ■ ••' V • i . . * " • •• • f v; V— ' ' *
; • • • • ■ -t • ! V<" •■ ?
' ";. ;-.■•. •
.!■,.■-•■
» <■
1
,<,,-•
if.*.. ■
(
- 33 -
ROLL CALL
December 12, 1944
lumlnum Phosphide T. G. Klose
The literature reports five binary compounds of phosphorus and
lumlnum — Al3Ps, A13P7, A15P3, A13P and A1P. Since the analyses of
pme of these compounds are unrecorded or questionable, an attempt
las made to find the correct composition of aluminum phosphide (s;«
Various preparative methods are given, the most successful one
eingthe process in which a mixture of finely divided aluminum and
aosphorus is heated in an atmosphere of phosphorus vapor.
A complete analysis of the product is given. This analysis is
ssigned to calculate phosphide phosphorus, free aluminum, total
Lumlnum and phosphorus pentoxide.
X-ray diffraction studies of the phosphide preparations were made
d determine the free aluminum concentrations in the various samples,
le results were in agreement with chemical analysis. X-ray studies
Lso indicated that the chief constituent was Alp and was identical
or all preparations regardless of the amount of free aluminum present*
Aluminum phosphide is dark-gray to yellowish-gray in color* It
Desnft decompose at temperatures as high as 1000°C. It is easily
ydrolyzed by acids, bases, or water, one of the products of the re-
st ion being phosphine.
sf erence:
lite, W. E. and Bushey, A. H. , J.A„C.S §6, 1666 (1944)
reparation of Potassium Chloroplatlnlte James V. Quaglia.no
Yellow, insoluble potassium chloroplatinate is prepared by the
eaction of solutions of chloropla.tinic acid and potassium olaloride:
H3PtCl6.6H20 + 2KC1 -> K2FtCl6 + 2KC1 + 6Ha0
le KfrPtCle is suspended in water and reduced with freshly prepared
)3-water. The vessel is placed on a steam bath and during the reduc-
ion procesr. the solution is stirred constantly with a mechanical
itirrer, Tetravalent platinum is reduced to the divalent state
pcording to the following equation:
PtCl6= + S03 + 2H20 -> PtCl4= + S04= + 2C1~ + 4H+
he "temperature of a steam bath" is indefinite and to insure complete
feductlon it Is necessary to state the temperature range (85-90°C)
d which the solution must be heated.
y
o sbs4- ,.
,"'"• '
r
•<• * . . ■ » 1
v. .. t
-,.■ >' *
* * 4
l'
•i ■
'-."'■'■■, ■ f
i. «■
-■
. .
•
>n
*.■'*:, '.••'■'-'
»
'
, , # •' ...
1
i
•
+
bO(S
+ gXO?^
8
3?"
WO
,jd©j»9ii aa
- 34 -
mphiprotlc Substances Elizabeth W. Peel
Basic substances are proton acceptors (election donors); acidic
ubstances are proton donors (electron acceptrs). The former are
xemplified by ammonia and amines, the latter by acids, Acetamicle
CH3CONHs) in water solution is essentially neutral, 6lnce it will
either accept a proton from H30 nor donate one to OH 7 which ions
re the strongest acid and base possible in water solution. In other
olvents., however, it has been shown to possess both rcid and basic
roperties. For instance., in glacial acetic acid solution, acetcmide
an be titrated with perchloric acid, the potentiometric curve showing
to be a weak ba6e in this case* Also, in liquid ammonia, it will
eact with sodamide to give a sodium' derivative, donating a proton to
he NHS*~ ion., thus acting as an acid.
The authors of this article have investigated further the be-
avior of acetamide in these solvents, determining the freezing point
urves for the systems CH3C0NH3-CH3C00H (l), and CH3C0NH3-NH3(2 ). In
ach case., they found definite evidence for e 1:1 compound between the
wo components.
In case (l), the compound melts incongruently, decomposing Just
elow its melting point (about (50G), so the curve shows a break, no
aximum, at slightly more than 50 mole percent acetic acid. The com-
ound was isolated and analyzed acidimetrically; it corresponds to
he following:
CH3C0NH8 + HC2H30s ^==r^ (CH3C0NH3)+ (C3H303)-
nd may be called acetylaa monium acetate.
In case (2), the compound decomposes well below its melting point,
he brerk in the curve coming at about 70 mole percent ammonia. The
ompound was not isolated, since it is so unstable. It would cor*
espond tot.
CHaC0NHa + NH3 ^=£ (CH3C0NHJ-(NH4 )+
nd may be called ammonium aquo-ammo no— acetate.
Acetamide has thus been shown to be definitely amphiprotlc.
ef erence;
isler, Davidson, Stoenner rnd Lyon, J, Am. Chem. Soc, 66, 1888 (1944)
'
"
,
- 35 -
Molecular Compounds Between Amines rnd Sulfur Dioxide. Comments on
Jandert s Theory of Ionic ReacTI^nT TrT^iinT-^ ~
A. L. Cppegard
work whLh^^nnt01^^11 J*nder's theo^ ^ based on experimental
mniL^Vo f ^^rfliable. Errors were made In analyses, and
molecular weight determinations were not made. The authors repeated
Jander» s work, but with vastly different results. repealed
Jander* s work and Interpretation,
L e)3N J L(C2H5)3N^
Br*
Colorless, crystalline m.p. 230°C
m.p. 73°C.
I
This article
II
(C3HS)3N -llS^ (C2H5)3N:^a. M^ (C3H5)3NH(HS03)
orangeoil Colorless
mol. wt. det'd crystalline
TTT m.p. ?4-75°C.
Ill TV
0
2
IV *
(C2H5)3NH(HS04)
m.p. >115°C.
V
It is pointed out that I and IV are nrnhphiv +^* „Q™« «
and also that II „aE probably (CaHs m"^^^"^^^
molecular compound R3N -!-_> &£" 1~1 ratio to Slve a simple
between amtne^anYl^1' "?? *£? a?thors °°«°l^e that reactions
and no" Ton^TklaT^ltltll^ ^^ *" m6rely addltl°n reactlons
•hownltoe^t SSJTSh^n?1 pUM\ed the Writers« The structure
exhibiterCllqSd sulfur aloxid". °°l0r' "^ the 8Ught °°»*">"vlty
Reference.
K, C. Bateman, E. D. Hughes, C. K. Ingold, J. Chem. Soc. 243 (1944)
tspectrireI„^gaJn?ceS;eSm^etryr: pale^8 "* ***«. ™°™
•
•
.
i a *T
!
.6 '
- 35a -
The Structure of Orthonltrlc Acid Hans B. Jonas sen
When dry air in passed through a solution of dilute nitric
acid at -15°C. neec.le-.Like crystals are obtained which have a
composition corresponding; to HN03.2Ha0. Erdnann (l)(2) and
Mellor (3) assigned the following structure to this "compound":
H0X /OH
N -OH
HO' ^OH
T£is compound is unstable above -15°C.
Ifuster arc. Krumann (4) however, repurting on the thermal
analysis of the system H*0 and HN03, obtained data indicating
that no definite j:<irpo:ji:'.d is formed at a positj.cn corresponding
to a. composition HNC3«£H30, Thci:•.-, data only indicate the
existence of "Jhe compounds HN03.H30 and HND3.3H308
If, however, a mixture of acetic anhydride and nitric acid
is distilled and the fraction boiling at 127°C is collected,
analysis shows tnat tne composition of this fraction corresponds
to. a compound (CH3COOH)8#HN03, This compound is called "Diacetyl
Orthonitrio:l acid (2^. It is unstable in the presence of water,
giving acetic acid! and nitric acid,
Biltz, reporting c>n his investigation of the system HN03 and
H80, states that the compound HN03#H80 should be called ortho
nitric acid, He assigned to it the following structure corre-
sponding to the structure :>f ortho-phosphoric acidi
H
0
HO- M-OH
Zintl and Haucke (6) report in 1935 that they were able to
isolate NaaN(J4 and that they subjected this compound to x-ray
investigations. These investigations seem to prove that during
the formation of this compound from Na30 and NaN03 the oxygen
atom of the HasO is able to push aside the third oxygen atom of
the nitrate ion to form the NCv,~3 ion which then acts as the
central group of the compound. This compound is stable although
the coordination number of nitrogen derived from the ratio of
radius of cation/radius of anion gives a coordination number of
three for nitrogen,,
Zintl , Kcrawitz, and Walter ado rf (7) investigated also
the crthonitr:i c- acid proposed by Biltz (5; by means of x-ray at
-15CCC„ and n't -30 °C'' They state that their data seem to indi-
cate the same structure proposed by Biltz (5) for the orthonitric
acid, bebau3e the x-rr.y pattern of tMs compound was somewhat
• .8
'■r:
:
\ ■ . ■ •
J
■
■
- 35b -
similar to that of the Na3N04. They state, however, that the
similarity is not outspoken enough to definitely prove this
structure.
The "orthonltric" acid HN03.2H20 isolated by Erdmann (l)(2)
and the related HN03,2CH3C00H seem only to be dipolar association
compounds of the following structure:
^-O.H20 ^O.HOOCCH3
HO-N ' and HO-N ^
^>0.H20 ^O.HOOCCH3
This dipolar association seems to be substantiated by the
following frets;
(1) "Diacetyl orthonltric" acid is unstable in the presence
.of water^ forming acetic acid and nitric acid,
(2) This instability can be explained if dipolar association
is assumed because in the case of such a linkage a group
with a higher dlpole moment may be assumed to displace
one which has a lower dipole moment. The dipole moment
of H20 is 1.80 Debye units whereas that of CH3C00H is
1.72 Debye units.
(3) Kuster and Krumann were unrble to show the presence of
a compound corresponding to the composition HN03.2H20
in their thermal analysis data,
(4) Constant boiling nitric acid has the composition
HN03.2H20.
Bibliography
1. Erdmann, Z. anorg. Chem. 32, 431, (1902), 34, 131 (1903).
2. Erdmann, Z. angew. Chem. 16, 1079 (1903).
3. liellor, Comprehensive Treatise of Inorg, Chem., Vol. VIII, p, 564.
4. Kuster and Krumann, Z. anorg. Chem. 41, 1, (1904)
5. Biltz, W. Nachr. Ges, Wise. Gottingen. Math. Phys, Kl. (N. F. )
1, 95 (1935).
6. Zintl and Haucke, Z» phys. Chem, A174, 314, (1935),
7. Zintl , Korawltz, and Waltersdorf, Naturw. 23, 197 (1935).
■ I
'
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.V
- '66 -
REACTIONS BETWEEN SOLIDS
Nancy Downs December 19, 1944
Introduction.
Reactions between solids have been employed for many years in
industry but the study of such reactions is of comparatively recent
origin. Since the beginning of these studies, over five hundred
scientists have investigated solid reactions, aporoximately thirty-
five of whom have been English or American (l)(2). Most of the
work has been done on the interaction of metals with each other or
the interaction of metallic oxides with other oxides or salts such
as halides, sulfates, and silicates. Some studies of double
decomposition reactions have been made.
History.
First work was done by Spring (1)(2)(3), and Sir Roberts-Austin
about 1895 ( 2 )8 Later Ma sing studied the effect of pressure on
metal filings in bringing about a reaction. Cobb began the research
of non-metallic compounds about 1910 (2)* He suggested that a
"quasivaporous" theory could be used to explain solid reactions (2).
Taradoire claimed that for two solids to react 9 one had to have a
vapor pressure. Also it was believed that the reaction didn't take
place in the solid state but in a fused state or e gaseous state- (4).
Our modern conception of solid reactions has been built largely by
the work of Tammann, Jander, Jost, Hut tig, Hedvall, Hume and Calvin,
Fischbeckj Seith, and Tubandt, in Europe (3) (2) and Ward and Wood
in the United States.
Mechanism of Solid Reactions,,
A, Four Stages in a solid reaction (5) (6).
1. A reaction takes place at the point of contact* It
results in an increase of catalytic action.
2e The second step is the formation of a thin reacting
layer or reaction skin. With the formation of this
skin, there is a decrease in catalytic action, an
increase in ability to absorb dyes and an increase
in solubility in weak reagents (7)(8)(5)(9)(ll)„
3. The third step is the change of reaction layer and
the formation of defective crystals.
4. The last step is the transformation of the defective
crystals into pure crystals.
The four stages take place at two different rates. At
first the reaction goes very rapidly, then it slows
tends to slow down (10). The explanation of the rapid re-
action rests on the fact that in the preparation of the
mixtures by grinding or because of impurities present in
the crystal, some crystals are deformed. The molecules,
atoms, or ions which are moved out of place can change
positions more easily at a lower temperature than perfect
crystals will and the reaction occurs rapidly untii the
deformations are removed by the reaction or by recrystalli-
zation. Then the reaction clows down. The rates of the
reactions depend upon the rate of diffusion and the rate
of crystallographic changes (l)(2) (3) (11 )(12).
- 37 -
B. Diffusion in solids (1)(3)(13).
1. diffusion may occur in solids in one of thj»ee ways (1$}0
a. Particles may pass along internal surfaces,
b. Particles may pass in lnterstitially within the
normal lattice*
c* They may pass as a result of the vacant places
within the lattice and movement of adjacent
particles into the vacant positions (12) (6),
2. Tammann*s equation (14) (15).
Derived from Fick' s law which may be stated mathe-
matically:
dn » -QK §g
By substitutions and integration the ftllewing
expression is obtained,
n * b logt + c
where n p quantity of substance which diffuses in terric t
b = fraction of "diffusion threads" broken during given
t =* time time,
c = constant
If the. percentage decomposition is plated against log
t., a straight line is obtained. This seems to indicate a
direot relationship between percentage decomposition and
the rate of diffusion. Applications to actual data seem
to prove the validity*
3. Jander*s equation (14),
This equation relates the thickness ef the layer to
the percentage decomposition.
x = the percentage decomposition.
2DCot * the square of the thickness of the reaction
layer. _
If the(100 v "100 ) % is plotted against t a
straight line is obtained,
4. Hume, Calvin, Topley equation.
This equation is based on their belief that a crystall©~
graphic change takes place in a solid (14) (16), The
rate at which the orystallagraphic change takes place is
dependent on (a) the rate of nucleation, (b) rate of
propagation of interfaces between the solids. In turn,
the rate of solid reactions depends on rate of crystall©.-
. graphic changes in addition to diffusion.
The equation relates the fraction decomposed to the
-UM. (14)
= (Kt)3~ 3(Kt)3 + 3Kf
These equations were applied to experiments by Wood
and his coworkers and were found to agree quite well
With experimental results.
C. Temperature affects the rate of reaction since it affects
both the rate of diffusion and the rate of crystallization*
ilasslflcatlon of solid reactions (l)
A, Two element s
M» ♦ MtV
,^.
»7a ©s x»a floiw w«
r-r; ■ >"iiis*xqxe.
■ -.. ., k; ■ __. * •., i '.. ., ..'>i..; • • •''
■ :' • . i " l. '. ' ' ' '—
' - . ' r ■'. »-
0. sri* to sewufoiri* ;• - *>P?-'I , ;;'??3a3 . ,-.
Vi'Mi** ■ ■'&*<&** ^iV^-iSfH: "**
■rf) *'»»Ioi/l*'"*o sJdi erffr-'(*J v - .v
^ * ""'" ' l ******** ' '* ^. ij '-^If^iL^'^'
— 08 -•
B. Two binary compounds with a common component.
M'X1 + MftXf or M'X1 + M'X"
An example is the reaction of CaO with . SiO*,
. C# Two binary compounds without a common component.'
M'Xf + Mf,X
The first two types have been investigated to the greatest degree
and the latter type perhaps has been neglected because no
accurate quantitative methods were known.
Double decomposition reactions in the. solid state.
Early work was done by Plato and Ruff~(T§T"£nd Berketoff (17).
hxlt ^nenUy Tam?ann (inHedrr.ll (3), Mathieu, Mathleu, and Paio(l9),
have done research on «uoh equations. ' '
Roland Ward and coworkers U4)(18) studied reactions between
alumina and barium sulfate, and between ferric oxide and barium
carbonate. From the results they obtained and from information they
Soi Jne2 b? ComParlnS their* results to. the Jender, Tammanrt and Hume-
Calvin-Topley equations, they set forth the idea that perhaps it is
possible for the rate of crystallographlc transition to be the
deciding factor in the rate of certain chemical reactions.
% J. Wood and his coworkers (17)(20)(31)(22)(23)(24) did a
series of experiments on the reactions of solid alkali halides both
i™VLG?£ below *he fusion point, using an x-ray spectrograph to
record the results. The results may be aunrsarlzed'as follows:
A. At temperatures above the fusion point (17)(20 )(21 ).
• ■ 1. In fifty seven out of the sixty reactions, the reactions
went in such a way that the average cube edge of the
o stabl® pair was less than tha* of the reciprocal pair.
d. In fifty-seven of the sixty reactions, the* sum' of the
heats of formation of the stable pair is greater than
the sum of the heats of formation of the reciorocal pair.
3. The cation of the larger atomic weight unites" with the
. anion of the larger atomic weight and the cation of the
smaller atomic weight unites with the anion of the
smaller atomic weight.
4. With the exception of the lithium salts, one member of
the stable pair has the highest melting point of any of
the four compounds formed.
5. In fifty-seven of the sixty reactions the reaction goes
to completion as evidenced by
a. Absence of x-ray patterns for two of the compounds
involved,
b. The cube edge of a restating solid solutions is
o a* Z same as the theoretical CUDe edge.
B% At temperatures below the fusion pqint" (22)(23)
^t5? twelve reaction mixtures containing lithium salts
?2lwf -brides,' the stable pair always had as a member,
lithium fluoride. The stable pair in six cases contained
me highest melting compound and in six cases the
reciprocal pair contained the highest melting point.
if u° tluo?,ide8 &re present in the lithium salts, the
highest melting compound was found in every case in the
reciprocal pair.
fl
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ptaa.
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ff
si
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-.
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- 53 -
3, In the reactions involving no lithium salts, but
fluorides, the highest melting component was contained
In the stable pair,
4, For fifty-four of the sixty reactions, there was a
complete or partial conversion of the reciprocal pair
to the f, table pair*
5, Little reaction occurs if the temperature is more than
290* below the fusion point and the reaction proceeds
quite rapidly if the temperature is within 100° of the
fusion point.
BIBLIOGRAPHY
1. Jose, Wilhelm, "Diffusion and Chemische Reaktion in Festen-
Stoffen", LeiDzig (1937).
2. van Klooster, J. Chem. Edp , r?, 361-3 (1940)
3. Hedvall, J, A., "Reaktions fahigkeit fester Stoffe", Barth,
Leipzig, (1938).
4. Taradoire, F. , Bull, soc. chim. , 6, 866-72 (1939),
5. Jander, W. and Weitendorf, K. F., Z. Elektrochem. , 41, 435-44
(1935).
Jander, Vt and Bunde, K. , Z. anorg. allgem. chem., 231, 345-64
(1937). "~w
Jander, W. and Schule, W. , Z, ancrp-, allgem. chem., 214, 55-64
(1933) ,
8. Jander, W. , Z. Ver deut, Ing. 80, 506-10 (1936)
9. Jander, W. , Z. anorg'. allgem. chem. 174, 11-23 (1928)
10. Ward R. , Trans. Ill, Acad. Sci. , 25, 167-9 (1933)
11. -Huttig, G, F. , Chem, Ztg. 61, 408-409 (1937)
12. Hedvall, J, A. ,,Proc. Symposium on Chemistry of Cements, 42-57
Stockholm (1938).
13. Garner, W. E. , Science Progress , 33, 209-2P9 (1938)
14. Ward, R. , and Booth', H. S. , J. Phys. Chem. 35, 961-84 (1932)
L5. Tammann, Z. Angew. Chem. 39, 859-75 (1926)
L6. Hume, J[. and Colvin, J. ,' Phil. Mag. V 8, 589-96 (1929)
L7. Wood, L, J. and Thomas, S. B., J. Am. Chem. Soc. 56, 92 (1934 )
L8. Ward, and Struthers, J. D. , J. Am. Cher. Soc. 59, 1849 (1937)
L9. Mm-me. Jjathieu, Mathieu, and Paci,' Comp. rend. 192, 416_8 (1931)
20. Wood, L. J., and Thomas, E. B. , J, Am. Chem. Soc. 57, 822 (1935)
21. Wood, L. J,, and Thome s, E. B. , J. Am. Chem, Soc. 58, 1341 (1936)
22. Wood, L. J., and Link, K. L., J. Am. Chen, Soc. 60, 2320 (1938)
23. Wood, L. J., and Link, H. L. , .J. Am. Chen. Soc, 62, 766 (1940)
24. Wood, L. J,, and Vogt, J. W., J. Am. Cherv. Soc. §6, 1259 (1944)
1
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- 40 -
INORGANIC CATALYSIS; INDUCED REACTION, FRECIPITATlON, AND SOLUTION
F. W. Cagle, Jr. January 2, 1945
While the action of a catalyst either accelerates or diminishes
the rate at which a reaction proceeds, it must "be firmly understood
that the presence of this catalyst in no fashion effects the extent
to which the reaction will take place. The equilibrium conditions
are uniquely determined for every reaction by the concentrations of
the reactants and a choice of sufficient physical conditions. The
calculation of this position of equilibrium is In the province of
thermodynamics and if proper thermodynamic datt. are given, it can be
calculated for any reaction for which the reactants and final
products are known. This may be done without consideration of the
intermediate products of the reaction.
In the field of rates of reaction, in wjiich the art of catalysis
finds its place, one discovers no "broad highway" which leads to
success. In fact, one cannot set down a single general law or
principle of catalysis. It is for this reason that the writer
refers to catalysis (and related phenomena) as an art rather than
a science. Knowing these things^ we shall discuss catalysis only
so far as the science is known and not ettempt to drew general
conclusions nor expect to see general principles resulting from
this discussion.
The writer further desires to introduce with catalysis the in-
duced reaction in which the "catalyst" suffers change in the reaction,
for it seems that the exclusion of this kindred phenomenon would
be not only highly arbitrary but objectionable as well. For the same
reason, the phenomenon of induced precipitation and solution will be
discussed.
It is of course evident that if a reaction could be found which
is catalyzed by a certain element or radical in a mixture but not
catalyzed by other substances, one could detect very small amounts
of the catalyst by observing its effect upon the reaction.
1. Catalysis Due to Complex Formation
a. The reduction of Ce+4 salts by dilute HC1 proceeds
very slowly at room temperature. This may be much
accelerated by the formation of HgAgCla (1,2).
b. Chlorates in a neutral or rrildly acid solution are only
very weak oxidizing agents. ~The addition of a trace of
0s04 suffices to make them behave as powerful oxidizing
agents*. It can be shown that the solubility of KC103
is markedly greater in neutral OsO* solutions than in
water. Further the oxiclation potential of such a
solution is much greater than that of a solution of KC103
alone. This has been interpreted ?.& indicative of the
formation of a complex JCC103-Qs04 (3, 4, 5).
2, Catalysis Due -to Principal Valence Compounds Compounds
J
... ..J
mfkl-. v . ■< . • ■ - ' ...,....■-
.
voter
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not If Jtt*f>. j
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- 41 -
a. H80a + NaaSa03 + 2HC3Ha0fl = NaaS406 + 2NaCaH302 + 2H20
but with a trace of i!o04- (6)
4Ha0a + NaaS303 = 3H20 + NaaS04 + HaS04
The same effect may be achieved with tungstates,
vanadates, and zirconium, thorium, and titanium srlts
(7).
b. 2H3As04 + KDH+ + 41- = 2As+3 + 2Ia + 8Ha0
2AS+3 + 3HaS = AsaS3 + 6H+
2Ia + 2H3S = 41" + 2S + 4H+
These reactions of catalytic nature are used in
qualitative analysis in order to avoid the slow precipi-
tation of AsaS5 (8).
c. 2NaNa + Ia = 2NaI + 3Na
This reaction is quite slow out very greet ly
accelerated by S~ in many forms (9, 10)<,
d. The salts of Cu++ enjoy the distinction of acting as
catalysts in both oxidation and reduction reactions.
This is clue no doubt to the formation of relatively
unc table Cu+++ salts in the first case and Cu1" salts
in the second case.
An example of the use of copper salts as oxidizing
catalysts is found in the oxidation of manganous ion
to permanganate by hypobromite. Unless a trace of a
copoer salt is present.' manganous dioxide (not per-
manganate) results (11 J.
The reaction between the ferric ion and thio sulphate
ion (2Fe^++ + 2Sa03== = 2Fe++ + S406 = ) is very greatly
accelerated by a very slight trace of a cupric salt.
This reaction illustrates the role of Cu+ as a
catalyst in reduction reactions (12).
3« Induced Reactions
If a reaction velocity is augmented by the occurrence of
another (apparently unrelated) reaction which occurs at the
same time as or just before the first reaction, that first
reaction is said to be an induced reaction (13;.
a. The classical example of an induced reaction is th3
oxidation of sodium arsenite solution by the oxygen
of the air (this reaction proceeds by itself too
slowly to be measured) in the presence of a. sulphite
which is itself being oxidized to a sulphate.
According to the classical nomenclature of Kessler, we
may consider this induced reaction in two steps:
2S03=_ + 02 = 2S04=_ f inducing reaction)
2As03= + 02 = 3A.'-o4= (induced reaction)
.. .... : . , .,
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- 42 ~
Such coupled reactions have a common component (o, in this
case) called the actor. The material in the inducing
reaction which reacts with the actor is called the inductor
tS03 )> and the substance which thereby undergoes chemical
changes in the induced reaction is called the acceptor
I a so 3 ). If we deiine a term called Induction factor which
is the ratio of oxidized equivalents of the acceptor to
?S ^e^eqU^lentf of *he induct0^ ** n»y observe that
the greater this value becomes the more nearlv catalytic
the reaction appears to be. Thus, the fields' of induced
reaction and catalytic reaction tend to merge. inauCccl
An example of an Induced reaction with a high induction
?n arilSnnnn°Xf U°n °f 0X?11° a°id by mercuric chloride
Un a solution 01 proper concentration this does not occur
+L m!??Urabj2 r"te) induced *V the oxidation of some of
le ° J aCid by Permanganate. In the presence of a
trace of permanganate a copious precipitate of mercurous
chloride is soon formed (14).
4. Induced Precipitation and Solution
A substance which would not normally precioitate under
iveri set of experimental conditions will sometimes
precipitate with another substance. The ohenomenon
given set of experimental conditions will sometimes
precipitate with another substance. The ohenomenon is
nn«ieSiin?!JC!^?!:;0iP"at,loe: inversely" it is occasionally
22l5hSe^° eff6Ct thG SOlUtl°n 0f » BUbstancrnot normali;
soluble in a given reagent by simoly allowing the reagent
It^nTl i1^ a.mi^ure of «iat substance and another^sub-
stance soluble in the reagent.
An example of induced precipitation is the crystallization
acetate EH*?*} f "»«****» ** noetic acid and ammonium
acetate by the formation of a trace of barium sulphate in
une solution. *
The phenomenon of induced solution is shown by the ability
of a solution of dilute nitric and tartaric acids to dissolve
completely and rapidly an alloy of tin and antimonv? Tin
alone gives ineta stannic acid.
References:
• P lel&} p2d Frankel, Ber., 65, 544 (1932).
* New fokfl^^^f Engl_' E^' N°rdemPnn P^ishing Co.,
3. K Hofroann, Bera '45* 3329 (1912)
t Fr^gi^o^Cii.^p.'ei?61'-6^ Ber" &> 1658 (1913)-
%* v* ^b?1/z- ^lectrochem„/l9, 430 (1913).
o t# d1!1' h. ^gew* Cheme,~|4, 741 (1931),
t ^Iew3Yok!h1938rpal2lf ntatlVe ^X**^> McGraw-Hill Bool: Co.,
9. F, Raschig Ber' 48, 2088 (1915).
■?• :> IfiZ1* OP- Cit.^T. 195 ff.
Ej* khn nn2a?°?ivSC^ Ehem' At>str 25, 5640 (1931).
B. jahn and Leinback, Ber., 55, SO^0~Tl922) ;
f SheSrfe^S?uttgertt2il5Fn "^^ ihre ********* «*
g- *• *eigl z. angew.Chem., 43, 550 (1930)
I, A.^zerwefc, Z anal. Chen' ~To, 505 (1906).
Boec-'fic fln^qHSiy?1? expellenT^discueslon of this sublect by F FptpI
$40", p? 65 ff?" factions, Slseview FublishinJ So. ,J Newport:, ^"
•
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• ■■■±c--
THE BORON HYDRIDES
Margaret Kramer January 9, 1945
I. Introduction:
About 1810, Davy noticed that the mass obtained in the
preparation of boron by reduction of B205 with potassium when
treated with water or dilute HC1 produced a gas which was mainly
hydrogen, but which has a disagreeable odor end which burned with
a blue flame tinged with green* Wohler, H„ St.C. Deville (1858),
and Koissan (1893), among others, tried to prepare boron hydride by
action of dilute HC1 on aluminum boride or by direct union, or by
other means, but without success(lO).
Jones (1879) obtained a mixture of the hydrides by treating
magnesium boride with acids. In 1901 Ramsey end Hatfield dem-
onstrated the gas was a mixture of severrl hydrides condensed by
liquid air (13).
From about 1912 until 1931 most of the work on the born hydrides
was done by Stock and coworkers (19). Since 1931 other investigators
have entered the field, and their further work has resulted in im-
proved methods of preparation for the hydrides aa well as an
elucidation of their structures.
Since boron is a trivalent element, it a simplest hydride should
be BH3. Such a compound has not been isolated, however, the
simplest boron hydride capable of independent existence being B2H6.
In certain chemicrl reactions B2H6 gives evidence of being composed
of BH3 units. Burg and Schlesinger (b) have noted that linkages
between boron atoms seldom occur in compounds of boron with elements
other than hydrogen* The tendency for such linking is so strong
that BH3 does not exist.
According to older theories of valency, boron should form hy-
drides of the general formula BnHn+2(l6). The boron hydrides now
known are B2H6 , 34H10,, B5H,t, B5H1:L, B6H1o, and B10H14. Such a
generel formula does not apply.
The advent of the electron theory of valency did not at first
improve matters. If one assumes B2H6 to have an ethane-like struc-
ture, 14 valence electrons are required, while B2H6 can muster only 12t
The result of this abnormality has been increased research on
the boron hydrides, their chemistry and their structures*
II. Preparation:
The first hydride prepared by Stock, Using a special technique
involving high y&cuum end low temperature distillation, was B4H1<5.
The yield was rather smell, and other heavier hydrides of boron were
in the reection product as well (19).
6Mg + B203 > Mg3B2 + 3Mg0
Mg3B2 -IQ&HCL^ b4H1o + traces of B5H« , B6Hl0, BlcH14 (26)
■ '*
i
'
i U P-
•
•
■ '■■ '
.
■
1
t*
B
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... •
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. *
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,9'! b OCll I
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-44-
Wlberg and Schuster found that 8N H3PO4 increa»ed the yield from
about 4/fo to 11$ (28). Upon heating at 100°, the hydride forms B2H6
and small amounts of BBH«j and B1oH14 (7).
A second method for the preparation is:
BsHu — 1QQ2-— > BftH,0 + B2H6 (4)
1.5 atm. §5f0
B. B2H6 is most simply prepared by action of hydrogen on boron
trichloride under suitable conditions (3).
Pure hydrogen is bubbled through liquid BC13 at -40° C. and
the resulting mixture is passed through a 12-15 kilovolt discharge
formed between water cooled copper electrodes. The pressure is
maintained between 5 and 10 mm. The products are much unchanged
boron trichloride and hydrogen, together with B2HSC1 and a small
amount of B2H6. The mixture is condensed from excess hydrogen and
fractionated to remove HC1. At fir pressure of 2 mm. at 0°C, B2HSC1
decomposes:
6B2H5C1 ^=~±. 5B2H6 + 2BC13
rhe dlborane is removed as fast as it is formed. Fractions rich in
lydrides are further fractionated and the resulting B2H6 is finally
purified by vacuum distillation at -150°C.
The method may be Improved by using 8Br3 instead of BC13, the
resulting HBr being more easily removed. BBr3 is lese volatile than
3C13 (122). Yields as high as 80$ of the hajide reacting have been
reported.
C. Other boranes are prepared by heating 32He under suitable con-
litions. .
B2H6 —HE— ^ H2 + B4H10 + BBHX1 (4)
(Main product )
B2H6 -hig^yac^ n^ + ^ (23,
250°-300 (Haln product)
Hg vapor
B2H6 ££ale.d_tube * B H (19\
6 160°, slightly above atmosV * x° K }
pressure.
vaouum
JeHio was prepared by Stock and Massenez (24) in small quantities
'rom the crude gas appearing upon decomposition of magnesium tooride
/ith acid,
, Properties (see table 1):
A. Thermal stabilities
1. 3gH|i least stable.
35Hix -* 38H6 + H4Hxo + H2 + B5H<, + 31(£14 (4)
■ISO'
»
', ' ■ ■
*
V '
B Jbr ' --W
" •'
, + 'I *K»S *
< . ': »
-r.
Lfg I *
.1 ..•• ■'
< • ?•
mi ,
, i i Bittd-gflS ox
.4
8HsS
i
• ■■- - ••
ua
as
- 45 -
2. 32Ha, stable, decomposes at 100° or above.
B2H6 -^> B4H10 + BBHXX + BBH<, + BX(,H14 (2)
3. BeHlo iinWli > 3aHs + H2 + BaiH9i (20)
° temp.
4. B5H9, stable uo to 150°. (16)
5. BxoHX4, stable* up to 170°. (16)
3. Chemical reactions (16, 19).
1» Oxygen
B5HX1 and BgH? burn spontaneously at ordinary tempera-
tures. BXoHx4 explodes at 100°. 3eHXo is only slowly
affected by air/ 33H6 and B4Hl0 react above room
temperatures. The products of the reactions are of
indefinite Composition.
2. Water
The boron hydrides are hydrolyzed by water to produce
boric acid and hydrogen.
The mechanisms of the reactions have not been
established. Wlberg suggests no less than 10 steps in
the reaction of diborance with water. Of the 9 com-
pounds formed, 5 are unknown, and 3 are hypo the tical
(16, 29).
3. Halogens (19)
Diborane, stable pentaborane, and decaborane react with
the halogens to produce substituted boranea.
4. Hydrogen halides (19)
Diborane and tetraborane react with hydrogen halides
to produce substituted boranes. The reactions proceed
in the presence of aluminum chloride.
Stable pentaborane and decaborane do not react.
5. Ammonia (16, 19).
Under carefully controlled conditions, diborane reacts
to produce a dl ammonia derivative:
32H6 + 2NH3 _sl§2-S> B2HS.2NH3
For this compound the structures (NH4 )2(H23;: BH2 ) and
H
NH4 HaBrN-.BHa
* •
H
Upon heating, the two products produce 33N3He, with a
ring structure.
6. Metals (16)
Sodium, potassium, and calcium react with diborane to
give compounds of the type M232H6, where M is a mono-
valent metal. 3VH10 reacts with sodium. 32H5I reacts
also with sodium.
32H6I + 2Na -> 34H1<3 + 2NaI (125)
l) •aK*
•
8 .5
.1
■
a i c Ul
■
■
■
-
7.
- 43 -
Metallo boronhydrides (6, 15, 17)
These are prepared by action of
pounds of lithium, beryllium, and
2CsH5L:t + 233H6 ^ Li3H4
33H8 on alkyl . corn-
aluminum*
+ (C8H5 )a.3aH4
3.
Coordination compounds (8, 16)
At relatively low temperatures 32He reacts to produce
coordination compounds of borine (BH3). The following
compounds react to form the coordination compounds:
(CH3)3N, CH3NHa, (CH3)8NK, CO, (CH3)20, PH3, CH3C1I, and
C6H5N.
IV* Structure
A, Sidgwick has proposed single electron bonds in the structure
of B8H6 (18). H H
B:3 : 3:H
H H
B. Pauling cossiders such a structure possible under the following
conditions: "a stable electron bond can be formed only when there
are two conceivable electronic states of the system, with essentially
the same energy states differing in that for one there is an unpaired
attached to one atom and for the other the same unpaired
is attached to the second atom" (14). Resonance produces
molecule.
electron
electron
a stable
H H
H:s: b:h r=»2*
H H
H H
H;5:3:H +
#
H
H
H and R;?i 3tU + H*
H H
C» 3auer (2), using electron diffraction methods concludes that
diborane has an ethane-like structure, tetraborane a butane-like
structure, unstable pentaborane either a pentane- or iso~pentane-
like structure. Stable pentaborane was assigned a methylene
cyclobutane structure. Hexaborane is said to have a dimethyl-
clyclobutane-like structure. Decaborane is said to have a double
4>-membered ring with DH3 groups at the two ends:
oo-
D. Nekrasov (11, 12) considers tftie hydrides to be coordination
compounds held together by ^^ H * % linkages.
f ' ^ ^ h --'
Longuet-Higgins and !3ell suggest S 3
IK
linkages
01.
Wagner discounts the ethane structure for diborane, suggesting
instead an ethylene-like structure (27).
H83H83H8.
+
3X
.
.?
. ■
.
oo ■
}
ibnod a
•'
•■
A
!
o
■
: ■
§
;.■;•'
- , J :
'.
,. .*,
: V ' '
•
.' *
3fl3 3D
»•
'
1 1 J
•
- 47 -
TABLE 1 (16)
PHYSICAL CONSTANTS OF THE BORANES
Name
Molecular
Formula
Di
snsity
Melting
Point
°C
Boiling
Point
°C
r
Vapor
Pension
Mm
Diborane
BgHg
0.577(-183°C)
0.477(-112°C)
-165.5
-92.5
2251
[-119. 9°C)
Tetraborane
B4H10
0.56
(-35°C)
-120
18
388
(0°C)
3table
Pentaborane
B5H9
0.61
(o°c)
46.6
48
66
(0°C)
Jn stable
Pentaborane
BgHj,!
-123
63
53
(o°c)
■lexaborane
BqH10
0.69
(0°C)
- 65
7.2
(0°C)
Decaborane
B1o H14
0.92
0.78
(99 °C)
(100°C)
99.7
213
19
(100°C)
Soc. 53,
Soc. 55,
Soc,
Soc
55,
62,
4321
4009
4020
3425
BIBLIOGRAPHY
Bauer, S. H. , J. Am. Chem. Soc,, 60,, 805 (1940).
Bauer, S. H. , Chem. Rev. 31, 43 (1942).
Burg, A B., and Schle singer, H. I., J. Am. Chem.
( 1931 )«
Burg, A B., and Schleslnger, H. I., J. Am. Chem.
(1933).
Burg, A B., and Schleslnger, H. I,, J. Am, Chem.
(1933).
Burg, A B., and Schleslnger, H. I., J. Am. Chem.
v J.y4U ) .
Emeleus, H.J., Annual Reports on the Progress of Chemistry, 139 (194C
Gamble, E. L, , and Gilmont, P. L., J. Am. Chem. Soc. 62, 717 (1940)
Longuet-Higgins, H.C., and Bell, R.P., J. Chem. Soc. "§50 (1943).
Mellor, J.W. , Comprehensive Treatise on Inorganic and Theoretical
Chemistry. Vs5, 33 (1922-193TT
Nekrasov, B.V. , J, Gen. Chem. (USSR) 10, 1021 (1940).
Nekrasov, B.VC, J. Gen. Chem. (USSR) 10^1156 (1940).
Partington, J.R. , A Textbook 'of Inorganic Chemistry. 7720 (1933).
Pauling, L., J. Am. Chem. Soc. 53, 3225 (I93l4.
Schleslnger, H.I., and Brown, HTcT. , J. Am. Chem. Soc. 62, 3429 (1940 )
Schleslnger, H.I., and Burg, A.3., Chem. Rev. 31 t 1 (l$42).
62eSln|erf V Sanderson' R*T«> and BurS> ^B>* J- Am« c.hem* Scc>
Siafwick, N V. , The Electronic Theory of Valency. 103 (1927).
Stock, A., Hydrides of Boron and Silicon, T~
Stock, A.
Stock, A
Stock, A;
Stock. A.
Stock! A.
Stock, A.
< 1933;
ana Kuss, "T. , ber. h6B, 789 (1923)
Martini, H. , and SuTCerlin, W. , Ber. 67B, 396 (1934).
Martini. H. , and Sutterlin, W, , Ber. W7E, 407 (1934 .
and Ma thing, W Ber. 69B, 145<d (l936-p~
and Massenez, C., Ber.~7F5\ 3529 (1912)
and Pohland, E. , Ber. 59F, 2215 (1926
as&rS!?^s%ss5B^.H^^^r;(a,*'» 32 (i93o)-
»i
iber
5, E. and Schuster. K., Ber. 67B, 1805 (1934).
!p E. , Ber. 69B, 2&16 (1936)
■
snai
snBTc
•X
enBii
s
66 -
(0
*
snsT
. .9 «A t
£>ns
t.a oA t8«iu
•
■
Ji>flB , .a .A t§;
ib t.a .a .g
ijh ■!■ ■
TT'
.(V99I) 501
•
.§*
-
9Q.
■;3T*£>nB < .A ,
iflM , .i
.In
£>HB
-..- -
6 . #A ,'
P8 tj§ tSK*^"_ «»A
- 48 -
A SURVEY OF INORGANIC NITRIDES;
PROPERTIES, PREPARATION, AND REACTIONS
Lawrence J, Edwards January 16 , 1945
I. General Consideration.
The affinity of nitrogen for other elements Is not mani-
fested at ordinary temperatures, but on heating combination often
occurs. Combination of a metal and nitrogen is usually exothermic,
whereas the formation of a non-metallic nitride is the result of
an endothermic reaction (23). The formulas of the nitrides, in
the cases where they have toeen definitely established, are
usually those which are to be expected from the ordinary valency
of the second element and the tri-valenoy of nitrogen.
Consequently, nitrides can be regarded as salts derived from the
anhydro-acld ammonia.
EI. Various Methods of Preparation and General Properties.
1. Direct Combination.
Generally, direct combination takes place at moderate
or high temperatures with the element or amalgams of the
element. Thus, Li, Mg, Ca, Sr, Be, B, Al, Sfi, Ti, Zn, V,
Nb, Cb, Ta, Cr, U, Hn, and some of the rare earths have
been prepared by this method. Lithium is rafiher unique in
that it gives the nitride at a red heat (21) (10) and even
in the cold (3). Amalgams of the alkaline earths are heated
in atmosphere of nitrogen (17). Metallic Lanthanum absorbs
nitrogen but sometimes in no definite proportions (20 )c
The nitride of these reactive metals are dark powders easily
hydrolyzed by cold water (9) (18). Ti, Ta, Zr, Hf and Cb
nitrides conduct an electric current without decomposition
and because of their high melting points, they are suitable
for arc lamp electrodes or for cathode tubes or discharge
tubes (1).
2. The Action of Carbon and Nitrogen on Oxides.
"~5lN Is formed when aluminum oxide, mixed with carbon,
is heated to a high temperature in a current of nitrogen.
However, this procedure sometimes gives in addition, cyanide
and cyanamide (9).
3« The Action of Gaseous Ammonia on Metals or Their Oxides.
When ammonia is passed over cupric or cuprous oxide
at 300*C, a nitride, having the composition Cu3N can be
separated (2). However, Using zinc dust and ammonia, the
product contains less nitrogen than is required by the
formula Zn3N2 (20). Nitrides of Fe, Ni, and Co giv$ variable
compositions (2 )(4) (7) (19).
4* Tne Decomposition of Amides and Imldes by Heat,
Each of the Intermediate compounds has been isolated,
and the conditions of the successive changes determined in
the case of arsenic (13).
2As(NH?)3 0lg-§4 As2(NH)3 + 3NH3
As3(NH)3 -2§Q^, 2ASN + NH
3
'
.
!
vi 9 rig
3t
-
obne fiB
•3 so e
ia ©rid' 1o
■
giM bjjo^ibV »
.
sdd
b nl
In
s io1
BJt
HB
- 49 -
5. Action of Aqueous Ammonia.
Aqueous "amnionic, at ordinary temperatures converts the
oxides of silver arid gold into the explosive nitrides,
Ag3N. Au3N, and Au3N3.'
6» R^lltJS.njL iH kll^lil Nitrogen,
The Strides of tin, lead and cadmium have been
pre]
the
spared by passing an electric arc between electrodes of
t metals immersed in liquid nitrogen (5* (6).
7. Heap fc ions jM? Liquid Ammonia,,
""L'oible dsooppo sit ions which occur between halides and
amides In liquid ammonia generally yield complex double
amides, frequently with ammonia of crystallization (8).
Bt3r3 * 3KNHa ^ EiN + 5KBr + 2NH3
®» 2-llSl A^l'fron of Dry Ammonia on Anhydrous Chlorides,
" Th'io type of reaction is applicable "more to the
chlorides of the non-metals, and especially those of Groups
give and six of the periodic table.
■^
II. Miscellaneous,
!• Transition vs. Non-Tran s i t io n Elements.
Hagg (11 ) found that binary compounds between metals
and nicrogen had metallic properties when the metal is a
transition element; non-metallic properties are shown when
the metal is not a transition element. Klemm and Sohuth
(14) found similar results from magnetic susceptibilties.
In the series of elements from Scandium to Nickel with
increasing atomic numbers, the stability of the compounds
formed between these elements and nitrogen decreases. In
the transition elements, if the ratio of atomic radii
(rm/rn) is greater than 1.7, the structure becomes more
complex, the smaller the radius of the metal ion (12).
Vanadium iron, copper, and tungsten do not absorb nitrogen
up to 125°, molybdenum absorbs only a small amount. The
absorption of nitrogen begins at 780° for Mg and Ca, at 800°
for Al and Cr, at 850° for Mn and at 900° for Ti (28). Mg,
Ca, and Al give nitrides with definite formulae, while Ti,
Cr, and Mn seem to form solid solutions of nitrogen in the
metal.
2« Rate of Reaction and Heats of Formation.
The- extermination of the rate of reaction, of the
formation of a nitride by "direct combination" is based upon
the color changes of the metal in contact with the gas (24).
By plotting a curve of the known heats of formations of some
of the nitrides against the corresponding atomic number,
the heats of formation of some of the less easily determined
nitrides can be obtained by interpolation (15).
3« Decomposition Pressure and Temperature.
Lorenz and Wool cock (18) measured the decomposition
pressure of BN between 1685 and 2045°C. They found the
reaction to be reversible and by plotting Log p vs. l/T,
they got a straight line. Similar investigations with
• \
■
IA «
■
. ...
- 50 -
yranlum rnd nitrogen Indicated the formation of U5N4 and
U5N2. An investigation conducted by Voznesenskil (25)
showed that the more simple the composition of the nitride,
and the smaller the atomic volume of its nitride, the
higher is its decomposition temperature and consequently
the more stable it is to the aatlon of various reagents.
4. Phosphorus Chloronltrides.
When an equlmolal mixture of phosphorus pentachloride
and ammonium chloride are heated together in a closed tube
at 150°, a curious series of compounds is formed, the general
formula of which may be designated by (PNCla)n,. where n =
3, 4, 5, 6, 7 and higher (22}(27). All members of this
series seem to be non-polar in character. Due to symmetries
in (PNCla')e <?-nd (DNC1S)7, these two compounds have remark-
ably low melting points. This series of phosphorus
chloronitrides reacts only slowly even with boiling water.
The rate of hydrolysis can be increased by the addition of
a little ether to the water. Upon hydrolysis, these
compounds yield hydroxy derivatives fPN(0H)aJ n.
References.
1. Agte and Moers, Z. anorg. allgem, Chem. 198, 288 (1931); Cf Af
25, 4480 (1931).
2. Beilby and Henderson, J. Chem. Soc. 71, 1252 (1901),
3. Beslandres, Compt. rend. 114, 120 (1892).
4. Despretz, Ann. chim, Phys. 42, 122 (1829).
5. Fischer and Ilionicl, Eer. 4T, 3802, 4449 (1908).
6. Fischer and Schroter, ibid., 43, 1465 (1910),
7. Fowler, J. Chem. Soc, 79, 285~Tl90l).
8. Franklin, J. Am, Chem,~goc. 27, 220 (1905).
9. Friederich and Settig, Zeitsch anorg. Chem. 143, 293 (1925);
C. A. 19 1669 (1925).
10. Guntz) Compt*.' rend. 12C, 77 (1895).
11. Kagg, Z. physik. Chem. B6, 221 (1930); 0. A, 24, 1591 (1930),
12. Hagg, ibid., B12, 33 (1731); Ct A. 25, 2615 TT931),
13. Hugot, Compt. rend. 139, 54 (1904).
14. Klemm and Schuth, Z, anorg. allgem. Chem. 201, 24 (1931); 09 A*
26, 887 (1932).
15. Kroger and Kunz, ibid.. 218, 379 (1934); C. A, 28, 7134 (1934).
16. Lcrenz and Woolcock, ibid. 176. 289 (1928); C, A, 23, 1343 (1929)
17. Macquenne, Compt. rend. 1147^5 (1892).
18. Hontemartlni and Losa^a, Grom. ch'im. ind. applicata 6, 323
(1924); C. A. 18A 3329 (1924).
19. Mute and Klrschbraun , J. Am, Chem. Soc. 28, 1343 (1906),
20. Muthmann and Kraft, Ann, 325, 231 (1902).
21. Ouvrard, Compt. rend. 114, 120 (1892),
22. Stokes, Am. Chem. #. 19, 782 (1897)
23. Strutt, Proc. Rcy. Soc. 85, 219 (1911); 87, 180 (1912)..
24. Tammann, Z. anorg. allgem. Chem. 124, 25~Tl922); C.. A. 17, 14
(1923).
25. Voznesenskii, J* Rusp. Phys. Chem, Soc. 61, 1323 (1929); C. A.
24, 4902 (lr-50).
26. White and Kirsofebraun, J. Am. Chem., Soc. 28, 1343 (1906).
27.. Yost ?nd Russell. "Systematic Inorganic CHemistry", Prentice-Hall
New York, 1944, p. 108,
28. Zhukov, J. Rus . Phys. Chem,' Soc. 40, 457 190); C,A„ 3, 871 (1909)
•
\
,
.
viinr>
^ |S
.8
2 ,A
.s
A ,1
r \ r
,a
■
til .8
.01
,11
-
X .M
,
*6i
1
■
§ej
I
-51-
ROLL CALL
January 23, 1945
Hydrides of Aluminum and Gallium Therald Moeller
For many years the boron hydrides have been regarded as
unique among the covalent hydrides because of lack of sufficient
electrons for the formrtion of complete series of electron pair
bonds. Recent reports of the preparation of a volatile gallium
hydride, Ga2H6 (l, 2); and a non-volatile polymeric aluminum
compound of composition (A1H3)X (3) would indicate this phenomenon
to be general among at least the beginning members of Periodic
G-roup 1 1 lb.
Preparation of the gallium compound (l, 2) involves reaction
of Ga(CH3)3 with H3 in a glow discharge to produce Ga2H2(CH3)4
which' in turn reacts with (C2H5)3N to give Ga(CH3 )3.N(C2H5 )3 and
Ga2H6. The latter compound solidifies rt -21B4°C. and boils, with
decomposition, at 139° C.
Preparation of the aluminum compound (3) is similar tn that it
first involves the reaction of Al2(CH3)6 with H3 in p glow discharge,
A complex mixture of volatile and non- volatile components results,
from the volatile portion of which Al2H2(CH3)4 can be separated.
Treatment of this material with (CH3)3N yields Al(CH3)3#N(CH3 )3
which, on heating, eventually gives &LH3)X, a white, non-volatile
solidj stable to 100°C, , but decomposing at higher temperatures
to Al and H2.
References:
1. Wiberg and Johannsen: Naturwisscnschaften 29, 320 (1941).
2. Wiberg and Johannsen: Die cher.ie 55, 38 (1942)..
3. Stecher and Wiberg: Bee 75, 2003 (T§42).
-52-
ROLL CALL
January 23, 1945
Report on the "Industrial and Electrochemical Conference" held In
Chicago, January 19, 1945,
John C. Bailar, Jr.
This conference, sponsored by the Chicago section of the
Electrochemical Society, was designed to convince businessmen of
the possibilities for a postwar electrochemical industry in the
midwest. The early talks dwelt on Chicago as 8 manufacturing
center rnd on its power supply.
Dr. Harold Vagtborg, President of the Midwest Research
Institute, predicted the growth of many such institutes to serve
the smaller companies that can»t economically have research
laboratories of their own. According to him, there are less than
3000 companies in the United States which ard doing research,
although there are 180,000 which might well undertake research
programs. Before the war, 0.5$ of our notional income was spent
on research, but the Russians were spending 1$ of their national
income.
The outstanding talk of the conference was given by R. 3. .
Wittenberg of the International Minerals and Chemical Corporation.
He spoke of the five M» s of the chemical Industry — management,
money, men, markets, and materials — and told of the importance
of each in locating a new chemical industry. The first two are
relatively unimportant in this regard. The chemical industries
do not require a great quantity of labor, but the quality must be
high, so new industries should be located where intelligent,
educated labor Is available. Markets and materials, of course,
play a large role, and may well be determining factors. Even 'in an
elect rochamiical industry, power may be of secondary importance.
This conference has been described in some detail in Chem.
and Eng. News. 23, 238 (1945).
,
-» 5o *-»
ADDITION COMPOUNDS OF THE ALKALI
METALS AND THEIR STRUCTURES
Hans Jonassen February 20, 1945
One of the outstanding properties of the alkali metals is
their extremely slight, tendency to form complex ions* One of the
first coordination compounds of these metal ions is reported by
Perkin and Flant (l) who isolated a sodium derivative of indoxyl-
spiro cyclopentane. Sidgwick and Plant (2) continued this
investigation of alkali complexes with indoxylsplro cyclopentane.
They succeeded in isolating an unstable derivative with lithium
and stable derivatives with sodium and potassium and assigned the
following structure to these complexes:
^
;
N"
[CHjs C^ ^M<^ . J> [CH8] 5 ~Y
All these complexes decompose in the presence of excess water,
Sidgwick and Brewer (3) extended this work; they were able to
prepare numerous solid alkali derivatives with organic molecules
containing two electron donor groups. They divided these compounds
into four groups with the following structures, X = C or N
(i) /yx-\
X M
Nx-o^
X M X
x = o X0 — X^
(III)
v — ir\
X— 0 H
(IV)
*\
X
\
0
X
\\
0
X
-^n-^M
.0 = X
x-q
/
X
^
X
H
These authors state in their discussion that compounds having
structure I are true salts since they show no definite melting
points and since they are insoluble in nonhydroxylic solvents.
A typical compound of this group is the sodium salt of benzoyl
acetone:
0 —> M — 0
// \
$— C CH = C-CH3
- 54 -
Compounds having structures II, III, and IV are coordinate covalent
compounds since they are soluble in organic solvents and shew
definite low melting points* Typical compounds of these groups are
the dihydrated sodium salt of benzoyl acetone:
H H
HO OH
\y
0— *M — 0
0 — C"-CH=C-CH3
and the addition compound of sodium and two salicylaldehyde
molecules
^— 0
Na
\S
y
/\
c~o
S. X
o=c
H
\y
Brewer (4) extended this work to include the most active alkali
metal ions cesium and rubidium. He prepared several new addition
compounds of these ions with organic molecules, especially salicyl-
aldehyde. In his conclusion Brewer givew a tabulation of all the
important addition compounds of the alkali metal ions. The most
important contribution of Brewer is that he was able to show that
the coordination number of the alkali metals increases in these
compounds as would be expected from the Increase in their ionic
sizes.
The addition compounds of 3 alanine prepared by King and
Rutherford (5) are of a slightly different type since in these
complexes both the positive alkali ion and the negative Ion add.
Brady and Badger (6), extending the work of Sidgwick, found
that in absolute alcohol a compound is formed between sodium ion
and salicylaldehyde and ethyl alcohol molecules; they tentatively
assigned it the following formula:
In the course of dye investigations, Brady and Porter (?) #er&
able to prepare extremely stable addition compounds of all the
alkali metal ions with 4-isonitro-l-phenyl-3-methyl-5-pywaolone,
These compounds are extremely stable in water, soluble in organic
solvents.
Hogson and Batty (8) continued this work and reported
isolation of sodium addition compounds with 2-nitroso-5-me
phenols and with some of their substituted derivatives.
the
thoxy-
During their investigations of the structures of dl-2-hydroxy-
1-naphthyl sulfide and the corresponding methane, Smiles and
coworkers (9,10,11,12) were able to isolate hydrated alkali
derivatives of these compounds* Due to its theoretical interest
- 55 -
this work was extended to include substituted benzenehydroxy
sulfides and related compounds.
Discussion of Structure
In all these papers and the subsequent reviews (13, 14) these
compounds are considered to be chelated inner complex compounds
with coordinated covalent linkage. However, many experimental
facts cannot be explained if such simple linkage is assumed. Most
experimental facts seem to indicate that the linkage in these
addition compounds is much more complex. They seem to indicate that
the linkage in these compounds is ion dipolar rather than coordinate
covalent. A few of these facts which seem to substantiate this
are given below:
(1) Benzoylacetone does not form addition compounds with
potassium, rubidium and cesium because their relatively large
radii decrease their polarizing powers.
(2) Sodium and lithium form tetrahydrates with 2-di-hydroxy-l-
naphthyl sulfide, selenide, and methane whereas potassium and
rubidium only form dlhydrates.
(3) In the benzene hydroxy sulfides alkali addition compounds
are formed only when the 6 methyl group is present. Since the
methyl group is an electron repelling group this increases the
electron density in the 1 position. This, in turn, increases the
attraction of this position for the hydroxylic proton, which then
favors the ketonic form of the benzene hydroxy sulfide. If the
alkali derivative formed were purely coordinate covalent it would
make little difference whether the ketonic or enolic form were
present, because in both cases unshared electrons are present in
the outer orbit of the oxygen atom. If, however, ion dipolar
linkage is involved the ketonic form should form a much more
stable form because its dipole moment is much larger. There is,
however, a further factor which has to be considered in the
formation and stability of these compounds — the size of the
cation and the distances between the" coordinating group in the
molecule whioh adds* A consideration of these factors explains
for example, why lithium does not form a stable compound with
indoxyl spiro cyclopentane*.
Sidgwiclds statement that solubility in organic solvents is a
criterion for covalency is not necesssrily valid. It can also be
explained if a "lock and key" arrangement is assumed similar to
that mentioned in Crlasstone's article on intermolecular complexes
(15), If such an arrangement is assumed, the Inorganic part of
the molecule would be completely hidden by the much larger organic
molecules surrounding it. This explains also why compounds having
structure I (cf. p. 53) are insoluble in organic solvents whereas
compounds having the other structures are soluble.
The experimental facts discussed in the above part seem to
indicate quite clearly that the linkage in the addition compounds
of the alkali metal ions with organic molecules containing two
electron donor groups is not as simple as maintained by Sidgwick.
r
i
- 56 -
Bibliography
1. Parkin and Plant, J. Chem. Soc, 123, 676, (1923).
2. Sidgwick and Plant, ibid. 127, 209 (1925 ).
3. Sidgwick and Brewer, ibid, 127, 2379 (1925),
4. Brew, ibid, 1931: 361.
5. King and Rutherjford, ibid, 1931, 3131.
6. Brady and Badger, ibid, 193,2, 952.
7. Brady and Porter, ibid, 1933, 840.
8. Hogson and Batty, ibid, 1935, 1617,
9. Evans and Smiles , ibid, 1937, 727,
10. Smiles and McClement, ibid, 1937, 1017,
11. Smiles and Shearing, ibid, 1957, 1933.
12. Smiles and Dvorkovitz, ibid, 1938, 2022,
13. Ann. Repts„ Chem, Soc., 30, 88 (1933).
14. ibid,, 35, 165 (1938).
15. G-lasstone, Trans. Far. Soc., 35, 200 (1957).
f »■
- 57 -
ADSORPTION AND SURFACE IONIZATION ON TUNGSTEN
C. R. Keizer March 6, 1945
I. Introduction
A. Definitions
1. Adsorption — the process in which molecules or atoms of
a gas or vapor become more or less firmly bound to the
surface of a solid.
a. adsorbent — the solid upon which the adsorption
takes place.
b. adsorbate — the gas which is adsorbed.
2. surface ionization — the process in which molecules or
atoms of a gas or vapor are ionized under the proper
conditions upon contact with a solid surface.
B. Properties of tungsten which account for its use as the
most common adsorbent (l, 2, 3, 4)
1. in powder form
a. available in rather pure, uniform samples or
easily prepared by reduction of the oxide
b. high sintering temperature permits reduction and
degassing at 750° without Irreversible alteration
of the surface structure,
2. in the form of filaments or wires
a. easily cleaned — heating electrically (flashing)
to a very high temperature for a few seconds frees
surface from all contamination and eliminates
gases from interior.
b. temperature may be easily measured
1) current-voltage characteristics (5)
lead-loss corrections (6)
2) optical pyrometer (7)
c. stable at high temperatures — can be heated in
vacuum for considerable periods of time even at
3000° K. , at which temperature all other sub-
stances vaporize.
d. electron emission serves as a sensitive indicator
of the presence of adsorbed films. (8)
6. temperature may be easily ar}d rapidly changed.
f. chemical stability
g. other properties not as directly applicable
1) vacuum-tight seals to glass
2) strength
3) ductility
4) connections to other metals
II. Adsorption (9, 10)
A. Types of adsorption
1. physical adsorption — weak interaction between solid
and gas; essentially surface condensation; also called
van der Waals, low temp, and secondary adsorption.
2. chemical adsorption (chemisorption) — strong interaction
between solid and gas; essentially surface reaction;
also called activated, high temperature and primary
adsorption.
Sf'x'3
«:-
■v:'
. . . • ..,
[I .1
•'-".:
•'■ .- • t " ' r
,«
-
- 58 -
B. Experimental Methods
1. Measurement of amount of adsorption
a, direct
1) volumetric
2) gravimetric
b. indirect
1) thermionic emission
2) photoelectric emission
3) reflection of polarized light
4) accommodation coefficient
5) contact potential
6) electron diffraction
2. Measurement of specific surface of adsorbent
a. chemical
b. physical
c. optical
d. electrical
3. Measurement of heat of adsorption
4. Presentation of data
a. isotherm
b. isobar
c. isotere
C, Experimental Observations and Deductions
1, on gases
a, Langmuir and co-workers (8, 11, 12)
1) used bulb method, W filament at 1500° K.
2) hydrogen decomposed to H atoms, which were
adsorbed on surface of bulb
3) oxygen formed W03 which evaporated from
filament
4) with mixture of H and 0, 0 disappeared
first, Shen H« Oxide film prevented
dissociation of hydrogen molecules.
5) nitrogen and carbon monoxide formed films
similar to oxygen and hydrogen films,
6) second layer of gases adsorbed at higher
pressures
7) Condensation-Evaporation theory developed
to exolain these observations.
b, Roberts (13, 14)
1) used accomodation coefficient for Ne as
measure of adsorption
2) found filament immediately covered with
film of H when exposed to the gas
3) similar chemisorbed layer of oxygen, stable
up to 1700 °C# and second layer unstable
above 60°
c, Frankenburger and Hodler (15)
1), isotherms for hydrogen, nitrogen and ammonia
adsorption on W powder — each formed monolayer,
2) \n mixtures, adsorption uninfluenced by
presence of other gases
3) assumed imide and nitride formation as
intermediates in decomposition of ammonia
:
- 59 -
d. Frankenburg (16)
1) studied hydrogen adsorption on W powder
over wide range of temperature and pressure
2) found saturation only at high pressures
3) differential heats of adsorption calculated
by Clausius-Clapeyron eauetlon
4) at slight coverage H was assumed to be
adsorbed as single H atoms; otherwise as
molecules
5) heat of adsorption- found to be sharply de-
pendent on extent of coverage; explained by
a) heterogeneous nature of W surface
b; differences in state of adsorbed H,
1. for metals
a. Cs studied by Langmuir and associates (8, 12).
These studies led to the recognition of the
phenomenon of surface ionization.
be Becker (17) also studied Gs and Ba and Th.
for Cs slight coverage at high temperatures,
more Cs adsorbed at lower temperatures*
thermionic emission a maximum with surface
Just covered with monatomic layer.
4) at still lower temperatures, still more Cs
adsorbed but emission decreases.
D. Surface Migrations-lateral motion of adsorbed molecules
or atoms over the surface on which they have been ad© rbed*
1. Bosworth (18) studied mobility of Na on W strip
filament
a. measured photoelectric properties of surface
b* found limit to the capacity of the strip to
adsorb Na.
c. exoess Na. stable on surface, spreads or migrates
d. strip becomes uniformly active in one or two
hours at 300° K or 5-10 seconds at 800° K.
2. Becker (19) investigated Ba on W filament
a. measured thermionic emission
b. Ba deposited on one side of W strip, mounted as
filament in thermionic valve
c. emission from bare side was found to increase;
that from covered side found to deorea.se until
rates were equal.
III. Surface Ionization
A. Metal vapors
1. first recognized by Kingdon and Langmuir (20) while
studying the thermionic properties of W filaments
coated with caesium^ later (21) they found the extent
of ionization to be dependent on the condition of the
tungsten surface and developed a theory based on the
Saha equation (22)
2. confirmatory and supplementary observations
a„ Ives (23) Cs on W
b. Becker (17) Cs on W, W-0
c. Killla.n (24) Rb, X on W-~like Cs
d. Meyer (25) K on W, Mo, Ta
* 00 -
ea Althertum, Krebs, and Rompe (26) studying Na
and Cs on W, Re found that the temperature
dependence of yield of Na+ from W agreed with
theory but yield of Cs+ fell below theoretical
value.
f. Morgulis (27) found that the yield of Na+ agreed
with theory at pressures in range 10" 3 to 10"*5
mmt Hg; at lower pressures secondary effects
caused disagreement*
g4 Mayer (28) studying K on Pt and W found yield
of KT lower than that predicted by Langmuir- Sana
theory,
3„ studies at higher temperatures (up to 2700° K) using
molecular beam methdd — Copley and Phipps (29, 30 )c
B9 Metal halides
1. first observed by Roclebush and Henry (31).
2. Phipps and ffo-workers investigated positive ions
a. KC1 with Copley (32) and Hendricks and Copley (33;
b. NaCl with Johnson (34)
c. BaCl8 with Arnett (35)
3. NaCl, KC1. and CsCl were studied by Dukelsky and
Yonov (36), who were interested in the negative ions
produced*
C* Halogens
1. Mayer with Sutton (37) studied iodine; with Mitchell
(38) studied chlorine,
2. Yonov (39) has developed a theory , similar to that of
Langmuir, for the case in which a halogen atom leaves
the metal surfade as a negative ion»
IV. Applications
A, Theory of surface forces of solids.
B. Mechanism of heterogeneous catalysis (40, 41).
BibliograTshy
1* von Angerer, Technlsche Kunstgriff e bei physikallschen Unter-
suchungen, F„ Vieweg und Sohn, Braunschweig, 1939. 4th
Edition, pp. 14, 16, 52, 108, 123.
2f Strong, Procedures in Exoerimental Physics, Prentice-Hall, Inc.
New York, 1942, pp. 23, 544.
3, Li and Wang, Tungsten, Reinholcl Publ„ Corp., New York, 1943.
4„ Hopkins, General Chemistry,, D. C# Heath and Co., Chicago, 1942.
3rd Edition, pp. 684-686. '
5, Jones and Langmuir, Gtn. Elec. Rev,, 30, 310, 354 (1927)«>
6. Langmuir, MacLane, and Blodgett, Phys, Revc , 35, 478 (1930).
7. Forsythe and Worthing, Astrophys. J., 61, 146"Tl925).
8, Langmuir, J. Chem. Soc8, 1940, 511.
"--..
- 61 -
9. Brunauer, The Adsorption of Gases and Vapors, Vol, I (Physical
Adsorption), Princeton Univ. Press, Princeton, N. J, 1943.
10. Smithells, Gages and Metals, J. Wiley and Sons, Inc., New York,
1937.
11. Langmuir, J. Am. Ch'em. Soc., 40, 1361 (1918),
12. Langmuir, Chem, Rev,, 13, 147 U.933).
13. Roberts, Proa, Roy, Soc,, 152A, 445, 477 (1935),
14. Roberts, Nature, 137, 659 TX956'),
15. Frankenburger and Hodler, Trans. Faraday Soc, 28, 229 (1932).
16. Frankenburg, J. Am, Chem. Soc,, 66, 1827, 1838 TX944).
17. Becker, Phys, Rev., 28, 341 (19207.
18. Bosworth, Proc. Roy,"l>QC, , 150 A. 58 (1935),
19. Becker, Trans. Faraday Soc.;' 28, 148 (1932).
20f Kingdon and Langmuir, Phys. Rev., 21, 380 (1923),
21. Langmuir and Kingdon, Proc. Roy. Soc, 107At 61 (1925).
22. Saha, Phil. Mag., 40, 472, 809 (1920).
23. Ives, Phys. Rev., £T, 385 (1923).
24. Killian, Phys. Rev., 27, 578 (1926).
25. Meyer, Ann, Physic, 4, 357 (1930)
26. Althertum, Krebs, and Rompe, Z. Physik, 92, 1 (1934).
27. Morgulis, Physik. Z. Sowjetunion, 5, 22l"Tl934); J, Phys. Chem,
(U.S.S.R, ), 5, 236 (1934).
28. Mayer, Z. Physik, 105, 725 (1937).
29. Copley and Phipps, "Wys. Rev., 45, 344 0934).'
30. Copley and Phipps, Phys. Rev., 4|[, 960 (1935).
31. Rodebush and Henry, Phys. Rev., 39, 386 (1932).
32. Copley and Phipps, J. Chem, Phys«> 3, 594 (1935).
33. Hendricks, Phipps, and Copley, J. CEera. Phys. , 5, 868 (1937).
34V Johnson and Phipps, J, Chem. Phys., 7, 1039 (1939),
35. Arnett, doctorate thesis, Urbana, 111. (194CL).
36. Dukelsky and Yonov, J. Exptl. Theor. Phys. (U.S.S.R.), 10,
1248 (1940).
37. Sutton and Mayer, J. Chem. Phys., 3, 20 (1935).
38. Mitchell and Mayer, J. Chem, Phys., 8, 282 (1940),
39. Yonov, Compt. rend, acrd. sci, (U.S.S.R.) "Doklady", 28, 512
(1940).
40. Griffith, The Mechanism of Contact Catalysis, Oxford Univ.
Press, London, 1936.
41. Taylor, Twelfth Report of the Committee on Catr lysis, J. Wiley
and Sons., Inc., New York, 1940. Chapters III, IV.
■
M- .?
*
- 62 -
THE STRUCTURE OF LIQUIDS
wu*«. < !^E* Horre11 Haroh 13, 1945
wnat is the arrangement of molecules In a liquid? Is It
random, as in gases? Does it resemble the ordered arrangement
found in crystals, being either microcry.stalllne (containing tiny
but almost perfect crystals) or quasicrystalline?
The simplest approach to the problem is through the considera-
tion ox pure liquids composed of non-polar and practically
spherical molecules. Such an approach avoids oroblems of orien-
tation, whether caused by the shapes of the molecules themselves
or by dlpoles, and avoids the cora-olioations that would accomoany
one presence of more than one species of molecule,
The structure of a liquid containing a single species of
spnerical, non-polar molecule can be expressed in terms of a
prooabllity or distribution function W (often called e(r) or f>(r))
W is a measure of the statistical density of moleculeVat a ~"~J^
distance r from any given molecule", 4T raW dr "is hence the
probability of finding a molecule within a distance r to r + dr
of a given molecule" (4), or it is the averse number" of molecules
around the reference molecule in a spherical " shell of radius r
and thickness dr, The total number of molecules within distance
r of the reference molecule is therefore rr.
4>/ Wr3dr
o
The distribution function uniquely characterizes the nolec-
^Gfh2°a ifUr5:?l0n SV \i^idB(^)- All that remains to be "done
is tne evaluation of ■& the distribution function,
of thpGwAvav JJf^0de ?'' •VRltt»*ipnsiav0 been tried,. A general idea
™+?22i *Y T V?rles witl\£ can be obtained intuitively. Mathe-
matical derivations are difficult, and have, in general, yielded
only approximate results (l-9)#
rHffr.f???rlmentaL?^uot;lonfl have in general involved (l) x-ray
diffraction, or (2) the use of models.
Wiar,e ^L;^r!Vsatisfaotory evaluation of the distribution function
! er hi Ky ^^V^^rry diffractions in mercury, gallium
and OCl* by Debye and Menke (16). Their calculations are bane 6 5n
equations derived by Zernike and Prins (1.5),
Various kinds of models have been used. Menke (17) soured
Pn£»in?Ke??e repeatedly onto a flat r-lats. and measured .ana"
CcDuintea che distances between two black spheres. P^ins (10 )
pcu.rect seeds cnto a ^lass plate, photographed them, *nd from
^csuroments obtained from the photograph's, tabulated the relet'"*
.requencies oi recurrence o? the various, distances between seed*
-., ••
■4 *:
"1
- 85 -
Morrell and Hildebrand (11) used three dimensions instead of two
by photographing solid gelatin spheres suspended in a liquid
gelatin medium and thereby duplicated Menkens curve for mercury 6
(Therefore, the atoms in mercury are rrranged much like oranges
in a pile haphazardly dumped into a grocer' s store window. The
oranges in the pile show somewhat more regularity or order than
do the atoms in mercury, however, as the weight and lack of
motion of the oranges causes them to pack relatively more tightly).
Stuart and Kast (12,13,14) went back to two dimensions and
photographed small discs shaken on a glass plate. They added the
effect of dipoles by attaching magnets to the discs.
While the use of models has been helpful, the most fruitful
approach is now through the diffraction of x-rays. By this means,
the distribution functions of quite a number of liquids have been
obtained (15-26). It has been shown that twelve atoms are
adjacent to each atom in liquid mercury (16,17), but in liquid
potassium each atom is directly surrounded by only eight (22).
Lead and bismuth, although they differ in crystal structures,
have identical liquid structures (20). Neighboring plate-shaped
molecules (eag. benzene) tend to have flat sides parallel (26),
Long molecules (e.g. hydrocarbon chains) tend to form
"cybotactic*" groups, small groups of molecules with similar
orientation, . ([Many references by G-. W. Stewart and coworkers. )
The hydrogen-bonded, sponge or .net-work like structure of
water is now, of course, well known, and was elucidated by aid
of x-ray diffraction measurements (18,23).
REFERENCES
Mathematical
1, Klrkwood, J* Chem. Phys". 3, 300-13 (1935).
2. Klrkwood, J. Chem* Phys* 7/ 919-25 (1939),
3.. Kirkwood and Boggs, J. Cher:.. Phys. 10, 394-402 (1942).
4. Bernal, Trans, Faraday Soc, 33, 27-45 (1937).
5. Prins and Petersen, Physica, 3, 147-53 (1936),
6. de Boer and Michels, Physic!.' § , 97-114 (1939),
7. Coulson and Rushbrooke,' Phys. Rev. 56, 1216-23 (1939).
8. Corner, Proc. Phys. Soc. (London) 52, 764-7 (1940)..
9. Corner and Lennard-Jones, Proc. Roy.. Soc. (London) A1781
401-14 (1941).
- 64 -
Models
10. Prins, Naturwlss., 19, 435 (1931).
11. Morrell and Hildebrand,' J.' Chem. Phys. 4, 224-7 (1936)
12. Kast and Stuart, Physik. Z. 40, 714-18 T"1939)
13. Stuart, Z. Electrochem. 47, TTO-12 (1941)
14. Stuart, Kollold Z. 96, 145-60 (1941)
X-Ray Diffraction
15. Zernike and Prins, Zeits." f. Physik. 41, 184-94 (1927).
16. Debye and Menke, Fortschr. d. Tech. Rontgenkunde, II,
(1931).
17. Menke, Physik. Zeits., 33, 593-604 (1932).
18. Bernal and Fowler, J. Chem. Phys., 1, 515-548 (1933).
19. Randall, Trans. Faraday Soc., 33, 105-109 (1937).
20. Randall and Rooksby, Trans. Faraday Soc, 33, 109-10 (1937)
21. Trimble and Gingrich, Phys. Rev., 53, 278 "(1938).
22. Thomas and Gingrich,' J. Chem. Phys., 6, 411-15 (1938).
23. Morgan and Warren, J. Chem. Phys,, 6, 666-673 (1938).
24. Barnes, Chem. Rev. 23,' 29-43 (1938).
25. Gamertsfelder, J. Chem.' Phys. , 9, 450-457.(1941)
26. Bell and Davey, J. Chem. Phys. 5, 441-50; 450-57 (1941).
Reviews
Ml I i i i
27. Herzfeld, J. Applied Phys. 8, 319-27 (1937),
28. Warren, J. Apolied Phys. 8, 645-54 (1937).
29. Fischer, Physik fcegelmassTg. Ber. 8, 113-26 (1940").
30. Lennar3-Jones, Proc. Phys. Soc. (London), 52, 729-47
(1940)
31. Kirkwood, Am. Scientist, 30, 191-201 (1942).
Miscellaneous
32. Hildebrand and Wood, J, Chem. Phys., 1, 817-22 (1933).
33. Hildebrand, Science 90, 1-8 (1939).
34. J, T. Randall, "Diffraction of X-Rays and Electrons by
Amorphous Solids, Liauids and Gases", London, Cha-pman
and Hall, 1934.
35. Volume 33 (1937) of the Transactions of the Faraday
Society contains many papers presented at a symposium
on "Structure and Molecular Forfc'es in Pure Liquids and
Solutions".
- 65 -
INORGANIC BENZENE
(Egon Wiberg, University of Munich)
Te G. Klose March 20, 1945
I# Introduction
The compound B3N3H6 has been named triborlne triamine,
borazol and "inorganic benzene".
Stock and Pohland were the first authors to mention borazol
and to study its properties to any extent. Their preparative
method is still in use and gives a good yield of the convoound.
B2H6 + 2NH3 _g|rf55r> 2BNH2 * 4H3
The compound was shown by the vapor density method to consist of
three empirical units, thus giving the formula B3N3H6. Stock and
Pohland also showed that the compound was quantitatively
hydrolyzed by hydrochloric acid:
B3N3H6 + 9HS0 > 3H3B03 + 2NH3 + 3H2
The greatest yield of "inorganic benzene" thus far reported is
41$, which was obtained by her ting ammonia and dlborane in the
theoretical ratio of 2:1 for forty-five minutes.
I, Constitution of B3N3H6#
This compound may have any one of several hundred possible
formulas with straight and branched chains or rings* Structures
containing the B-B bond are eliminated since they would be too
unstable to meet the physical properties of inorganic benzene.
This limits the compounds with an empirical formula of B3N3HQ to
less than a dozen.
The decision as to the correct formula was made by studies
on the two trimethyl substitution products of inorganic benzene
B3(CH3)3N3H3 and B3N3(CH3 )3H3. Most of the trimethyl substitution
products have bean prepared by Schlesinger, Horvitz and Burg who
suggested a mechanism for their formation.
A hydrogen atom was found to be attached to each boron and
nitrogen atom by a study of the hydrolysis of the isomeric
trimethyl benzenes:
B3N3(CH3)3H3 + 9H0H > 3B(0H)3 + 3NH2CH3 + 3H2
and B3(CH3)N3H3 + 6H0H -« > 3CH3B(0H)2 + 3NH3
The only structural formula which is possible in light of
these hydrolytic properties is: H H
^N — Bv
H b' Vh
N — B
i i
H H
Stock and Pohland have pointed out that such a "benzene
formula is consistant with all the experimental observations.
- 66 -
Bauer has made diffraction patterns of B3N3H6 and found
them to correspond almost exactly with diffraction patterns of
benzene.
The borazol molecule may exist in one of two possible forms
or it may resonate; as with benzene:
11 <— - o
o
H-
H
a
-N N-
1 1
-H
~ >
H-
H
-NAN-
1 II
•H
H-
-B ,B-
-H
H-
•Bv B-
V
H
-H
k
(I)
(II)
Wiberg reports that the calculated parachor for molecule
(I) would be 1S5 and the calculated value for (II) 260. The
experimental value wrs found to be 208. It thus appears to be
in resonance forms*
There are other cases besides "inorgrnic benzene" in which
the C-C pair is substituted with the B-N pnir with a remarkable
retention of chemicrl and physical properties.
Boron nitride ("inorganic graphite") is analogous to
graphite. In fret, two adjacent C-ctoms may be replaced with B-N
without changing the atomic distances in the lattice.
Ethane and BH3NH3 show a close similarity rlso, as could be
predicted from their electronic configurations:
H H H H
h:b:n:h and H:c:pJH
ft H H H
II. Mechanism.
Wiberg' s suggested mechanism:
(BH3)a ■■■ NH3 > BH3 NH3 — =£ls — > BH2==NK2
"ethane" "ethylene"
H
/B^
H-N-' N-H , condense
\
Hi
1;
H-B, E-H
i
H
"acetylene"
IV. Physical Properties.
Inorgrnic benzene, like benzene, is p colorless, mobile,
inflammable liquid with good solvent properties and a characteris-
tic aromatic order.
- 67 -
Summary of Properties
"Inorganic
Benzene
Organic
Eenzene
Molecular weight
Boiling point K°
Melting point K°
Critical Temperature K°
Density of the liquid at the BJP.
Heat of vaporization at the' B0P«
Molecular volume at the B.P.
Parachor
C <- — -yC distance; B<— — - >N distance
78
80
353°
328°
279°
215°
561°
525°
.81 g/cc
,81 g/cc.
7.4 Kcr.l.
7.0 Kcal
96 cc.
100 oo. .
206
208
1.42 &
1.44 %
V. Chemical properties.
Inorganic benzene is slowly hydrolyzed at room temperature.
A fresh solution of the compound acts as a reducing agent on
such ions as Mn04* and Cu++#
Three moles of a compound of the formula HX (HC1, HBr, KOH,
H0CH3 ) add to the 3 double bonds in B3N3H6 forming an "inorgenic
cyclohexane",
p
H-N N-H H'" VNH
I !
X H
X
:B
1: I
H-B <B-H
?
H
+ 3HX >
-H,
x
H H
H-N'
-> I
X-B.
\
'N-H
N
B-X
This reaction is not rapid and doesn't appear to be salt formation
between HX and the lmino group -NH-,
Heating the "cyclohexane" at 50-100° causes the splitting out
of Ha and the formation of the aromatic systems
In some cases, heating of thd addition compound causes
fission of the ring into three equal parts:
OR /
H-N /N-N
!-< it
R0-BN ^-OR
—4L- 3R0.B 55=: NH
*N'
1
H
\
Catalytic hydrogenation of 33N3He failed to yield a
"hexahydrobenzol"*.
- 68 -
Bromination of "Inorganic benzene" leads to the "m-
dibromo benzene" whereas with C6H6, the p~dibromo compound
results:
H H 3r ?r
Bv Brx /^ <<*K
H-H NN-H 2Br, H'M N-H _2HBr H-N N-H
H-B. &-Z _> Br.' ;I.H Spontaneously"^ ' |_H
H 3f ^
k
The hydrolysis product of the dlbromo compound is volatile with
steam rnd is thought to be "inorganic resorcinal".
BIBLIOGRAPHY
Stock and Pohland, Ber,, 59.' 2215 (1926).
Wiberg, Ber,, 73, 299 (1940),
Bauer, J. Am. CJhem. Soc, 60, 524 (1938)*
Schlesinger, Horvitz and Curg^ J. Am* Chem, Soc., 58, 409
(1936).
Stock and Wierl, 2, anorgan. allgercu Chern. , 203, 228 (1931).
Wiberg, Z. anorg. allgern, Chem. , 173, 199 (1928),
Stock, Wiberg, rnd Martini, Ber. 63, 2927 (1930)*
~69«-
ROLL CALL
March 27, 1945
ehavlor of Metals in Nltrin am* Ca R> Keizer
snodlt^rl^L^ elef^ch1erai^l theory of 'corrosion'of 'metals the
an°f_icA reaction is relatively simple involving; the passage of
le ^ 1nns lntSn.solution, which may be represented by the
^ "™M --~>Mn+ + ne (n = 1,2,3,..). The cathodic reaction is
more complex involving reduction of the reagent surrounding the
°eai;fllJ? th* °ase of nitrlc acid two reactions are most probable,
Z^2 % ng h^dr?gen uP°n reduction and the other nitrous" acid,
wmcn decomposes in acid solution, '
nri* ^T/8 ?vl*™Ce ^at the eduction of nitric acid to nitrous
acid are these: * ' * p03F'ible steP8 ln reduction of nitric
?l) HN03 + H+ + e — - > NO 8 + H20
2 N02 + Ht + e -> HNO,
(3) HN02 + JT + e > NO + H20
(la) N03~ + 2H+ + e 1> N0a + Ha0
(2a N02 + e -> N02-
mv, +u (3a' NOr t 2Hf + e -A N0 + H20
onlv?'twn°n^?^iiderS i2a)D Very probable reaction since it involves
Zl/.rX PrrtJ°nles-. One British chemist thinks that N03~ and N02~
are not powerful oxidizing agents but that HN03 and HN02 are- this
(II) in?Slv(l) rnd lV °^r (la) ftnd (3a>- ™°* Produced b^ (2) or
(2a) Sf HNy02^^r"!l?82^2^H^aCti°n
mon?e6 anfmore0^;?^ been f°me^ the reductlon of HN0* P— ds
Highly reactive metels such as Hg, Zn, or Cd generally nrofluo*
denflitv mL?m? VB ?u"f°fently ra?ld t0 Produce a cathodic current
density capable of maintaining the fornetlon of hydrogen
(even^l^S"^1? {% ^ fhe faction pr^ucefnltrous acid
in the «iXt?l Z s)* ^J*8 been found thRt the Presence of urea
bv the fait L/TeSSeS *he fttack of the metal- n»ie is explained
,,Ln 2* thot urea res°ts with nitrous acid. On the other tend
urea was found to have no effect on the attack of M*. It h" been'
En^L ! Ct^0k °LT° 0n noble met?ls inmost raoiV at
cracks and crevices where HNO, could accumulate. Stirring was found
theSsurfa0crofhthe°me0tal!reSUmably be0an" °f ™°^ °'™'*™
of ^^tton°"f°« a ?etai d^B0 ln Ktl°3 ™* found ^ Increase the rate
of solution of Sn, Zn, Mg but to decrease the rate for Ag Cu
A™ Cu^an^n"?* SSS6 lnJ«""ng ^sults when he rotatfd discs of
of'ooncen^ra^on"^03^801"^0"- For A% he found that »»h HNO,
in to n°"*tr" lo" * ess than 4H "° welSh?blo amount of Ag was dissolved
xn „u minutes, the sample being rotated 220 x Der minute With
rapIdlvlngSlo„rntrf J?" °f ^ the ^ ««olveS more and more
solution of Ag! rotaUon was found ^ increase the rate of
1
-70-
Upon examination of the metal discs after being rotated in the
HN03 he found unique patterns. These he interpreted
as indicating that the rate of solution of Ag in HN03
is affected by the presence of N03. As the bubbles
of N02 are formed they move out toward the edge of
the disc due to centrifugal force. In prssing along
the surface of the metal they accelerate corrosion
at each spot momentrrily. These lines were found
to be always bent according to the direction of
turning the disc. At a higher rate of rotation he found more lines
but they were not as deep as those found with lower rates of rotation.
This is explained by the fret that the gas is not removed as rapidly
when the disc is rotated more slowly.
Copper was found to give patterns similar to those obtained with
silver. With zinc no lines were found — which might be expected.
The Zn being very reactive dissolves very rapidly and the catalytic
effect of HNO3 or N03 would not be noticeable.
References
U. R. Evans, Trans. Faraday Soc., 40, 120 (1944).
A. Urmanczy^ Z. Anorg. Chem., 235, 363 (1938).
ROLL CALL H. A. Laitinen
I. Removal of oxygen from commercial tank nitrogen.
A. The common method of passing the nitrogen over copper
turnings or gauze heated to temperature of 450-600° is
limited in efficacy by the thermal decomposition of cupric
oxide. The use of activated copper dispersed on fuller1 s
earth is superior, since a "temperature of 200-250° can be
used. Finely dispersed copper oxide is prepared by dissolving
basic copper carbonate in concentrated ammonium hydroxide,
suspending the fuller1 s earth in the solution, evaporating to
dryness and heating to 180° . The copoer oxide is reduced by
hydrogen at 200-250°,
Reference: Meyer and Rouge, angew Ck^m, 52, 63? (1939).
B. Chromous chloride solution can be used for the efficient
absorption of oxygen. Lightly amalgamated zinc in a hydro-
chloric acid solution keeps the chromium reduced to the
chromous condition*
II. Sensitive Methods for Analysis of Oxygen in Gases.
A. Probably the most sensitive method known is based on the
measurement of phosphorescence which is caused by the
presence of oxygen.
Reference: Pollack, Pringsheim and Terwoord, J. Chem, Phys. 12, 295
(1944).
3. The Pauling meters based on the paramagnetism of molecular
oxygen,, has not yet been commercially perfected although it
has been under development for some time.
C. An electrolysis method based on diffusion of oxygen through
a porous graphite cathode is being commercially developed.
The oxygen depolarizes the cathode and an electrolytic'
current proportional to oxygen content of the diffusing gas
mixture is observed.
-71-
ROLL CALL
A NEW PERIODIC T^BLE
Donald Ra Martin
The new table Is simply a different geometric configuration of
the Bohr table* Hydrogen is made the rpex of m isosceles triangle,
one side of which is the alkali metal family rnd the other side the
halogen family. Thus the relationship of hydrogen to both families
is shown. By such a configuration all the rare earths then fall
into their regular position in the 6th series,,
The four different types of elements as classified by Bohr are
shown by different types of circles around the elements.
The electronic configuration o£ Werner8 s coordination number of,
the minimum and maximum valence exhibited by, the elements are also
included in the table.
The abbreviated table below shows the generrl configuration of
the table:
PERIODIC GROUPS
I II .III IV V VlNfll
if
<£
•&
{ 3 ),ftev<-Mvia/
(i) 0
w
/
'Ga • .
— *w
\s*,
%
35^
(5)'Kr/^Y^r\
V-^3e£H,N3&>
6 j/OCe/CsYSaf I^V_._
~V54' J,5 5/v^aS?/
lft\k
\
>Q
Electron!
Periods
K L M N 0 P Q,
i
Z
2
2 Z
3
2 8 Z
4
2 8 Y Z
5
2 8 18 Y Z
6
2 8 18 X Y Z
*
2 8B32XY Z
>A11 groups
■ Complete
1 Group
■'Incomplete
Types of Elements
O
g Groups
■ Incomplete
/,;( jj 3 Groups
V^J/ Incomplete
Sloping Lines Represent Degrees of Similarity
Very close similarity
Close similarity
Some similarity
Wa
agner,
H. ii. and Booth, H. S. , J. Cher. Ed. 22, 128-9 (1945),
-72-
COORDINATION COMPLEXES OF DIPYRIDYL AND RELATED SUBSTANCES
F. W. Cagle
Coordinating Agents
A. Pyridine (functional group ^N^ )
B« Compounds with the functional group
1. 2, 2* -blpyridyl f\ /*k
April 3, 1945
n n
2. 1
a. Derivatives
1) Substitution in the 3, 3» position destroys
coordination ability.
2) Substitution in 6 position reduces
coordination ability,
3) Substitution in 6, 6» position destroys
coordination ability.
be Preparation
1^ Pyrolysis of copper 2-plcolinate (l)«
2) Decarboxylation of 3, 3s-dicarboxy-2,
2" blpyridyl (2).
3) Condensation of 2-brompyridine by ethyl
magnesium bromide and cobalt chloride (o).
4) Dehydrogenation of pyridine by ferric
chloride (4),
10-phenanthroline >,? <
^=N
a, Derivatives
1) Products of substitution in 5 and/or 6 position
retain coordination ability^
2) Substitution in 3 position lowers coordination
ability0
b„ Preparation
1) From 1, 2-ph'enylenediamine by a double Skroup
reaction (5).
2) By the transformation of 2-n i t roan i line into
8-amino~quinoline and the subsequent formation
of 1, 10-phenanthroline (2 Skroup reactions
involved)' (6).
3. 2-(2« pyrldyl)-quinoline
4* 2, 2»-biquinolyl
C, Miscellaneous related coirrpounds.
1. 2, 2» , 2®~terpyridyl
(7)
(7)
(a byproduct from the preparation of 2, 2» -blpyridyl
by dehydrogenation of pyridine)
-73 -
2. 2-(2« pyridyl)-pyrroW\ L jl [I J
r \ ^N' ^NX (8)
L JLnHNHb
3. 2~pyridylhydrazine ^N^
4„ 2, 2*-bi-indoyl
II. Complex Compounds
Ae Complexes with pyridine involving simple coordinate bonds.
• ar&sa (s«Sfe<Py)4j (SCN)a- i?d(p^3(scN^] •
*" Cu*(lClTN"d|(l2): cI^(lU3l? ^•lu)!et'n,lnatl0h °f
B. Pyridine complexes of a chelate nature,,
1. Complexes with iron.
a, With 2, 2'-bipyridyl
Ferrous iron forms a bright red complex (15).
We may write
+ 3
+ e
- -r
Fe(bipy)3
I"1"4*
red
'J
3 / E (formal) (16) = 0.97V
plue
bipy = 2,2»-blpyridyl
This bright red complex is often employed for the
colorimetric determination of iron (17) .
With 1, 10-phenanthroline and its substituted
products.
Ferrous iron 'forms red complexes with these
compounds (5). These compounds are used in the
qualitative and quantitative determination of
iron (18,19), and as oxidation-reduction
phen = 1, 10-phenanthrollne.
indicators (20).
[Fe(phen)3] + 3 + e
u blue J
For other members
= [Fe (phen Ja]*8
red J E(f) ■ 1.06 (21)
we observe similar reactions
with the following E (formal) values.
Indicator as FeS04 Complex E (formal) volts
5-Nitro-phen 1.25
5-Methyl-6 Nltro-phen 1*23
5-Bromo-phen 1612
5-Chloro-phen 1*12
5-Methyl-phen 1*02
(21)
-74-
c0 With 2,2« ,2"-terpyridyl
Ferrous iron gives a reddish purple compound (22),
No value for the E(f ) can be given. This reagent
is superior for small amounts of iron. The
ferrous complex has the formula, [Fe(terpy )^1 h2.
d. Complex with 2-pyridylhydrazine "•
Ferrous iron forms a purple complex with this
reagent. The structure of this is in question
(23,24,25). In any event, the material is never
employed to estimate iron since it does not
conform with* the Eeer-Lambert law (25),
e. Complex with *2- (2-* pyridyl)-pyrrole
Ferrous iron gives a reaction completely analogous
to that in (d) above (26).
f. With 2-(2' pyridyl)-quinoline
A red color is produced with Fe+2 (27). The Fe+3
form is not described and the E(f ) for the
couple is unknown. There is some question
concerning the ferrous complex (25;.
20 Complexes with ruthenium
a. With 2, 2'-bipyridyl.
A bright red complex of the formula,
[Ru(bipy)j C1S.6H20, may be prepared (28).
This results from heating 2, 2'-bipyridyl and
RuCl2 together.
b. With 1,10 phenanthrollne.
A red compound of presumably the same structure
as that given for the dipyridyl analogue has
been prepared (29 )a
3. Complexes with platinum
a. With 2, 2' -bipyridyl.
Several complexes of this type are known but the
one which has received the most attention is
PtCl2.bipy which exists in anomalous isomers
(30,31).
[Pt en bipy] CI,
°o
%
PtCl8.bipy ^ PtCls.bipy
£
yellow *>\ / red
J?t bipy(C5HsN)8] CI;
b. Complexes with 2, 2» , 2"-terpyridyl.
A situation entirely analogous to that with
2, 2»-bipyridyl is found here (32).
4. Complexes with copper.
a. With 1, 10-phenan thro line
A brown cuprous compound of unknown composition
is formed. This has been used for the colori-
metric estimation of traces of copper (33, 34).
b. With 2, 2?-biquinolyl
A compound similar to that in (a) above is formed
and has been used for the determination of copper
(35).
-75-
References.
1'. Blau, Ber. 21, 1077 (1888). '
2. Wlbaut and WTllink, Rec. trav. Chim. 50, 287 (1931).
3. Smith and Richter, Phenanthroline rndTubstituted Phenanthroline
Indicators, Gc Fredric Smith Chemical Co.: Columbus, Ohio, 1944.
p. 19-21. • • ' 9
4. Morgan and Burstall, J. Chem.' Soc. (1932) 20.
5. Blau, Monatsh. 19, 666 (1898).
6. Smith, J. Am. Chem. Soc. 52, 397 (1930).
7. Smirnoff, Helv. Chim. ActaT 4, 802 (1921).
8. Emmert, Ber. 60, 2011 (1927); 62, 1733 (1929); 66, 1971 (1933).
9. Tacnilschibalin and Itasovenow,H3hem. Zentr. (1915) II, 16.
LO. Smith and Richter, op. Cit. p'! 16, ; '
LI. Spacu and Dick, Z. anal. Chem. 71. 185 (1927).
L2. Spacu and Dick, Z. anal. Chem. TI, 442 (1927),
L3. Spacu and Dick, Z. anal. Chem. 73, 279 (1928).
L4. Spacu and Dick, Z. anal. Chem. W. 97 ( 1927k
.5. Blau, Monatsh. 10, 375 (1889).
.6. Smith, Transo III. Acad. Sci. 36, 132 (1943).
.7. Hill, Froc. Roy, Loc. London (OT, 107, 208 (1930 )9
.8. Geigl, Chem. Ztg. 44, 689 (1920).
j9. Saywell and Willard, Ind. Eng. Chem. Anal. Ed. 10, 13 (1938).
». walden, Hammett, and Edmonds, J. Am. Chem. Soc.~6, 350 (1934).
;1. Smith and Richter, Ind. Eng. Chem. Anal. Ed9 16, "^80 (1944).
I1 20[??n end Burstall, J. Chem. Soc. 1932, 20a _
• Mellan, I. , "Organic Reagents in Inorganic Analysis", The
Blaklston Company: Philadelphia, 1941, pe 6.
4. Emeleus and Anderson, "Modern Aspects of Inorganic Chemistry"
« u * „ TNostrand ComPany, Inc.: New York, 1942, p. 153.
W S28S> J • L^ Ph'D* Thesis, Purdue University (1942).
6. Emmert and Brandt, Ber. 60, 2211 (1927).
7. Yoe and Sarver, "OrganicTTnaiytical Reagents", John Wiley and
Sons, Incc: New York, 1941, p. 164.
8. Burstall, J6 Chem. Soc. 1936, 173.
9. Smith, G. F., UnpublishecTwork. '
0. Morgan and Burstall, J. Chem; Soc. 1934, 965.
1. Kosemblatt and Scheede, Ann.' 505,' 58TI935)
2. Morgan and Burstall, J, Chem.Toc. 1934, 1498*
3. Tartarinl, Gazz. chim. ital. 63, 597~TT933).
4. Moss and Mell , Ind. Eng. Chem~Anal. Ed. 15, 116 (1943).
o. reckenridge, Lewis, and Quick, Can. J. Research 17B, 258 (1939).
-.76-
PHOSPHONITRILIC CHLORIDES AND "INORGANIC RUBBER"
L. J« Edwards March 29, 1945
It was shown by Lieblg (6) in 1832 that when phosphorus
pentachlorlde Is treated with dry ammonia and the product heated,
a white stable material is obtained to which Laurent (5) assigned
the empirical formula FNCla. On the basis of" vapour density studies
Gladstone and Holmes (4) represented the compound ©s (PNC13)3. It
has since been realized that the trimer is the lowest member of the
series of polymers*
Numerous disagreements have arisen concerning the structure of
these polymers and several postulations were made to account for
their physical and chemical properties^ Because of tha stability
of these compounds towards heat and hydrolyzing agents, as well as
the requirements of valency, cyclic formulae have been assigned
to the halonitrides in which the rings are composed either of
2N-PC12 or of ^N and 5PC12 alternately (11, 12). Wichelhaus
suggested the following cyclic formula for the t rimer:
I PC13
A
C18P— N — N— PC18 (I)
After an extensive study of the hydrolysis of the trimer,
Stokes (11) thoroughly disagreed with this structure, stating that
since,
the compound decomposes into orthophosphoric acid and ammonia,
it is formed from ammonia and phosphorus pentachlorlde,
there are no indications of double or triple linked
phosphoric acids or of hydrzine in the decomposition products,
it is probable that the phosphorus atoms are united by nitrogen
atoms. Therefore, he agreed with the structure?
C12P^ PC13
Cls
(II)
If this series of phosphonitrilic chlorides is considered to.be
made up of acid chlorides analogous to P0C19, and if formula II is
assumed to be the correct structural representation of the trimer,
then hydrolysis should yield triphosphonitrilic acid corresponding
to the form:
-77.
/P.- (OH) 8
N
ii
N
(HO)2P P(OH)8
(III)
N
By analogy to many organic compounds, it is not unlikely that
this acid could undergo transformation into the tautomeric form:
/
HN
i
F.^O
NH
HO"
F,0
OH
,/P-OH
hn/ Vnh
10 qj
HO-P .-0—P-OH
N
H
trine taphosphimic acid
N
H
(IV)
Stokes found that by properly controlling the conditions of
reacting sodium trinetaphosphlmate with silver nitrate, two crystal-
line salts could be obtained in fairly pure form. The two compounds
correspond to the following:
/
N
Fr(0Ag)
N
I
and
(AgO)2P /P(0Ag)2
^.F-OAg
Ag-N^ ^N-Ag
AgO-J^° Off -OAg
N^Ag
(V)
The angle af least strain of the polygorvs is known to be 135°,
which is most closely realized in the tetramer compound, which is the
most stable of the series. Both the trimer and tetramer have been
subjected to X-ray studies. The data obtained lead to the con-
clusion that the tetramer is in the form of ft puckered ring.
Resonance occurs between the two possible arrangements of the
double bonds in the rings analogous to that in aromrtic compounds.
01$
p
'In J
C1*P> £*C1:
f.
Trimer
Cla
N—P-N
ClaF
I!
N
F-Cl;
•P--N
Tetramer
CI
CI
CI
^/
• • • *
Lp — n — P=H — P^=N . T.
CI
CI
j
CI
(VI)
higher polymers
...
■ ■
•
'■'.:.
-78-
Audrleth and co-workers (l) state that ^ail the experimental
evidence points to the fact that both the trimer and the tetramer
possess cyclic structures with alternate phosphorus and nitrogen
atoms, whereas the higher members including the •* inorganic rubber*
possess chain structures".
An examination of the physical properties of these polymers
reveals a distinct change in going from the tetramer to ".the pentamer.
The trimer and tetramer are also less easily polymerized than the
higher members which indicates their ring structures.
In addition to the definite compounds of (PNC13)X which have
been discussed, the following have been reported? (8, 2, 3)
a. a high molecular weight oil, in which x = 11*
b. gums
c. waxes
d. inorganic rubber, with an extimated molecular weight of
20,000.
e. an infusible, non-»elastic material lt
Below 250»C. the trimer and tetramer give little or no
polymeric material, whereas the oily polyhomologs are converted
rapidly to rubbery masses below 200°C. Schenck and Romer (10)
describe the polymer as an elastic and pliable material like rubber.
In the pure state it iw colorless and insoluble in the usual
organic solvents. The elastomer is stable towards acids and
alkalies but is decomposed by prolonged boiling with water.
The mechanism of polymerization of the trimer and of the
tetramer, both of which possess ring structures, must be different
from that of the higher chain-like structures. It is supposed that
the following reactions take place during polymerizations
Gla Cl8 Cla . .
(PNCla)3 — -? <,..P~N=P~N^P-N ... -—;> (PNC12)S + PNC13
ring rupture or
3PNCla
In substantiation of this postulated mechanism, Audrietn and
co-workers consider the depolymerization of Inorganic rubber, which
always gives appreciable quantities of the trimer and tetramer as
well as oily and waxlike polyhomologs^
References
1. Audrietn, Stelnman and Toy, Chem* Reviews 32, 99, 109 (1943).
2. Besson, Compa rend. ,114, 1264 (1892),
3. Besson and Rosset, Ibid*, 143^ 37 (1906 )*
4. Gladstone and Holmes7^ranse Chem. Soc8 17, 225 ( 1864).
5. Laurent, Cornpt. ,rend« , 31, 356 (1850).
6. Liebig, Ann., 11, 139 (T§34).
7^ Pouleno, Compt. rendM 75, 113 (1891).
8. Renaud, Ann0 , 3, 443 (1§35)«
9'. Schenck, Ber3ff"~60B. 160 (1927). .
10* Schenck and Romer, ibid.. 57B, 1343 (1924)*
11. Stokes, Am. Chem. J77T<U ^ (1895); 18, 629 (1896); 19/ flQ2 $£&?)
12. Wichelhaus, Ber. 3, 163 (1870).
••
-79-
THE HALIDES OF SILICON
Margaret Kramer April 24, 1945
I. Introduction-
The hydrogen atoms in the silicon hydrides may be replaced atom
for atom by halogen. As with carbon, chain halogen derivatives
may thus be built. Of the elements in Group IV, germanium alone
exhibits a similarity to silicon in the formation of certain
compounds.
II. Fluorine derivatives.
Only two fluorides of silicon are known, SiF4j and SiaFRo
A. Completely halogenatedV.
1. Silicon tetrafluoride is prepared from silica or
silicon and HF, or from silicon and fluorine.
2. SigFs is prepared by action of ZnF2 on Si2Cls (l).
B. Properties*
Both of the fluorides are colorless gases, readily
hydrolyzed by water.
3S1F4 + 3H80 > H8Si03 + 2H2S1F6
n a B$zF* + 4H*0 > H* + H2Si204 + 2H2SiFs
o. Subfluorldes have been reported, but have not been
established (2).
Halohvdrldes
A. Preparation
Recently the series SiH3F, SiH2F2, and SiHF3 have been
prepared by action of SbF3 on the corresponding chloride,
and subjecting the products to fractional distillation (3).
B. Properties
All undergo slow disproportionate to produce SiF4 and
SiH4.
4SiHF3 - > 3SiF4 + Sfia + Si (5)
4SiHF3 > SiH4 + 3SiF4 (4)
SiHF3 forms an explosive mixture with air.
I. Chlorine derivatives.
.,.. I**!! series is more completely known, derivatives from
m««i* siioCl22 having been prepared. Some of the intermediate
members are not known, however.
Completely halogenated,
A. Preparation
1. SiCl4 from Cl2, Si02 and C at elevated temperatures;
or from ferrosilicon and chlorine. Holding the
temperature around 550° results in a 94$ yield (6).
At lower temperatures some Si2Cl6 is produced (7).
B. Higher members are produced from a Ca-Si alloy and '
chlorine if the temperature is held sufficiently low,
esjTsiCl thG folloWlng composition is thus produced:
30$ SiaCl6
4% Si3Cl8
1^)^^}1° separated by fractional
iSi5Cllg distillation (8).
(Si6Cl14
,
-80-
Metallic chlorides have been used as chlorinating
agents; e.g., CuCl2j PbCl2 (2), Schwarz and coworkers
have prepared Si10Ci22 by action of SiCl4 and its decom-
position products with hydrogen at high temperatures
(9,10,11)* The following mechanism was suggested to
account for the formation:
SiCl4 ^L^SiClg SiSla-^SiaCle =Sl-> Si8ClB SiSla^ Si3Cl8,
etCe^SijoClaa, SiCl4, Si2Cl6, Si3Cle, S110C122 were
identified in the reaction products,
B. Properties
Lower members are colorless liquids* Si6Cl14 and up are
white solids* They hydro lyze readily, and fume in moist
air. Vapors of the higher chlorides flame in air.
Increasing the temperature during the preparation of the
chlorosilicons generally leads to Increasing amounts of
silicon tetrachloride* This fact has led to the suggestion
that upon chlorination, complex silicons are first built
up containing the Si-Si links originally in the element*
Further chlorinction plus heat cause these linkages to be
broken, the final product being SiCl4 (7).
An alternate view is that silicon totrachloride is' first
formed which by reaction with Si produces Si2Cl6 etc. One
objection to this is that ferrosilicon when heated with
silicon totrachloride, does not produce higher derivatives
(5).
Hydrolysis of the chlorides may proceed stepwise?
SiCl4 SaS^siclafOH) BaQ-> Sl01a(OH)» Sa2-^SiCl(0H)a
2aQ->Si(0H)4
This may be controlled by diluting the compound with
anhydrous ether and using a moist organic solvent for the
hydrolysis (2)*
SiCl4 also reacts with (Me4N)8S03 in liquid sulfur
dioxide, precipitating SiQ2x50s (12)* This dissolves in
excess reagent at low temperatures, but reprecipitntes upon
warming to 0°*
With ammonia, under temperature control^ silicon tetra-
chloride forms a series of compounds, including Si(NH2)4,
' HNSi(NH2)2 ... S13N4 (13)*
C* Subchlorides
(SiCl2) has been prepared by passing S1C14 and H§ over a
glow discharge (14), (SiCl)x has been prepared by cracking-
SiaoclsoH2 or Si10Cl22 at 300° (10).
Halohydrldes
A« Preparation
These are prepared by action of HC1 on SiH4 in the presence
of AlCl3tt Direct reaction with halogen is explosive and must
be carried on at low temperatures* CHC13 may also be used to
produce higher chlorosilanes*
B, Properties — these too hydrolyse readily and react with
ammonia (15).
-81-
!V. Bromine derivatives.
The bromine derivatives both in preparrtion rnd properties
resemble the chloro compounds. This series is not as completely
known, however, having been prepared only as far ae Si^Br*© *
Si3r4 is a liquid, the succeeding members are crystalline solids.
S'lllco bromo form is spontaneously inflammable when poured through
airc It hydrolyzes readily and rapidly,
V, Iodine derivatives
These are less stable than the chloro or bromo derivatives,
A. Prepai^ation
1, Sil4 from silicon and iodine in an atmosphere of
carbon dioxide, no
2, Si2I6 from: Sil4 + 2Ag -322-^ Si2Is + 2AgI
Heating decomposes this into Sil4 and (SII)4 (16).
Iodosilanes have been prepared from SiH4 and HI (l?)0
The iodosilanes are liquids with pungent odors, decomposing
in sunlight, SiHI3 forms an explosive mixture with air.
The iodosilanes also hydrolyze readily,
fl. Mixed halides
Mixed halides containing 2 different halogens and 3 different
halogens are known (18,19,20,21), Halides of the type SiwX/Z or
SiHXJfZ are not yet known.
The general methods for their to reparation are:
S1C14 SbE.a_>SiF8Cla. S1F3C1
3bFs ?
These are gases, hydrolyzable to hydreted silica, fluosilicic
acid, and HCla They have nauseating odors and &x*e irritating to
inhale (18).
Si2F6 + XsBr3 ->SiF23r2 + 3IF3Br + SiF4
These two are colorless gases, readily hydrolyzed by moist air
(19),
Complete series of chloro bromides, chloro iodides, and bromo-
iodides are known,
More recently derivatives containing 3 halogens have been
prepared (20).
4SiFBr3 + 3C12 -~™>2SiFClBr8 + 2SiFCl3Br + 3Br2
SiFBr3 -SMX.> SiFCl2Br + SiFClBr2
SiFClgBr and SiFClBr2 hydrolyze with ice cold water to silicic,
hydrochloric , hydrobromic, and fluosilicic acids,
I. Oxyhalides
Oxyhalides of fluorine, chlorine, and bromine are known (2,22,23)
Ac Preparation
A fluoro derivative is prepared by action of SbF3 on
SiaOCla.
The chloro and bromo oxyhalides are prearred by action of
bromine or chlorine and oxygen on silicon at high
temperatures:
Si + 02 + Br2 2QQZ-y (SiOBr2)4 + Si2OBr6 + Si302Br8 +
Si403Brlo + Si504Br12
-
-82-
B, Properties
The oxyhalides are colorless, oily liquids, except for
(SiOCl3)4 and (SiOBra)*, which are solids* They hydrolyze
readily. They react with absolute alcohol to form ethyl
esters. The esters are colorless, oily liquids with' high
boiling points, which hydrolyze slowly, even at 100 °e
II„ Silicon plastics.
Recently the silicones have been shown to be of commercial
importance. Since their preparation depends upon the properties
of the silicon halides mentioned above, they are Included briefly
here
SiCl4 Mg — — RC1
RSiCl;
Grijmard
^
R3SiCl2
I
hydrolysis
w
R3SiCl
RSi(0H)3
R8SI(0H)8
1 _
Condensation
R3S1(0H)
R
-Si-O-Sl-0-
6 '
r ±
R
-Si-0-
»
R
Ra-,Si-0-Si-R3
(24, 25)
The resins have for their backbones a framework of Si atoms
joined by 0 to each other -S'i-O-si-, The resins rre much more
stable thermally than the best of organic resins (26), They
show relatively little change of viscosity over quite a
temperature range.
The resins actually stem from the work of Kipping in England
(27) who in 1937 had said that the outlook for this branch of
silicon chemistry was not very hopeful.
References:
1« Schumb, W. C,, and Gamble, E, L. , J. Am. Chem, Soc* . 54.
583, (1932),
2. Schumb, W. C., Chem. Rev. 31, 587, (1942),
3. Emeleus, H0 J,, and Haddock, A; a., J. Chem. Soc, 293 (1944)
4« Booth, H. S., and Stlllwell, W. C. , J. Am. Chem, Soc. , 56,
1529 (1934), ' — •
5. Friend, J. N. , Textbook of Inorganic Chemistry, V6 5, o. 187.
6. Andrianov, K. A., Uompt. Rene..' Acsd. Sci, U.RTS.S,, 28, 66,
(1940) from C. A. 35, 2431,
7. Martin, G. , J, Chem. Soc, 105.' 2836 (1914).
8. Schumb, W. C., and Gamble, E. L. Inorganic Syntheses, V. I,
Pi 42e
-83-
9. Schwarz, R^and Meckbach, H# , Z. anorg. allgem.. Chem.-, 232,.
10. Schwarz) R. , and Gregor, U. , Z.~ anorg, allgem. Chem. 241, 395
11. Bctamrz^ lC, and Thlel, R. , Z.. anorg.. allgem. Chem. 235, 252
12. Jand|^y and Hecht, H. , Z. anorg. allgem. Chem. 250, 287
13. Emeleus, E„ J., and Anderson, J. S. , Modern Aspects of
Inorganic Chemistry, o.- 479.
14. Sohw|^»(^7and Pietsch/G., Z. anorg, allgem. Chem. 232,
15. Ephraim, F. , Inorganic Chemistry.. 4th Ed., p. 637.
17 F^«nZ' R. , and Pflugmacher, A., Ber. 75B, 1062 (1942).
17. ^el™*'fe£y Maddock, A. , . and Reid, (T^'j. Chem. Soc!,
18. Boot^-(^2and Swinehaart, C.. F. , V, Am. Chem. Soc., 54,
19. Schumb^ ^C^and Anderson, H.- A., J.. Am. Chem. Soc., 58,
20. Schumb^ ^^^'and Anderson, H. A.-,, J.. Am. Chem. Soc., 59,
21.- Sch^43W-(l^/}and Gamble, t. L. , J. Am.- Chem. Soc. 54,
22. Schu^W.^C8, and Klein, C. , J. Am. Chem. Soc., 59, 261 .
23.- ^^/-(.^ and Holloway, D. P., J, Am. Chem. Soc. 63,
24. Bass, S. L Hyde, J. F., Britton, E. C. , and McGregor, R. R„
25 Hv„ T6rS PlaS,tlSB' 124-128/ 212-214 -(November, 1944):
'(1941^ ' Dej-ong> *• C-> J.' A*. Chem. Soc., 63, 1194
26. Moses^ G^, Westinghouse Engineer 4, 138, (1944) from C. A.
27. KlppiFg, F. S.-, Proc. Royal Acad.- (London) 159, 139 (1937).
-84-
ROLL CALL
April 17, 1945
Synthetic Optical Crystal,, A, L# 0ppegard
Synthetic optical crystals of sodium chloride, potassium
thenar ih»t££Uffl,f\U0?lde 3nd sodlum nitrate are being male by
10 1%' M ah *^°a\ C°mpeny: The crystals are 8» in diameter,
10 1/S ,bieh» and wel6h about 35 pounds. A 60° lithium fluoride
prism with a 19mm. face and 15mm. high costs #1000. Ilu°rice
ThP nS^M17''?1' °re made of pure salts ln Platinum crucibles.
cost too on^,MMne 8haped bottom' wl8h 85° sraras and
£h£L?!i: 0nen crumble can be used to make twenty sodium
nuorlde1 crystals'. "" be US°d *° "**• only fou* lithlum
in i ^?«?tlnUm 0rS°ible oontaining the molten salt is placed
in a special oven. The oven is a vertical cylinder divided into
rnd°rsrgradua??vri^er;a ^ CrU°lble l8 pla°ed ln ^ SSr^ven
ovrn f? ?nv y„i !red by a snycnronous motor to the lower
wlth'w«»nJ^?« ? a.year t0 determlne the optimum conditions
witn respect to temperature gradient and rate of lowering.
When the temperatures ln the ovens are right, the lowering
?hf™1Sm *S 8laZted' and a cold Pln Pln°ed aglYnst the tip org
e,t °°nf ^aped bottom to start crystallization. It is thought
forces ahead t??oSnathS Tl micr°s?0pi° ^stals, and then one
tafcl s 7 10 L= °^ ^8 m8-,in «*•**« tte growth of the crystal
one orv«t2i ^ ' d ?hSr" lS n° Way of filing beforehand whether
one crystal or several have formed.
cube ?«e™™yv^VB removed £ron the crucible much as an ice
t6 the <.£?«?£ J*?? a? loe *ray' i'e-« intense heat ^ applied
5inL le of the lnverted crucible. After annealing; for
d;s?redys8hape? ^'^ i8 ***** t0 b° 8pllt 0r sawed in"° ^
rmnh ^i.Val*u 0f these orystals lies in the fact that they are
of larargori^anBnatU^al W1? and pe™" the "MufaotSre
oi large prisms and other optical equipment for infra red
spectographs. By the use of the infra red analysis oetroleum
take davs bv^th" ldentlfied in ^™ minutes where iVused to
taice days by other means.
Reference
Taylor and Kremers, Chem. Ind., LV, No. 7, page 906 (1944).
M
:
-85-
RDLL CALL
Solvent Effect of Llthl^ Nitrate on Zinc Acetate in Acetic Acid
Nancy Do "tons
tha JrH^ acet?te Jf °nly sll^htly soluble in acetic acid. Upon
™ <-«+ « ° sodium or ammonium acetate the solubility of zinc
cxetate increases. Special chemical effects may enter into the
solvent action of acetates. The authors believe that the salt
flllt:Lm&l e ?'rge for aoetic ao" because of the low dielectric
constant of acetic acid.
MHt?!/ffl0t of a neutral salt/ lithium nitrate, on the solu-
oility of zinc acetate was studied.
Several methods of procedure were applied. One involved the
freezing points of solutions containing fixed amounts of lithium,
nitrcte and variable amounts of zinc acetate. The solubility '
was obtained over the range from 40°-80°. The other method was
to prepare solutions of known proportions of lithium nitrate and
acetic acid and to add excess zinc acetate. After sealing these
mixtures in tubes and keeping the tubes at constant temperature
lor several weeks, the samples were removed and analyzed.
-, J^f^reB]ilts showed th*-t lithium nitrate increases the
solubility of zinc acetate but not' to the same extent as the
sodium acetate or ammonium acetate.
,„ n T?f lar?! dlfferemce m the solubility of the zinc acetate
in c.cetic acid containing lithium nitrate and containing sodium
acetate Is explained by chemical interaction in the behavior of
zinc acetate to other acetates.
Reference: (Mswold^ Ash, and McReyholds, J, Am. Chem. Soc. 67, 3,
Comparison of the Ammlnes of Cobalt and Cop^r" " " j." 'y. Quagliano
The bonding power of the Cu-NfU bond in PuCwr \ ++ * « f™>«v
weaker than the Co-NH3 bond in Co ^ ) +++ Tn I , 4 is much
the cnbfllt mmr,i Jt 4 in wu^igjg # In aqueous solution
td^nt f i? m°re stable> that ^, much ammonia is liber-
ree-rdfl ?hP SnnSf'mmlne °UpriC salt is ^solved in water. As
regards the bonding power and the ntjttrili+v ^-p <»->,« < ~ f^
the electronic configurations: stability of t]?e lons, consider
Cn++ 3d 4 s 4p
™, , ++ xx xx xx xx
^u^nh3;4 xx XX XX XX
The one unpaired electron
-86-
In the case of cobalt, wo have:
z°+,::. . ^ xx xx xx 4s 4p
Co(NHs)e+++ S
tneir bonds directed toward the ™J^ h^se six °rbitals have
Tr-e cobalt complexes, a" ReneS-l «?%£f * regu^r octahedron,
transition elements, differ fro-, th ° *$e oomPlexe8 of the
charge of the catioAs aw "0 l^ft?*? °°»«> *e slze and
■ ent energy
Popples Comp„„nflfl of Ph^C,' J,^^;^- ,~ ;
Margaret Kramer
^ NH »„
XNH-C— NH-C-NH9 «, H •'
^2 r^NNH ~C — NH— C -NH,+
O
HD,S
I
II "Zwitter ion" '
The substance is Drcctinmiv «„ *, , -,
Ph?°3 ^NH
N— C
' \
/ NH
M (eq) / * M (eq) = 1/2 Cu++, l/2 N1++
^NHa+
W- ran%form' since the c?s for" ^ho,^ h WaS, lEOlCted> Probably '
because of the proximity of two negative gro'up's:""^^ unsolubl«
PhS03-
HgN*- — P AT <! ^NH
TO* N- ^NH-C"
n* .. N--C-— NH,+
PhS03-
trans
-86a-
The cobalt complex (octahedral) ought to show geometric isomerism:
II
III
f
= PhS03~
III should be most stable because of the distance of the PhS03~
groups from each other.
Coordination with copper or nickel increases the acid character
of the ampholyte. Coordination with cobalt somewhat enhances the
strength of cationic acid and anionic base.
Reference :
Ray, P. and Siddhanta, S. , J. Ind. Chem. Soc. 20, 250 (1943).
-87-
THE DETERMINATION OF CRYSTAL STRUCTURE
K. J. Plpenberg May 1, 1945
I. Introduction. The crystalline state has long intrigued in-
vestigators. The methods and tools of research were limited
to optical methods in the visible range — which permitted a
study of the outer form only. With the discovery by Friedrick,
Knipping, and Laue (1) that x-rays could be diffracted by
crystals which acted as three-dimensional gratings, a new door
was opened — that of complete analysis of the crystalline state.
II* Methods Used. Many techniques of recording x-ray diffraction
patterns have been devised; of these, four have found wide
use (2-8).
A. Powder Method (2-7). An essentially monochromatic beam
is permitted to impinge on a finely powdered sample. The
crystal fragments of the sample are randomly orientated
so that smooth concentric rings or arcs are recorded on
the cylindrical film. The pattern recorded on the film
is a "fingerprint" of the compound.
B. Laue Method (2-7), A single fixed crystal is placed in
the path of an x-ray beam containing all wave lengths. ' A
pattern of symmetrical spots is recorded on a flat film.
Each plane in the fixed crystal selects a wave length
from the x-ray beam so that the Bragg Law, n)^= 2dsln6
is satisfied. '
C. Rotation or Oscillation Method (2-8). A single crystal
is rotated or oscillated about one of its axes in a mono-
chromatic x-ray beam. The pattern, which consists of a. ,
series of spots lying on parallel lines, is registered on
a cylindrical film, each set of planes recording only
when it is in such a position that the Bragg law is obeyed.
D. Weissenberg Methods (2-8), This is a modification of the
rotation technique. A single crystal is rotated about one
of the principal axes while at the same time the
cylindrical film is translated parallel to the axis of
rotation. A shield is used so that only one layer line
oan be recorded at one time. The pattern obtained is a
beautiful network of symmetrical spots.
G-eneral Procedure (4, 5, 6). There is no completely stan-
dardized procedure for the determination of a structure. Each
new structure becomes a novel problem presenting fresh and
unexpected difficulties. The following steps are usually
encountered in one form or another*
A. A study of the external symmetry of the crystals-including
such phyaical properties as optical, electrical, magnetic,
.
-88-
Bo The determination of the size of the unit cell*
1. Rotation or oscillation patterns about the
principal axes.
2. Indexed powder patterns.
3„ Laue patterns -- a rough approximation,
C. The determination of the space lattice or scheme of
repetition.
D. The calculation of the number of molecules per unit cella
n = D V 6*05 x 10
8
n = number of molecules per unit cell.
D a density.
V = volume in cubic angstroms.
M - molecular weighty
E« The selection of the space group.
F". The tabulation of all possible atomic arrangements.
G» The choice of the correct arrangement,,
Ht The determination of the parameters of this arrangement
that fix the exact position of the atoms in the unit cell©
1. Deduction method— applicable only to the simplest
structures^
2. Fourier series method*
+© +00 +00
/°(uvw) = ^JE- Z_ 5~F(hkl)oos 21T(hu + kv + lw)
3. Pattern-Harker Series.
V
-r-> ±JP±J£ +0^ j ,
p (uvw) =2. "2L 'F(h3tl)r cos STTthu + kv + lw)
h=ook?=oo l=oo
4. Bragg » s optical synthesis of Fourier Series0
5. Huggins5 modification of the Bragg method.
IV. An Example. The crystal structure of copper sulfate penta-
hydrate as determined by Beevers and Lipson (9) illustrates
the problems encountered and the methods employed for their
solution©
A. Available data which was useful.
1. Decomposition on heating proceeds in three stages*
CuS04.5H20 — ?CuS04c3Ha0 ~ »CuS04.Ha0 — > CuS04
2. Four waters are replacable by ammonias, while the
fifth is not.
3. Jordahl (10) predicted from magnetic susceptibilities
the tetrahedral arrangement of oxygens arpund the
copper atoms.
4. Optical examination (11 ) indicrted a tricilinic
system, with centro symmetry.
a. Space Group — c!
b. Axial ratio: a:B*c = 0„5715jls0„5575o
c. Angles:c\= 8fc°16«, ft = 107°. 26' , Vs 102o40fa
d« Well developed [001] zone. '
B. X-
-89-
-ray Data.
1. From oxoillation patterns the unit cell dimensions
were found to be
a0 = 6.12 A .
b0 = 10*7 A
c0 = 5.97 &
of the crystal was calculated to be 563
of CuS04.5Ha0 per unit cell calculated
2.
3.
The volume
The number
to be 2.
£3
From the extinctions noted on the_pho to graphs, the
space group was found to be C^ -PI.
4. Determination of copper and sulfur positions,,
5. The complications which arose in the establishment
of the other atomic positions prevented the direct
solution of the structure. The intensities of 89
(hkO) reflections were measured (12) and the Fourier
projection "(13) of the unit cell on the (001) plane
was made, establishing the remaining positions.
6. The structure obtained was verified by a comparison
of the observed and calculated (14) intensities.
Discussion of the structure. The copper atoms lie on the
special positions (000 ) and (lio) and the sulfur upon the
general position (0.01 0.29 0.54). Four waters are
arranged in oquares around the coppers, and two oxygens
with these form an approximate octahedron. The fifth
water is not coordinated, but is in contact with two
oxygens and two waters.
Bibliography.
1. Friedrlck, Knipping, and Laue, Sitzungsbere Bayr0 Akad. , 1912
305 ' ' " '
2. Clark* G„ L. , "Applied X-Rays", Third Edition, McGraw-Hill,
New York (1940).
3. Bragg, W. H. , "An Introduction to Crystal Analysis", Bell,
London (1928).
4. Bragg, W. L. , "The Crystalline State", Vol. I., Macmillan,
New York (1934).
5. Wyckoff, R. W. G. , "The Structure of Crystals", Second Edition,
Chemical Catalogue Co., New York (1931).
6. Barrett, C. S., "Structure of Metals", McGraw-Hill, New York
(1943).
7. Davey, W. p., "A Study of Crystal Structure end Its Appli-
cations", McGraw-Hill, New York (1934).
8. Buerger, tf. J., "X-Ray Crystallography", Wiley, New York (1942),
9. Beevers, C„A0, and Lipson, H. , Froc. Roy. Soc, A 146, 570 (1934).
10. Jordahl, Phys, Rev., 45, 87 (1934).
11. Tutton, " Crystallography and Practical Measurement", Vol. 1,
p. 297, Macmillan, New York (1922).
12. Bragg and West, Z. Krlstallo'g. , 69, 120 (1928).
13. Bragg, W. L. , Proc. Roy* Soc, A"T23, 537 (1929).
14. James and Brindley, Z. Kristallog. , 78, 470 (1931).
-90-
Additlonal References:
Strukturberioht, Vol. I - VII, Edwards Brother, Ann Arbor.
temSrXi Yor£' hSr °f ^ Dlffractlon ln ^Btals",
^ss^-C^brlSe^e):"011 t0 CryStal *"*•***. diversity
Stillwell, C. W., "Crystal Chemistry", McGraw-Hill, New York (1938).
Smeleus and Anderson, "Modern Aspects of Inorganic Chemlstrv"
Van Nostrand, New York (1943). ^ uiemisury .
^r^L V "In?rSanl° Chemistry", translated and revised by '
Kman'-New ^Ml^1*"' fc *" F°Urth ReVlSed Edltlon»
-91-
SIR HUMPHRY DAVY
Virginia Bartow May 8, 1945
Youth and Education — 1778-1798.
1, Born — Penzance, Cornwall, December 17, 1778.
2, Ancestors among the 200 year old families of Cornwall.
ae Grandfather a builder.
b, Father a woodcarver and famer, " Died in 1794
c. Mother a milliner.
3f Education
a„ Mr. Bushnell — for reading and writing.
b0 Grammar school from six to fourteen,
5* ?£of° -" The Reverend Mr. Coryton one year 1793.
* !' Sny^ar Settled, no responsibility.
«£ T\CTab?r?te scheme of self study comprising all
the Liberal Arts.
ft 1795, Apprenticed to Dr. Borlase — surgeon and
apothecary of Penzance, '
lo Jjjpuential studies -- . Mathematics, Nicholson's
Dictionary of Chemistry" and Lavoisier's "Ele-
mentary Chemistry"; Locke, Berkeley, Hume.
Condorcet and Kant.
20 Friends Gregory Watt and Davies Gilbert
3, Essays on Heat and Light,
Establishment of Reputation, 1798-1812
1798 1. Pneumatic Institute at Clifton near Bristol under Dr.
•Deacioeso
1801 Royal Philosophical Institution —
p!^ftant 17 ^ct?rer in Chemistry and Experimenter.
Professor of Chemistry
Establishment of Popular Lectures
Research both of his own choosing and that of his
directors,
1812 Knighted*
Marriage to Mrs, Aprecee — incompatibility of
temperament .
Resignation from the lectureship at the Royal
Institution.
L«L.D. and lectures at Dublin.
Published the "Elements of Chemical Philosophy".
Retained connections with the Institute.
Last Years,
i8i8_ %32^tt°l^&^^
1820 European Travels.
1824 No^h%^ ?n6land -Presidency of the Royal Society
ie24 North Sea Voyage - Sudden, Denmark, Holsteln, Hanover,
-92-
1827 Winter in Italy due to ill health,
1828 Last continental trio for health.
Died at Geneva May 29, 1828,
V. Estimation of Character.
A poet — imagination.
A humanitarian — safety-lamp.
Disposition — spoiled by success and Jealous of rivals.
tactless and irritable toward critics,
unfriendly to Faraday and Davy.
A genuine scientist — Facility to modify prevalent belief e
Foresaw change of opinion.
Convictions based only upon proof,
Davy* s place in history not due to human frallity, incidents of
his life or popular audiences. His significance i'sscientific
and the summary of his work is a review of the science of his
time and its progress.
V. Scientific Interests and Achievements.
1. Essays on Heat and Light — youthful speculation.
a. Contemporary theory of combustion — phlogiston versus
oxygen. Temporary substitution of phosoxygen — a
combination of oxygen and light.
b. Heat of Combustion — ejection of caloric, an imponder-
able fluid.
— motion or vibrations of particles.
c. Heat capacity — products of combustion have less
capacity than original substances.
2. Physiological effects of gaseous medication — Ns0
Contingent research — composition of HN03, NO, Na04 and
nh3;
3e Electrochemical studies.
Consideration of the production of hydrogen and oxygen by
the electrolysis of water,
Theory-Ritter, elements at electrodes had been com-
bined with electricity^
-Davy, a conducting chain,
Unexplainable appearance of acid and alkali at
electrodes.
Contemporary definitions*
Acid — the present oxide of a non-metal.
Oxide - A substance not sufficiently
oxygenated into an acid.
Salt — combination of an acid and oxide,
(Metal part of oxide and non-
metal in acid might not be known).
Trials to eliminate the acid and alkali lead to
the discovery of Nr, K and later, at an amalga-
mated electrode, Ca, Br, Sr and Mg„
Connection established between chemical and electrical
affinity.
-93-
4* Alkaline nature of K, Na and NH3,
K and Na do not contain hydrogen nor does NH3 contain
oxygen. (Subjected to experimental proof).
5, Study of halogens.
a. Elementary nature of chlorine established*,
Basis — Chemical properties.
the "proportions" with which it combines.
(Mr. Daltonss ingenious idea).
Dry Cl3 and Fe in red hot tube) same product
Fe and HC1 ) without water
Contingent discoveries — C0C13 and C103 — euchlorine,
HC1, HI and HCN acids have no oxygene
Broadens definition of combustion.
b. Characterized F3 — suspected "fluate of calcium",
c. Solved French riddle by classifying I3.
6, Composition of the air — mild combinations.
Individual gases stirred by an atmospheric turbulencea
1833, Grahams Law — gaseous diffusion explained later by
the kinetic theory0
7, Chemistry of the diamond*
Argument for differently arranged particles in apparently
elementary forms of matter.
8, Minor experiments.
Theory of volcanoes. Attempt to get chemical effects
H3Te end PH3 from magnetic effects.
Torpedo fish.
9, Practical and humanitarian work*
Safety lamp — copper for ships sheathing
Zinc to preserve boilers*
10, Lectures? Tanning and Agricultural Chemistry.
11, Chemical Philosophy and Predictions.
1. Appreciation of theories, analogies and hypotheses.
2. No formulas and no equations.
3. Elements of bodies merely points possessing weight
and attractive end repulsive forces.
4. Intimate connection between chemical and electrical
phenomena.
5. "One good experiment is of more value than the Ingenuity
of a brain like Newton* s. "
6e Dalton* s atoms became "proportions" — the hypothetical
discarded for the practical.
7, Natural orders of resemblance, K, Na, NH*
(Gay-Lussac S and 03 ) Cl3, Ie and 03.
8. H30 as a formula for water — based on volumesa
9a Prout* s Hypothesis.
10. Liquifaction of gases by self compression from slow
generation. HC1 by Davy followVct by Cl2 by Faraday.
11. All acids contain hydrogen.
12, Conclusion — Davy1 s greatest success in the realm of facts.
His attempts at theory not happy.
-94-
REFERENCES
Davy Humphry, "The Decomposition of the Fixed Alkalies", Alembic
.Club Reprint, No. 6. W. Fc Clay, Edinburgh, 1894a
Davy, Humphry, "The Elementary Nature of Chlorine" Alembic Club
111 1906 9" ThG University of ch^ago Press, Chicago,
Davy, Humphry "Elements of Agricultural Chemistry in a Course of'
Lectures for the Board of Agriculture", Longman, Hurst, Rees,
.Orme and Brown, London, 1813, B ' ' '
)avy John "Memoirs of the Life of Sir Humphry Davy, Bart". Longman,
Rees, Orme, Brown, Green and Longman, London, 1836, 2 Vols.
[reg^hiMC'' "The Scientific Achievements of Sir Humphry Davy",
Oxford University Press, London, 1930, '
lamsay, Sir William "Essays Biographical and Chemical", Archibald
Constable and Co., London, 1908, 41-56. ^
Helen, Sir William A. , "Famous Chemists, The Men and Their Work",
Routledge and Sons, London, 1930, Chapter 7, "
-95-
THE HALOGENOIDS OR "PSEUDO-HALOOENS"
Nancy Downs May 22, 1945
Demoreti^;.tr.In2Ly?1Valrt ohePloal aggregation composed of two or
character?^* !? t«2 f °mS£ !*» i0h showe ln free state ^rtaln -
Stn^.nLf5e free halogens, and which combine with hyd-
rater" (if I™ nd Wlth sllver t0 form r salt insoluble m
History.
Gay Lussac first isolated cyanogen (CN)a in 1815 by heatine
"radiLl»°asadff?n^S^yff 5?' ,^lB Was the fil^ ^lltio^of a
cyanogen bv \llllnl Jft L<leMg (3)% nLiebig ^led to isolate thio-
cyanogen by passing chlorine over silver or lead thiocvanatp hnt
butWsucSeSdedei8n^a, P™*™ f80 tried to P^paretMo cyanogen
sulfide ((CN)Jrin 186? preparing th* mterhalogenoid, cyLogfn
butSCSei901 ^Idbe'rfstal'd t^Tf.f. *° lsolate ^eethlo cyanogen,
prepared, WJ-aDer6 stated that free thiocyanogen had not yet been
reco^iL1??^^^^^0*"06^11 ^Ulflde (SCSN3)a but he did not
Soderoick (t) TKtS t^l\J^192° **°<**™&* was obtained by
S.f » ]* , Soderbackts work, new interest arose in the
the haWeno?df "ft **U**lBl and recently "lany invesUgatians of
been madf? 6lr struct^es, Properties and compound s-have
Phe HalogenoldSo
A. General properties.
lfl t^.Ii1^ °J eifcpfomotive series (from a study of elec-
m i conductivity measurements) F"\ ONC~ OCN~ CI"
2 sLi'l^™^ 8?r' SCSN^ ^/Secft-, Tefa2 (l). f
2. Similarities to true halogens. •
a. ^ogenoids, in general, are quite volatile.
b. solid substances are apparently isomorphous, '
h?n?n2eI? ' Jhey show an affinity for metals, com-
bining directly to form salts. Silver, lead and
mercurous salts are insoluble in water'
in S^fr1'^7 f0rm hydrGClfis w^h hydrogen which
in water solution are highly ionized.
~Ty/re caPablS of Arming interhalogenoid com-
pounds such as CN-SjCN , CNN3 etc
K(SeON)^ p°^h£a°Senoid complexes such as Cs(SeCN)3,
ge nh^i!?«il0^en0!ds.may be PrePared, in general, (l) by
chemical or electro-chemicsl oxidation of the
t^erperhlndres Gir **1%* °T (2) by deCOm position of
B. Possible explanation of halogenoid properties.
p ^lerman5 G?d Birckenbach use the octet theory (15 6)
2lJSL?I the Valence eleotrons of the atoms in W '*
t^°UP,T be ai™need ^ saturated shells of
tron* IfS^V11^ additional shell of seven elec-
trons, similar to that of the halogen atoms.
E
nJ n<
*•¥
-96-
3. Examples: azide (8 + 7 = 15), selenocyanate (8 + 7 = 15),
azidodithiocarbonate (8+ 8+ 8+ 7 = 31 )•
4. Other radicals also have a total of valence electrons
Which can be arranged in shells of eight electrons.
Ex. N03" (23 = 2 x 8 + 7); 0H~ (7).
5. Formula,
outer electrons + valence e~ = 8n + 2m - 1.
m = number of hydrogen "atoms.
n = number of atoms surrounded by octets.
IV. Thiocyanogen (SCN)3.
A. Preparation.
1. The preparation of thiocyanogen suggested by Inorganic
Syntheses is by the oxidation of lead thiocyanate by
bromine.
Pb(SCN)3 + Br3 > (SCN)3 + PbBr3 (8).
2. Solutions of thiocyanogen may be prepared by oxidation
of the free acid by manganese dioxide.
4HSCN + MnOa = 2H30 + Mn(SCN)2 + (SCN)2
4HC1 + Mn02 = 2H30 + MnCl2 + Cl2
3. Thiocyanogen may also be prepared by electrolysis of
thiocyanates, in alcoholic solution (16).
B. Properties
1. Physical.
a. The solid is a crystalline material which melts at
-2 to -3°C,
b. Liquid (3CN)2 can be supercooled to -20° and then at
-30° it solidifies.
2. Chemical.
a. A solution of (SCN)3 in ether or carbon disulfide
(l) liberates iodine from iodides (7); (2) oxidizes
copper from cuprous to cupric state (3#'4jf.(3) com-
bines directly with metals; (4) reacts with mercury
diphenyl to yield phenyl mercuric thiocyanate;
(5) reacts with aniline to give p-thiocyanoaniline
and aniline thiocyanate: y\ NH*
2CQK6NH2 + (SCN)a = f i -f CGH5NH2HSCN
(6) reacts with unsaturated hydrocarbons to form
addition products (o): C3H4 + (SCN)2 = C3H4(SCN)3;
(7) aminolysis of thiocyanogen results in formation
of compounds analogous to chloramines:
(SCN)2 + 2NHR3 = NCSNR2 + NHR3.HSCN; (8) silver
thiocyanate reacts with nitrosyl chloride to form
nitrosyl thiocyanate; (9) reacts directly with
mercuric cyanide to form a substance of composition
CN(SCN) (4).
C. Formula.
In 1922 there was doubt as to the formula of thiocyanogen
but Lecher and G-aebel determined the molecular weight of
thiocyanogen and found that it corresponds to (SCN)2 (9). In
solutions of more than one n:.- ro.il/ there exist higher
polymers.
-97-
D. Structure.
It has been proposed that thiocyanogen exists In two
tautomeric forms (3).
S-C*N ^C*N
I 3 = S.
S-C^N XC=N
I II
The evidence obtained by Mario Strads by his x-ray studies
of thiocyanates, supports the first structure (9). He found
the three atoms in a thiocyanate ion are arranged in a straight
line. This is the structure suggested by Soderback.
Selenocyanogen (SeCN)a«
A. Preparation.
1. Selenocyanogen has been prepared by Birckenbach and
Kellerman by the electrolysis of potassium selenocyanate in
alcoholic solution (1). They also prepared it by the action
of iodine on silver selenocyanogen.
2AgI + (SeCN)a ?=—=- 2AgSeCN + I8
2. Kaufmann and Kogler prepared selenocyanogen (10 ) by the
reaction of lead tetracetate' in chloroform f?nd potassium
selenocyanate in dry acetone. The lead tetraselenocyanate
decomposes to give selenocyanogen.
B. Properties.
1. Physical, Selenocyanogen is a homogeneous yellow powder
and soon turns red in color. It is strble if dry and
kept in a vacuum.
2. Chemical.
Selenocyanogen decomposes in water to form a mixture
of H2Se03, HCN, HSeCN."
2Se(CN)a + 3H0H = HsSe03 + 3HSeCN + HCN
Selenocyanogen and carbon disulfide react when heated
to form Se3(CN)2 and Se(CN)».
C. Formula.
Molecular weight determinations in benzene indicate that
the formula is TSeCN)3 (3). Determinations in glacial acetic
acid Indicate that (SeCN)3 dissociates, maybe forming the
unsaturated radical.
D. Structure.
1. Tautomeric forms (3).
SeCN ^M
\ Se = Se^
SeCN ^CN
2. Linear structure (11).
Pierre Spacu in the study of the Raman spectrin KgeCN,
found that the frequency corresponds to the vibration of
CEN, and concluded that the formula of selenocyanate is
N5G-Se. Also selenocyanate is isosteric with Br-C=N and
since this is linear one might expect selenocyanate to be
linear.
i. J,
.
.
fr '•'«'
,M
Jjii ••
■ ft
■i
.
AS
10H
' t
■>'i
1
a. .
r
,/-.v,,-.y. f3
* ' • «
■'"' % • ■-■>* ■■*?■
t ■■
•"
i
■
• r
J -
i
: 'V J
•*. «v. <■
t C
1 ^•'•- .
#1*»
-98-
VI. Oxyce.no gen (0CN)3.
A. Preparation (1, 12).
1. Potassium cyanr.te reacts v;ith a neutral (25) solution of
hydrogen peroxide, cupric oxide or sodium hyoobromite to
form oxycyanogen.
2KCN0 + H303 = K2CN03 + CNO + H30
2. Nitrogen dioxide can be reduced by carbon at 150° to
oxycanogen.
3. Cyanogen bromide reacts with silver oxide to give
oxycyrnogen,
B. Properties
1. Physical.
(CN0)3 is a gas, lighter than carbon dioxide and may
be present in human exhalation.
2. Chemical.
Osycyanogen (a) liberates iodine from potassium iodide,
(b) reacts directly with copper, zinc and iron, (c) forms
interhalogenoid and halogen halogenoid compounds (13),
(d) gives a white precipitrte with a solution of barium
hydroxide, and (e) is believed to be the anhydride of
oxanic acid, H2CN02#
C. Formula and structure.
Little work on the formula and structure has been done.
According to Lidor, two isomeric oxanes may be obtained by
varying the conditions or procedure.
N = C = 0 0 - N = C
N = C = 0 0 - N = C
o< oxane ft oxane
II. A ziclo carbon disulfide (SCSM3)2.
A. Preparation.
1. (SCSN3)3 may be prepared by chemical oxidation of azide
dithiocarbonates such as KSCSN3 by H202, KI03, K3Cr04,
HgCl2, FeCl3, KHn04, KhO», Cl2, I8 and Br2 (14, 15). The
best procedure uses the reaction of a solution of iodine
in potassium iodide on a solution of potassium aziclodi-
thio carbonate. .
2. (SCSN3)2 may also be prepared by the electrolytic
oxidation of a solution of KSCSN3.
B. Properties.
1. Physical.
(SCSN3)2 is a white unstable crystalline solid which
is slightly soluble in water. It is very sensitive to
both shock and impact.
2. Chemical. (14).
a. (SCSN3)3 reacts slowly with dilute acids and rapidly
with concentrated acids, liberating sulfur. Nitric
acid reacts but no sulfur precipitates.
b. (SCSN3)2 reacts with "alkali in a, manner similar to
that of chlorine at -10 °C.
(SCSN3)3 + 2K0K = KSCSNg + K0SCSN3.
On acidification:
KSCSN3 + KOSCSN3 + H3S04 = K3S04 + (SCSN3)3 + H30
-99-
c. There is some indication that K0SCN3 is converted
to chlorate analog of azido carbon disulfide,
3K0SCSN3 = 2KSCSN3 + KO3SCSN3
d. HSCSN3 is an acid comparable to H3S04 in strength.
(K = 2.14 x 10~2). This acid is stronger than HP,
HCN and NH3 and weaker than HC1, HBr and HI.
C, Formula and structure.
Browne and coworkers confirmed the formula (SCSN3)3#
S S
N-N=N-C-S-S-C-N=N=N N=N=N-C-S-C-N=N=N
M it it
s s s
I (15) II
It was suggested that (SCSN3)3 exists in two tautomeric
forms, but Erow-ne believes the first structure to be the
correct one.
II. Cyanogen (CN)8 (16).
A. Preparation.
1, (CN)3 is prepared by the thermal decomposition of Hg(CN)3.
2. It can be prepared also by reaction of KCN on CuS04'.
•3. It can also be prepared by the dissociation of AgCN.
B. Properties.
1. Physical.
Vapor density is 2.321 g/l at 19.4° and 316.6 mm.
pressure. The boiling point is -21.17° and the melting
point is -27.9°C. It is a colorless gas, with a
distinctive odor, very poisonous and it is soluble in
water.
2. Chemical.
In alkaline solution it hydrolyzes to cyanide and
cyanate. It decomposes in sunlight forming ammonium
oxalate, ammonium formate and uren.
C. Structure and formula.
The formula- of cyanogen has been shown to be (CN)3.
Cyrnogen at first was believed to hove a ring structure but
after much spectroscooic and electron diffraction work
evidence has shown that the structure is NEC-CEN. The
parachor and small dipole moment seem to uphold this structure
(16).
IX. Azide (N3~).
The preparation of the free azide has not as yet been accomplished
although Browne has attempted several times to isolate it (17)'.
The radical has many properties similar to those of halogens.
A« Chemical properties.
1. Silver salts are insoluble.
2. Mixed halogenoids may be prepared.
3. Azides show absorption in the near ultra-violet region
similar (18) to iodine.
B. Structure
Much research has been done on the structure of the azide
ion. Among the structures proposed are the following:
N
HVNR R - N = N =* N R - N «-N E N
1(19) 11(20) III
I.
-100-
The ring structure was supported by Lindemann and Thiele
^o obtained pr.rrchors corresponding to ring structure, and
by riant sen wrio based his studies on spectroscopic absorption.
ihe linear structures are supported by Sidgwick and Freuci.
oidgwick bases his proposed structure on heats of combustion
and low dipole moments (20,21),
x« Tcllurocycnogen (TeCN)g.
Birckenbach and Kellermann attempted to prepare (TeCN)a by the
electrolysis of KTeCN in alcoholic solution but were unsuccessful
' I isoLte Lf radiccfl!1011 *" ^ "*" Blnoe th°Se first atteI^ts
I, Fulminate ion.
f^nlV?' few ^Periments on the fulminate ion have been tried thus
irft f^okenbaoh and his coworkers hrve attemoted to study it but
with little success (3).
%m Polyhalogenolds.
Several polyhnlogenoids have been prepared and their properties
studied. Included are K(SoCN Ia,X(SeCN 2I,K( SeCN )3, Cs(SeCN)3 <3).
Interhalogen-halogenoids. ' bVQbU-^3 \°>*
areT^e^\\riowirng:iStS * ***** nUBbeP °f SU°h 00^°^s- deluded
A. Azides.
IK3h(24Klde' C1K3 (22'23)J bw»»*"*, BrN3 (24); and iodoazide
B. Cyanogen compounds.
■ ioSde^CNlf (16^25 )TC1; Cyanogen «»»■"•. CNB^ *** cyanogen
C. Thiocyanogen compounds: thiocyanogen chloride, SCNC1; thio-
, cyanogen trichloride, SCNC13; thiocyanogen monbromide! SCNBr:
thiocyanogen tribronide, SCNBr3' (26,27).
D. Azido-csrbondi sulfide conroounds.
C1-SCSN3, BrSCSN3 rnd 3r3SCSN3 may exist (28).
^ 0CNBr?n°gen COmpOUnds: l0^xycyancte, ICNO (13); bromoxycyanate
Interhrlogenoids.
PY^^ *"* In the hnlogenoid field has been devoted almost
n V° the study of the structure of halogenoids and inter-
ndogenoid compounds.
o^n?HdpherMSte^;l0gerl0ld co^oun(3-s studied are the following: .
oyc.nazide, CNN3 (24) cyanogen thiooyrnate CN.SCN), oyanopon
selenocyanate (10, 27); cyanogen Czidodithiocarbonato CNOCSN, (27)
uniocyanogen azidodithiijearbonate SCN.SCSN3 (14) '
*o^C?h?i1L31r?n?-n?10? ??d hls oow> **«•<» have tried to extend the
divalent ralicall. ln0lucle mGny ^organic radicals including many
-101-
REFSRENCES:
1. Birckenbach, L. , and Kellermann, K#l Ber, 58B, 786-94, 2377 (1925).
2. Smith, G. B. L. , Browne, A. V, and others, J.A.C.S. 56, 1115-18,
(1934).
3. Audrieth, L,F. and Walden, P., Chem, Rev. 5, 339-59 (1928).
4. Soderback, E. , Ann. 419, 217 (1919); C.A. 14, 1808 (1920). '
5. Birckenbach, L. and Kellermann, K. , Ber. 64B. 218-27 (1931).
6. Birckenbach, L. and Kellermann, K., Ber. 67b, 1729-34' (1931).
7. Kaufnann, H. P., and Kogler, F. , Ber. 58, 1553 (1925).
8. Booth, H. S. , "Inorganic Syntheses", r>. 84, McGraw-Hill, New York
(1939).
9. Strada, Mario, Gazz. ohin. ltal. 64, 400-9 (1934), C.A. 28, 6382
(1934). *^
0. Kaufnann, H. P. and Kogler, F. , Ber. 59, 178 (1926).
1. Spacu, Pierre, Bull. boo. chim. [5j 3, 2074-6 (1936).
2. Lidor, A. P., C.A. 6, 2368, 2359, 30^3, 3094 (1912).
3. Birckenbach, L. and Linkard, M. , Ber. 62B, 2261-77 (1929);
Ber. 63B, 2544-58 (1930).
4. 3rowne, A. W. and others, J.A.C 'S. 45, 2541 (1923).
5. Sommer, F. , Ber. 48, 1833 (1915). '
6. Cook, R. P. and Robinson, P. L. , J. Chem, Soc. 1935, 1001.
7. Browne, A. W. and Lundell, G.E.F. , J. Am. Chem, Soc. 31, 435 (1909).
8. Levene, P.' A. and Rothenr A., J. Chem, Phys. 5, 985-8"Tl937).
9. Hantsch, A., Ber. 66B, 1349-54 (1935).
0. Sidgwick, N.V., Trans. Faraday Soc. 30, 801 (1934); J. Chem. Soc.
1929, 1108-10.
1". Frivel, L, K. , J. Am. Chem. Soc, 58, 779-82 (1936).
2. Browne, A. W., Frierson, W. J., and Kronrad, J., J. Am. Chem. Soc.
65, 1696, 1698 (1943).
3. Ephraim, F, , "Inorganic Chemistry", Fourth English Edition, Thorne,
P.C.L. , and Roberts, E.R. , Nordeman, New York (1943).
4. Yost, D. M. , and Russel, H, R. , '" Systematic Inorganic Chemistry",
Prentice-Hall, New York (194-1-).'
5. Beach, J. Y. and Turkevioh, A., J. An. Chem.- Soc. 61, 299 (1939),
6. 3aroni, A, Atti. accad. Lincei, Classe sci. fis. mot. nat. 25,
871-3 (1936).
7. Audrieth, L, F. and Browne, A. W. , J. Am. Chem. Soc. 52, 2799
(1930).
8. Browne, A. W. and Gardner, W. H. , J. Am. Chem. Soc. 49, 2759 (1927).
Inorganic Seminar
1945-46
Table of Contents
'Principles of the Boron Hydride Structure
Hans B. Jonassen 4
The Structure of Diborane
Margaret Kramer • 6
A Mineralogist Talks to 6hemists
T. T. Quirke 7
Basic Strength of Ammonia and the Methyl amines
Mark M. r:oyski .• 8
Habit Modification of Ammonium Dihydrogen Phosphate Crystals
J. A. Mat tern 9
The Preparation and Properties of Chlorine Azide
C . G. Overberger 9a
Solubility of Cesium Antimony Chloride in Hydrochloric A.cid
Henry Holtzclaw 2%
Rearrangements in Compounds of Carbon, silicon, Germanium,
and tin containing Halogens, Isocyanate, and Thiccyanate.
R. W. Parry 23
Researches on Residual Affinity and Co-Ordination XXXVIII
James V. Quagliano 25
Hydrogen Fluoride as a Solvent
Robert Burton • 34
Oxidation States of Copper
Henry Holtzclaw 38
Bibliography 42
The Production of Aluminum
John C • Bailar , Jr 40
Recent Tevelopments in the Chemistry of Organic Phosphorus
Diclorides and Their Derivatives
Arthur Toy 44
Some Studies On the Plating Of Cobalt and Nickel from
Coordination Compounds
Margaret Kramer • • • 49
Electronic Quantum States of Atoms and Molecules
H. A. Laitinen 52
Industrial Preparation and Uses of the Rare Earths and Thorium
Foward E . Kremers 59
Table of Contents -2
Isosterism in Inorganic Compounds
G. K. Schweitzer 63
Techniques in the Construction of Laboratory Apparatus
R. A. Penneman 68
The Metallic Borohydrides
Donald Starr 73
Magnesium Metal Production
Henry Holtzclaw 78
Photoconductivity in Alkali Metal Falides
C . J. Nyman 84
Donor Properties of Phosphorus and Sulpher Compounds
Clayton Callis 87
The Sodium Metaphosphates
Mary Ryan 92
Stability of Chelate Compounds
Hung Kao 95
The Carbides
Ann Lippincott 99
The Flourination of Non-Polar Chlorides and the Thermochem-
istry of Halogen Exchange Reactions
M. M. v:oyski 10?
The Stereochemistry of Complex Compounds Containing Organic
Molecules
Hans 3. Jonassen 105
The Reduction Potentials of some Inorganic Coordination
Compounds
James V. Quagliano 108
The Preparation and ^ror>erties of Some ^latinum Amines
J. A. Mattern Ill
A Study of the Olefin to Platinum Bond
A. L. Oppegard 114
The ^lectrodepostion of Chromium
R. W. Parry 117
-4-
Eclectron Deficient Molecules
Principles of the Boron Hydride Structure
Hans B. Jonassen October 23, 1945
K. S. Pitzer, Journ6 Am. Chem. Soc. 67, 1126 (1945)
sspisrs.te.d ssssr^SoJss!*6* for the buWne siiv-
This protonated double bond
formu^RdMSet-W8en e\ec*ro" Pair ^nled groups of general
„, shell^roiLiro^ atoV* 1SSS ^ the nuBber °f ™lenCe
^Snl°ne hydrogen «tom and one vacant orbital in each
e, i u up ,
3) is stable because there exists a moderate increase in
electron density around the protons. -"create in
The orbit*! characteristics of the new bond are
1] great%rW?haSnioSl°rbitalS at b°nding angles not ***
2) The hydrogen atom has an s orbital available.
=an ^^.'JniySrSiVSKc^: are^ t°*" *»***• "^
relsonab^L^fV11? boron-boron distance. This is in
^X^rdirzrlctlorda?^ a°°°rd "ith the eleot™ and
agreement rw?tht^tW,1St"ng rs a double bond. This is in
3) The double bon.6 tlnfrared and vibration ^ectra.
ever n. d Protons can be removed by acids- how-
4) Presence o??w "S„pr0°£ iS glVen fo/thls statement,
of the double bond- ?hlS«en-°eS theJ8^ °' breakage
that th/o « , ' ■ T is ls ln ao°ord with the faot
hvdro^n »? 8 moleoule splits when more than 4 of the
nyarogen atoms are substituted.
soectSni^ f£eotl?,_are very similar to the double bond
in thTt^f ?SVh? Patens can not move appreciably
6) h?„^ !♦ ?e of ,ele°tronlc transition. P y
Pofarlzatio/for^thsne" ff B*H?: 8S 00fflPa^ w"b 0.0
bond struct„J o? ,ne i&v°r? the protonated double
from ehl: Similar conclusions may be reached
with ammonia^ P°lFr Mtur« °f B.H. 1" its reaction
, ' • i ■-■:
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'* "• rT.ii
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7> : '.
' ■ C ■'■>.'.'■ *
, ",'H« :•• ■■■- •■
?• i'r
;'f J. .- ; ':'■ • ■
(*
z1 .•■>
• *'- ■ ... • O •: i' ' *i> Xl* -•■■*'"
.. „ «. ,. ...«-..-V • irJ -■' :- : ' ' - - - v ■
'■ >J •'■ •■'" . , <:■■>.-. -y .'o ■ \-
■'■■■'■■' »{- :s1 '•'! ;•;. r ■. ;;
v J.
if n
: :^ (.
!■-,'■( J-.''
... .ll?
., ■•> 'I
I ".i") 't.
V- w
! .1.
-5-
7) Specific heat, optical spectra, and diamagnetic suscep-
tibility data also favor this structure.
8) The theory is consistent with wave mechanics.
Pitzer also explains the absence of triborates by this struc-
tural theory although some of the reaction mechanisms proposed
are rather out of the ordinary.
The structure postulated here is a development of the struc-
tures proposed by Wiberg7, and Longuet-Higgins and Bell'.
Bibliography
i Longuet-Higgins and Bell, Jour. Chem. Soc. 1945, 250
2Dilthey, Zeit. angew. Chem. 34 596, (1921)
3Core, Chem. and Ind. j5, 642, (1927)
4 Win stein and Lucas, J. Am, Chem. Soc, 60 836, (1938)
sRamaswamy, Froc. Indian Acad* Sci. 2A 364, 630, (1935)
6Eistert, 2. phys. Chem, B52 202, (1942)
7Wiberg Ber. 69B, 2816 (1936)
■'-..■ t
.:;v »' ■ L '■:■'■.- , ;. .!. *;. j i: :
^ « v.. ).j ^ ...... 4 » ~> ^ .
■:; :> ' ■ ■■ a ■ )
... f „/■■■•■ ■- ♦ - '
•■•/ • ' . .•■-> • £»v
-6-
THE STRUCTURE OF DIBORANE
Mrrgaret Kramer October 23, 1945
Further ideas on the structure of diborane are discussed
by Burowoy1' who bases his Interpretation on the structure
originrlly proposed by Longuet-Higgins and Bell.8
H... ,H. „H
^ "bC
The linkages on the hydrogen, different from other hydrogen
bonds, were called resonance links by Longuet-Higgins and Bell.
Burawoy believes the hydrogens are electrostatic in nature
for the following reasons:
1) The presence of opposite charges on the 2 atoms (the
B is positive, the H is negative).
2) The chance for close approach of the atoms because of
their small sizes. He admits that the interpretation of the
infra-red spectrum will doubtless indicate the structure more
specifically.
In reply to the above, Longuet-Higgins and Bell3, while
agreeing that their approach is not the only one, discount the
electrostatic nydrogen bond for the following reasons:
1 ) If a dipole were present, polymerization would not
necessarily stop with B2HS — higher polymers would be possible.
2) The small size of the boron atom is not a decisive factor
for hydrides of Al and Ga are dimeric,
3) Calculations4 of the normal vibrations of the B2H6
molecule indicate the hydrogen to be the same distance from
each boron. This would not be true if the hydrogen bond were
electrostatic*
i Burawoy Nature, 155, 328, t945)
3Longuet-Higgins and Bell J. Chem. Soc, 250, (1943)
43ell and Longuet-Higgins Nature, 155, 328," (1945)
Bell Proc. Ro y al Soc. 183, 328, (1945)
i ; ■
-7-
A Mineralogist Talks to Chemists
T. T. ^uirke October 30, 1945
A geologist goes back to minerals as a chemist goes back
to atoms. "A mineral is an inorganic substance of definite
chemical composition vfcich occurs in nature." Since minerals
occur in nature, they are stable substances, and they are there-
fore limited in number of varieties. Their limited number makes
identification comparatively easy. The limited number of min-
erals which occur in igneous rocks, together with the uniformity
of chemical reactions under conditions of high temperature and
pressure which control their development, makes possible optical
methods of petrographic analysis. These methods are very
rapid T^y comparison with usual chemical procedures,
The stability of the commoner minerals often results in
their being economically unusable as sources of metals*
Mineralogists have a "phase rule" similar to that of the
chemists. The mineralogist's version is that "the number of
minerals in a rock is equal to the number of constituents of
which the rock is composed." The mineralogist's "constituents"
are usually oxides: CaO, Si02, etc.
The formation of crystal generations of the same common
mineral, derived from a m Iten source containing relatively
rare elements, a.lmost always results in replacement of a plenti-
ful atom by atoms of a closely related rare element in the later-
formed crystals. For example cesium and rubidium are found in
the late orthocla.se crystals, replacing potassium, and not in
the first-formed crystals. Futhermore lithium and other less
related rare elements also are concentrated in other minerals
with the late-forming orthoclase crystals.
Chemists and geologists working together would form an
advantageous combination in searching for rare minerals.
Many minerals might be found to be less rare than is now
supposed.
-8-
ROLL CALL
Basic Strength of Ammonia and the Methylamines
Mark M. Woyski November 6, 1945
Herbert C. Brown J. Am. Chem. Soc. 67, 378 (1945)
On the basis of the inductive effect of the methyl group the
base strength (or donor ability) of the ammonia molecule should
increase regularly with the number of methyl groups substituted
for hydrogen. Actually the basic strength (relative to the
proton as reference aPld) increases up to RaNH and drops for R3N,
This fact may be interpreted on the basis of steric hindrance.
The bond angles in the ammonia molecule are 90°; the introduction
of larger groups increases these angles until in R3N the angles
exceed the tetrahedral angle. In this case bond strain results
when the molecule assumes, or attempts to assume, the normal
tetrahedral ammonium ion structure or formation of a salt. This
steri- interference of the methyl groups prevents the formation
of a coordinate covalence of maximum strength, or, it is said,
the base strength is diminished*
The authors have termed this 'B'-strain' at the 'back' of
the molecules as distinguised from the front where salt formation,
takes place.
The relative base strength of ammonia and the methyl amines
is also dependent on the reference acid. It will be seen that
steric hindrance may be introduced if the acid molecule is large
or has large attached groups. (F-« Strain') It will also be
obvious that steric effects will be greater the greater the
number of hindering groups on the base so that, comparing the
base strength of ammonia and the methyl amines against progess-
ively more highly hindered acids the order of base strength will
be found to change from the initial order (proton or hydronium
ion as reference acid)-.
RaNH < RNHa < R3N <NH3
to R2NH <RNHa <£NH3 /VR3N
to RNH2 <NH3 < RaNH<R3N
to NH3 < RNHa <^R2NH<R3N
Data on dissociation constants of compounds of ammonia and
amines with trimethyl and tributyl boron support these views.
I should like to point out that this may also be explained,
in part, by adopting the view that introducing larger groups
into an acid such as trimethyl soon decreases its acid strength.
.1 L
a-
i ; .o
c- -i .
-9-
ROLL CALL
Habit Modification of Ammonium Dihydrogen Phosphate Crystals1
J. A, Matt em November 6, 1945
Ttfhen ammonium dihydrogen phosphate is crystallized from pure
solution, its crystal consists of a. second order prism in combina-
tion with a second order bypyramid. TVhen crystallized from
solutions containing certain metal ions, the prism faces are
tapered as much as 16°.
Ions which produce
taper
SnJ* Aui3
Cr+3 A1+3
Fe+3 Be+S
Tl+4
Ions which produce
observable taper
Hg+s Ni+2
Cu+S
Zn+2
Pb1"2
Ag
Ca+3
Ba+2
no
Tl+
K +
Na+
It is see
which produce
n that small j highly charged, cations are the ones
wnicn produce this modification of crystal habit. These positive
ions are adsorbed on the crystal lattice, expecially at points
where the concentration of negative H3F04~ ions is the highest,
A study of the crystal structure2 shows that the concentration of
H3F04 is the greatest on the prism faces and second greatest in
alternate layers of the pyramid faces* Adsorption, then, will be
very pronounced at the intersection of prism and pyramid faces
when the latter consists of H3P04~ ions. Vttien the next layer of
H3P04~ ions in deposited they will be pulled in a little closer
because of attraction for the adsorbed' positive ions« Thus*
stepwise, the prism face is drawn in and the observed taper is
produced.
it wJffnnnlV^^f \i0nS °f sufflc^ntly high concentration,
it was found possible to prevent crystal growth entirely,
tin1Pnrol0US/1nV^Sl1?a^i0ns of adsorption with consequent modifica-
tioa of crystal habit has been reviewed by W. G. France. 3
References
*Kolb and Comer, J„A.C.S, 67, 894 (1945)
3Hendrlcks, Am. J. Sci,, 14~ 269 (1927)
3NpffXvndvr\TMCSll0,id Chemistry\ Reinhold Publishing Corp.,
New York, N. Y. , 1944 Vol, 5, p. 443
I ".) 0
J.' A
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I ':
If) fV«v ••••:: •
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I. <•-
t x ■
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.••3fto
I ' -V
1 i.
■: / -..Pa '*
■,■ ,'V
fV , ,;-
T '
<*£
'■' -.d
9a
ROLL CALL
The- Preparation and Properties of Chlorine Azidei
C G. Overberger November 6, 1945
azide is'undolbtedlv^Sf t^tS^06?"1^ the Parties of chlorin,
+-V, uuuuuubeaiy aae to the extremely explosive charpntpr of
the compound which in undiluted condition detonltee violently
without apparent provocation. ^ncttes violently
w
reparation
1 agNa + CI 4 AgCl + C1N3
aold t~' eaSj2^1S». The gradual nddition of acetic
in anueous aolit'Ln ^f S^1Um S=Mfc Rnd sodlum hypochlorite
in* SSilibS™ ' 6 re?ctlon "* ^ expressed by the follow-
ing equilibrium
HN3 + *0ClxZzzz^=zzz^ clNa + Ha0 '
Properties
1) Physical: boiling point, approximately -15°: melting
? lv 2f°^m?' dy -J00°; " is lightly soluble m'wa rand
readily soluble in most organic solvents.
2) Chemical
*0 i-roooole behavior toward liquid ammonia
T# i ClN3 + 2NH3 + Nk2C1 + NH4N3
If tne ammonia, is greatly in excess
oClN3 + 8NH3 ^Ns + 3Nh4C1 + 3NH4N3
b) Behavior toward oentane
CIN3 + C5H12 ^ HNa + CgHnCl
c) 3ehavior toward metals
4Ci.%+ 6Na ^ 4NaCl + 3Na + 2NaN3 (violent
Hg reaction;
Zn
violent. ^ S n°naqUeoU8 B0lvent ^ used the reaction is less
d) Behavior toward phosphorus
were conden*^ * ^^of pure liquid chlorine a.zide
d"^a??onnoccur5eS In'ev? f°^ho^8 ** -"»•, * spontaneous
It may be ascriSable eVherV^ ^^ the lapse of a few minutes.
probably detonate with !vt~ ^e liberation of azine wMch would
an un.tib ' .h extreme violence or to the formation of
an unstable phospnorus azide or complex chloro azide.
Reaction of chlorine azide with silver azide3
3C1N3 + 2AgN3 -=Z1__> 2N3AgCl + 3NS
>■' .:■ ' , J. .-"
.
f ■
■'■■ - ' >
> . . f
- ■ .
r
• j ;.
" V
9 b
REFERENCES
1) Frierson, Kronrad and Browne, J. A». Chem, fco., 65, 1696 (1943)
2) Raschlg, 3er- 41, 4194 (j.908)
3) Frierson and Browne. J. to. Chem. Soc. ., 55, 1S9P <1943)
ROLL CALL -X2-
S0LU3ILITY OF CESIUM ANTIMONY CHLORIDE
IN HYDROCHLORIC ACID SOLUTIONS AT 25°C.
Henry Holtzclaw November 27, 1945
Ret: Bender, J. Am. Chem. Soc. 67, 1771 (1945).
The isolation or purification of cesium salts is usually
accomplished by precipitation from a hydrochloric acid solution
of the double salt cesium antimony chloride. Until the work
described herein, however, no previous satisfactory data on
solubilities in this system had been determined.
In the experimental work, spectroscopically pure cesium
chloride and standard analytical reagents of other materials
were used. Analytical determination of antimony was accomp^
llshed by titration with tenth normal iodine solution, stan-
dardized against arsenic trioxide. Hydrochloric acid solutions
were standardized gravimetrically by precipitation of silver
chloride. A Bausch and Lcmb Littrow Quartz Spectrograph was
used for spectrographs determinations.
In the determination of solubilities, temperature was
maintained at 25.00+ 0.05°C. Duplicate samples were taken each
time, equilibrium being checked by analyzing additional dupli-
cate samples taken after extra time had elapsed, A pycnometric
method of density determination was used to convert results
to the volumetric basis. The probable error in solubility
data is about 0.3fo,
The double salt which was used showed an antimony content
of 25.38 ± 0.05$, substantiating the composition 3 CsCl . 2SbCl3
(calculated 25.33 ± 0.05$ antimon^. A difference in color of
the double salt was noted for various conditions of prepara-
tion. In all cases, however, the salt showed the same composi-
tion. In cases of recovery of the salt by routine methods,
thallium was found to be th« cause of the darker color, 0.005$
thcUiruL/ in one cesium cftioTTcie be^ng^^uTTTtcjTeTiir-iro'^fuaTioe ~
darkening. ^
Table of solubility of cesium antimony chloride in
hydrochloric acid solutions at 25°C. :
Molality Grams salt/100 cc
of HC1 Grams salt/ 100 grams solution
solvent " ~
2-086 * T??ZZ 1#778
2.953 1.389 1.444
4'027 1,236 1.304
4-869 1.178 1.256
6.875 1,114 1#217
,o'^7 1-0e3 1*218
12.92 1.093 1.258
16«20 1.134 1.333
Results show sufficient solubility to make practical the
separation of cesium from the filtrate. The suggestion is
made for use of stannic chloride to precipitate Cs8SnCl<
-6 •
■
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I
"
it ■'■
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( ... ■ ■• .■* i
u
•23-
Rearrangements In Compounds of Carbon, Silicon, G-ermanlum,
and tin containing Halogens, Isocyanate, and Thiocyanate,
R. W, Parry November 27, 1945
Forbes and Anderson - J.A.C.S. 67 1911 (1945)
Forbes and Anderson - J.A.C.S. 66_ 931 (1944)
Fundamental calculations by Urey and coworkers on isotopic
exchange equilibria emphasize the fact that not even units so
closely similar as isotopic atoms attain a truly random distri-
bution among similar molecules; however, Calingaert and co-
workers found that random exchange of organic radicals occurs,
within experimental error, among certain alkyls, chloroalkyls,
and esters and among different halogen atoms of ethylene halides.
They were able to make quantitative equiliqrium predictions
based on the laws of probability only. Chemical or energy
factors did not seem to influence the random distribution.
This work of Calingaert has been extended by Forbes and
Anderson to a number of halides, isocyanates, and thiocyanates
'Of Group IV A elements. The mixtures chloroform and bromoform;
methylene chloride-methylene bromide and methylene chloride-
methylene iodi d e were heated in sealed tubes in the presence
of moistened A1C13 and KC1. At eouilibrium, mixtures were
analyzed by a form of fractional distillation. That distribu-
tion was very nearly random is shown by the data for an
original mixture of C^C13 and CHBr3.
Prig. Mixture <fo Equil, Mixture $ $
o.Uml. CHU13^ CHUT3 ~ CHCl^r CHUTBr2 CTE?ra
2.1ml. CHBr3 f observed. 17 43 31 9-:*
calc., for 17.4 41.4 32.6 8.6
random dist.
Random distribution was also observed for the methylene halides.
b) The equilibrium constant for the reaction 4SiCl3 SCN=-="^
3SiCl4 + Si(SCN)4 was determined by this same technique
as K (Mole fractions) = 0.11
c) Studies of Si(NC0)4 and Si(SCN)4 revealed the orobable
existence the new compound Si(NC0)3 SCN boiling at 126°C
under 28 m m nrfiflsufe. Isolation nf the compound was
considered possible, but has not yet been attempted.
d) Studies of GeCl4 and Ge(NC0)4 indicated the probable
existence of a very unstable comoound G-eCl3NC0 boiling
at 112° and 760 mm.
The stability of compounds produced on rearrangement de-
creases from carbon to tin and from chlorine to iodine (i.e. with
decreasing electronegatively of the halogen or psuedohalogenj.
r< c -J X
i ..'■.' ■ ■■ ■• ■ . -
\A Nfc • :••■ ••/ ■•; • hJ3
r - ■ .- .. <*• > ;
I . I
\ ' I ' '.'
, (
. rjjfi^i
X1
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-25-
ROLL CALL
Researches on Residual Affinity and Cb-Ordi nation XXXVIII
James V, Quagliano November 27, 1945
Burstall, J, Chem. Soc, 1938 1672.
r V — * y » is a
:olecule which functions as four-fold coordinating group.
Polypyridyls are bases in which two or more pyridine rings are
linked but net fused together. Six isomeric dipyridyls are known
but only 2 : 2* dipyridyl has noteworthy properties as coordinat-
ing agent toward metallic salts. The linkage necessary for ■
coordination is = #-C-8-N=# Burstall has made the dl,
trl, tetra, penta,"and hexapyridyls* The tetramine combines with
many metallic salts forming coordination compound? of the type:
[M+ tetrpyj X, (K tetrpyjX3, and [K4" tetrpy) X3. These com-
pounds contain only one molecule of base oer ion of metal a.nd
differ from compounds containing two molecules of dipyridyl per
ion of metal. Morgan and Burstall prepared salts of Fe, Co, Ni,
Cu, Ag Zn, Cd, and Pt, having anticipated that tetrapyridyl
could function as a quadridentate coordinating unit.
Univalent Salts: Reactions of Ag+
AgN03 + tetrpy -|^g^n-U ^g+ -tetrpyjN03( yellow)
This compound resembles [Ag1 2 dioy] N£3 in appearance but
the silver ion in the former compound is nst oxidized to t he
divalent state by persulfate, (S"208=)
Divalent Salts: „ n_ , h .,
FeS04 + tetrpy -H|Q^lc^ol^ ^ tetrpyjS04.4HsO
reddish-
brown
/jJ/120o
[Fe tetrpy] So 4
green-yellc
CoCl2 ♦ tetrpy |i^l^ [CO tetrpy] CI.. 2^0-^^--)
(CctetrpyJ Cl3. H20 Pink
brown
[Ni tetrpy]Br2. 2H20 , [Cu tetrpyj Br2 1/2 H20 , (zn tetrpy] CI,.
(Cd tetrpyj C12.H30, and (pt tetrpyj jptCl*/, were also prepared.
Triyalent Salts: m
[CcJ^tetrpy] C12.2H20 gflg{U» [p? tetrpy ClJ CI. 3H20
grey-green
fir Cl3 tetrpyj 3 IrCl6 was also prepared.
>
« . •
-26-
Horgan and Burstr.ll regard 2 : 2» : 2" : 2* ' ' tetapyridyl as
having four pyridrine rings in one plane and state that when
the four nitrogen atoms are all co-ordinated to one metallic ion,
the base and the metal lie in the same plane,
With compounds of the types [k tetrpy) X and CI tetrpy) X3, a simple
plandr arrangement exists. Compounds of the type m tetrpy XgJ X
have an octahedral configuration with the X groups in the trans
positions, only one isomer could be obtained, Morgan and 3urstall
do not prove conclusively the configurations of the compounds but
state only that they are most in keeping with physical and chemica:
properties.
Tetrpy =2:2' : 2" : 2' ' ! t&trapyrldyl
dipy =2:2' dipyridyl
.! &
I t : i
-34-
Hydrogen Fluoride es a Solvent
Robert Burton n ^xven&
December 10,
1945
fact that experimental dlfnSultlei %~ Proba°ly due to the
special gold or platinum «Z „ ^! ^P freat in that
nydrogen fluoride is a ver- dan^nL re?ulred- and also that
Thenard, Faraday, Fremv and Mnf = S ??lnson- Soheele, Davy,
and several other, early ?nves?ll^ 8l1 suffe™d from poiJn^ng
iiy investigators were killed,
hydrogen ?f luorldi, "and^is^elhod^o?1'61531'6 pUre hydrous
(8). Gore 3) studied soluhi'ntVf Preparation is still used
few inorganic compounds in hydrotn^ °on^ct^"ieS of «e
was done until FredenhageS and co SnSUOrl2e* Llttle raore
tions in 1928 (6, 7, 8,^" lof e°-workers begin their investiga-
same way^X^er Te?%T *&£' «?VltaU metals in the
only superficially. ' bUt °tner metals d° not react, or react
ocrrespondLffi^ridfls'fn8 T n* "a* ^ely evolved and the
and ferrous chloride.
manganous chloride
from
uoride
ing
Table 1
Freezinp- r 3ni iinff — f — rr . eiaied Compound r
Point og ml1^ ^&aF~ J-MoW ^^
! ?,!? °f ' 1e»t of Const,
Fusion
Calorie
Vapor iza-j
tion
Calories
6020
ctric
tant
.'v
b.- ■ r
-35-
The specific conductivity of hydrogen fluoride is less
than 1.4 X 10"5 (5); the dielectric constant is 174.8 at
-73°, 134.2 at -42°, and 83 at 0°C. (4).
A comparison of the properties of hydrogen fluoride with
those of the other substances in Table I indicates that hydrogen
fluoride is a highly associated, oolar substance, and it would
be expected to be an excellent solvent, which it is. Its acidic
nature, or non-accepting properties, make it quite different
from water.
Gore made qualitative solubility measurements as did
Franklin (18), but Frendenhagen and Gadenbach made the first
careful determinations.
2.
Their results are summarized in Table
Table 2
Solubility of Inorganic Substances in Hydrogen Fluoride
Slightly
Soluble Soluble Insoluble Soluble with reaction
H80
NH4F
TiF
NaF
KF
RbF
CsF
TIF
Ag+
Hg(CN)2
HN03
NaNOa
AgN03
K2S04
Na2S04
Organic molecules
Containing
0, S, N, or C=C
React.
Product Insol.
MgPji
CaP a
SrFs
BaF8
CaS04
KCIO4
H2S
CO
CO 2
A1C13
FeCl2
MnCl2
CeCl3
MgO
CaO
SrO
BaO
PbO
BaO 3
A1203
CuO
.uble with reaction
alkali halides
alkaline earth halides
KCN
NaN3
KPSiF6
KCIO3
BaC103
Hydroxides
2
3
3
AIF3
ZnF2
FeF3
PbF2
CuF2
HgFs
HC1
HI
HBr
HN3
SiF4
Cu(N03'
Bl N03!
Pb(N03;
Co(N03,
ZnS04
CdS04
CuS04
Ag2S04
Insoluble
Unreactive
ZnCl2
SnCl2
NiCl2
CdCl2
CuCl2
Kgl2
AgCl
AgBr
Agl
HgO
Pb03
MnOs
Sn02
Cr203
wo 3
Satii7*ated hvdrocarbonR
: I I
E
■
■36-
Fredenhagen and Cadenbach determined equivalent con-
ductivities of many substances, both organic and inorganic,
over fl ranee of dilution. Their results Pre summarized in
Figure
Sod-
KMO,
eM*o
CuHsOH
j
j
30 *+o sro 6^
70
So
c\0
r
{jON0ucTiVtT/^6 IN Liquid H VOfiOG/rM rLuoftlQB
It is apparent that the/\0 values fall in several ranges.
These ranges correspond to the formation of various numbers of
ions per molecule. Potassium fluoride and silver fluoride have
nearly the same conductivities and are apparently completely
dissociated into two ions, but potassium nitrate, and potassium
cet
Fred
KF — K+ + F
KNO3 + 2HF K + H?N03 + + 2F~
HMO 3 + HF H3NO3+ + F~
Water gives two ions which are shown to be from the following
reaction:
Hs0 + HF H30+ + F~
iductivity of HsS04 is slightly greater than that of
sociatea into two ions, out potassium nitrate, ana pox
;ate, both binary in water, apparently give four ions,
Lenhagen explains this by oroposing the following:
The
w<
'ter and has been explained by the following:
H3S04 + HF HSO3F + H30+ + F~ ,
the H303F being slightly dissociated.
Alcohols act as binary electrolytes; two theories to
account for this have been proposed; either a fluoride and water
preformed, oi* a proton is added to the alcohol and a fluoride'
ion formed. The latter is more probable. The same process
"holds in general for other organic substances. Specific groups
■ „ . .. i
-37-
such as 0~~, S", N~, or ~C=C" must be present in the organic
molecule or ionization does not take place (15). Klatt, a student
of Fredenhagen1 s, has investigated many organic systems (13,14,15,
16, 17, 19). A summary of the uses of HF in organic chemistry
has appeared recently (20).
Ac id- base theory is very helpful in explaining many of
the observed reactions, For instance, trichloracetic acid is
very slightly ionized in hydrogen fluoride. In water it is a
stronger acid than acetic -, that is, it is a stronger donor and
weaker acceptor. Thus it would have less tendency to take the
proton in HF, hence its conductivity is less than that of acetic
acid. Phenol is more acidic in water than is alcohol; hence it
is a weaker acceptor and should be a poorer conductor in hydrogen
fluoride than ethyl alchol. This is the case.
A comparison of the three solvents, ammonia, water, and
hydrogen fluoride shows that ammonia is more basic than water
as water adds a proton to ammonia, and water is more basic than
hydrogen fluoride as water is the acceptor in this case. It
is therefore to be emphasized that the nature of a polar solvent
depends largely upon its acid-base properties. Hydrogen fluoride
acts as a donor.
References
1. Fremy: Ann. Chem, phys. , (3) 47, 5 (1856)
2. Simons: Inorganic Synthesis, Vol. I, 134, McG-raw
Hill 1939
3. Gore: Phil. Trans, 159, 173 (1869)
4. Fredenhagen and Dahmlos: Z-. anorg. allgem. chem.. 178, 272 (1928
5. Fredenhagen and Cadenbach: ibid., 178, 289 (1929)
6d Fredenhagen and Cadenbach: Z. physiRT'Chem. , 146, 245 (1930)
7., Fredenhagen: Z Elect rochem. , 37, 634 (1931)
Br Simons: Chem, Reviews, 8, 213 TT931)
9, Fredenhagen,, Cadenbach, and Klatt: Z physiK. chem., A164, 176
(1933)
10 o Fredenhagen, Klatt, and Kunz: Z anorg. allgem. Chem., 218, 161
" (1934.,
11, Fradenhagenr Z physik, chem., B40. 51 (1938)
12„ Fredenhagen and Cadenbach: Z anorg. allgem. Chem,, 243, 39(19:
13. Klntt: Z. phyeilC chem., A 173, 115 (1935)
140 Klattj Z, anorg, allgem chem., 222, 225 (1935)
15. Klatt: ibid., 222, 289 (1935)
16. Klatt: ibid., £33. 307 (1937)
17. Klatt: ibid., 234, 189 (1937)
180 Franklin: Z. anorg. chem., 46, 3 (1905) footnote
19, Klatt: Z. physiK, chem., A- 18 5 , 306 (1939)
20 . Wie chert: Die Chemie, 56, 333 (1943)
f. *
-38-
Oxldatlon States of Copper
Henry Holtzclaw December 18, 1945
I. Introduction
The three elements coooer <?11vpv •>** ~ -i a
known to have three oxidatinn i+fj lver' and gold, are each
oxidation states or silver ZJ*' +1i +2' Pnd +3- Th^
0. Bailar, Jr. ^a? a University ni,f ,Vr°fassor John
in 1944 (3) the wtPf \i J • y or Illinois Inorganic Seminar
year (4) ' „ the &ubl fhed later in the same
+ 2 are well recognize! A ??£ & oxidation states of +1 and
copper briefly. gSaven*and Snder ^°k? mention bivalent
ietry" (7), ?nd Latimer "Ox !„ ^™ F0,,1"?^010 Ch^~
one sentence on trivalent Conner °? '' te? (i4)> each h™e
leal Chemistry" (22) a"'J?Pf rl T«ad.well and Hall, "AnaHy-
L, majority of textbooks oalTment? on fnt?rely X^f f
u'f concerns trivalent copper, principally. ^ S dlscussl°n
11 . Summary of Early Work
copper^ndf in0i8l4irSre^f *he exlstence of trivalent
valent cooper by oxidltion of ?,"P?ra^12n °f a °™P°und of tri-
Fremy (9) in t.!! ° ouPrlc hydroxide with chlorine
*afn(?kal"eSec ee/^ou^f^ unsuccessful attemptfto
to react with potassium hyoochlorite a}lftnS°^rla hydroxide
potassium nitrate. Crum (l) , illk d ^ fusinS brass with
upon a mixture of'cupric hvdro^d. fi USed Caching powder
Ported the analysis of the t ^ n Jnd CUprlC nltrate and re-
to the formula Cu3o° M,^m r° °orrespond approximately
work, revived the wn* ?„ ? { '' forty years after Fremy s
amount of potassium hydro xfdf S? hydr°^da with a large
potassium perchlorate dissolving £ ° °^Prl° 0xlde with
in each case, In ice cold fnrli g uhe Produot of the reaction,
when he decomposed copper cerox^ Hf °btalned similar results'
Vital! (23) reported 1„1B4 (^°s) Wlth filing water,
valent copper by react} n of' /°rmat"n of an oxide of tri-
hydroxide. reactl n 0f sodium hypobromite and cupric
telluriurfro^coPDer^L^L0" * ne" method ot separation of
during oxida?ion of telluro,^nI'-rd bls™th, noticed that
potassium persSlfate toe ^ , ? d !° tellurl° by means of
when traced or copplr were 'pre ent *"%? ^^nsely purple
pro^siS^^^ studied the
(or)2Cua03.Cu0.3Te03.2Ks0.xH20
2Cn°oe S" WSS the 00™er a*d trivalent:
2Cua03.3Te03.2Ks0.13H20
Kuzma felt that the salts were salts of complex Oopp^tellu^c
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-39-
Kawrow (18), in 1900, and M0ser (19), in 1907, oxidized
copper salts with hypochlorites and hypobromites, obtaining
products which contained only/ very small auantities of active
oxygen, probably because compounds were analyzed after partial
decomposition by drying. Muller (20), in 1907, reported obtain-
ing a brownish-red precipitate both of oxidation by cupric
hydroxide with chlorine in a strong potassium hydroxide solution,
and by che interaction of hypochlorites or hypobromites on
metallic copper, or on cupric hydroxide. Together, Muller and
Spitzer (21; followed this work with further experiments
the same year proving the trivalency of copper and showing the
ratio of copper to oxygen to correspond to Cu203 in a product
obtained by anodic oxidation of copper in concentrated solutions
of potassium or sodium hydroxide.
III. Work of Vrtis on Composition of Trivalent Copper Compounds
a. Preparation and analysis of compounds:
Vrtis became interested in establishing the composition
of the complexes containing the trivalent copper. He prepared
his solutions according to two methods;
1. Oxidation with potassium persulfate: An excess
of telluric acid was added to the solution of cupric
sulfate and warmed with potassium hydroxide and persulfate
on the water bath. If the ratio of telluric acid to
cupric sulfate was low, a reddish-brown precipitate
occurred. If en excess of telluric acid was used, a
clear, de-ply purple solution resulted, without any
precipitate.
2. Anodic oxidation: The anode was a platinum
cup, plated with copper, and filled with a solution of
potassium tellurite and hydroxide. The cathode was
platinum, dipped in a dia.phram containing potassium
hydroxide solution. A high current density favored
immediate formation of the purple trivalent copper
solution. Vrtis used the anodic oxidation method,
principally, to eliminate reaction products formed by the
oxidizing agents.
Vrtis carried out analysis of the products by titration
of the active oxygen with hydrogen peroxide and gravimetric
determination of copoer as the sulfide. The amount of
trivalent copper was calculated from the value of active
oxygen. Solutions prepared by either persulfate or anodic
oxidation contained 95.8 to 98.1$ of the copper in trivalent
form. Those containing persulfate were more stable than
those produced by anodic oxidation. Total decomposition took
place after one to two weeks. A rise in temperature favored
decomposition; cooling favored stability.
A number of experiments were carried out substituting
other bases in place of the potassium hydroxide, and hypochlori+
in place of persulfate, with varying success.
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-40-
Investigation was made of the importance of the tellurate
in the reaction by carrying out the anodic oxidation without
the tellurate, followed by dipping the anode deposit into a
solution of tellurate. The tellurate, apparently, is not
necessary for formation of the trivalent copper compounds
but does accomplish two things:
1. Solution of the trivalent copper precipitate
through peptization, due to the tendency to form complexes:
KOH.Cu(OH)3.nK3Te04,Te(OH)6
(n exceeding five in the case of the tellurates and one
in the case of the oeriodates).
2. Increase of stability of the trivalent copper
because of the high degree of oxidation of the tellurate.
Periodates were found to fulfil the same conditions as
tellurates. The compounds obtained, using periodate instead
of tellurate, contained 96.5 to 98.2$ of the copper in the
trivalent form.
The trivalent coooer solutions proved to be colloidal when
investigated ultramicroscopically. When spectroscopically
analyzed, the solutions gave no selective absorption band,
showing only continuous absorption in the violet region, a
phenomenon characteristic of colloids.
b. Determination of composition of compounds:
Potentiometric determinations were made, in order to deter-
mine the composition of the trivalent copper compound. A
copper electrode in solutions containing trivalent copper
has a potential, due to the electrochemical process:
e~ + Cu+++ -> Cu++
Thus, the half-reaction+e.m.f . is given by the relation:
T = ES In — $]]++.< + K
By considering the relation of all the ions present:
p£7P (6u++3q (9H-jr (Te04=Js = const.
and by varying the concentration of one component, keeping
those of the others constant, calculation could be made of
the number of ions combined with one copper ion. The value
obtained was greater than 3.5. The concentration of tellurate
ions was found to have no influence upon the concentration of
the trivalent copper ions. The concentration of hydroxyl ions
had an inconsistent effect, which might be explained by the
variability of the potential Cu Cu(CH)2 found by Allmand
(19,20), The concentration of the trivalent copper ions was
found to be indirectly oroportianal to that of the potassium
ions. The fact that the potential of the electrode depends
upon the concentration of the potassium ion shows that
potassium is a constituent of the trivalent copper compound.
The .formula KCu(D2 would explain behavior of the electrode,
by decomposition. The stoichiometric composition is, apparent!,
nearest to the formula KCu(0H)4.
- . j ;
i ■ ■ • ■
-41-
Trivalent copoer hydroxide is an acid and, thus, bears
out the theory that the basicity of an oxide decreases with
increase in oxidation number. Cu20 is a. definite base, Cu(OH)2
is less basic, and Cu(OH)3 is on the acid side.
IV, Summary of Work since 1925
In 1935, 3untin and Vlasov (6) dissolved freshly precipitate
cupric hydroxide in excess 34^ sodium hydroxide solution and
treated the resulting solution with Na.H03. A violent reaction,
for which the temperature must be controlled, ensues, resulting
withing ten to fifteen minutes in a red precipitate of Cu203.
The yield, based on NaCu02, is 80 to 80^. With sulfuric acid,
the Cu203 does not give hydrogen peroxide and is, therefore,
a. true oxide. In the presence of nitric acid, the compound,
oxidized oxalic acid to carbon dioxide and water. These
experimenters substantiate the waTrk of Vrtis on stability,
by showing that the compound is quite unstable at elevated
temperatures.
Malatesta (15)16,17), in 1941 and 1942, worked on pre-
paration of pure trivalent copper and trivalent silver tellur-
ates and periodates* The periodates of trivalent copoer were
of the composition M7+Cu+"H"(I06 ) 2. nHs0. The trivalency in
such complexes in indicated by the method of preparation, their
chemical properties, their magnetic susceptibilities (compounds
are diamagnetic ) , cnCi by the fact that the corresponding gold
compound can be prepared directly from a. salt of trivalent
gold. The compound K7CuI2012# 7H20 was prepared as follows:
a. Filter a mixture of potassium oeriodate (23 grams),
aqueous Potassium hydroxide (27 grams in 70 cc), and fresh
oupric hydroxide (0,05 M).
D. Electrolyze in a. porous cell containing 10$>
aqueous potassium hydroxide (lOcc) with a Winkler screen
anode and a platinum wire cathode and current of one-
ampere for two hours.
c. Evaporate in vacuo.
d. Filter and wash residue with ethyl alcohol.
e. Dissolve in minimum of water and repeat the
operations*
The compound is emerald green; }.ts aqueous solutions are brown;
and it is decomposed by acids with evolution or oxygen.
Malatesta prepared tellurates of trivalent copper and of
trivalent silver, of general composition M«+ If*"1"* (Te06 )2.nH20,
in a way analogous to the preparation of the periodates.
Na5H4Cu(Te06 )2.18H20 is a maroon red compound which, with 20^e
aqueous sodium carbonate, can be changed* over to another form,
Na7H2Cu(Te06 )2.12H20, dark chestnut red, insoluble in dilute
aqueous sodium carbonate. In aqueous solution, the second
form is slowly transformed into the first.
V. Conclusion
Enough work has been done on compounds of trivalent copper
to prove their existence and something of their composition
and properties. Although the field seems to show considerable
promise of new compounds, recent work is somewhat lacking.
-42-
BI3LI0GRAPHY
1. Allmand, J. Chen. Soo.. 95.. 2151 (1909).
2. Allmand, Ibid, 97, 603 (1910).
30 Be liar, Inorganic Seminar, Univ. of 111. (1944).
4. Bailar, J . Chen, Ed., 21. 523 (1944),
50 Brauner, 3er0 , 40, 3362 (1907)o
6. Buntin and Vlasov, Act?? Univ. Voronegiensis, 8, No. 4, 6-11
(1935)
7. Caven and Lander, "Systematic Inorganic Chemistry", p. 113
(1930).
8. Crum, Ann., 55_, 213 (1845).
9. Fremy, Ann. chim. Dhys., (3), 12, 457 (1844).
10. Kruger, Ann. Phys. (Poge. ), 62, 447 (1844).
11. Kruss, Ber. , 17, 2593 (188477
12. Kuzma, Rozor. c. ak. tr. (2), 10, 31.
13. Kuzma, ibid, (2), 14, 11.
14. Latimer, "Oxidation States", p. 169 (1938).
15. Malatesta, Chem. Zentr. 1942, I, 2114-5.
16. Malatesta, Gazz, chim. ital., 71, 467-74 (1941).
17. Malatesta, ibid, 71, 580-4 (1941).
18. Mawrow, Z. anorg. Chem., 23, 233 (1900).
19. Moser, ibid, 54, 121 (1907).
20. Muller, ibid, "34, 417 (1907).
21. Muller, and Soitzer, Z. ElePtrochem. , 13, 25 (1907).
22. Treadwell and Hall, "Analytical ChemlsTry", I, p. 113 (1921),
23. Vitali, Bull. chim. oharm., 38, 668 (1894).
24. Vrtis, Rec. trav. chim., 44, 425-434 (1925).
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-40-
The Production of Aluminum
John C. Bailar, Jr. _ January 8, 1946
Although aluminum is the most abundant metal in the earth's
crust and occurs in many minerals, practically all of it is
produced from one ore — bauxite. This is essentially A1203.
2H20, but it always contains Borne ferric oxide and varying ' j
amounts of silica. Practically all aluminum of commerce is
obtained by purifying the ore by the Bayer process and reducing
it by the Hall-Heroult process^ The Bayer treatment is applic-
able only to low silica bauxites, which are not abundant or
widely distributed. Many countries (i.e. Germany and, to some
extent, the United States) have therefore become dependent upon
imported ore. A tremendous amount of work has been done upon
methods of obtaining aluminum from high silicate bauxite or
other ores, but most of it has not found its way into the chem-
ical journals, and is not even mentioned in the text books.
It is to be found in the patent literature.
The methods of attacking this problem fall into two
classes — those which modify the Bayer process, a nd those which
approach the matter from entirely different points of view.
Modifications of the Bayer Process
A. 3enef ici'ation of the ore by washing , flotation, or other
mechanical means. While this is sometimes effective in re-
moving admixed silica, it is not applicable to silicate ores,
and shows little promise. (1,2)
B. The lime-soda sinter process. (1,3), When bauxite
is digested with sodium hydroxide, any silica which is present
precipitates as Na20.Al203.3S102,9H20 or some similar compound
so that each pound of silica holds 1-2 lbs. of alkali and a.
similar amount of alumina. Titanium exerts a. similar effect.
If the ore contains more than 5-7$ silica, it cannot be treated
economically by the Bayer process. The lime-soda sinter involve?
sintering with limestone and soda to give insoluble calcium
alumina te, dlcalcium silicate and unchanged ferric oxide. The
finely ground clinker will react with aqueous sodium carbonate
to give sodium alumina te, the solution of which may be very
highly concentrated. Many "red muds" have been put through
this process In -recent years. Modifications of this process
are known as the "Pederson Process" and "Deville Process"
The former has been put Into operation in Europe.
C. Ferrosllicon Process (1) When a mixture of bauxite
(or rluminosilicate ) and 4ron oxide is heated with carbon and
a limestone flux, the iron and most of the silica.on are re-
duced to ferrosiliccn, rnd 95-98$ of the aluminum remains in
the slag as Ca(A102 )s. This reacts readily with sodium carbonate
to give Na.A102, which is treated as usual. The commercial
development of this process depends upon the development of
uses for ferrosllicon.
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Other Methods
A. Acid decomposition (2) Most aluraino silicates are
attacked by hot concentrated sulfuric acid, aluminum sulfate
passing into solution. Crystallization removes impurities (Fe),
after which the sulfate is thermally decomposed to oxide, the
S03 being recycled. This process reauires expensive materials
of construction and does not give pure aluminum.
B. Ammonium sulfate decomposition (1,2,6). This is a
variant of the above, ammonia being liberated during the initial
heating process. The aluminum sulfate is crystallized as the
ammonium alum and precipitated as the hydroxide by addition of
the ammonia liberated in the initial digestion. The ammonium
sulfate is recovered from the filtrate and recycled.
C. The Kalunite process (1). Alunite is a crude hydra ted
potassium aluminum sulfate which ocours in large amounts in
several western states, particularly in Utah. After calcining,
it is dissolved in water containing a little dilute sulfuric acid,
and crystallized as the potassium alum. This is hydrolyzed
to a basic alum which is thermally decomposed to K2S04 and A1203,
the S03 being used to decompose clay. For each ton of alunite,
two to three tons of clay can be treated.
D. Ammonium Oxalate Method. The ore is digested under
pressure with aaueous ammonium oxalate, the complex going into
solution as (NH4)3f"Al 0x3] and half of the ammonia escaping.
The ammonium oxalate is recovered and the aluminum is precipita-
ted by the action of ammonia.. The reactions are said to go read-
ily and to give excellent yields.
E. Chlorination (4) Many oxide and silicate ores can
be converted to anhydrous chlorides by heating with chlorine
or hydrogen chloride in the presence of carbon. Separations
can be effected through the differences in ease of chlorination
and in volatility of the resulting chlorides. Thus, ferric
oxide is more easily formed than aluminum chloride and the
reaction A1C13 + Fe203 — ^ FeCl3 + A1203 proceeds readily
even below 200GC. Chlorination of ores has been studied, not
only for aluminum, but for iron, nickel, manganese, chromium,
tungsten and many other metals.
F. Hydrochloric acid extraction (5) The bauxite is
dissolved in hot hydrochloric acid, and the silica is removed
by filtration. The ferric chloride is extracted with butyl
acetate or similar solvent.
G-. Reduction by Carbon, Carbides, Hydrocarbons, etc.
At sufficiently high temperatures, alurinum oxides and silicates
can be reduced to metal, especially in the presence of excess
iron oxide. This gives an alloy of iron, silicon and aluminum,
frim which the aluminum is volatalized in vacuo (4mm, of mercury
at 1250-1360°). Ferrous sulfide has also been suggested as
the reducing agent (8) Ma.tuura (9) has suggested adding copper
compounds to the ore, and reducing the mixture wi*h carbon. This
gives an alloy of aluminum and copcer, from which the aluminum
is distilled.
. , r - < , -
-42-
I. Boron trifluoride method (10) At 450°, BF3 reacts with many
oxides and silicates.
2BF3 + A1203 2A1F3 + B203
,^(B0F)3
6BF3 > 3Si02 33iF4 + 2(B0F)3
MSlOa + 3BF3 MF2 + SiF4 + (B0F)3
K AlSi308 + 3F3 A1F3 + SiF4 + (B0F)3 + KBF
4
Most of the fluorides are volatile, but aluminum remains behind.
Iron oxide also remains, as it is una t tacked below 500°. No-
details are given for the treatment of the simplified mixture.
.---
ft)
BJblio.icrr.phy.
Dean, Mininr and Metallurgy 24 9 356 (1943)
Wflson, Mining and, Metallurgy 24, 359 (1943)
(3) Pedersen, Ginsberr: nnd Wrig/re, Metal und Erz 41, 32 (1944)
(4) Lebedev, Moscow Institute in Honor of J. V, Stalin 1935, 5
Carl, U4S. Frtent 2, 296, 422 (Sept. 22, 1942)
(5) Hixeon and Miller, U. S. Patent 2, 249, 761 (July 22. 1941)
(6) Moss and Dye Australian Patent 111, 758 (Oct 8, 1940)
(7) Gentil, U.S. Patent 2, 294, 546 (Sept 1, 1942)
*rnandias British Patent 532, 115 (Jan. 17, 1941)
Schlecht and Jahr ft ->rfer U.S. Patent 2, 242, 759 (May 20,1941)
Clark, U.S. Patent 2, 297, 747 (Oct 6, 1942)
(8) Societe d» electrochimie. British Patent 523, 621 (July 18.
1940 )
(9) Matuura Japanese Patent 137, 708 (Aujt 2, 1940)
(10) Ba.um^arten and Bruns Ber, 74B, 1232 (1941)*
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-44-
Recent Developments in the
Chemistry of Organic Phosphorus
Dichlorides and Their Derivatives
Arthur Toy January 15, 1946
Intrcduction
The study of the chemistry of organic phosphorus chlorides
constitutes a phase of the research program on organic and in-
organic phosphorus compounds at the Research Laboratories of the
Victor Chemical Works, The choice of the organic phosphorus
chlorides as the parent compounds is due to the versatility of
the reactive chlorine atoms from which many other compounds may
be derived. Since there are a great many organic phosphorus
chlorides, a discussion of each individual one would be too in-
volved. Therefore a representative compound of this type was
chosen for this discussion. This compound is the one which we
have made readily available, phenylphosphorus dichloride or
phosphenyl chloride, C6H5PC12. Some of the other orgrrtc phos-
phorus chlorides will also be mentioned in the discussion for
specific illustrations.
1. Phenylphosphorus Dichloride
A. Preparation
1. C6H6 + PC13 — SiSis^ c6H5PCl3 + HC1 (13)
2. C6H6 + PCI3 -5QQ=700!C_> C6H5pCl2 + HC1 (l0)
3. 2C0C13 + C6H5PH8 ^C6H5PC12 + 2C0 + 2HC1 (12)
4; PCI3 + Hg(CeHs)2 4 C6H5PC12 + C6HBHgCl ( 6)
(Preparation of some other organic phosphorus chlorides):
1. (C6H5)2C=CH3 + PC15 -> C6H5)2C-CHaPCl4 ( 3)
2. RCH=CHa + PC13 JgSgg* RCHC1-CH3PC13 ( 4)
B. Hydrolysis 0
",H
C6H5PC12 + 2H20 -> C6H5Pv + 2HC1 ( 5)
OH
(white crystalline monobasic acid)
C. Esteriflcation
1. With aliphatic alcohols (11)
C6H5PC12 + 2R0Na -) C6H8P(0R)2 + 2NaCl
C6H5P(OC3H7)2 b.p. 138-140° C at 4-5 mm.
2. With phenols
C6H5PCi3 + 2Ar0H -> C6HSP (OAr) 2 + 2HC1
i.
-45-
The trivalent phosphorus atoms in these neutral esters in-
dicated that they may be useful as inhibitors, antioxidants,
and oil-additives. Kany such uses for the aromatic esters have
appeared in the patent literature (14). All of these esters
have a characteristic phosphinic odor.
D. Oxidation
1. Phenylphosphorus tetrachloride (10)
C6H5PCi2 + cia ■* C6H5PC14
2. Phenylphosphorus oxydichlorlde (10 )
a. Preparation
C6H5PC13 + 0 * CSHSP0C1S
C6H5PC14 + Hs0 -> C6H5P0C13 + 2HC1
C6H5PC14 + S03 -) C6H5P0C13 + S0C13
b. Hydrolysis
CeH5P0Cla + 2H30 'C6HsP0(0H)3 + 2HC1
(white crystalline dibasic acid)
c. Ssterif ication
1) With aliphatic alcohols
a) C6H5P0(0Ag)3 + 2CH3I — ^ C6H5P0 (0CH3 )3 + 2AgI
(8)
b) C6H5PCC13 + 2R0H 4 C6H5P0(0R)3 + 2HC1
These esters are colorless liquids. With the
exception of the lower esters, they are rather stable to hydrolysis
by water. Their volatility is fairly low and the heat stability
pretty high. Their properties are analogous to the aliphatic
esters of ^hthalic acid which are widely used as plasticizers.
The phosphonates have the additional advantage over the phthala-
tes in that they impart some fire-proofing characteristic to thU
resin they plasticize. Formerly aromatic phosphates such as
tricresyl and triphenyl phosphates were used as fireproofing
plasticizers. However, these aromatic esters have several weak
points: (a) poor light stability, and (bj low temperature flexi-
bility. For example, vinylite sheets plasticized with elkyl
esters of phosphonlc and phosphoric acids will remain flexible
at temperatures as low as"-40~to -50° C while similar sheets
plasticized with aromatic ohosohates become brittle at around -4
to -5° C.
2) With phenols (7)
C6H5P0C13 + 2Ar0H > C6HsP0(0Ar)3 + 2HC1
These esters are similar to the triaryl phosphate
Many of them have been evaluated as plasticizers.
f "■■
-46-
3. Fhenylphosphorus thiodichloride
a. Preparation
CSH5PC12 + S -i§Q°C4 c6H5PSCl3 (9) |
b. Hydrolysis
Decomposes in water. Pure C6HBPS(OH)2 has never bee-
isolated.
c. Esterification
1) With aliphatic alcohols
No pure aliphatic esters have been prepared
2) With phenols
C6HBPSC18 + 2CfiH50H 4 CsHBPS(OCsHB)2 + 2HC1
When the reaction w^s first carried out by heating
the mixture at refluxing temperature, it proceeded very slowly,
Several drops of PC13 were then added as catalyst. This catalyst
was first discovered in this laboratory for the synthesis of
(C6HB0)3P=S by the action of PSC13 on C6H50H (2). The probable
mechanism involved may be illustrated by the following equations,
PCI* + 3CeHB0H -* (CQH50)3P + 3HC1
(CQH50)3P + C6H5PSC12 > rC6H50)3PS + CeH5#Cl2
CBKSPC18 + 2CSH50H — } CsH5P(OC«He)2 + 2HC1
CeHBP(OCflHB)a + C6H5PSC12 -> CflHBPS(OC6HB )3 + GeU5?Ck
As can be seen from the eauations, the real active
catalyst is CRH5PC12. In the actual experiments it was found that
in the absence of the catalyst after ten hours, 66% of the theroet-
ical HC1 was collected while in the presence of 0.5% of PC13,
91.7% of HC1 was collected after only three hours of heating.
Organic Phosphorus Polymers
In the duscussion on the esters of phosphonic acids, some
emphasis was placed on the fact that they are good pla sticizers,
and that they impart fireproof ing properties to the resins plastic-
ized. An ideal situation would be the synthesis of a phosphorus-
containing resin. Such a. resin, among other things, would be
non-flammable by itself without the addition of an external agent.
The only well known phosphorus-containing polymer is the
polymeric PWC13. (l) This polymer has a tendency to depolymerize
and also to liberate HC1 in the presence of atmospheric moisture.
We have attempted to obtain polyesters by reacting the
phosphorus trichlorides with dihydroxy compounds. However, due
to the trifunctional characteristic of the trichlorides, only an
infusible and insoluble mass was obtained. Even the reaction c*f
such compounds as CfiH50P0Cl2 with dihydroxy compounds failed to
yield any fusible or soluble polymers. This was due to the libera
tion of P0C13 from CBHB0P0C13" under the influence of heat from
probably the following equilibrium:
•1 :.
t ... ■ ■- . d
. J
I
-(
1 '. > ' y*
-47-
CsHsOPOClac——"* (Cr,H50)2POCl + (C6H50)P=0 + POCl3
With the advert of the organic phosphorus dichlorides
in which the organic radical is attached firmly to the phosphorus
atom by C-P bond, a new field was opened up for research on
phosphorus polymers. From a portion of our research projects we
have been able to obtain some very interesting phosphaus ther-
moplastic as well as thermosetting polymers.
A, Thermoplastic Phosphorus Polymers
These are polyphosphonates. They are linear polymers of
large molecular weight.
Properties: 1. Non-flammable
2. May be drawn from molten state into fibers with
cold drawing property9
3. Soluble in some organic solvents, and the solution
usable as transparent lacquer.
4. Varies from brittle solid to very tough and
strong horny solid depending on degree of
polymerization and composition.
5. Light yellow to dark amber color
3. Thermosetting Phosphorus Polymers
These polymers are obtained from the catalytic polymeriza-
tion of the unsaturated organic phosphorus monomers*
Properties: 1* Solid transparent plastic.
2. Refractive index around 1.58.
3, Water- white to light yellow,
4. Flame resistant,
5, High heat distortion temperature.
6.
f? '• Insoluble in organic and inorganic solvents.
More scratch rerirt^nt than pomnercial thermo-
plastics.
The monomers may also be copolymerized with some
commercially available thermoplastics to convert them into thermo-
setting resins and to impart to them the desirable properties
listed for the pure phosphorus polymers.
Conclusion
This brief discussion on some ohases of the chemistry of
organic phosphorus dichlorides indicates that the field of organic
phosphorus chemistry is varied and extensive, Many valuable
derivatives with properties inherent to the phosphorus atom have
been discovered. However, we have redely touched the field. The
extensiveness of this field is certainly a challenge to any re-
search chemist.
.: 'SO.
r ,-. ?
» Vi
'-. '■ ^ ■•* .*v\' ■ - ■ r, * k\ fry '< i'r.<; i'j
.< MI-
...f -.. ^ -'
: i c
t ' w ■•
-" r ; '
-' i •• ? ' " : i
■ ■ ■.
" • ''
■'.... „ , ' ■■■ i
I t>\ f ■■•■ "?:'••.
. J ....
'■ - !
-48-
Biobliography
1. Audrieth, Steinnan, Toy, Chem. Rev. 32, 109 (1943)
2. Gottlieb, J. Am. Chem. Soc. 54, 748 Tl932)
3. Harnist, Dissertation, Strassburg, oo. 1-48 (1910)
4* Kharasch, Jensen, Urry, J. Am., Chem. Soc. 67, 1864 (1945)
5. Michaelis, Ananoff, Ber. 7, 1688 (1874)
6. Michaelis, Graeff, Ber. 8, 922 (1875)
7. Michaelis, Kamnerer, Ber. 8, 1306 (1875)
8. Michaelis, EenPinger, Ber. 8, 1310 (1875)
9. Michaelis, Kohler, Ber. 9, 1053 (1876)
10. Michaelis, Ann. 181, 265-365 (1876)
11. Michaelis, Kohler, Ber* 10, 816 (1877)
12. Michaelis, Dittler, Ber. 12, 338 (1879)
13. Michaelis, Ber. 12, 1009 ~Tl875)
14. U. S.Pa 2,274,291 and 2,174,019 (1942) and (1939)
■! -
v' '• >
* ■ - •
V
"J ♦
-. ■•■)■■■■■ ":
c
4 > • •
'- /
-49-
5ome Studies On the Plating Of Cobalt and Nickel
From Coordination Compounds
Margaret Kramer January 22, 1946
Introduction
Coordination compounds have long been used in electroplating
bath because experience has shown that such complexes are effect-
ive in producing smooth plates and are quite useful for plating
alloys.
The constituents of electroplating baths have been chosen
largely by trial and error, and not as the result of systematic
studies of the role of coordination compounds as electroplating
agents. Recently, however, at least one author has stressed the
study of cyano complexes as examples of Werner complexes (l)»
In addition to their use as sources of metal ions, coordina-
tion compounds have been thought by some to be the key to the
effectiveness of addition agents (2). Such a^ hypothesis of
the nature of addition agents has not been subjected to system-
atic study.
There is little variety in the types of complexes used by
industry for plating. The major use of coordination compounds to
date has been the use of the cyano complexes in the plating of
copper, zinc, cadmium, gold, silver, and brass. Perhaps the lack
of a study of electroplating agents as examples of Werner complexes
has retarded the development of other types of baths.
The study reported in this particular discussion was under-
taken • tn an attempt to determine whether some property or proper-
ties of a complex were important in characterizing the plating
ability of that complex,
A variety of stable cobaltic ammines is available for a
study such as this. Later some of the few stable cobaltous ammin^
were used.
Since nickel ammines also are generally stable in solution,
and since nickel plating, unlike cobalt electroplating, is commerc-
ially important, nickel ammines were chosen for additional in-
vestigations.
Experimental
Many of the compounds of cobalt studied were available from
laboratory stock; others were made according to methods found in
the literature. All of the nickel ammines studied were prepared
by methods outlined in the literature.
Preliminary plating tests were run on the cobaltic complexes,
using 0.5$ solutions, platinum anodec, and varying current densitte
Tests on the nickel complexes were done in the same fashion* but
using nickel anodes and 1$ solutions.
-50-
As a result of these plating tests, the complexes were
classified according to their plating ability as good, fair, or
poor. Examples of each type follow.
Good: |Coen3]ci3 , £Nien3lCl3
Frir: (Co (NH3 )4C03J 3S04 , (Coen3 G1«]C1, [NipnJ Cl8 , [NibnJ Cl3
Poor: jCo(NH3)6j Cl3 , [Copy4Cl3]ci , fNipy4]ci3, Ni( stien )8]C1B,
§i(dlp)3jCl3
All of the ammonia derivatives containing nitro groups
were poor plating agents. An example of this type is
TnuLCo(NH3l2(N0374].
The change of pH during plating was studied, using 0.5^
solutions and a current of 0.2 ampere for 20 minutes. The change
in pH is apparently not an important factor in producing good
plates, for complexes producing good plates showed the same sort
of pH changes as those producing poor ones* Fluoborate was
found to be an excellent buffer for nickel plating baths, a comple
sQch as /'Nien3"j (BF4 )2 showing little or no change in pH during
plating.
Current efficiency studies were made on many of the baths.
In the case of (CoenJ Cl3, it was found that cobalt plates from
the trivalent state but dissolves from the anode in the divalent
condition. We were not able to find a coordinating agent which
would allow the cobalt to dissolve from the anode in the trivalent
state. There is ^evidence that [Coen3]Cl3 is regenerated in the
bath, the [Coen^--^ j_on which is probably first formed being oxidised
by air to [Coen^+»
A bath containing [Nieng*"4" pn$ some excess ethvlenediamine
gave cathode efficiencies of 90$ or above. This bath is being
studied further.
Discussion
The data collected during this study indicate definitely the
effect of stability of the complex and the effect of steric
hindrance offered by the coordinating amine to the metal ion
during plating. It has been found that an ammine of intermediate
stability toward reduction is better for producing a plate than
a very stable one or a very unstable one. It has also been
found that large organic groups can so shield a metal ion that
the plate produced is progressively poorer as the size of the
substituent group increases.
Using half-wave potentials (3,4) as a measure of stability
toward reduction, it is found that complexes with potentials more
negative than about-0.75 v. are poor or non-plating agents; com-
plexes with half-wave potentials between-0.70 v. and -0.50 v. are
generally good plating agents; while those with half-wave potent-
ials less negative than about -0.50 v. are poor plating agents.
In each case, the exceptions to this generalization are ethylene-
diamine complexes. This leads to the supposition that stability
Is not the only factor,
a.,J U n^T :'.:J
/ . ■••
-:■ f
"" F\ /
>.• !■
1 ■: ?
I
-51-
As a result of studying a series of substituted ethylene-
diamines as coordinating agents, it was found that the size of
the coordinating group is important. The effect of stability
cannot be neglected here, however, for stability usually de-
creases with increasing weight of the amine. Moreover, the
diamines can achieve stability through chelation, iiterer.a a
coordinating group like pyridine cannot.
The progressively poorer plating character as the size of
the substituent group increases is partially a steric effect.
Substituent groups actually serve to hinder the plating of the
metal ion.
Further data are needed 'to establish the bounds of stability
and the limits of substitution more exactly.
The actual mechanism by which a complex accepts electrons
becomes important; for if the metal plates directly from the
complex rather than from the aquated ion, some of the coordinat-
ing amine might be included in the plate. This inclusion may
account for the non-adherence of sme of the plates. We have
Summary
1. A series of cobaltic ammines and one of nickelous ammines,
together with a few cobaltous ammines, have been studied ffom the
point of view of their function as electroplating agents.
2. It is suggested on the basis of the data collected that
stability of complex ions and character of the coordinating group
are decisive factors.
3. The ability of coordination compounds containing substituted
ethylenediamines to produce good plates decreases with increasing
size of the coordinating group.
4. Stability of the complex ion is an important factor for the
ammonia derivatives ae well as for the ethylenediamine derivative f
A compound may be too stalie toward reduction or too unstable to
plate satisfactorily..
5. Within the limits of the data collected, we have not been
able to demonstrate that pK is an important factor in the forma-
tion of a good plate.
6. Fluoborate has been found to be superior to -oyrophosphate as
a buffer in the nickel plating baths of the type used in this
study.
Bibliography
1. Thompson, Trans, Electrochem. Soc. 79, 417 (1941)
2. Fuseya and Hurata, ibid 50, 235 (1926)
3. Herda, Thesis, University of Illinois, 1943, o. 24
4. Willis, Friend, and Mellor, J, Am. Chem. Soc/ 67,1680 (1945)
it-
r
t-i" s ;j- •: ■", SCoi
;" £" . "i
; ?'.''.• ■''
■■ ■ • •, I
'
-52-
Electronic Quantum States of Atoms and Molecules
H. A. Lr.itinen January 29, 1946
Quantum mechanics has provided rn exact interpretation of the
possible quantum strtes of a single electron in a. hydrogen-like
atom or ion, but not in general for multiple-electron atoms or
molecules. Cn the other hand, spectroscopy is an elegant method
for the experimental determination of energy states of electrons
in simple or complex atoms or molecules. The theoretical explana-
tion of the energy strtes of complex systems in only approximate,
and is essentially an expansion of concepts well established for
simple systems to account for experimental observations on complex
ones,
A. Quantum States of Single-electron Systems
One-electron systems such as H, He , Li++ etc, can be' exactly
described by a system of four quantum numbers. The energy of an
electron is defined by just two quantum numbers (n and j£) for such
simple systems in the absence of an electric or magnetic field,
+ The important energy states of atoms like Na, K, or ions like
Ca , Sr , Al++ can be accounted for in a similar manner, since
they are essentially one-electron systems with a diffuse central
charge, which acts to separate the energy levels of a given n but
different i value.
3, Interaction of two or more electrons in Single Atoms
In accordance with the Pauli exclusion principle, a many- '•■
electron system can be resolved into a series of closed shells
of equal n, and subshells of equal £ values,
A detailed consideration of energy levels requires an examina-
tion of the victor summation of angular momenta of the various
electrons, both with regard to spin and orbital motion. The
variouE spin contributions are added to give a resultant S and
the orbital momenta to give a value L for the atom. The S and L
values combine to give a resultant J which describes the total
angular momentum due to electrons. Adding the nuclear spin I
gives F, the total for the atom. At each step of the summation
the resultant as well as the components are quantized.
The spectroscopic "term" or energy state designation gives
the values of S, L and J in a short hand fashion. The following
generalizations are often helpful:
1. A closed shell always forms a 1So state, indicating a
zero resultant electron spin (paired electrons) and zero L value,
2. The principal quantum number n does not determine the
spectroscopic term. Thus atoms in the same periodic family
usually have the same term in the ground state.
..c, ■ '■■■
w \ 1 1
■\ 1 •
< k
•» \ ■■»
i. ::rl
i i
■ ■■ ■:
•
-53-
3. For a given subshell (/.value) the term for q electrons
is the same as for r-q electrons, where r is the maximum number
of electrons in the subshell, that is 2 )\ d + 1). For examole,
there are 6 possible p electrons, and the same spectroscopic
term arises for 6 or 0, 5 or 1 and 4 or 2 electrons.
4. The lowest energy state (ground state) of the terms given
by equivalent electrons (same n and JL ), is that of the greatest
multiplicity. Of terms of equal multiplicity the term of greatest
L has the lowest energy. (Hund Rule), Thus of the terms of XS
or XD, or 3P or 3t? the latter has the lowest energy,
5 A regulrr multiplet is one in which the energy increases
with increasing J, and an inverted multiplet is the opposite.
For r given sub-group equivalent electrons), the multiplet is
regular when less than half of the shell is occupied, and inverted
when more than half is occupied. Since the stable ground state
is that of lowest energy, this rule is of great importance in
describing the magnetic properties of groups of elements like the
•rare earths.
C, Quantum States of Molecules; Molecular Orbitals
The present discussion is limited to the ground state and
activated electronic states of diatomic molecules. For each
electronic state there are a series of robatlonal and vibrational
energy states which are not considered. Fundamentally, the elec-
tronic states of molecules can be derived in three ways: (a) bring-
ing together the atoms, (b) splitting the united atom, thus coming
from zero nuclear separation, (c) adding electrons one by one to
the nuclei, in an analogous fashion to building up atoms. To
emphasize the analogy between atomic and molecular orbitals, the
latter two concepts are considered here.
1, The system: 1 electron, 2 nuclei
Stationary energy states can be characterized by three
quantum numbers (disregarding electron spin), a s in atoms. How-
ever, only one quantum number can be precisely defined for all
separations of the nuclei. This is X, the component of the orbital
angular momentum along the internuclear axis, corresponding to £
for atoms. The other two ouantum numbers can be defined only
approximately and in two ways depending on whether the nuclear
separation is very small or very large. For small separations,
the molecule acts like an atom in an electric field, while for
large separations the electron is associated either with nucleus
A or nucleus B, with an electric field produced by the other
nucleus. For actual nuclear separation, a. correspondence is
recognized between orbitals for small and large separation, and
the energy state is intermediate between the two extremes.
2. The system: several electrons, 2 nuclei
The Pauli exclusion principle holds for molecular orblfcaJ»«
just as it does for atomic ones* As a combined atom is.spll*',
and the separation increases the quantum numbers n and H lose
more and more of their significance, but the number of states is
not affected.
r.ri
. 10 J .' > . •
]■- f '
"»i
'£< t f ■ ■ ..*-.- - -; [j
s*>
: l ' "" " '" <
r .-:■
r. ........... .......
7 ( '\ ! r<li:9*.
■
:
'■■■■. :- '■
... .. .... .?'.f, .£.
>.? u
' -1 •■ - ■ . f • -.
^ - : f ■ ■ i ■ . ■ '
n ■
. '■ ■ I
■ ■ ■
t . s .
■■ ■ • , ; i*. , ■ ... . ""■
+ . . «
-54-
The spectroscopic terms of molecules are derived in a fashion
analogous to that used for atoms, with Greek letters replacing
the L^tin for each designation. A X molecular state ^responds
to a *S atomic state. As with atoms, the state with the greatest
multiplicity lies deepest.
D. Selected Applications of inorganic interest.
1. Reaction of H2 with Cl2
The Cl2 molecule absorbs light and splits
into atoms,
one of which is in the ground state (2Pi) °nd the other in an
excited state (2P^). The excited atom ^excitation energy 2.5
kcal. ) can react with H3 to give HC1 and H, but with the normal
atom the reaction is endothermic to the extent of about 1 kcal.
2. The molecule He2
This molecule can not exist in the ground state, but can
exist in excited states, for example in electric discharges.
This stability can readily be understood from molecular orbitals.
The limiting case of the ion HJB2+ is also stable*
3. The molecule 02
The molecular orbital picture explains the paramagnetism
of molecular oxygen in its lowest energy state.
References
1. Herzberg, "Atomic Spectra, and Atomic Structure", Dover Publica-
tions, New York, 1944
2. Herzberg, "Molecular Spectra and Molecular Structure, I. Di-
atomic Molecules", Prentice -Hall, Inc., New York, 19390
Chapt V VI, VIII.
3. Palmer, Valency, Classical and Modern", Cambridge University
Press, London 1945)
Jp -
• \ t.. -
J >
:) '<:
» ■
-59-
INDUSTRIAL PREPARATION AND USES
OF THE RARE EARTHS AND THORIUM
Ho word E. Kreners March 19, 1946
Lindsay Light and Chemical Company
The rare earths and thorium are usually obtained commer-
cially from monazite sand, Monazite is essentially a phosphate
of the rare earths and thorium. The industria.1 preparation of
the rare earths involves (l) the isolation of purified thorium,
cerium, lanthanum, neodymium and praseodymium compounds and (2)
the removal of non-rare earth impurities such as silica, phos-
phates, iron, etc. Both types of processes are complicated by
the fact that expensive reagents such as oxalic acid cannot be
used unless economic or purity conditions warrant such use.
Although thorium is not a rare earth, its separation from
the rare earths is usually a rather tedious process. When start-
ing with monazite sand, two types of initial treatment are
possible. One kind of treatment leaves the thorium as an in-
soluble material, while the rare earths are left in a soluble
form. The other method gives a material in which both thorium
and the rare earths are soluble. The particular thorium process
chosen for use, however, can be essentially the same for both
kinds of treatment.
Cerium is the most important of the rare earths. It can be
separated from the latter in rather pure form by a. modification
of fractional basic precipitation after oxidation of the cerium
to the eerie state.
Cerium-free rare earths (commercially known as "didymia")
are separated into individual rare earths wherever possible by
fractional crystallization methods. In large scale work, a.
continuous fractional crystallization scheme is used.
Valuable by-products of monazite working are me so thorium,
europium, and yttrium earth concentrates. These are recovered
when the demand is grer't enough.
The principle use of thorium is still in the manufacture of
incandescent mantles. Thorium and lanthanum are used in special
optical glasses for making lenses with high resolving oower at
large aperatures.
The princiole use of cerium and rare earth mixtures is in
the glass industry. Cerium replaces arsenic as a glass decolorize!
and didymium acts as a physical decolorizer. A specially prepared
eerie oxide is replacing rouge in precision optical polishing.
Ceric oxide shows promise as an opacifier in vitreous enamels.
Considerable Quantities of rare earth oxide and rare earth
fluoride are used in cored carbons for arc lighting.
-60-
General references: U. S. Patents: 1,087,099 1,981,126
1,366,128 1,182,880
1,069,959 1,335,482
rrltish Patents: 129,624
510,198
120,748
Eu recovery: H. N. McCoy: J. Am. Chen. Soc. , 58, 2279 (1936)
Y-earth recovery: Moeller and Kremers: Ind. Eng. Chem. ,
Anal. Ed., 17, 44 (1945).
-63-
ISOSTERISI: IN INORGANIC COMPOUNDS
CK K, Schweitzer April 2, 1946
I , Inti • o d u?-tio n
The outer sphere (l) of an atom eeanL to control its
valency. The chemical behavior of an eloment is controlled
by two factors?
1. The surplus nuclear charge (the atomic number)
which determines the comparative place of an
element among its congenerr, and
2, The outer electronic grouping which determines
an element's valency and hence its group*
The phenomenum of isosterism is directly related to this
outer sphere of the atom.
II, Preliminary Work
In 1918, alien (1,2) suggested from the analogy of
molecular weights, that there should be molecular numbers
obtained by adding together the atomic numbers of the com-
ponent atoms in a molecule, in the same manner as the mol-
ecular weight is obtained by addition of the atomic weights.
He called attention to the fact that the ions of sodium and
ammonium, both having a "number" of 11, show a very close
kinship in chemical behavior*
HI* Langmulr1 s Original Consideration
Lan gmu £ rf 3 ) , in 191.9, became interested in the structure
of carbon monoxide and noted that this compound, though
thought to be unsaturated, was a relatively inert substance*
Very few other substances combine with it at ordinary room
temperatures^ which does not fit in with the previously held
i&c of divalent carbon.
He noted that carbon monoxide resembles nitrogen to
an extraordinary extent as is shown by their physical orop-
erties, which within the range of experimental error are
practically identical.
The evidence shows that carbon monoxide and nitrogen
are of nearly identical structural arrangements. The case
is amplified by the fact that the total number of electrons
in the molecule is the same for both gases,
IV» ^e Idea of Isosterism
A short time later, Langmuir (4) noted that carbon di-
oxide and nitrous oxide show the same realtionship that car-
bon monoxide and nitrogen do. He found that if the cubical
models of nitrous oxide and carbon dioxide are bui-t up,
they both have the same arrangement, The are identical in
electronic grouping, the only difference lying in the nuclear
charges of the component atoms.
When the physical properties of these two substances are
compared, it is found that they show striking resemblances.
Their viscosities, critical temperatures and pressures,
densities, and many other properties are practically identical
under the same conditions. A difference in freezing points
is the only disagreement, and this is explained by the fact
that carbon dioxide has a more symmetrical molecule, due to
resonance in the nitrous oxide molecule.
•,• ■.. j .... !.„. . . ... ■ ■_/ . 1, ,.J ' •
(•• fm ■ ■ '..*; ^ ,;,-; »:
'■•
.;r :■;-•' ;j
Q f '■ . . • • ■ ■ ...
r rS h «•
. . . ( ,
.5 S -.v. , i. ' ■'■■■> Cu*.
rfririlvw $ ■'..'.:
! 1
:>.fi ■.:: -■• ?«
r
r-
:.-vi-
C^X O^ «K 3S.M *t* "
S«t.<US*0Yt 3.2.S *.*3
Mt«t c~~& . o. d So v o*t so*.
•' ;s*i ( ;/.•; '*."";.';.■ ■ 1.
-64-
V.
^nd .i^Q^, ^Pounds contain the same number of atoms
i_nd the same total number of ele3t^HiT~tHiFf^e~e^TFH^tPfl
*s isosteric c3m5o"unds or KoqtPrPQ — t J^r-4 — SSsign^tea
T r- ; ^ iU-b ri_ -Lsosxiereso Lanemuir suerereqtq that
isosteres should show remarkable similarities in ?W
properties which do not involve R splitting of the mjtMi»
When molecules are isoelectric (!.£, having the same charee
i ?r?rr,uvM,'1in addition to ^ein^ ^ostLic^this e
similarity Is even closer
-able o£ Isosteres (4)
Tffie ^<Hf^.^ Atom -^ Z*^ ^.
2- 0=; F-'Ne, Na+ Mg++ Al+++ ^^^CO^,,
3. S=^ CI" A, K+ cf++' cox*^o.
4« Cu , Zn++
£• Br", Kr, Rb+, Sr++
6. Ag+, Cd^
l> *"", Xe, est Ba++
o" Na, CO, CN"
®' CH4f NH4+
*?• C°3> Na0, N3-, CNO"
11. NO 3-, CO 3=
}**. NO a-, 03
13«> HF, 0K~
15° £°0 SO,!, P04f
.~m cio3 , so3~ P0,a
16
'a, P03"
JS- S2°^~> p2o7==
"?• Mn04-, Cr04=
dL* Se04=, AS04=
Hence
VI.-. Predict Ion of General Properties
«*.*< direct oomparison^carTBe" made of the physical nrnn
sBlHlr:! "Ff ss^-isa^ Sri ? ■
electrical force around the sodium ion is qUffiH»nt «■„
account for the difference in properties. SUlfl°lent to
each other "then Utt^U -ha- " tW0 stances resemble
stances resemUe el c «?b < Uo*te™s of these two sub-
argon $£&* en^resem^ acf ot^rVuiT cL^iv f" W'
Kf ^b I^nTa^hfcv a^ - *r*l0"?^"-^!
to resemble each other "Lv^b^ lon J ls?«teric with nitrogen
^ obtained from the°table glten inaction V^^ 0an be
■TH« Crystallotrrpphln Applications
are isosteric with ^.' J sodium ?nd flouride ions
Sodium0?Ltur?d:\^Xntfiufo^rto^ve\T%aSmeWeeX-0t
i v r.\ y. v.' r ' ' "■"" ..' '..'.■ ~y,:XlX[XL^Tx X ■/■"'■".' " ""-X
■: • • .-•■ • ■-' :;:• "-, t -,":«•-*,* o ;■;,;■ ■ ■' ■ ■ ? ; v. ■ • ■.■,.'
j. c . '. ■:■ v ■
t -; .;. -, *
^y.t:. 'l? tJ&sL ■.:'..:' :l' "'.• 'IS-
. t, .
.1'. , :•,' <~A.
or
. - .
' » ■
, . "' + *-t ->■ .-. T - * .* t • > "> ■ •'..'"'
• • \ .,- • ■'.'-.., j.l r X . . :. \;i 1.V.I ■* : ••'. ■ O .' • j ^3 • . . ,
' ■' . . ■ .""'•■ - '■' ■'■'' '.': !\ ' • - "' "' '■ ' ' '■ ■' "* » '
*.:••/■ ',-■■■■ -f>X •■•■.•••■•: ■ "' ! " .* ' ■ "^ -
:■•••• '.'.! .'•;;":'' " " .; : v>" ' '
--
0 ,;•
• ; ! >. .;. ■ ■ »
-65-
crystallographic form. This is found to be true. Found
also to be of the same form are the compounds magnesium
flouride and sodium oxide. Other substance.s which would
be expected to be similar .ares potassium chloride and cal-
cium sulfide, potassium sulfide and calcium chloride, cuprous
sulfide and zinc chloride, etc.
For a more precise and definite understanding, let us
use Barker's rule of isomorphism. Kopp (5) and Retgers (6)
regarded substances as isomorphous when they were capable
of forming mixed crystals, T'. V0 Barker, however, maintains
that isomorphism should denote similarity of structure.
The following cases of isomorphism are of some con-
sequence:
Type (from table in Section V) Compounds
2. NaF, MgO"7; MgFa , NaaO
3, KC1, CaS : CaCig, K2S
5. RbBr, SrSe j SrBr2 , Rb2Se
7. Csl, BaTe; Bal8, Cs2Te
8, N2, CO,
10. KNCO, KM 3
11, NaN03, CaC03; KN03, SrC03
14. KC104, SrS04, NaHS04,
CaHF04
15. N8CIO3, CaSOa; KHS03,
SrKP03
17. Na2S306, Ca2P206
18. Na2S207, Ca2P207
20. RbMn04, 3aCr04
21. MnSe04, FeAs04
In all of these cases, the predictions have been verified and
the compounds are found to be isomorphous (8).
Quite a few isomorphous compounds exist that seem to bear
no relation whatsoever to isosterism. Thus isosterism is not
the complete explanation for compounds of this types
Specific Studies
Uot a lot of verification work has been done on iso-
steric compounds, but a few works of consequence can be noted
as follows:
1. The isosterism of the cyanate and nitride ions
Langmuir (4)rrade the observation that the ions CN0~ and
N3"" are isosteres, and naturally compounds derived from them
are also isostericc There are very few data available on the
physical properties of cyanates and trinitrid^s, because of
the explosive character of the trinitrides and the difficulty
of handling them. The salt solubilities and crystal structure^
(8) are very similar. From this information, it is safe to
rssume that the salts of cyanic and hydronitric acids will be
found to be almost identical.
,
» . Jr.
rt , • 7 :
« *' ■
tl<\t\-<
« ••
.1'"
ih
:ir to b
1 i
* - •> «
U-, ^■.,-
y. ■■-,
V- .
I :.M.;;<.M>/> • -I' :- 3
-66-
2. Isosteric Parachors
According to our information, the parachors of iso-
steres should be equal, if they have the same electrical
charge. Copley (9) made many of these paraohor measurements
and found excellent agreement. He constructs and explains
the use of a new parachor chart.
3. Diazomethane and Ketene
Murty (10), in his study of the isosterism between
these two compounds, gives support for the open structure
of diazomethane. He bases his assump t ions on the fact
that diazomethane is isosteric with ketene and ketene is a
straight molecule.
4. Nitrogen and Carbon Monoxide
Erlenmeyer and Leo (11 ) review the properties of
nitrogen and carbon monoxide. They also give several helpful
tables of the isosteres of carbon dioxide and nitrous oxide,
5. Acetylene and Hydrogen Cyanide
Bahr (12) discusses the striking parallel between the
properties of acetylene and hydrogen cyanide. He points out
that the ladical ~C= Kf has properties very similar to the
radical ~C=CH. ^%Hw +c**H
6. Rotation and Absorption (13)
7. Spectrographs Investigations (14)
8. Organic Compounds (15, 16, 17, 18, 19, 20, 21, 22)
IX. Conclusion
From the above information, it is easy to see that a
great deal of investigation of isosteric compounds in
relation to physical properties is yet to be carried out."
Much information for verification is needed and the pheno-
menOm of Isomorphism is wide open for research. One review
paper on this subject exists, but it is not available at the
present time. The r.uthor suggests, when this article becomes
available, that it should be excellent reading on this subject.
The article will be found in Z. anorg. allgem, Chem. , 1942,
*UUL
.•■■■*■ ■ « ' . . '
I i I,' ' t
«;i ::/yf\ ±i
1 o
.'•> :":■ /' f " !"j r;v ."!0"J '"*.' <V-^.: J ■'i]
♦ ••'>
/ :
.■•;■■-':.-.;'■ i-s "' '; .-, -> f.- .• : - , • - I,- -j,
,s .■ ■ ■ . ' j V ...
'■ :'.'V 'r':
{ K'i" '; s..;Kl " '#v-! ./' •■''•.■.
-■..-. T ,
/ '
1 : %
c r
<* ■' \
j -
..' F ■::• f \.t'\
>I
• ■ >
" 3
1 C?
-67-
Bibliography
1. Stewart and Wilson, "Recent Advances in Physical and In-
organic Chemistry", Longmans, Green and Co,, New York,
Ed. 7, 1944.
2. Allen, J. Chem. Soc. 115, 389 (1918).
3. Langmuir, J. Am. Chem. Soce 41, 868 (1919).
4. Langmuir, J. Am. Chem. Soc. 41, 1543 (1919).
5. Kopp, Ber. 12, 868 (1879).
6. Retgers, Z. physik. Cheme 3, 497 (1889).
7C Barker, Trans. Chem. Soc. 101, 2484 (1912).
8. G-roth, "Chemische Crystallographie", Leipzig, Pt. I$
1906, Pt. II, 1908,
9. Copley, Chemistry and Industry 59, 675 (1940).
10. Ilurty, Current Soi, 5 424 (1937).
11. Erlenmeyer and Leo, Helv. Chim. Acta 16, 897 (1933).
12. Bahr, Z, physlk. Chem. A168 , ' 363 (1934).
13. Preiswerk, Helv. Phys, Acta 7, 203 (1933).
14. Preiswerk and Erlenmeyer, ibid* 17, 329 (1934).
15. Erlenmeyer and Schmidt, Helv. Chem. Acta 22, 709 (1939).
16. Erlenmeyer and Uberwasser, ibid. 22, 938 (1939).
17. Erlenmeyer and Meyerburg, ibid. 21, 108 (1938).
18. Erlenmeyer and Kleiber, ibid., Ill (1938).
19. Lutz, JD Am. Chem. Soc. 60, 2628 (1938).
20. Erlenmeyer, Kleiber, Loebenstein, Helv, Chem9 Acta 21,
1010 (1938).
21. Burger and Bryant, J. Am. Chem. Soc, 63, 1054 (1941),
22. Erlenmeyer, Uberwasser, Weber, Helv. Chem. Acta 21,
709 (1938).
,,T p-i
• '•■■ ;'"; f ) W ■■.■■■ •-,-.-: .f-«. H
,. -;.-. . i ,%.
•;.u*;
^ ■>■■ f ->■ *
,80 r t::"
nl
.!"o;:'i
.»:■■ a r:
• ■•
.... . , .
*>.. .
■■<
,i. :>. ./.:.:.
, ; '; - ■ ,v ■■:,-
.
>V .. 5 . j.f!.r.£>J . : U t1'3- 1 10 J 1
* I
-58-
TCKMrjUES IN THE CONSTRUCTION OF
LABORATORY APPARATUS
R, A. Penneman April 9, 1946
Many research problems require the construction of
apparatus and demand techniques or "know how" which the in-
vestigator has not developed. ■ The feet that the same problems
have been solved before is often of no help since Chemical
Abstracts usually gives no hint of experimental technique.
Sources which give leads to specific journal references are
given below.
Strong, J., "Procedures in Experimental Physics", Prentice-
Hall, New York, 1944
Farkas, A. and H. W. Melville, "Experimental Hethods in Gas
Reactions", MacMlllan and Co., 1939
Mttller, R. H. , R. L. Garman and M. E. Droz, "Experimental
Electronics" , Prentice-Hall, New York, 1944
I. GLASS MANIPULATION
A, Breaking Tubing
a. Small tubing (less than 15 mm. ) — use wet file mark.
Advantages of flat file over more common triangular
file.
b. Medium tubing, — file mark and hot glass bead or cir-
cular cutters.
c. Large tubing — hot wire or carborundum wheel (such as
located in Room 168),
d. For very thin, blown-out tubing, use a diamond scratch.
e. Breakoffsky — use diamond scratch and magnet to move
iron. Other techniques.
B" Sealing Operations (l)
a, Polaroid for detection of strain,
b. Strain point is that temperature below which the
strain pattern is not altered regardless of cooling
rate. A strain will disappear in about 4 minutes at
annealing temperature; 4 hours is reauired at strain
point.
• .» ' •
i z ...
1 ■•■../: j
/•",. ( ; ,
O'
H ■■■it
f
•i»'.
,:: T ■..*.::., -f.
-i r?».-
^ •
M .*.,
#Jvi ;>
. . ' < JVC:
. • <
to
i -r •;*
, >
-69-
Strain Point Annealing
Temp
, G-lass
389° C 425° C
Soft
486 521
Nonex
503 570
Pyrex
1020 1120
Quartz
hernial Expansion coefficients
(x 107)
Lime Glass (G8) 92
Copper
162
Lead Glass (G5) 90
P l:i tin urn
91
Nonex (G7C2?) 36
Tungsten
47
Porcelain (20°-790°) 41
Fernico
47
Pyrex 32
(25 '-450°)
Quartz 5,
8
Ko va r
(25°--500°)
56
d. Graded Seals (2). Quartz rod of samll diameter can
be sealed directly to pyrex if joint is heated very
hot and worked into the quartz,
Soft glass-pyrex seals can be made by grinding glass
to powder and mixing in ratio, 4:1, 3:2, 2:3, 1:4 and
melting mixes into rods. Rods are applied in a series
of rings to join two glasses.
Quart z-pyrex and pyrex-soft glass seals can be pur-
chased; this is recommended since such seals require
techniaue beyond the average chemist' s ability.
C. Metal to Gla. s s Seals
a. Tungsten wires of less than 1,5 mm diameter can be
sealed directly into pyrex. An intermediate of nonex
is necessary for dia.meters up to 4 mm.
The wire is heated to white heat, cleaned of oxides by
polishing or heating with NaN02, washed, and re-
oxidized slightly before costing with nonex, A good
seal is red. To prevent leaks, end of wire should be
sealed with advance or nickel* Copper welds easily
to these latter.
b. Platinum wire seals directly to soda, or lead glass,
Platinum-pyrex seals use the following: Pt, 707,
Canary, pyrex. (707 and Canary are special Corning
glasses).
Platinum coated glass can be joined by tin or solder
to metal wet by these bonding agents. Preparation of
these Joints described in references (2,3) and involve
burning off a platinum compound in presence of organic
material to leave an adherent deposit of the metal on
the glass*
* ■ 1
•: .
i v ■■: :, ■■■
>.
:~f.
' I
; ■•• v - > » '•-
-70-
c. Kovar can be soft soldered, copper-brazed, and spot
welded. The coefficient of expansion closely approxi-
mates that of Corning G-705AJ glass over a wide
temperature range above room temp.
Kovar-pyrex seals use the following glasses:
Kovar, G-705AJ or 705BA, nonex, canary, pyrex.. Or,
Kovar, G-705AJ, 710, nonex, pyrex.
Before sealing, Kovar is heated at about 900° C in wet
hydrogen.
d. Copper-pyrex or soft glass seals depend on the use
of thin metal at junction so distortion can accomodate
difference in expansion coefficients,
e. Iron and steel can be fused to soft glass (3,5) b"
using flux of equal parts ZnO, borax and powdered soft
glass* Metal tube is coated on inside with flux, soft
glass; tube to be joined is flared so it meets metal
at right angles.
II. BONDING MATERIALS (6)
A. Metallic
a. Properties of Solders
Composition
50Bi, 12.5Cd, 25Pb, 12.5Sn
36Pb, 50 Sn
50 Pb, 50 Sn
20 Ag, 3 Cu, 2 Zn, 75 Sn
45 Ag, 30 Cu, 35 Zn
54 Cu, 46 Zn
A flux for the first four is: 40 ZnCl2, 20 NH4C1,
40 H20, Dry borax or "Handy Flux" is used for the
last two.
Phosphor-bronze alloy (Meetinghouse) wets only copper,
mp about 750. Excellent for joining parts to copper
tubing, can be used Copper to brass with persuasion.
b. Spot welding, (located in Room 168)
c. A laboratory arc welder can be made using a series
resistance of about 15 ohms (capable of dissipating
400 watts) and carbon electrodes. An ordinary cone
heater will serve as the resistance.
Solder
n
Woods metal
61
Eutectlc
181
Soft solder,
188
Medium solder
400
Silver solder
720
Braxing
875
>: '» ' J
*/,
:r * < ->
.'i " ?
f -..'f
J ■■"
« ., J..
.•!■ . i
' W
« - - -
.■' I •'••; *:■;*$&
-71-
B. Non-metallic ( 6 )
a, Picein, fluid at 80° C, useful adhesive, low v. p.
b. Apiezon compounds. Sealing putty "Q", _3
Apiezon "W"— very low vapor pressure (10 mm at 180 C),.
fluid above 80 C. Apiezon "N" — very low vapor pressure
stopcock grease.
c. Silver Chloride, mp 455°C, wets most metals and glasses,
Used for sealing windows on glass tubes, etc.
d, Irreversible cements; Plaster of Paris; Litharge
and glycerol (to 260°C); Water glass and carbonates or
oxides of Ca, Mg, Zn, Fb, or FV; Water Glass and talc
forms a cement that holds at red heat; nine carts
kaolin and 1 part bora.x mixed. Water used for ease
in application. After evaporation of water, cement is
heated slowly to yellow heat to set it.
III. ELECTRICAL DEVICES
A. Miscellaneous
a. Polarized outlets recommended. Laboratory outlets
should be marked as to "hot" terminal
b. The 200-C Variac (5 amp) can be operated to give either
0-115, 0-135 volts in clockwise or counter-clockwise
rotation. At intermediate voltages, maximum current
is 5 amps; at low or high voltages (close to line
voltage) 7.5 amps can be drawn,
c. Nickel-chromium alloy wire should not be used in con-
tact with Insa-lute, SauerEisen, or sodium silicate,
since the wire is attacked at high temperatures,
Alundum refractories are satisfactory* (7)
d. Uses of 12J5, and 117N7 tubes in the laboratory.
Advantages of microampere currents through relay points,
etc. Circuits given on blackboard.
e. To measure voltages above scale of ootentiometer, use
two standard cells in series with setting one-half their
sum. This doubles range of potentiometer*. Alternative
method is to connect standard to EliF terminals, set slide
wire to one-half standard, and balance. This also
doubles range r but requires changing connections at EKF
terminals when it is necessary to check the working
battery* 3oth methods put twice normal current through
potentiometer,
f. To measure voltages below range of potentiometer use
galvanometer and two standard resistors. Circuit given
on blackboard.
; - :' **
&■? •-• ' ,/•;.
r U«-
>•■■ :.
-■ : i '
■ j ) i sr: v
t
: :
! v r ,■■ : , .■■■■ - i
.
J •• i . ■ . I .4
I .*». . «. . i .... .......I.
;.r-
M ,'. -
■••■ i. : .
- : . ■ - r .
'/ -u^ r »:,: :
-72-
IV. Miscellaneous Topics
A, To plate Cu on glass dissolve 2 g Ciuic2 in 100 ml
H2Q, add NH40H until ppt dissolves. To 100 ml of
this solution add 15 ml 40$ hydrazine hydrate. Four
mixed solution in object at 60°C, allow Just enough
Cu to plate out to make shiny layer. Wash with hot
water, place object in water at 60°C and allow to
cool slowly to room temperature,
3, Use glacial acetic acid for marking celluloid.
C. Stopcock greases insoluble in organic solvents (9).
Mix 25 grams of anhydrous glycerol, 7 grans of dextrin,
and 3.5 grams of C.P, d-mannitol. Heat resulting paste
to boiling, and rllow'to cool without stirring. Another"
type is made by mixing bentonite with glycerol to desired
consistency..
D. Devices for delivery of liquids at constant rates. (10 )
REFERENCES
(1) Strong, J. t "Procedures in Experimental Physics", Prentice-
Hall, 1944, Chapter I.
(2) Farkas, A, and H, W. Melville, "Experimental Methods in Cras
Reactions", MacMillan and Co., 1939, Chap teFT;
(3) McKelvy, E. C. and C, S. Taylor, J. Am. Chem, Soc., 42,
1364 (1920)
(4) Williams, D. and G-. S, Haines, Ind. Ener. Chem. (Anal* Ed.)
16, 680 (1944)
(5):<raus, C,A, , United States Patent 1,046,084
(6) Strong J, loc. oit., Chapter 13.
( 7 ) "The Construction of Electrical Furnaces for the Laboratory" ,
Revised Edition, Morton Co., Worcester, Mass,
(8) Jones, J. H. , J. An. Chem, Soc, 64, 965 (1942)
(9) Lange, N. A., "Handbook of Chemistry", Handbook Publishers
Inc, Sandusky, Ohio, 1941, p. 1516.
(10) Orohin, M. , Ind. Eng. Chem. (Anal. Ed.) 17, 99 (1945)
T$.L-?.
■■■.?•
'IX. ,;
t) ■■ - '- \ \ ' •■.■• a |l '-.;;• rj .l .■.!:.■■
'"i jV 'V.''; ! .'; f ' '
.' .'."»' I
I . . .»
* t
! •
• * t
I ■'■
,, . , ,f ; j
f; . r J" £ i,i
• .
*_"...
« t *
• ! I
" ■.-.■-■•■ ■
■ CM
-73-
THE METALLIC BOROHYDRIDES
Donald Starr April 16, 1946
I. Introduction
The hydrides of boron are a group of compounds which
have been of interest for a long time because of their un-
usual chemical properties and because of their relationship
to the Ideas of valence and the chemical bond, The simplest
compound BH3 cannot be isolated, although it may have a short
existence as an Intermediate in certain reactions; it is known
as the tfimer B2H6 , a gas which boils at -92°. Others in the
series lire B4HlotB5Hy, B6Hl0, and B10H14. (9)
Tq.e development of the electron theory of valence did not
immediately clear up the difficulties in explaining the struct-
ures c*f these compounds* For B2H6> fbr example, it is evident
that fhere are only twelve valence electrons; for the usual
etharje-like structure, fourteen are .'required. This situation
produced many suggestions as to the possible structure of the
compounds (4). Wiberg suggested that diborane would have the
structure of a weak dibasic acid* Sedgwick suggested that
tyjo of the hydrogen atoms in diboran^ were attached through
szngle electron bonds. Another suggestion was that the boron
atoms were joined through a resonancH bridge of two hydrogen
atoms*
Early it was seen that no one p^posal for the structure
of diborane was in complete agreement with the then known
facts. Therefore, much work was donfr on the chemical properties
of the boron hydrides as well as worlc on their physical charac-
teristics.
II. Borrne Salts
One of the very interesting reactions of diborane is
its Interaction with amalgams of high£y active metals (Na,
K) according to equations such as:
*5
Ca
2M(Ht)x + B2HS --_* MSB3H6 + fH'r)
x
Stock and his co-workers (10) preparef. a number of borane
salts from 32H6 , B4H10, and B5Hq0 Th$ non-volatile white
solids produced were quite stable; the addition of two elect-
rons to the electronically unsaturated diborane would lead
to an ion having a structure analogous to that of ethane,
and therefore stability would be expeked.
-74-
III. Prediction of Metal BH4 Compounds
It had long been postulated that compounds with the
anion (BK4~) should exist. It may be presumed (4) that 3, C
and M+ have identical electronic configurations in the ground
state; from this it should follow that (3H4) should exist
since CH4 and NH4+ are known.
Stock and Laudenklos (11) were unsuccessful in their
attempts to prepare KBH4 by the action of atomic hydrogen on
potassium diborane, K232H6, Thomas and Stevens (12) reported
that they failed to prepare salts of the type M(BR4), where R
is e hydrocarbon radical, by heating t rime thy 1 boron with
ethyllithium, lithiumphenyl, and other metal alkyl'S,
IV Preparation of the Borohydrides
Sohlesinger, Sanderson, and Burg (7) reported that they
obtained a new compound of aluminum, boron, and hydrogen by
treating trimethyl aluminum with an excess of diborane. The
volatile compound was determined by analysis and molecular
weight checks to be A1B3H12 and was termed aluminum boro-
hydride. "Borane salts" were used for those compounds formed
by the addition of metals to the boranes, whereas other salts
containing the same constituents, but in different proportions,
were called "metallic borohydrides". Reports on other metal-
boron-hydrogen compounds followed this first preliminary ob-
servation. (8, 2, 5, 6)
A# Aluminum Borohydride
A13(CH3)6 + 432H6 -> 2B(CH3)3 + 2A1B3H12
For a satisfactory preparation the diborane must be
present in a quantity somewhat greater than indicated
by the equation. The physical properties of the com-
pound are those of a non-polar substance. Its
chemical properties resemble those of diborane greatly;
its reactions with 3ir, water, HC1 are analogous to
those of diborane.
B. Beryllium Borohydride
The similarity between beryllium and aluminum
suggested that diborane might react with dimethyl
beryllium to give beryllium borohydride. The reaction
went and in steps that could be recognized, and
intermediate products were isolated. (2)
Be(CH3)2 x SaSeL* (Ciy BeEH4 BaH£-> H3e3H4 -25L%
(3K4) 3e(BK4)
Burg and Schle singer intended the above series to
represent the series of reactions; they c'id not
propose this as a mechanism or suggestion of
structure.
&/.;f;i;
(-..•»■,'•* i»
rjj ■ j . .
^*. '" ..-■
6 :':o(:t:""tB
'->
t!
r *"
-75-
Th e final product of the reaction, BeB2H8, showed many
properties that closely related aluminum borohydride with
it. Its reactions with air, water, and HC1 are similar.
In physical properties it differs more decidedly from the
aluminum compound. Although both are readily vaporized
at room temperature, the beryllium compound is less
volatile than the aluminum borohydride, and its melting
point is about 180° higher. These differences indicate
that the beryllium borohydride may be more polar in
character.
C. Dimethyl Gallium Borohydride
At -45° in a typical experiment trimethylgallium was
treated with an excess of diborane (5) and the crystalline
borohydride formed was found to melt at 1.5°. This was
reported in a preliminary observation and is being in-
vestigated further,
D. Lithium Borohydride
2C8HsLi + 2B2H6 4 2LIBH4 + (C2H5)8B2H4
The reactions of the methyl derivative of aluminum and
beryllium lead Schlesinger end Brown to try to prepare a
similar derivative of an alkali metal. (5) A very stable
solid, LiBH4 , is produced according to the above equation.
This compound reacts with HC1 and H20 similarly to its ana-
logs. However, lithium borohydride differs in a number
of respects from the aluminum and beryllium derivatives.
Lithium borohydride is unaffected by dry air. Its salt-
like character (m.p, 275 with decomposition and no apprec-
iable vapor pressure up to this point) is another striking
difference. While trimethylamine removes borine groups
from the Al and Be derivatives (the latter with a~little
more difficulty), it has no effect on LiBH4tf Another way
to prepare LiBH4 is as follows:
A1(BH4)3 + 3LiC8H5 ^ 3LiBH4 + Al(C2H5)3
This should Indicate that the basic structures of the
aluminum and lithium bo rohydrides are closely related.
An example of the long predicted class of compounds, M(BR4),
was prepared by the reaction of trimethyl boron with ethyl-
lithium. (5) Schlesinger and Brown seemed to have no doubt
that this was an example of a quaternary boron derivative
Li C2H5B(CH3)3# Recently, the commercial availability of
lithium borohydride was announced. (13)
. . . . . f.
I p
- ■:. * .
J
: . ■
■•»
oir: r
. i ; • . v. ■ ■-.
.0
I
■
. , , r ;
-76-
V. Comparison of Chemical and Physical Properties (5)
Diborane Aluminum Beryllium Lithium
Borohydride Borohydride Borohydride
Anal,
formula
3sH6
A1B3H12
BeBsHs
LiBH4
Reaction
formula
(H3B)a
Al'(BH4)a
Be(BH4)a
LiBH4
M.p. °C.
-165.5
-64.5
123°
+ 275°
3.. p. °C.
V.o. at 0°.
,o 5
-< >m D
44.5
91.3°
dec.
275°
mn
very high
('"15.000)
119
0.5
Increasing tendency to react as BH4 derivatives
, Increasing tendency to react as 3H3 derivatives
very low
(U 10"*5
The data in the table indicate that there is a transition
from diborane to lithium borohydride. The latter appears
to be rather polar in character while the former is decidedly
non-polar in nature* It seems that in some respects, the Al
compound is more like diborane and the Be compound is more
like lithium borohydride* Similar relationships exist in the
chemical behavior. There appears to be a trend in the reaction
with trimethylamine.
and B
Schlesinger (5) suggested that LiBH4
H4"~f then assuming an analogous struc
consisted of Li
,jture for the Al or
Be compound, it is seen that the smaller and more highly
charged Al and Be ions would exert a much greater deforming in-
fluence on the BH4*" ion. As a result, the polar character of
the Be compound would become less than that of the Li borohydride
and still "less in the Al compound, ps is actually the case.
The deformation of the BH4 would make it more susceptible to
disruption.
VI. Structure Considerations
The configuration of aluminum borohydride has been deter-
mined by Beach and Bauer (l) using electron diffraction
methods. They propose the Al(BH4;3 structure where there
are several resonance hybrids possible. No experimental work
• "i f' 'T f * r -' ^ * .''
it
■-" «t
!.
I v ■ S.
I J. ~
. r:
[ !
*• r > " p r
r i- . . ->■
, ■ ' . i - . i '. . .' .• ;
' - ■. r~, f •
%-nYid
-. • -.■ ..
f v
f
r. •, *
■-.-.
-77-
has teen done on lithium or beryllium borhydride; but the ionic
structure for lithium borohydride does not seem Improbable,
and for beryllium borohydride these investigators suggest
Be(BH4)3 by comparison with Al(BH4)3.
Longuet-Higgins and Bell (3) have suggested certain bridge
link d structures for the more volatile borohydrides* They
also believe LiBH4 to be ionic.
VII. BIBLIOGRAPHY
Beach and Bauer, J. Am. Chem. Soc. 62 3440 (1940)
Burg and Schle singer, ibid. 62 3425 (1940)
Longuet-Higgins and Bell, J. Chem. Soc. 1943 252
Palmer,' W. G, : "Valency - Classical and Modern", pp. 60,
133, 225. Cambridge University Press, Cambridge (1944)
Schlesinger and Brown, J. Am. Chem. Soc. 62 3429 (1940)
Schle singer, Brown, and Schaeffer, ibid, 65_ 1838 (1943)
Schlesinger, Sanderson and Burg, ibid.. 61_ 536 (1939)
Schlesinger, Sanderson and Burg, ibid# 62 3421 (1940)
Stock, A,, "Hydrides of Boron and Silicon",
Cornell University Press, Ithaca, N. Y, (1933)
Stock, A,., Zy rnorg. Chem. 225 225 (1935)
Stock and Laudenklos, ibid, 228 178 (1936)
Thomas and Stevens., J. Chem. Soc. 1933 556
Chem„ and Eng. News 24 680 1 1946
(1)
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-78-
MAGNESIUM METAL PRODUCTION
Henry Holtzclaw April 2% 1946
A. Introduction
Magnesium is a silvery-white, malleable, ductile metal
which weighs 109 pounds per cubic foot* It is the eighth most
abundant element and the sisth most abundant metal0 It can be
cast, extruded, rolled, welded, and machined and forms alloys
of great strength with Zinc, aluminum, and manganese. The
average amount of magnesium used in each plane during World War
II was nearly one-half ton (13 )e Whereas production was 122 tonr.
in 1925, 20,500 pounds were produced in only one month during
the first quarter of 1944 (19). The price has dropped from
£5 per pound in 1914 to 20,5 cents per pound in 1943 (4),
B. History
Sir Humphrey Davy, in 1808, discovered the element magnes-
ium when he found it as one component of Epsom salt (MgS04)*
(6, 15). In 1830, Bussy obtained the first pure magnesium
metal, and Bunsen obtained the metal by electrolysis of fused
magnesium chloride in 1852a German industry began using
Bunsen' s process in 1886, The United States bought all of its
magnesium from Germany until 1914, when the supply was shut
off and the price rose to $5 per pound0 Dow Chemical Company
and American Magnesium Corporation (6,15,19) became the
principal United States producers. In 1927, American Magnes-
ium Corporation became a fabricator only, thereby giving Dow
a monopoly which it held until 1941 (6,19), Dow began sales
to foreign countries (6) in 1928, sales being made principally
to England, Poland, Holland, Mexico, Japan, and Germany, Export
sales became the major portion of total sales during the 1930' s.
Great Britain began producing in 1935, when Magnesium Elektron
Ltd. , was founded. The company used the process of I, G,
Farbenindustrie of Germany, largest manufacturer of magnesium
in Europe,
C. Production for World War II
I. Production in United States — Between 1939 and 1943,
fourteen plants were built in the United States with both
government and private funds (19), Plants were owned by the
government and managed by the various companies,
TABLE (19)
a. Electrolytic Processes
1, Dow Chemical Company :
(a) From brine — Magnesium extracted in Midland,
Michigan comes from a fossil sea that lies under the state. (5)
Brine containing 3.5$ magnesium chloride is pumped to the plant
where it is dried, first in air and then in hydrogen chloride
atmosphere, and electroly zed, producing magnesium metal and
chlorine gas (6), 99*9$ pure magnesium is obtained (15,14).
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-80-
(b) From sea-water — Dow Chemical Co., in 1943,
opened a plant in Freeport, Texas, for production of magnesium
from sea-water (12, 15, 9). Lime, made from oyster shells, Is
reacted with the sea-water to make magnesium hydroxide, which
is filtered off and reacted with hydrochloric acid. The result-
ing magnesium chloride is partially dried and used as cell feed
for Dow electrolytic cells. Chlorine obtained in the electroly-
sis is recycled to produce hydrochloric acid (15):
CH4 + H20 4 3H2 + C02
Ha + Cl3 ^ 2HC1
The Freeport plant also extracts bromine from the sea for
manufacture of ethylene dibromide for high octance gasoline.
Forty-two other materials could be removed from the waste sea-
water, but processes are not commercially feasible as yet.
Diamond Magnesium Co. — The plant, located at Painesville,
Ohio, utilizes Dow electrolytic cells, but the preliminary
method of obtaining magnesium chloride differs from Dow* s
method (l). The plant is coordinated with a near-by ammonia-
soda plant. By product, chlorine, is converted to calcium
hypochlorite, 120 tons being produced per day during the war:
2 Ca(0H)2 + 2C12 -> Ca(0Cl)2 + CaCl2 + H20
2 NaOH + Cl2 •» NaOCl + NaCl + H20
CaCl2 + 2NaOCl ■> Ca(0Cl)2 + 2NaCl
2. Basic Magnesium, Inc., Les Vegas, Nevada, uses a pro-
cess developed under supervision of Magnesium Elektron, Ltd.
(2) originated by I. G-. Farbenindustrie of Germany:
MgO + CO + Clg -) KgOla + C02
The molten, anhydrous magnesium chloride is used as feed for
electrolysis.
3. Miscellaneous — International Mineral and Chemicals uses
Dow Electrolytic cells to electrolyze magnesium chloride (12).
The Mathieson Alkali Works and the Consolidated Mining and Smelt-
ing Co. of Canada use an electrolysis method developed jointly
by them <12).
b. Ferrosllicon Process (Pidgeon) — Ford Motor Co. reduces
calcined dolomite with crushed 75$> ferrosllicon (12) at 2100
degrees Fahrenheit. Magnesium is liberated as a vapor and
deposited on an air-cooled condenser.
c. Carbothermic Process (Hansglrg) — Permanente Metals Co.,
Fermanente, Calif* , use a process by which magnesium oxide (12)
obtained by treatment of dolomite, is reduced by carbon at
high temperature. The magnesium vapor is shock-cooled by
natural gas (16). A by-product, magnesium black, consisting of
a mixture of carbon magnesium oxide and magnesium dust (19),
is sold to synthetic rubber, refractory, and rayon industries^
; VY.';' ■■:■'. ,
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-81-
II. Production in Other Countries — In 1943, Germany produced
magnesium at the rate of 100,000,000 pounds per year, Japan
at the rate of 28,000,000 pounds per year, and Great Britain at
the rate of 72,000,000 pounds per yerr (13).
1. Production in Great Britain — Four companies produce
magnesium metal (3), of which the only one in active production
is Magnesium Elektron Ltd. (2, 10). The other plants which
never progressed past pilot plant stage, used a thermal d it illa-
tion with f erro-silicon reducing agent, a carbo thermic process,
and a thermal process with calcium carbide as reducing agent.
2, Miscellaneous — Thermal reduction and f erro-silicon
processes have been used in Canada, Carbide reduction has been
used in Canada. Carbide reduction has been used in Australia
(13).
P. Research for New Processes
Following are three examples of research processes which
have received patents but have never been utilized commercially.
H. H. Dow and E. 0, Barstow (17) obtained patents, in 1930,
for:
MgC03»CaC03 + S03 -* MgCla + Ca.S04 + 2C02
The calcium sulfate is filtered out leaving magnesium chloride
in solution, which is then evaporated to dryness. Chlorine
obtained from later electrolysis makes possible a cyclic process.
Satisfactory raw materials, however, are expensive and the by-
products are so cheap that they do not aid materially in bring-
ing down cost of process, causing the method to be of small
promise commercially.
H. S. Booth obtained a patent (17) in 1938 for preparation
of magnesium oxide by dissolving dolomite in fused sodium
chloride or potassium chloride and effecting a separation of
the magnesium carbonate, and crlcium carbonate by maintaining
a temperature between the two decomposition temperatures. The
magnesium carbonate decomposes, forming a precipitate which
may be filtered out. The calcium carbonate remains in solution.
The process is of doubtful Success, commercially, because of
the expensive solvent and several difficult and costly steps.
A proposed process for obtaining magnesium hydroxide,
worked out and patented by J. D. Delang (17) in 1919 might have
commercial possibilities in areas with low cost electric poller:
CaC03.I!gC03 + HgSC-4 + SK30 -> 2 Mg(OH), + 2Ha
(all at cathode)
+ CaS04.2H20 + 2C02 + 02 (all at anode).
The magnesium sulfate may be obtained from a reaction of dolo-
mite r.nd niter cake (by-product in manufacture of nitric acid
from sulfuric acid snd sodium nitrate). The hydrogen and oxygen
obtained would have market value.
i r
-82-
E. Predictions for Future of Magnesium Hetal
As early as July, 1944, the United States Government
closed five of the fourteen plants recently built, and limited
the production of four others. By the end of 1944, production
was completely stopped in all tut four government-owned plants
(19). The U. S. Tariff Commission, after a thorough investiga-
tion of magnesium industry during the early part of 1945,
estimated (18) post-war consumption of magnesium to be 64.5
million pounds, as compared to a total production capacity of
between 500 and 600 million pounds. 40.5 million pounds would
be utilized by the transportation industry. Some active work
is being carried on to encourage the magnesium industry in
western United States to continue production (8), The situation,
in general, is not too promising for selling govenrment plants
to private concerns (19). The U. S. Tariff Commission feels
that the Dow process and the Permanente carbo thermic process
are most likely to succeed in post-war years and will be able,
Jointly, to produce more than the total consumption. The only
hope of new entrants to the field, therefore , would be in the
event of increased consumption, or ability to produce the magnes-
ium appreciably cheaper than either Dow or Permanente. Some
plants may be changed over to other products. The Mead,
Washington ferrosilicon magnesium plant operated by Electro
Metallurgical Co., for example, is now producing metallic sodium
CO.
New improvements in fabrication of the metal allow many
applications which before the war were considered impractical.
Decreased cost of production of magnesium should take place,
which would encourage further use, but Arthur Lowery predicts
(11) on the basis of his experience with the War Production
Board, that the price cannot go lower than about fifteen to
sixteen cents per pound.
-83-
BIBLIOGRAFHY
1. Avery, J. Ma , and Evans, R. F. , Chem. and Met, Eng., 52,
94 and 130 (April, 1945)
2. Ball, C. J. F., Metallurgia, 32, 153 (Aug., 1945)
3. Butterbaugh, H. W. Atkins, T. W. , and Davidson, L. H. , Modern
Metals, 1, 8 (Aug. , 1945)
4. Cone, E. F* , Metals and Alloys, 17, 692 (March, 1943)
5. Doan, L. I., Ibid, 18, 547 (Sept., 1943)
6. Dow, W. k., Metal Progress, 45, 675 (April, 1944)
7. Editor, Chen, and Met; Eng., 52, 168 (Sept., 1945)
8. Grant, L. B. , Ibid, 52, 262 Nov., 1945)
9. Kirkpatrick, S. D. , Chem. and Met. Eng. , 48, Special section
at beginning of issue, (Nov., 1941)
10. Knight, H. A., Metals and Alloys, 17, 57 (Jan., 1943)
11. Lowery, A., Technology Review, 47, 236 (Feb., 1945)
12. Manning, P. D. V., Metals and Alloys, 18, 547 (Sept., 1943)
13. Metallurgia, 29, 79 (Dec., 1943)
14. Metal Progress, 48, 497, (Sept., 1945)
15. Stedman, G. E. , Metals and Alloys, 20, 941 (Oct., 1944)
16. Stedman, G. E. , Ibid, 22, 102 (July, 1945)
17. U. S. Bureau of Mines, Inf. Circ. No. 7247 (Aug. 1943)
Includes following patents used:
Booth, H. S. , U. S". Patent 2,112,904 (A^ril, 1938)
Delange, J. C. , Brit. Patent 134,626 (Nov., 1919)
Dow, H. H. , and Barstow, E. 0., U. S. Patents 1,749,210
and 1,749,211 (March, 1930)
18. U, S. Tariff Commission, Chern. and Met. Eng., 52, 80 (Aoril,
.1945)
19. U. S. Tariff Commission, Ibid, 52, 133 (May, 1945)
r- »
-84-
FKCTOCONDUCTIVITY IN ALKALI KETAL HALIDES
C. J. Nyman April 30, 1946
Introduction
The photochemical properties of the alkali metal ha 1 ides
have been investigated largely by Hilsch and Pohl (7), Mott
and G-urney (3,4,5,6), de Boer (l), and their co-workers* It
has been found that 'these crystals under ordinary conditions
are insulators, and dp not conduct a current on illumination
with light. Howev^ri when an excess of alkali metal atoms is
added to the crystal,.- illumination with the proper wave lengths
of light will cause the; liberation of photoeiectrons within the
crystal. The absorption'' spectra (F-band) of such a crystal
with dispersed alkali metal atoms is considerably different
from that of the pure crystal. The illumination of the crystal
containing alkali metal atoms with wave lengths of light in
its F-band gives rise to e third type of spectra • (F» -band)
when an electric field is applied to the crystal* By illumina-
tion of this crystal with- light in its F'-band, a change occurs
which causes the reappearance of the original F-band. In
both of these latter" two "transitions, the production of photo-
electrons is observed by placing the crystal between two
electrodes in series with a galvanometer or electrometer and
applying a high potential to the electrodes.
Absorption Spectra Of Pure Alkali Hal ides.
Hilsch and Pohl (7) found that the alkali halides have
absorption bands in the ultraviolet ranging from 0.1 to 0.24
microns, and that the position of the principal maximum nearest
the visible is determined essentially by the halide ion. The
effect of the alkali ion seems to be of secondary importance.
The position of the maximum moves toward the longer wave lengths
as the atomic weight of the halogen increases. This maximum
corresponds to the amount of energy necessary to convert a
halide ion into a halogen atom in the normal state within the
lattice,
Mott and G-urney (5,6) consider that the electron is free
to move throughout the crystal until it becomes lodged in a
hole in the crystal at the center of six alkali ions. They
consider that even a nearly perfect optical crystal contains
vacant lattice points, the number of positive ions missing
being equal to the number of negative ions missing.
Hilsch and Pohl (7) and others (1,2,8) consider that the
electron moves from the halide ion to one of the six nearest
alkali metal ions, forming a neutral halogen atom and an
alkali metal atom.
-85-
Production of F.^.^ (1,5,7),
•fewl"™r?'irtSf4as«l:s!s5«s e"hr °f the tw° «»««*.
which lies m the Jeglon of 0? " b8"d Salled the F-band
centers involved are call°J °*. mJcrons- The absorption
centers. °alled reenters, "Farbzentren", or Color
^«ini0tehe"l8Jirh^Se1^8?SP?r«eB may be produ0ed *
metal at high temt»eratuM« $,% An a vapor of the alkali
of F-center! produced per 06 i™™^ QUenohinS- T^e number
alkali metal atoms pe/£ 0°? J'pS^^^^V'
in ^chC?hetesraSmrLshlSo0„baesP^?hU0^tby Radiation with X-rays
case there is a limit to the n^bero^^f llght' In a^
depending on the number of defect* L^J"oKS.P-W**6a»
Photoconductivity
that Jh5h<n,oS*S" the" eWt'7 Pho^elactrio current as
to the conduction We V Ul5S?„%?f0*n,ninf"lat°r are raised
In some crystals, the continued^as^^ Jn its ab™rption band,
appears to break down the resign™ g^ ?i 8 Prlmary current
electrons to enter the conduction T f'5e it***1' and aHo»S
Such a current is a seconds™, ^\ n ls from the cathode,
primary current is pwporUonal t^l^10 cur"nt. The*
moves toward the an^eP(ran«e of ?h= n^f3"?6 the electron
of F-centers per cc of thlfrvsLl a e^ro2)' and the "umber
increases, a saturation t^J^k^S* ^^
"H^W^^'SotSE^ ^V'lght in the^ ab-
move through the la? Ice unUl "SpJ'. "^ * These electrons
another vacant lattice point oimuL ?n ^ther trapped in
from, or until thev n~ ?«« oimllar to the one they were e 1eofPr!
electrons ^e now Lapsed ^^"siLf °th?r Center' ?„o eje°ted
a new absorption bandP?urther towafd%h°le'/nd give rise *>
microns. This new band is 0^11^^ Se ?ed at about 0.7
with two trapped electrons are can ed l,'^ *nd the centers
centers are Illuminated with light of £~?enters' Wben the F'"
the second electron is emitted ,n* * lir ab«>rption band,
fiia explanation agrees with f.y.^ "° F-°enters are reformed,
for every F--center formed tw F l?Mntal observation that
' IW0 F-oenters are destroyed.
c=nsidTerd?iSrstbI Ssuf^ff.Ef the Ph°toelectric current
but with no applie?fiai„COn.tainnlng " certain number of F-center,
will execute a tvpe of Brownf? ele°tron released by the light '
an F-center. The length of It Tth Unt11 " is captured by
jereeiy proportionalT^' nu^oTFVT U ***»»** ""-
«■ field is applied to the , „' 0£.F-Oent?rs P«r co. when
will execute Ttvoe0 of Brownf" ^T™ leased o^th Hght
an F-center. Th^length of the C T"1 " ls °aPtured
versely proportional to the n„m>,! row5lan Path is naturall
a field is applied to ?he "rysLl °h F-Cente^ per cc, „,
electron drifts down the fi^M ?i'<Jhe m?an distance that an
total length of the BroSnian oath Bn„°?ly ProPorti°nal to ?he
to the number of F-centers per cc ' At nlnvefeely Proportional
P^r cc. At low temperatures, this
-86-
current can be measured and is found to start and stop instant-
aneously with interrupted, illumination. At higher temperatures,
a dark current is observed* The primary photoelectric current
is proportional to the field applied at low potential gradients,
but reaches a saturation value very rapidly as the gradient is
increased above 200v/mm.
The Migration of F-Centers.
If a crystal containing a stoichiometric excess of alkali
metal is mounted between two electrodes in a field greater
than 200v/cm and at temperatures above 300°C. , the color is
observed to migrate toward the anode. The electrons are
ejected from their holes and move toward the anode, and the
vacant lattice points appear to move toward the cathode. At
these temperatures, the crystal is an electrolytic conductor,
and the electrons will form new color centers on drifting into
previously uncolored regions.
BIBLIOGRAPHY
1. de Boer, J.. H, ; "Electron Emission and Adsorption Phenomena",
Cambridge (1935 ) .
2. Klemm, W. ; Z Fhysik, 82, 529, (1933).
3. G-urney, R. W« and Mott, N. F, ; Trans, Faraday Soc; 34
506, (1938).
4. Mott, N. F„; Trans. Faraday Soc; 34, 500, (1938).
5. Mott, N. F. ; and G-urney, R. W, • "Electronic Processes in
Ionic Crystals", Oxford, (1940),
6. Mott, N, F. and Littleton, N, J.; Trans Faraday Soc., 34,
485, (1938).
7. Fohl, R. W. (and Hilsch, R. ); Proa. Phys. Soc.; 49, 3, (1937)
8. Von Hippel, A; Z Physik, 101, 680, (1936).
* Review of work by Pohl, Hilsch, and co-workers.
v ■:
-87-
DONOR PROPERTIES OF PHOSPHORUS
AMD SUL-HUR COMPOUNDS
Clayton Callis May 7, 1946
Tricovalent phosphorus compounds, like ammonia and its
derivatives, and dicovalent sulfur compounds, like water and its
derivatives, would be expected to be capable of complex formation
by coordination through an unshared pair of electrons.. However,
H80 and H3S show very little similarity in their coordinating
tendencies; the same is true for NH3 pnd FH3.
The difference between He0 and H3S is indicated by their
dissimilarity as solvents, H8S being very poor in this respect;
and also by the marked difference in the stability of their co-
ordination compounds. (1) (2) Considerable work has been done
on the thiohydrates by Biltz and Keunecke,, (l)
The series of coordination compounds with nitrogen and with
phosphorus have very little in common. Nearly all the known com-
plexes of phosphorus are non-ionic and are of several types which
are very characteristic. After examining the experimental evi-
dence, it might well be concluded that these compounds exist
solely because of the additional stability of a configuration made
psssible by the addition of a phosphine or substituted phosphine
molecule.
Since the phosphine molecule possesses a lower dipole
moment than the ammonia molecule (4) its donor ability would
be expected to be much smaller than that of ammonia. The sub-
stitution of larger groups, whether positive or negative, in
general, appears to increase this ability; for coordination com-
pounds of the trialkyl phosphine and phosphorus trihalides are
comparable to those of ammonia* It is interesting to note that
this is not generally true in the case of ammonia and its derivat-
ives except in the simplest case, i.e. , in their coordination
compounds with the hydrogen ion. Perhaps this can be explained
by a consideration of steric hindrance since the N ha s an atomic
radius of 0.53 and F 1,08 A,
The linkage of the metal to a substituted phosphine is very
firm and the substituted phosphine group is not easily displaced.
In many cases the phosphine appears to be held more firmly than
halogens or other charged groups.
On more or less theoretical grounds, several investigators,
especially Holtje (4), who carried out rather extensive experi-
ments with the group IV halides, have suggested that the compounds
of FH3 and HaS should bear close resemblance to each other just
as the compounds of ammonia are akin to those of water.
-88-
?he followi
Holtje (4) conce
group IV hrlides
trins results of
ng trble give
rning the coo
. For co riven
s r summrry of the drtr compiled
rdinrtipn compounds of FH3 with
ient comprrison the trble also c
the behrvior of the e&'lts towrrd H3S rnd NH3
by
the
on-
Behr.vior towrrd
5r.lt
H.F,
FH3(4)
HSS (1)
NH3
nn-i
-23.8
s. in lie, FH3
s. in lieu Hr,S
SiCl4
-68.7
s. in lie, PH3
s, in lie, HaS
converted to Si(NH8),
G-eCl<
-49* 5
s. in lio. FH3
2 StlCl4»3FHi
converted to G-evOTg
9aCl4-2NH3
SnCl*
-33
SnCl/.»?H8S
(yellow)
SnClA*4H83
(white)
SnCl.i»4NH3
sniA
+ 145
no rerction
no reaction
severrl ammoniFtes
FbCl.-
-15
reduced to
PbCls
reduced to
FbCl-s
several rmmonirtes
TiCl4
1
-24
T1CU*FH3
TiC!4.2FHa
(yellow)
TiCl,..HpS
TiCl^«2H2S
(yellow)
severrl ammonirtes
ZrCl4
no rerction
no reaction
severrl rmmonirtes
A1C13
+ 190
no rerction
A1C13.H3S
severrl ammoniates
Til,x
+ 150
no rerction
no rerction
G-el.i
+ 144
no reaction
Observrtions rnd fienerrlizrtions mrde by Holtje on this
rrther smrll rmount of informrtion:
1. Srlts behrve similrrly towrrd FH3 rnd H8S,
2. Biltz rnd Keunecke concluded thrt only srlts with mole-
culrr lrttices (low melting) rerct with H8S. Holtje asserts the
same is true for FH3.
3. The rerction with FH3 shows the similrrity between G-e
and Si.
4. FH3 possesses scrrcely any similrrity to NH3 in these
rerctions.
5. FK3 rnd NH3 rre in similar relrtion to erch other as
H8S rnd H80.
6. The similrrity in the coordinrting tendencies of FH3 rnd
H8S prrrllels thrt of NH3 rnd H80.
The phosphine compounds rre considerably more stable thrn
the sulphines or thiohydrrtes. The decomposition pressures of
the- thio-ethers rre (rround 0°C) generrlly grerter than 100 mmf|
while with the phosphines, the decomposition pressures rre only
a few mm (4). Strbility has been evrlurted from decomposition
pressures, temperrture-pressure curves, rnd crlorimetric determinr.
tions of the herts of rerction. (11)
The grerter strbility of the phosphine compounds can not be
explained on the basis of dioolc moment; for H3S hr s r higher
dipole moment thrn phosphine.
U
NH3
HpS
FH3
1.50
0,951
0*55
R (Molc-culrr Refraction )
5 ..60
9.45
11.73
. ..' .
'.
* '
-69-
If one considers rise the def crmability of the donor mole-
cule the- stable compounds of ?H3 seem plausible (6).
The negative constituent of the salt also influences the
stability of the compound; the chlorine containing compounds
being less stable than those contrining bromine.
Since the stability of the phosphine rnd sulphine compounds
is grer.tly increased by substitution, there is a greater opportun-
ity for comparison among the coordination compounds of the dialkyl
sulfides and the trialkyl phosphine s,
CLASSIFICATION
Except for r few minor exceptions, all of the known addition
compounds of phosphorus are of the simple additive type
a Mm Xm • bPR3
where M represents a metal of valence m, X is a univalent radical,
R may be hydrogen, a halide, or rn alkyl or alkyloxy group. In
the table nothing is implied as to structure.
a:b = 2:1
a:b = 3:2
a : b = 1:1
a:b = 2:3
a:b = 1:2
Cu
Q4X?FR3
CuX"2FR3
Agt1
2AgX.PR3
AgX-FR3
Au+1
AuX«FR3
<l
CdX3"FR3
2CdX3.3FR3
CdX3«2PR3
-j +2
2HgXa.FRa
3HgX8.2FR3
KgXs'FR3
2HgX2-3FR3
KgX3«2FR3
Fd
FdX3*FR3
?dX3-2FR3
r t
FtX3.FR3
FtX3»2FR3
a-, + 3
2BX3.FR3
AuX3«FR3
BX3'FR3
i
A1X3«FR3
ft +3
As,
AsX3'FR3
Sb+ 3
2SbX3.FR3
l
31+3
BiX3'FR3
" +4
TiX4'FR3
TiX,,.2FR3
Sn
2SnX.i43FR3
I, , ,
The number of known coordination compounds of H3S is indeed
very small, The more important ones are (l)j
AlCl3-HaS; A1BR3<H3S; AlI3*2HaS) AlI3.4HaS;
Be3r3.2H3S; BeIa«2HaS; TiCl4.HsS; TiCl4<2H2S;
Ti3r.:.»H3S; TiBr^2HaS; SnCl4.2H3S; SnCl4-4H3S.
Several sulphines of the type [KXa <-— SR3], particularly of
platinum, palladium and mercury have been investigated (7), (8),
(9), (10), (41).
-90-
ENCLATURE
All the compounds of known structure can be named according
to the accepted system. For uniformity, it is perhaps best to
consider the phosphorus halid.es and the esters of phosphorous
acid as derivatives of phosphine. In a like manner, the compounds
of HoS are named as substituted sulfines.
c
STRUCTURE
There is very little evidence on the structure of many of
these compounds. The type of work that has been done is in-
dicated below*
A . X- ray '•• studies
1. The structure of (£3P ---- ^ I'XJ, where 1T is Ag or Cu,
has been thoroughly investigated. The molecule is
four-fold with the netal atoms arranged at the corners
of a regular tetrahedron. (15) (19).
2, A study of the disulphine compounds of platinum
supports the planar arrangement of valencies (17),
3. |Jrig, Cd )X2«FR31 compound's in the solid state have the
chimeric symmetrical tetrahedral structure, (12)
4, In[2PR32?dCl CsO^i. the oxalato group is the bridge
connecting the Fd atoms, -a"****
P. Molecular weight determinations in various solvents, a^***-**
1. IH3F ~> Cul] is shown to be four-fold in solution (15),
2. Gold shows a coordination number of 2 in compounds of
the type fR3F — -> AuCl] (solvent, benzene) "(19)
3. Several investigators hrve shown that formulas of the
compounds of the tyoe [FtCls*R3S]and (PtCl3»PR^ should
be doubled (18) (25") (26).
4. The unimolecular formula. [2R3P — ->10C81 was found to. ^.
be correct for He. Ft. Fd . and Cd. (12).. *^» * **»-• -Xo* . b»* 1
be correct for Hg, Ft, Fd, and Cd. (12).
C. Chemical Evidence
1, Study of *- «' dtpyridyl derivatives (15),
2,' Structure and isomerism of phosphine and sulphine com-
pounds of platinum and oa.lladium compounds (20) (9)
(21) (10) (28).
3. Studies of solubilities in various solve'nts with
analogies to known compounds.
D. Dipole moment measurements
1* Existence of trans isomers in the platinum and pallad-
ium compounds is verified (22),.
E. Cry sta. lie graphic studies
1. Hann, Furdie and Wells have confirmed the unimolecular
formulas of the aureus compounds [AuCl *- FR3I (19).
2. Study of Cs3)Au2Cl.3 crystals confirms linear and
planar configurations of gold, (42).
OTHER WORK DONE IN ESTABLISHING- EH-IRICAL FORMULAS
A, Observations of the volume ratios of the gas generated
in dissociation (29).
3. Conductivity measurements, Jensen (18) worked with the
conductivity of aqueous solutions of B- (PtCls- (Et3S )j .
Ce Vrpor oressure curves used to calculate calorific data
,Pft3
•P^Im . ^'^3
llil
EA* ^c**--^1-
P«5
Cuw- - - — — ~ - — - - C**-.
Pfc
3.
«*t*
a»«^JLw %\<
X >-. * v ->■ <5^
r+r+~£** ^*
P*5
7 ?
^x'
N*«?
-91-
BIBLIOGRAFKY
(1) Eiltz r.nd Keunecke, Z. r.norg, rllgem. chem, , 147, 171 (1925).
(2) Eph rim, "A ?ext-nook of Inorganic Chemistry", Gurney rnd
Jrckson, London, 1926, p. 427,
(5) Holtje rnd Schlegel, -2, anorg*. allgem. Chen,, 243, 246 (1940).
(4) Holtje, Ibid. , 190, 253, (1930).
(5) Schwrrz r.nd Shenk, Ber. , 63, 296 (1930),
6) Frjrns, Z. Electrochem. Angew, Phys. Chem. , 34, 502 (1928).
(7) Kir. son, Ber,, 28 1493 (1895). •
(8) Ardell, Z. rnorg. Ghen, 14, 143 (1896).
(9) Angell, Drew, et. rt., J. Chem, Soc. 1930, 349.
{10) Drew, et. rl, , ibid., 1953, 1295.
(11) Holtje, Z. rnorg. rllgem. chem, , 209, 241 (1932).
(12) lir.hn, Evrns, Peiser rnd Furdie, J. Chem. Snc, 1940, 1209.
(13) Hrnn rnd Furdie, ibid., 1940 , 1230.
(14) Hnnn rnd Purdie, ibid. , 1940, 1235.
(15) lir.nn, Furdie rnd Wells, ibid. , 1936, 1503.
(16) Cox, Wrrdlr.w rnd Webster, ibid. , 1956, 775.
1934, 1012.
225, 115 (1935).
Soc. , 1937, 1830.
1934, 182.
229, 225 (1936).
(17) Cox, Sr.enger rnd Wrrdlow, Ibid";
(18) Jensen, Z. rnorg. rllgem. ^hem,
(19) Hrnn, Purdie rnd Wells, J. Chem,
(20) Cox, Saenger rnd Wrrdlr.w, ibid.
(21 ) Drew rnd Wyrtt, ibid. , 1934, 56,
(22) Jensen, Z. rnorg. rllgem. Chem,
(23) Holtje, ibid. , 197 93 (1931).
(24-) G-rossmr.nn rnd von der Forst, Z, rnorg. rllgem. Chem., 45,
94 (1905).
C25) Rosenheim rnd Lowen, ibid. t 37, 394 (1903); 43, 35 (1905).
<26) Hrnn rnd Furdie, J. Chem. Soc. 1936, 873.
(27) Mr.nn rnd Furdie, ibid. , 1955, 1549.
(28) Emeleus .~nd Anderson, "Modern Aspects of Inorganic Chemistry",
George Routledge, London 1938, p. 107.
(29) Besson, Compt. reud. , 110 80, 516 (1890).
(30) Holtje, Z. rnorg. rllgem. Chem., 190, 241 (1930),
(31) Lindet, Ann. Chim. Phys. 55, 11, 177 (1887).
32) Lemoult, Compt. rend-., 145, 1175 (1907).
(33) Molgaon, ibid., 115, 203~Tl892).
(34j Chrllenger, Frichrrd rnd Jinks, J. Chem. Soo* , 125, 864 (1924)
(35) Arbusoff, "er. 38 1172 (1905).
[36) Dr.vies rnd Writers, J, Chem. Soc., 1935, 1786.
\ot; Hertz rnd Drv'is, J. *m(. Chem. boc, , 50, 1085 (1908).
(38) Trnble, Compt. rend., 132, 83 (190177
(39) Hrnn rnd Wells, Je Chem. Soc., 1958 702.
(40 ) Hrnn rnd Chrtt, ibid.., 1938, 1949.
(41) Bennett, et. rl.7~lbid. , 1930, 1668.
(42) Elliott rnd Pruling, J. Amj Chem. Soc, 60 1846 (1330).
143) Fink, Compt. rend., 115, 176 (1892); 126, 646 (1898).
1. 1
-92-
THE SODIUM METAFHOSFHATES
mry ^an May 14, 1946
I. Introduction
varie^prolSo^f ^'igh'molecSa^M Xt to P^^-ize and form
that these products 8how^BomS?L^*t'vt2?!ther wlth the fact
within the indlvid«r£oleoS?r« tSt^? fem^mn^eilt
appear to have the same molecular !! , va?Ilng constitutions may
the most complicated of &&lSS^^&TS^AiS&1^
this field6"3 ^tolr'n^ltef 8coere afV°. """" P™b1^ in
with so little succe^s'conlL8^ tna^^f* eiuoldat^
spent. The question as tn q?™,»?m the "me> Interest and energy
and the relationship between th^rlou^?8'0™?"0" in solution
forms is a problem often attaov^rl «1^S^SOmerio and Polymeric
are almost as many lnteroretatinni ="^the Tsult that there
in the field. interpretations as there have been workers
out on%rhe%\erao0mnpoundnsretdhoyuKhrSforVthStigat,10nS have been — ied
a laboratory curiosity until^he ^ m°St part they remained
sodium metaphosphate glass ■.™.5i"OOV?,7 that solutions of
plex corresponding to such I ?«£ ~ r oaJoium In a soluble com-
that the usual prfcipitants for «.'£ ?"°entfatlon of calcium ion
cipltate. Following thi. « oalolum do not produce a pre-
application wen? forward ".« !°r27*' lndu^lalPdevelopme^ and
seven years there hive been hundred,^?6 f?d I* the last slx °r
of preparation of soluble or in so luM? pa?ents given on methods
galsses. or ^soluble sodium metaphosphate
Hi Characterizing the metaphosphates
varied^o%otundfannTmlxWes''roes?Pin°Srte"' the~ *»> ma^ a"*
uniformity of naming of these a , 2 * am?2lnS lack of
cribed in a half-dozen diff^-n? * i slngle salt may be des-
of a half-dozen differs* JnwstlStorf P6??1?g °" the theorles
that an organized manner of SSnttfTSTft " therefore appears
ize each compound by its method ion"ould be *> character-
number of reactionsl preparation and by a limited
condition of tos pwLS?*?^^0?8 °f these ^pounds, the
method of heating^d bv chan^inf T'^ deP^dent'on the
melt, these various highly £0?™^ h rate of °°ollng of the
Homogeneous products are not «h?f^ffd Products are produced,
tained break down into un?°L? °S * rule~and melts ob-
Very soluble and very insoluble^Cr?*8 **" treated with water,
modifications are obtained so It JT^SV1 Wel1 as thelr °«n
character of the compound if not dev^ \See that the *rue
studies. Many specific reactwL *I E8d by wster solution
the differentiation nfthf8 h8Ve been 8iven as bases for
in the cass of^sta^e SSf &£ *— ralxt— b»* only
• »
■93-
III. Degrees of Polymerization
A. Monometaphosphates — Pascal* s salt; Maddrell* s salt.
Cryoscoplc measurements In water at various concen-
trations extrapolated to infinite dilution give an
apparent molecular weight of 51.
B. Dimetaphosphates — Fleitmann1 s salt; Warschauer* s salt.
No definite proof,
C. Trlmetaphosphates — Knorre»s salt.
Crystalline compound closely related to G-raham' s salt.
D. Tetrametaphosphates — Fleitmann' s salt.
Insoluble crystalline salt, apparently a distinct
compound but real nature entirely unexplained^ a
product of devitrification of hexametaphosphates.
E. Hexametaphosphates — Graham1 s salt.
Measurements of the dialysis coefficient indicate
much more polymerized state than hexameric,
F. Higher polymer — Kurrol's salt.
Insoluble glass.
IV. System NaP03-Na4P207
The combined evidence from thermal, optical and X-ray
investigations has given close insight into the complexity ex-
hibited by the compounds and mixtures in the range of composition
from sodium metaphosphate to sodium pyrophosphate.
3oulle found two distinctive X-ray patterns for the de-
hydration of monosodlum orthophosphate at different temperatures.
Partridge, Hicks and Smith applied differential thermal" analysis
in order to study the transformations and found the same invers-
ion described by Boulle. However, they found three X-ray diffrac-
tion patters, though no definite difference between two of the
forms could be found with the petrographic microscope.
The temperature-composition diagram of this system was
worked out by Partridge, Hicks and Smith from studies of mixtures
representing intervals of 10$ in composition between the end
members. The investigations were made by four independent
methods: thermal, X-ray, high- temperature microscope, and polar-
izing microscope.
From the collected data, the investigators arrived at the
following conclusions!
a) Sodium metaphosphate may be obtained by thermal
processes in three crystal forms.
b) Sodium pyrophosphate probably exists in five different
crystal forms, but all transformations are reversible
and only one form can be obtained at ordinary temperatures
c) Only one of the hypothetical polyphosphates in the
system exists as a crystalline individual. This is
Na5P30lo, which may exist in two crystal forms at ordinary
temperatures.
. -
u
., ■ .; i
' '''"'." ■ '. '.'. ' ". Y
" .•-^,>>..
> ? 1
1
1 .. . \
a. '
•'! >
,
■ T
".
" '
* '.
> . '«
: . • -
: .,.,
. <
:-■ ' . "•
■ » •. ;
«Hx>-
io»- •
*,•<•
500 -
V j - :' , ■
■ ' " "'
JOO
H+r^+mf&o ■•■I.iiisVS
-ii ■■• ' '»'
.*i—
%* set v#; «©
■
• - - : ■ ' t .
(' *
»ij J
, !
•( ..
:..-..
-94-
BIBLIOGRAPHY
1. Karbe and Jander, Kolloid Beihefte 54 1-146 (1942)
2. Partridge, Hicks and Smith, J. Am. Chem. Soc. 63 454-466 (1941)
3* Boulle, Compt. rend. 200 635, 832-4, 658, 1403~T1935)
4C Boulle, Compt. rend, W)6 517, 915-7, 1732 (1938)
5. Beans and Kiehl, J, Am. Chem, Soc. 49 1878-1891 (1927)
6. Ephraim, "Inorganic Chemistry" Nordeman Publishing Company,
New York 1943, pp. 727-730
7» Yost and Russell, "Systematic Inorganic Chemistry"
Prentice-Hall, 1944, pp. 210-224
ft r • ' : ;
(
■ >■•••: i ''-,■
-95-
STABILITY OF CHELATE COMPOUNDS
Hung Kao May 14, 1946
I. The method
Recently two studies have been published (1,2) on the in-
fluence of certain structural factors upon the stability of
chelate compounds of divalent copper in a more or less quantitat-
ive manner. The second paper (4) in this series will be pub-
lished in the J. Anu Chem. Soc. for this month. The stability
of chelates is defined with respect to the reaction
Cu
++
>Ke'
CuKe:
where Ke represents the anion of a
aromatic aldehyde.
(A)
diketone or a O-hydroxy
The method used consists of determining the H concentration
of a solution containing known quantities of copper, chelating
substance ,r acid and base. Fifty, percent dioxp.ne-water solutions
of Cu(Cl64)2, HKe(0.02M) and HCl#; (0.02M) were titrated with
aqueous sodium hydroxide. The total copper present is of the
order of 10~3 M. It was found that the equilibrium was not as
simple as represented by (A). J. BJerrum' s method of calculation
was then used. Assume that the reaction goes in steps
Cu++ +
CuKe+
Ke
+ Ke"
and
Ki = , ( CuKe* )
(Cu++)(Ke-)
— > CuKe (p)
> CuKe2 (C)
(CuKe2)
Ka =
(CuKe+)(Ke~)
at equilibrium we have:
++
TCu++ = Cu + CuKe + CuKe8
THKe ■ HKe +
CuKe+ + 2Cu++
Ke"
+ CuKe + 2CuKe-
+ Na + H+ = C104"" + OPT + Ke"
KD= (H+) (Ke")/(HKe)
= A + 2TCu++
CIO*
From these eauations we obtain:
TT=(Na+-A+H+)/Tcu++
Where N is the average number of Ke" bound to Cu'^, plot N
against F£e and Kx and K2 determined approximately from the
curve at N = 0.5 and 1*5 respectively. At IT = l.O^A. gives an
average constant Kav such that (Kav)2 = K, K3
(D)
(E)
(F)
(&)
(H)
++
(I)
Ke"
.
:
-
"■> "
I M
-96-
II. Results of determination
The value Kay can be taken in a first approximation to
represent the equilibrium constant of the general reaction
Jb - 0" t %0 - 0"
-CT + * Cu'r+ r===- -C* 1 Cu
^J = 0 ^C = 0 ^
The accuracy of the data as yet does not warrant any discussion
of the difference between K1 and Ka. Another limitation im-
posed by the character of the data concerns the absolute
values of the constants themselves* Until the temperature
coefficients are determined and by that the heats and entropies
of the reactions, we will be concerned only with the relative
values of the constants.
Table
I*
Compound
*i
K2
Kav
KD
solicylaldehyde
io7-5
5,8
10 *
io6'6
IO"9*5
3-N-propyl
io8-0
106.3
7 7
10 '*
IO"9'6
5-methyl
io7-7
io6-0
io6'8
io"9-7
4,b-dimethyl
io8-3
io6«7
io7-5
io-10-4
3-ethoxy
io7*95
io5,85
io7-1
IO"9'4
3-nitro
io4'9
io3-4
IO4'2
io'6'0
3-fluoro
io6-6
IO4,9
105.8
io"7-8
2-hydroxy-
naphthaldehyde-1 10 ''b IO6,0 IO6*8 IO"8*4
2-hydroxy- "~~~~ ™
naphthaldehyde-3 est 10 10" *
acetyl-acetone
109.0
io8'1
IO8' 75
10~9»7
Trl fluoro acetyl
acetone
io6-3
IO5-9
io"6'7
Furoyl acetone
io8-7
. io8-2
IO"9'3
Benzoyl acetone
io9'0
IO"9'8
C-methyl benzoyl
acetone
IO8*5
IO7*3
io7-7
IO"11'8
Aceto acetic ester
10B«4
10s.s
"lo"*5"""
-"-=1172-
The first seven are derivatives of salicylaldehyde the next
two are derivatives of /Q naphthal, the next five are derlvat-
ives of acetone.
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III„ Conclusion
-97-
A plot of log
fall Into at least
class the linear re
slopes of two lines
forces responsible
made up of at least
the same character
other plays a diffe
copper than it does
due to enolate reso
Kp against log
K shows
that the compounds
two and possibly^four classes. Within each
lationship is approximately followed and the
obtained are very nearly the same. The
for holding the copper in the chelate are
two different components, one which is of
for both copper and hydrogen while the
rent and far greater part in the bonding of
in the bonding of hydrogen. The latter is
nance between
\3 - 0-
//
•C
\
C = 0
Ex
and
-C
\
C = 0
/
C - 0"
Ea
Thus the CuT+ in the chelate may either form a fromopolar bond
as \ .♦_ \
-CT x^i Cu and
-C
C = 0-
X - 0
1 , ++
or a six-membered ring is involved in the chelate as
~CC 77 cu and
IV Evidence from kinetic studies
\
The rates of exchange of a series of copper chelate com-
pounds with copper ion, the copper ion being mashed by contain-
ing a radioactive copper isotope
Cu*+Ke3
Cu++ * Cu
++
#
++
Ke:
Cu
have been measured (2) and it has been found that tie reaction
is bimolecular in the chelate and the copper acetatt*. The
remarks and conclusions concerning the effect of the organic
structure upon the stability of the chelates as determined
from equilibrium studies can be applied here. This may be
seen in the following pair of compounds measured under the same
conditions
Acetylacetone ethylenediimine
Salcylaldehyde ethylenediimine
1
■ 37 hrs*
2*
■ 2.1 hr.
3
•. . ( .<
!.' :
■■f ^*
'- I*
■ ■ i ;■- «
1
, * '
)' - i I
. .-' '•
-98- "
References
(1) Calvin and Wilson J> Am. Chem, Soc. 67 2003 (1945)
(2) Calvin ?nd Duf field, ibid 68 557 (1946)
(3) J. BJerrum: "Metal Ammine Formation in Aqueous Solution"
P. Haase and Son. Copenhagen. (1941)
(4) Calvin and Belles, J, Am. Chem. Soo. 6£ May (1946)
(5) Branch and Calvin: The Theory of Organic Chemistry
Prentice-Hall Inc. (1941)
.
-99-
THE CARBIDES
Ann Lippincott May 21, 1946
I. Types of carbides
The compounds of metals and carbon are of two kinds, the
refractory type and the salt-like type.
The refractory type Is formed by the elements of groups
IV, V, and VI of the periodic system. They have many of the
properties of true metals: high electrical conductivity with
a. negative temperature coefficient, superconductivity, and weak
paramagnetism. They do not react with water or with dilute
acids.
The salt-like carbides are formed by the alkaline earths,
the alkalies, the r^re earths, and the iron group. They are
colorless, transparent, crystalline solids, non-conductors of
electricity* They are decomposed by water or dilute mineral
acids, with the formation of hydrocarbons* The exact products
of the hydrolysis depend upon the structure of the compound,
and the salt-like carbides may be classified according to these
products:
a) Those yielding methane — 3e2C, A14C3
b) Those yielding acetylene — Na2C2, K2C2, CaC2, 3rC2,
BaC2, Au2C2, Ag2C2
c) Those forming mixtures
1) Chiefly methane and hydrogen — Fe3C, Mn3C, Ni3C
2) Chiefly acetylene — UC2, LaC2, NdC2, ThC2, MnC2
II. Structure
The refractory carbides are interstitial compounds which
have a structure determined by the metallic atoms. The non-
metallic atoms are packed into the interstices between the
metallic ones. The metallic properties are therefore explained
by the fact that their structure is primarily that of the metal.
"Tie salt-like carbides possess ionic lattices (hence their
name). The cations are in the interstices between the close-
packed carbon anions. The nature of these carbides depends
mainly upon two factors, the first of which is the electro-
positiveness of the metal from which it is formed. The salt- ■
like character of the compound decreases as the electropositive-
ness of the metal from which it is formed decreases. In the
series Be2C, A14C3, SiC, the most salt-like is Be2C, and SiC
is of an almost completely hcmopolar character.
The second factor is the size of the cation, in conjunction
with its valency. The close packed structure of the anions
allows two " tetrahedral" cavities for occupation by cations for
each anion present. If valence considerations reauire more
than two cations, there is no room for them. Thus, there are
no "methane" salts of the alkali metals such as Na4C. Divalent
<•>.
\
-100-
cations of the alkaline earths could be present, but they are
large enough that the anion lattice would be deformed. The
carbon lattice seems, therefore, to break up into distinct
C2= groups, and the known alkali and alkaline earth carbides
are of the type Na2C2 or CaC2. It is because these compounds
contain carbon pairs (acetylide ions) that their hydrolysis
product is acetylene.
The rare earth carbides, which give chiefly acetylene on
hydrolysis, are similar. The other products vary with the
conditions of decomposition, but are chiefly other saturated
and unsaturated hydrocarbons. The irregular products are
believed to be formed as a result of the change of the metal
from the bivalent to its ordinary tri or tetravalent state,
If methane is a hydrolysis product, as with Be2C and A14C3,
the carbide has a lattice in which the carbon atoms are separated
from each other. The hydrogen which is set free then reacts
with the carbon atoms separately, rather than in pairs.
Magnesium carbide is not similar to any of the carbides
which have been mentioned. Its formula is Hg2C3, and it yields
allylene on hydrolysis, which implies that C3~4 exists in the
crystal lattice.
The iron group carbides are intermediate between the re-
fractory and the salt-like carbides. Structurally they are
like the refractory. Chemically they are not as stable, and
not as perfectly metallic. There is serious distortion of the
metal lattice unless
radius of metal ^
radius of (3 / ^7 A
o
That is, since the radius of C is 0„77A, the metallic atomic
radius must be greater than 1.3& to avoid distortion. The
radii of all the iron group metals are smaller than this limit-
ing value. Therefore, while sha„ring the metallic character-
istics of the interstitial compounds, they have modified
properties and crystal structures distinct from those of the
metals.
III. Preparation
Hoissan was the first to do extensive work on the carbides,
and he prepared them by heating a mixture of the metal or its
oxide or carbonate with carbon and heating the mixture in an
electric furnace, Heating the metal in acetylene is a less
satisfactory method of preparation.
Calcium carbide, used for making acetylene and in the
manufacture of cyanamide, and silicon carbide (carborundum) are
manufactured commercially, and the methods used are essentially
the same as those of Hoissan.
.'■'■, '■> .
:>v; h ;
-101-
BIBLIOGRAPHY
1. Emeleus and Anderson; "Modern Aspects of Inorganic Chemistry n
Routledge, London, 1938, p* 453
2. Lebeau, P.; Compt. rend., 121, 496 (1895)
3. de Mahler, E, Bull. soc. chim. , (IV) 29, 1071 (1921)
4. Moissan, H, Ann. chim. yhys., (7) 9, 302 (1896)
5. Moissan and Etard, Compt, rend., 2ST, 593 (1896)
6. Moissan and Lenfeld, ibid, 22, 651 (1896)
7. Myers and Fischel, J. Am. Chem. Soc. 67, 1962 (1945)
8. Ruff, 0., 2. Elektrochem, 24, 157 (19T5)
9. Schmahl, N. G. , ibid, 40, 68 (1934)
10. Schmidt, J., ibid, 40, 170 (1934)
11. von Stackelberg, Z. physik. Chem. (B) 27, 53 (1934)
\ I -.'
-102-
THE FLUORIDATION OF NON-POLAR CHLORIDES AND THE
THERMOCHEMISTRY OF HALOGEN EXCHANGE REACTIONS
M. M. Woyski May 21, 1946
The halogen exchange reaction is the most important method
for the preparation of the less common metal and non-metal
fluorides. Although a large number of such reactions have been
observed the course of halogen exchange reactions in general
has not been predicted.
Table 1 gives the heats of formation cf a number of chlorides
and fluorides and the differences (per equivalent) of these
quantities. The algebraic difference of these values for any
two chloride-fluoride 'couplets1 gives the enthalpy changes
for the halogen exchange reaction. These enthalpy changes may
be used in lieu of free energy data for calculation of equilibr-
ium constants since the entropy of exchange reactions (except
those involving some of the lighter elements) is negligibly small
Table 1 may be considered as a scale of fluorinating agents
in decreasing order of thermodynamic activity.
For lack of thermal data most of the non-metal chloride-
fluoride couplets cannot be placed on this scale. That the
chlorides (with some exceptions, e.g. sulfuryl) are readily
fluorinated by antimony or calcium fluorides indicates that
they are low on the list.
Experimental Work
1. Anhydrous hydrogen fluoride, at 25°C. , is capable of
fluorinating several of the non-polar chlorides, namely, phos-
phoryl chloride, phosphorus trichloride, phosphorus pentachlorlde
thionyl chloride, chloro sulfonic acid and silicon tetrachloride.
2* Anhydrous hydrogen fluoride reacts with sulfuryl chloride
to a very slight extent, if at all* It is not decided whether
this is due to equilibrium conditions or to chemical inertness
of sulfuryl chloride,
3, The relative rates of reaction of the several non-polar
chlorides with anhydrous hydrogen fluoride have been observed
roughly.
4, Intermediate products of the fluorination of phosphoryl
trichloride by hydrogen fluoride (P0C13F and P0C1F2 ) can be iso-
lated in good yield by proper control of the conditions of the
reaction.
5, Hydrogen fluoride exhibits high chemical reactivity as
a fluorinating agent. It reacts with all chlorides with which
the exchange reaction has been shown to be thermodynamically
possible.
n 3 ' i
t '
v ■ (
-103-
6. Limited evidence indicates the non-polar fluorides to
be comparatively unreactive in exchange reactions up to a temper-
ature of about lOO^C,
7. Fluorosulfonic acid reacts slowly with phosphoryl
chloride, phosphorus trichloride and thionyl chloride at about
100°C. with formation of fluorine compounds but the reactions
are not straight- forward exchange reactions. Phosphorus tri-
chloride, PC13, for example, give rise to phosphoryl trifluoride,
FOFs.
8. A study of halogen exchange reactions involving hydrogen
fluoride and the non-polar chlorides in the gas phase was not
successful.
Reference: Ph.D. Thesis. M. M. Woyskl
University of Illinois, 1946
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-105-
THE STEREOCHEMISTRY OF COMPLEX COMPOUNDS
CONTAINING ORGANIC MOLECULES
Hans B. Jonassen May 28, 1946
On the basis of the work of Jaeger (1) and Smirnoff (2)
Bailar (3) predicted in 1936 that complex Inorganic compounds
might be used to resolve optically active bases. Several
attempts (4) in this laboratory to bring about such resolutions
met with failure.
However, the experimental evidences obtained by Huffman (4)
indicated that in the reaction of d-tartrato bis-ethylenediamino
cobaltic chloride and calcium nitrite an active form of the
dinitro bis-ethylenediamino cobaltic chloride complex was formed,
Huffman also found that he never was able to obtain more than
40$ of the theoretical yield; under no conditions was he able to
increase this by more than about two percent. These data seem
to Indicate that the two forms of the d-tartrato react at
different rates.
It was decided to study the reaction of d-tartrato bis-
ethylenediamino cobaltic bromide with ethylenediamine since in
the presence of activated charcoal (5) trisethylenediamino co-
baltic bromide is formed without the necessity of heating. How-
ever, since the bi_s-ethylenediamino cobalt complexes racemize
very easily whereas the bls-levo-propylenedlamlno complexes are
so stable that they can be subjected to a very severe treatment
without racemlzation, this study also includes the reaction of
bls-levo-propylenediamino cobaltic bromide with levo-propylene-
diamine. Huffman's work with this complex also indicated that
the two forms of the tartrato complex react at different rates
when the dlnltro-bls-levo-propylenedlamino complex is formed*
EXPERIMENTAL
The resolved complexes used in this study were available
from laboratory stock; the other complexes were made according
to methods found in the literature.
Preliminary tests on resolved trls-^ethylenedlamlno cobaltic
bromide showed that no racemlzation of the active complex oc-
curred either upon shaking with Norlte (activated charcoal) or
upon heating the solutions at 50°C for more than 24 hours4
Studies of the reaction of d-tartrato bis-ethylenediamino
cobaltic bromide and 69$ ethylenediamine showed that the tris-
ethylenediamlno cobaltic complex formed under these conditions
was a racemic mixture. The reaction of this complex with 69$
of ethylenediamine in the absence of Norite, however, produced
an optically active form of the tris-ethylenediamino cobaltic
bromo tart rate. The yield was 140$ of the theoretical one which
showed that 40$ of one form has been rearranged to the other
form during the reaction. Measurements of rotation on the filtr&t
showed that the originally leVorotatory complex increased in
negative rotation as the tris-ethylenediamino cobaltic bromotar-
trate was removed.
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-106-
i
The data obtained from the reaction of dl-tartrato bis-levo-
propylenediamino cobaltic chloride and levo propylenediamine
indicate that a partial resolution has occurred,. The reaction
mixture is heated at 70° C for one hour* Upon pouring this solu-
tion into ice cold methyl alcohol trls-levo-propylenedlamino co-
baltic chloro tart rate is precipitated and is removed by filtration
(precipitate 1). The methyl alcohol filtrate is returned to the
steamcone and evaporated to dryness at 70° C„ (precipitate II )c
The precipitates (I and II) are treated with lead nitrate after
several recrystallizations and the insoluble lead tartrate is re-
moved by filtration* It is suspended in water and saturated
with hydrogen sulfide. The lead sulfide is filtered and the
excess of hydrogen sulfide removed from the filtrate by boiling.
The filtrate is then evaporated in a stream of air, The tartaric
acid obtained from precipitate I shows a high positive rotation
whereas that from precipitate IT, has a high negative rotation.
The yields of the two fractions: Fraction 1 75$, fraction II 80$
of the theoretical^
DISCUSSION
The high yield in the partial resolution of tris-ethylene-
diamino cobaltic bromotartrate obtained from the reaction of
d-tartrato bls-ethylenediamlno cobaltic bromide and ethylene-
diamine can be explained only if it is assumed that the follow-
ing reactions take place:
. I) dextro Coen2d-tart Br ?==-levo Coen3d-tart Br
II) dextro Coen2d~tart Br +en* * dextro Coen3 Br d-tart
III) levo Coen2d-tart Br +en *levo Coen3 Br d-tart
Equilibrium I is displaced to the right as indicated by
the negative rotation of the original bisethylenediamino complex.
As ethylenediamine is added and the reaction mixture is shaken
trls-ethylenediamino cobaltic bromotratrate is formed which has
a high positive rotation. This seems to indicate reaction II is
occurring predominantly in the reaction mixture* This displaces
equilibrium I to the left and more of the dextro complex is former
this change in the equilibrium concentrations will produce an
increase in the negative rotation of the original complex re-
maining in the solution. Reaction III is also occurring in the
mixture but at a much slower rate. This is shown by the fact
that the rotation of the tris-ethylenedlamino complex formed is
slightly less than that of the completely resolved complex*.
This is an example of resolution by the "equilibrium method"
described by McKenzie and Smith (6) and others for compounds
containing asymmetric carbon atoms. This is the first time it
has been used for a partial resolution of Inorganic complexesr
The studies with dl-tartrato bi s-levo-propylenediamino co-
baltic chloride and levo propylenediamine show that the first
tartrate ion removed from the complex consists mostly of the
d-tartrate ion. Complete evaporation of the reaction mixture
brings about displacement of the 1^-tartrate ion from the remain-
der of the complex* It is thus possible to effect a partial
reso-lution of the two forms of tartaric acid,
-abbreviation for ethylenediamine.
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-107-
SUMMARY
1) The first example of partial asymmetric synthesis by the
"equilibrium method" is described for inorganic complexes. It
involves the formation of dextro tri s-ethylenediamlno cobaltic
bromide by the displacement of the d-tartrate ion from d-tartrato
bis-ethylenediamino cobaltic halides by ethylenediamine.
2) A reaction mechanism for this resolution is proposed.
3) It is shown that it is possible to resolve racemic
tartaric acid by means of the displacement of the active
tartrate ion from dl-tartrato bis-levo-propylenediamino cobaltic
chloride by levo propylenediamine
4) It may be possible that this method of resolution may
be applied to determine the absolute configuration of optically
active groups which coordinate.
5) Possible application of this method for the resolution
of other racemic acids or amines is discussed.
6) The advantages and disadvantages of this method over
other methods of resolution are discussed.
BIBLIOGRAPHY
1) Jaeger, Optical Activity and High Temperature Measurements,
McGraw-Hill Book Co., 1930, p. 143-156.
2) Smirnoff, Helv. Chim. Acta. 3, 177, (1929 )„
.inois, 1934; Huffman, Thesis
^egman, Thesis, University
of Illinois, 1937.
5) Bailar and Work, J. Am. Chem. Soc. 67,, 176 (1945).
6) McKenzle and Smith, Ber, 58, 899, (1925)*
«?0I-
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-108-
THE REDUCTION POTENTIALS OF SOME
INORGANIC COORDINATION
COMPOUNDS
James V.: Quagliano May 28, 1946
The purpose of this investigation was to make a quanti-
tative study of the reactions that take place at the dropping
mercury electrode when a solution of hexammlne cobaltic ion is
electrolyzed in the presence of a large excess of various inert
salts, and establish the conditions under which the reduction
of this ion is reversible. Half-wave potentials of oxidation-
reduction reactions obtained at reversible conditions have, over
those which are Irreversible, the great advantage of a thermo-
dynamic significance which can be related to the ordinary stand-
ard potentials. Furthermore, the quantitative measurements can
be applied advantageously to the study of the strength of the
bonds between the central atom and the coordinating molecules,
to the determination of diffusion coefficients of complex ions
(and molecules)/ to obtain information about optimum conditions
in the preparative work of inorganic complexes, and to the study
of inorganic systems that can not be studied by classical methods,
PREVIOUS INVESTIGATIONS
Most of the complex ions which have been studied by the
polarographic method were prepared by the addition of the
metallic ion to a large excess of the complex forming substance,
which also acted as the supporting electrolyte. Brdicka found
that the hexammine cobaltous ion is oxidized by dissolved
oxygen in ammonlcal solutions and the resulting hexammine co-
baltic ion produces a double polargraphlc wave. The analysis
of solutions prepared by dissolving pure complex cobaltic salts
was ma.de recently.
APPARATUS AND EXPERIMENTAL METHODS
The principle of the method of determining the half-wave
potentials is illustrated by the following description of some
preliminary experiments. Purified hydrogen gas was passed
into the electrolysis cell (containing the solution to be
analyzed) for about twenty minutes to displace all of the'
dissolved oxygen, at which time the flow was discontinued. The
potential of the dropping mercury electrode was increased in in-
crements of 0,05 volt, and the amperage reading was recorded
from a Fisher Electropode.
EXPERIMENTAL RESULTS
The effect of gelatin and octyl alcohol in the reduction
of the hexammine cobaltic ion at the dropping electrode are very
interesting for they not only eliminate the incipient maximum
but also displace the wave to more negative potentials. The
presence of agar from concentrations of 1.9 x 10~5 to 1,4 x 10~4
per cent produce no change in the half-wave potential of the
hexammine ion.
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The half-wave potentials and the diffusion currents of
the hexammlne cobaltic ion were obtained in the presence of six
different supporting electrolytes. The half-wave potentials are
less negative in solutions of the "indifferent" electrolytes
which have little (or no) tendency to coordinate (viz., nitrate
and perchlorate). The half-wave potential in the presence of
acetate ions is shifted to a more negative value by 0.1 volt,
and that in the presence of sulfate ions is more negative by 0,
2 volt. A series of experiments was made to determine the
effect of an Increase in concentration of the supporting elect-
rolytes and the presence of ammonia on the reduction curves,
A 0,002 per cent solution was found to be the minimal concentra-
tion of sodium methyl red which would suppress the maximum,
DISCUSSION
The displaced curves rise more steeply in the solutions
which contain the gelatin, and gelatin and octyl alcohol. The
adsorbed gelatin and octyl alcohol cause the potential drop
to occur in a very small region of solution near the mercury
surface. If the potential fall nearly all occurs in the adsorbed
layer, no deformation of ions can occur. Normally, the central
atom (Co) is attracted by the electrode, and distortion of the
reducible ion (hexammine cobaltic) occurs whereby the central
ion is attracted toward the electrode and the coordinating
groups (NH3) distorted away from the electrode, but this is
determined by the potential gradient in the solution. In the
presence of gelatin a higher potential is necessary.
Although a negative slope in the diffusion current does
not occur in the decomposition curve of the hexammine cobaltic
ion in the presence of sulfate ions, the presence of a trace
(0,002 per cent) of sodium methyl red decreases the diffusion
current. This indicates that a new type of maximum behavior
takes place in complex cobaltic solutions, namely, that the
stirring effect in the solution at the region of the mercury
drop which accompanies the maxima continues with increasing
applied potentials.
In the polarographic experiments the concentrations cf
the indifferent electrolytes are at least one-hundred times
that of the ion undergoing reduction. Most likely the aniens
of the supporting electrolyte are bound by ionic bonds in o
second sphere about the hexammine cobaltic ion,
SUMMARY
1, The polarographic reduction of the hexammine cobaltic ion ir
the presence of chloride, nitrate, perchlorate, acetate,
and sulfate ions and ammonia has been studied in the ran^o
of -0.05 to -0.8 volt.
29 Capillary active substances such as gelatin and octyl
alcohol markedly shift the half wage potentials of the
hexammine cobaltic ion to more negative potentials* In the
presence of these substances a stirring effect which accompan
ies the maximum continues with increasing applied potentials.,
.. I -
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3. The polarographic analysis of the hexaramine cobaltlc Ion
can be made In the presence of methyl red to suppress the
maximum.
4, The hexammine cobaltic ion is present as the central ion of
the super complex in the media of chloride, nitrate, per-
chlorate, acetate and sulfate ions. In the presence of sulfate
and acetate ions, in contrast to the other media, fairly stable
"super-complexes" are formed which results in shifting the
half -wave potentials to more negative values, and to lowering
the diffusion currents.
Reference: Ph.D. Thesis
James V. Quagliano
University of Illinois, 1946
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-111-
THE PREPARATION AND PROPERTIES OF SOME PLATINUM AMINES
Jt A. Mattern June 4, 1946
Although It Is generally believed that chelating groups
such as ethylenediamlne are unable to reach across trans posi-
tions in the coordination sphere of a metal, there is no reason
to suppose that a chelating group of sufficient size cannot,
under the proper conditions, coordinate across trans positions*
However, previous attempts to prepare simple chelate rings of
seven or more members have given inconclusive or negative results,,
The general procedure has been to treat a metallic salt or com-
plex with a large diamine, such as pentamethylenediamine, in the
hope that both amine groups will coordinate to the metallic ion.
This reaction presents difficulties, howeverf Although there is
an excellent chance that one amine group in the course of its
motion will encounter and coordinate to a metallic ion, the
probability that the second amine group will reach and coordinate
to the same metallic ion is rather small because the motion of
this second amine group is comparatively unrestricted. Accord-
ingly, one or more of the following reactions takes place instead
of chelation: (l) The precipitation of the metal as an insoluble
hydroxide (2) the formation of polymer-like materials by coordi-
nation of one diamine molecule to two different metallic ions
(3) the filling of the coordination sphere with more strongly
chelating groups as, for example^ the formation of [Co en3] Cls
from [Co en3 C13J CI when it reacts with long chain diamines.
Little work has been -done to ascertain whether or not these side
reactions can be avoided' by the use of nonaqueous solvents or
the use-. of. catalysis.
Diethylenetrlamine, although its end amine groups are Just
as far removed from each .otjher as those of pentamethylenediamine,
is. readily able to place .Its two end amine groups in trans posi-
tions of the coordination sphere because coordination of the
center amine group greatly resticts the motl'on .of <an uncoordi-
nated end group and thereby increases the probability of coo'rdi-
nation, ..." This .amine, therefore, coordinates preferentially as a*
tridenta'te group. Mann (l), in fact, has found It difficult to
prepare a bidentate compound of diethylenetriamine, by direct
means. .. . . M .. ^
If It is possible to remove the middle amine from the
coordination sphere of such a tridentate complex, and eight-
membered chelate ring may be produced which spans trans coordi-
nate positions. Two possible methods fo £ doing this are; (l),
to take advantage of the change of coordination number with
change of valence which some metals exhibit lind (2) to replace
one group with another in the coordination sphere, Chernyae:'
and Fexlorova (2) used both of these methods to prepare monodantate
compounds of ethylene diamine from the corresponding bidentate
compounds*
, The tridentate compound used in this Investigation was
2-chloro-lr6-dIammine-3,4,5-diethylenetriamine piatlnic chloride
which was prepared by the following series of reactions! ' s
•
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-112-
(1) HsPtCl6 — iL_^ ptCla + SHC1 + CI 8
(2) PtCl8 + 4NH3 * fPt(NHa)4] Cla
(3) [Pt(NHa)Jcia -—-> trans jPt(NH3)a C18J + 2NH3
(4) trans [Pt(NH,).s CI,] + ci3 > trans [pt(NH.). OlJ
(5) trans jPt(NH3)3 C14J + dlen *
trans [Pt dien (NH3)3 Cl]ci3
foMnrt1?^ IV' Wul0h ™s used by Kharasch and Ashford (3), was
d?nv?fl! *6 ?uCh easier t0 °arry °P than eduction by sulfur
Mn^i S h?r me8n8' Reactlon OB) was Improved by the use of
Droduct« R°a\f a,°atalyst whl°h eliminated troublesome by-
n^pn ?In Reao"on 03) was conducted at 230-240' C. at a pressur,
?L t£eoret?IVf Krh Reaction (5) was conducted by shaking
iPt b fl f10^* of dlethylenetriamine with trans
1"™?, ~ *L e Presfnce of Norlte eharooal-aTrbom
duction to Tp r (\raT ?,f 1 hifher temperature resulted in re-
the 5?pi£Mn ?5? C}s-' and the ^se of excess amine produced
we Dls-dietnylenetrlamine complex jPt dlen3j£lV,
Jflallnunl was oh°een for this investigation becauqe h)
cry amine cnnHinn^ k«~* • utoreasea stability or second-
^ethylenelrflmi^tr ? f^ °0mp0Und °oLntainlSg bidentat'e 3
sobered Rearrangement ?^nnt° ^ Positions of the coordination
nnti^n 4*. *a g s not exPected in the course of this re
S to each ogS WMOh l6aVe thS -°^iaation s^here^
founds givra^urfwhl^ (NH*>»C1)C1» * electrolysis was
^^MTl' £2 IT S- a ^ur^^es't^L^t^r8-
auction^roduct of frf dien ^Lci^\;2t£Ml0,\,0f the re~
approximately one-sixth of h.ff' With base showed that
hydrochloric^™!/ tms^ *"" 2f ?rln%!f " PrS?nt as "alible
contains both bldentatp nnflgf tZ 2 ! the reduction product
triamlne, the former belnS J^??nt8te ComPound* of diethylene-
cording to the equltion: g ? Converte(i to the latter ac-
lhhdiZ1/Cl (NH^C1* —- 'ft dien NH3]C13 + KH4C1
to rinses TtltnTTTe l^frr1""* a<°lae groups Joined
highly^irooabl*0 coordination sphere, this reaction is
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-113-
The reduction product of [Ft dlen (NH3)2 CljCl3 was found
to react readily with hydrochloric acid to produce trans di-
chlorodiammine platinum. Identification as the trans form was
made by ultraviolet absorption studies and by the_ preparation
of the bisoxalato derivative [Pt (NH3)3 (HC304 )3 J according to
G-rinberg (4). It is difficult to believe that the trans di-
chloro salt would be obtained from a tridentate compound of
diethylenetriamine except under very severe conditions* Pro-
duction from a bidentate compound would require that diethylene-
triamine span trans positions unless rearrangement takes place*
Further work is needed to ascertain whether or not such a
bidentate compound can be isolated in pure form. It is suggested
that the use of diethylenetriamine or similar compound containing
a somewhat poorer coordinating group in the center may, by the
method outlined, prove useful in synthetic work.
References
1. Mann, F. G. , J. Chem, Soc., 1954, 466
2. Chernyaev, I. I.- and Fedo'rova, A. N, , Ann. secteur olatine,
Inst. chem. gen. (UBS. S.R. ), No, 14, 9-18 (1937)
3i Kharasch, M. S. and Ashford, T. A., J. Am. Chem, Soc. 58,
1733 (1936)
4. Grinberg, A. A,, Helv. Chim. Acta., 14, 455 (1931)
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-114-
A STUDY QF THE OLEFIN TO PLATINUM BOND
A. L. Oppegard June 4, 1946
I, Introduction
Although many metals (Pt, Pd, Fe , Ir, Al, Zn, Cu, Ag and Hg)
will form coordination compounds with olefins end olefinic sub«-
stances, those formed with platinum are the most stable and are
best characterized,, The fact that the olefins do not have a
free pair of electrons has aroused considerable speculation as
to the nature of the bond that is formed, for the compounds are
very similar chemically to other types of complex salts* Many
theories have been advanced, none of which is entirely satisfact-
ory. The object of this research has been to establish certain
important facts about these compounds which have remained in
doubt.
The plat inum-ole fin complex compounds can be divided into
two distinct series, (PtCl3«uns)2 &nd M(PtCl3«uns). The former
are non-ionic compounds soluble in organic solvents and dis-
solving in aqueous solutions of MCI to form the second series
which is ionic. They can be made from plat in ic or platinous
compounds. The two most common methods of preparation are 1)
Anhydrous platinic chloride in an anhydrous solvent such as
glacial acetic acid plus the olefin, 2) Potassium chloroplatinlte
in al cohol-* water solution plus the unsaturated substance. Hydro-
carbons, unsaturated alcohols, acids, aldehydes and esters can
form coordination compounds.
The stabilities of the compounds vary widely and depend
on the nature of the olefin.* Ethylene, styrene end trans-stilbene
give very stable compounds. Ethylene can be displaced by a less
volatile olefin, although the resulting compound may be less
stable* Hydrogen will reduce the ethylene compound to platinum
and ethane at atmospheric pressure and below 50°C. Concentrated
hydrochloric acid and strong coordinating groups displace the
olefin unchanged, but under controlled conditions a series of
the type (PtCl2«uns*A ) can be made.
It has been generally assumed that these are platinous
compounds. Ethylene platinous chloride can be made from platin-
ous chloride and ethylene. Replacement of the olefin with
other groups always gives a platinous compound. This is all
indirect evidence however and does not really establish the
valency of the platinum when coordinated to the olefin. Recently
Hel'man has reported that in the electrometric titration of these
compounds with permanganate in acid solution no oxidation was
observed whereas platinous compounds were oxidized.
II. Structure
The structures which have been proposed can be divided
into two classes, those in which the olefin rearranges and makes
available a pair of electrons to the platinum, and those in which
the platinum contributes a pair of electrons to the olefin*
Dimer formation is explained by' halogen bridges, olefin bridges
and a platinum to platinum bond.
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III. Discussion
At Is the double bond broken?
The evidence is conflicting on this point. Previous
workers have shown that in the case of cis and trans isomers
generally only one form will react to give a crystalline com-
pound and there is no transformation from one form to the other.
Polymerization is only rarely observed.
This phase of the problem has been attacked in
several ways,
1. Ultra-violet absorption spectra.
Due to its high resonance energy, trans- stUbene ex-
hibits strong absorption in the ultra-violet at 2950 A. If
the double bond were broken when the bond is made with platinum
it might be expected that the absorption would decrease sharply
due to the decrease in resonance energy. Absorption curves
for trans-stilbene and trans-stilbene platinous chloride are
almost identical. In the case of the styrene complex a new,
strong peak appears in the region of the stilbene peak. However,
pentene-1 platinous chloride has an absorption curve with very
little character. No definite conclusions can be drawn from
the ultra-violet work*
2. Infra-red absorption spectra.
Structural features in organic compounds give rise to
characteristic absorption peaks in the infra-red. It should
thus be possible to determine if the double bond is broken by
the absence of the characteristic absorption peak of the double
bond. It was found that in the case of styrene platinous chloride
the double bond is completely gone. This observation is to be
checked by studying compounds of cis- end trans- pentene-2^
ethylene, cylclohexene, etc#
3. A study of cis- and trans- isomers
Infra-red studies on the complex compounds of cis- and
trans- pentene-2 should prove very interesting. In addition to
the determination of the existance of the double bond, some in-
dication should be given as to whether there is free rotation if
the double bond is broken or whether the structure is rigid.
It seems quite probable that there is not free rotation since
in some cases only one form will give a crystalline compound.
For example, cis-pentene-2 platinous chloride is crystalline,
the trans isomer is an oil.
Maleic and fumaric acids have also been used* Both
react with potassium chloroplatinite but each in a different
manner* Using the method of continuous variations and absorp-
tion in the visible it has been demonstrated that maleic acid
reacts with potassium chloroplatinite in a ratio of 1-1. In
the case of fumaric acid there is some reduction of the platinite
to colloidal platinum which intefers with the measurement of
the absorption spectrum,.
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However, working with the methyl and ethyl esters of
these acids it is possible to isolate the complex compounds.
A comparison of these products should be of value*
3. What is the nature of the bridging group?
The dimeric structure of (PtCl2»uns)2 has been explains
by three different mechanisms already mentioned. If it is a
halide bridge, it is to be expected that it would be broken
upon the addition of 2 chloride ions to form PtCl3«uns "1,
and the ion should be monomeric* This would not be true for an
olefin bridge and the ion should remain a dlmer. The molecular
weight has never been determined.. The same purpose will be
served by determining the molecular weight of (PtCl2»C2H4#auino-
line). Boky has reported that the X-ray investigation of
(PtCl2«NH3«C2H4) shows that it is dimeric with a platinum to
platinum bond and each platinum exhibiting a co-ordination num-
ber of 6. An actual physical determination of the molecular
weight should settle this question.
References:
1. Keller, Coordination Compounds of Olefins with Metallic
Salts, Chem. Reviews, 28, 229-267, (1941)
2. PhuD. Thesis, A. L, Oppegard,- University of Illinois., 1946
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THE ELECTRO DEPOSITION OF CHROMIUM
R. W. Parry June 11, 1946
I. The Commercial Chrome Plating Process
The commercial chrome plating bath is a solution 2 to 4 M
in chromic acid (added as Cr03) and .02 to .04 M in sulfate ion.
^i?® 8Ul£ate is essentlal to the process since chromium can not be
plated from pure chromic acid. For most efficient operation the
molar ratio of Cr04= to S04= is maintained at 100 to 1.
II. Limitations of the Present Process
■,« Although widely used, the chrome plating process has several
limitations. 1) The current efficiency for chromium deposition
runs about 5 to 20% of the theoretical value (based on Cr*6 )
2) Extremely high current densities ranging from 0.1 to 5.0 Amps/cm2
are required. 3) Throwing power of the solution is poor. 4) The
plate is porous, and 5) Chromium plated out on the cathode can
not be replaced in the bath by anode corrosion.
III. Theories of Chrome Plating from Cr04= or Cr307=
Chromium deposition differs from normal electrodeposition
in several particulars. 1) The metal to be reduced is carried
in the anion 2) Deposition is not possible without an anion
catalyst. (Deposits of chromium from pure Cr04= have been reported
a very to current density but in such orses the purity of the acid
may be questioned since present day evidence indicates that
rigorously pure Cr04- will not plate) 3) The metal plated out can
not be replaced satisfactorily by anode corrosion.
A. Theory of deposition now current in the literature.
**. £? a8SU™ed "that Cr04=* (or Cr307= etc.) ions diffuse to
otLS?ga 2 oathode against a potential gradient. At the cathode
stepwise reduction of Cr04= 4 Cr"* — - + Cr > Cr is
postulated; IT ions are used up simultaneously in the liberation
» J?8! J?-. lB a,lkaline region immediately surrounding the cathode
a basic film of chromic chromate forms and covers the cathode
surface. It is assumed that the film thus formed is permeable to
ions* but not to Cr04 ions; thus Cr04= ions are unable to
K ?«* *! electrode and hydrogen is evolved. Sulfate ions supposed-
tl S?,ln some wy» as yet undefined, to break the continuity of
tne film and the reduction of chromium then proceeds. (Many
investigators attribute the reduction of chromate to nascent
hydrogen produced at the cathode.) The sulfate is also thought to
to aid in stabilizing a layer of chromous ions on the metal surfacec
The most obvious objections to this theory are 1) Although
reduction is assumed to go through the Cr*3 state, Cr+3 solutions
?n n«v4g ?v.R satisfactory plate. 2) The action of sulfate ions
in making the film permeable is far from well defined, 3) A very
?f2??Un!;e2 I11™** visible over electrodes containing chloride
catalyst but reduction is very efficient in this medium. 4) Reduc-
tion or Cr04 by nascent hydrogen seems improbable. It is also
noteworthy that the reverse reaction (oxidation of CpH++ to CrOA=
is virtually impossible at a bright platinum anode but at a lead
anode or in the presence of Pb^ the efficiency of oxidation
approaches 100%. Here film formation is very improbable.
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B. Chrome Plating from the Standpoint of Ionic Structure
A new theory of chromium deposition can be advanced from
theoretical considerations based on the structure of Cr04~ Ion,
According to Rice (3) the chromate ion is in the form of a
tetrahedron with the chromium atom . in the center and the four
oxygen atoms at the corners. The ion may be considered as formed
from Cr++ and 40" groups. (Most stable structure from energy
standpoint). The process of electrodepositlon can now be broken
down into a series of steps similar to those employed in the
Born-Haber thermochemical cycle*
a) CrO<T(aq) \ Cr++(g) + 4 °~(g) aH = 957 k oal
b) Cr+^ j <¥ 2e * Cr (solid metal ) AH = -629 "
c) 4 0- + 8H+( \ + 4e ^ 4H30(1x/iH = -393
.i i ■ ■ ■ - i ~ . "
Cr04=/ x + 8H+/ * + 6e — — * Cr/„\ + 4H30/t\/\H = -65 k cal
(act) (**> U) U' E = about O.CV
The energy of the first step of this process (a psuedo activation
energy) would be 957 k cal/ mole, and the presence of hydrated
Cr in the solution woul£+result from side reactions of hydra-
tion and reoxidation of Cr rather than from the formation of
Cr+++(r \ as an intermediate in the process.
The reduction of trivalent chromic ions may be subjected to
similar thermochemical treatment*
a) Cr(H20)6+"H' *• Cr++tg) + ^s0/-,} A H = 1320 k cal
b^ Cr***"*'
' (g) + 3e »> Cr (metal) /.iH = -1255 k ca]
' " ■ " !■■ II | jl .1 I . . - ■ I — II I II l ...
Cr(H30)6'H'+ + 3e — ^ Cr (metal) £> H = + 65.0 k cs
In this case the&H valve for the initial reaction or the psuedo
activation energy is 1320 k cal as compared to 957 for the reduc-
tion of chromate ion.
A similar consideration of chromous ion shows:
a) Cr(Ha0)4 A Cr**, N +4H30 (-jx £>H - 672 k cal
b) Cr++, . + 2e ^ Cr (metal OH ■ -629
(g)
Cr(H20)4++ + 2e ^ Cr(metal + 4Ha°(i\ ^H = 43 k cal
In this case the "activation energy" is inly 672 k cal.
"Y~
IV. Experimental Evidence
A number of plating trials in this laboratory and a large
amount of data selected from the literature indicate a good
qualitative correlation between ease of plating from CrO^-,
Cr , and Cr and the previously outlined activation energies,,
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Cr^ plates well? eft iciencies of 20-55$ reported
Cr04~ plates well, efficiencies of 5-30$ reported
Cr + plates poorly, literature confused
627 K cal
957 K cal
1320 K cal
A more detailed study of the reduction of chroraate solution
In the presence of different catalysts Is under way* The cathode
potential during electrolysis Is being followed In a special cell
as a funotlon of current density. Several curves are shown In
Flgrf 1-, In the region A-B the solution darkens noticeably and
C1O43 Is reduced to Cr r As current density Is Increased the
voltage suddenly jumps to a higher valve and hydrogen Is evolved.
If the potential Jumps to a valve above 0.91 volts (H8 std. )
chromium is deposited along with hydrogen. If the valve Is
below this no chromium is deposited although hydrogen is evolved.
It is interesting that this is close to the valve 0,86 V given by
Latimer for the reaotion Cr * + 2e -«* Cr (metal). These
observations are difficult to haromonize with the film theory and
with the theory of nascent hydrogen reduction.
An Interesting but unexplained point is the varying efficiency
of different anion catalysts* Without a catalyst hydrogen only
is evolved and the chromate ion is not reduoed* The=relatiye
efficiency of the catalysts in the reduction of CrO* to Cr
frlls in the order. Cl*"> SO^NO***. H8p04- ls entirely without
effect. The efficiency of the catalysts for metal deposition
falls in the order S04=> CI". NOj*" and HaPO*- were of no' value.
The nature of catalyst action is still under Investigation.
References
1. Latimer- Oxidation Potentials- Prentice Hall, 1938
2. Bichowsky and Rossini-thermochemistry, Reinhold Rubl and Co.
(1936)
3. Rioe- Electronic Structure and Chemical Binding
McGraw Hill Book Co, (1940)
4. Parry- Ph.D. Thesis- Univ. of Illinois (1946)
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Inorganic Seminar
1946-47
TABLE OF CONTENTS
Metal Derivatives of Azo Dyes
Clayton Callis 1
The Structure of the Silicates
G-. K. Schweitzer 3
Some Applications of Electronics to Experimental Chemistry
Robert A. Pcnnoman 7
Electrode Reactions in Liquid Ammonia
Jack Nyman 12
Inorganic Chromatography
A. R. Matneson 16
Ion Exchange
Donald Starr 21
Valence States of Iron
Eugene Weaver . • ♦ .25
Compounds of Methyl Sulfide with Inorganic Substances
William G-. Britton 29
The Intorhalogens and Related Compounds
Elliot N. Marvell 35
Sup er co ndu c t i vi ty
Carlylc E. Shoemaker 39
-4/
Preparation; of Solid Elements in a State of Purity
Karl M. Beck 45
Structures of the Phosphates
0. F. Hill 50
Complex Formation with High Molecular Weight Amines
Morton A. Higgins 55
Alkaline Earth and Heavy Metal Soaps
T. U. Vial 58
The Role of the Catalyst in the Sandmeyer Reaction
John Spezialo 62
Organo- Chromium Compounds
Roy D. Johnson 66
Methods of Measuring Aqueous Vapor and Dissociation Pressures
Philip Faust 70
Sulfur Monoxide
J. B. IlcPherson, Jr . 73
Crystal Chemistry
A. U. Matheson 77
Table cf Contents - 2
The Poisoning of Contact Catalysts
J. C. Richards 84
Uses of the Ionic Potential
G-. K. Schweitzer.... 88
T e t r a val 3 1 i t I" i c k c 1
Elliot ::. Marvel 91
The Builders by Vannovar Bush
Leon 5 Ci ereszko . ^ 92
Separation of Radioisotopes
0 . F. Hill 94
Elements 85 and 67
Caryle Shoemaker .... 96
Methods of Dot jrming the Adsorption of Gases and Vapors
on Solids
V,'. G. Britton, 101
Addition Compounds of Sulfur Dioxide
Carl \7oatherbee 106
Theories Concerning the Passivity of Metals
Peter C-. Arvan. 114
Zirconium
Roy D. Johnson 116
Polarographic Characteristics of Chloro Complexes of
Pentavalent Antimony
Jack Nymari 121
The Oxygon- Carrying Synthetic Chelate Compounds
Clayton Callis 122
Origin of the Hydrogen Continuum
R. A. Ponneman 124
Preparation and Stabilization Properties of Black Phosphorus
Paul Mohr 125
Separation and Identification of Volatile Liquid and
Gaseous Products
Roy E. Dial 126
n 4. "i o i^^ ~ Clayton Callis
October 8, 1946
METAL DERIVATIVES OF AZO DYES
(Based on the master's degree thesis of Mr. Callis)
I. Introduction
The importance of the formation of metallic lakes of many azo dyes
about^he'str'L^rfft6" *? S nUmber °f ^S« V^ **«!• ™ known
tSov <Zma 2 6 tnese la*es until the last decade, even though
they louna wide use in the dyeing of fabrics. w gn
The coordination of the dye "molecules with the ne tal atoms srestlv
improves their fastness, to washing and rubbing, as well as to fifnl *
£*t" aa\°V, ln)P°rtant effe^ in modifying the shades. One of the
most recent developments in connection with mordant dyes is the -r dual
D?efe^Lp°tnrlthe USe °f the »«**li° lakes themselves as dyesfin
noLLTL ,m! ?r0C?BS °f m°rdant dyein^- T^se two processes are by
jo means equivalent. In many instances, the mordant process leads to
the deposition in the fiber of more than one coloring" lake whereas the
dyeina with^^fn^f th%lake lt5S" may be re^deS a" equivalent to
advantage in substance. Obviously, it would be of considerable
advantage, in considering the mechanism of dyeing on vpnous fibers to
know more ,bout the structure and properties of these coloring iSee.
II. Previous Investigations
.id-JSil9!?*^?^9* (^> P°lnted 0ut that inner implex salts show con-
* n S ^ and that the color of suoh complexes depends uoon
dyes , J ^l,T*dinnttd gr0UP' Slnce the Gallic lakes of azo
assumnTion th=? ?w proP^tles- m«"y authors (3,3,4,5,6) were led to the
Gallic * to? -vn If nus\ exist some type of inner coordination of the
metal^° atom "lth °ne °r D?th nitrogen atoms of the azo group.
*nd c ,;;t;M!, irat r,eaf attemPt "as made to determine the structure
and composition of tnese lakes. A systematic study of the chromium lakes
Evens (9f T*he ™ ', J ^^ <?)' torS«> and Fo^er <8> ^nd Morgan ant
wlfn %;?;; Mn? °oba"ammlne lakes of azo dyes were studied bv ilor^an and
These invtt^!;.^ ^v^" a,d Kins (11) ffii b? ::°rS«" a"d Moss (iff
These investigators, who used cobaltammines as sources of the cobalt
resiluer^undln^* ^ lakeS oontai"^ one metallic atom to three dye
residues bound in the inner sphere of coordination, but suer-ested that
SM'S'S.'SSg.!' a ^-^oxy dye was not implicat^i^e^-
nnV, f ;:ins /'"d Hunter, (13) -ho in 1935 prepared nickel, cotroer and
mat?™ oS'r"leX':S ff°? nono-°rt^ hydroxy azo dyes, point 'out' that the for-
mationoi coordinated compounds is common to all o-hydroxy azo comoounds.
end Brole mSP naVPSCtr^°f SeVeral latea *?re studied by Ernsberger
™in^fi ' and by ri"endler and Smith (15), who conclude that the
ttX^JtuenTS™^1? apparently influenced less by the character of
chelate bond? g P S or8;anic Portion than by the formation of the
i -» = The r'03t l!a2°rt°nt instigations of the structures of tnese metallic
lakes were made bv Drew in England. Cooper lakes were studied by Drew
and Landquist 16 in 1938, and by Beech and Drew (17) in 1940 Drew
ercvro?1t"ii^8Lr^ interested in "»d^ °^ what e?fect the xtra
valency of trivalent chromium, as compared with divalent coooer would
bylrew £l ^cWl7r)°f f?- lakS3; AZ°,lakeS of"aluminum°arerde:cribea
ILf , ? ( V ana tnose of vanadium by Drew and Dunton (19).
comoounas isliven'e?"- "" *** l° ^^ ab°Ut ^ ^ucture of these
causeHh^ftioC*10" °f the ™tsl atom t0 the ""rogen is possible be-
cause the nitrogen possesses an unshared oair of electrons.
ordinate! X^tS,;1*'0^" at°1mS °f the "z0 ?rouP can bec°^ <=o-
ralnre^p J:;;!^lUy is probably enhanced by a resonance process.
+„ Vi formation of a stable three-me nbered rin? including the metal
atom and the two nitrogen atoms is not probable since the dis?fnce be-
■■'-.een the nitrogen atoms in azobenzene is 1.23 Ao, whereas the nitrogen-
v. ~y
■
nitrogen distance in[co(NH3)d cig is~7„8A°
4. Coordination of the metal stonTwith azo nitrogen is dosiIMp
v/h "ornNHh? 7tBi at°m,la ^"iXed by covalent "SS such as OH,
ft-H, or ,ffl2) which are in the o-position to the azo groups.
.f this kind In th' n i? lnof«fsed b^ ^e presence of two substituents
,PJ1 h? tCt Positions, the lakes assuming fused ring forms,
ub-tltuerts"? tSJ I ^7eetiSation was tc study the effect of the
he central n,?oTh%*"P0S"ti°nS °n the valenoe OTd coordination number of
,e!sS™t" to ii-f =tJnd *° °xtend the use of magnetic susceptibility
surements to the study of these metal derivatives.
II. Discussion of the experimental work (20).
mn^.V^n ?rfer 1° coraPare the effect of substituents in the oo> posi-
h xv „M^^ ¥ the C°,mplex formed- cobalt a"d nickel-omSexes
to hydroxy, oo' dihydroxy, o-hydroxy-o '- carboxy, and o-hvdroxv-o > -
du™°^?m?°Und,S ^^ PreP5red- ^he-ratio of metal ata' e reS-
o^l !v -, f rElned , °y analysis, and the magnetic susceptibility of each
omplex was measured on a modified Curie-Cheveneau balance.
2. The data obtained indicate that the valence st=te of the cobalt
lt"^Up^Pn^y1ithe-naPUre °f the d:''e molecule. Cobaftous complexes
s cooSd?n»?S till 10nl° tet^hedral or octahedral bonds when the metal
coordinated thru oxygen or nitrogen atoms.
-oio o Jnh«m!t?ief S of di-o-substituted dyes are tetrahedral. With
)Mlbll" 4mi~nl? le e\ther a tetrahedral or a planar structure is
referred contra /lon^ Plan*r Stru0ture is ™*° staole and is the
BIBLIOGRAPHY
1. Werner, Ber. , 43, 1062 (1908).
2. Baudisch, Z. angrew. Chem. , 30, 133 (1917)
3. Morgan and .Iain Smith, J. Chiil Soc 125 1731 (1=24)
I. Cnarner and fieretta, (Jazz. Chim. ital 56 865 tlopsi
■ Cnpoa, Gazz. Chim. ital., 50, 20, (1937)-' U9'io)-
7* ->™1RT' ?3ZZ- mChla- ^"Si. 372 (1928).
/. uorgan, J. soc. Dyers Colourists, 37 43 (iQ?n
l-Joraan and Porter, J. Chem. Soc, 107 645 (1915)
3.' Morgan and Evens, J. Chem. Soc". Tib 1186 (1919)
). Morgan^d Main Smith, J. Chem.'socT,' gff 204^921); ^ 60> 266
L. Morgan and King, J. Chem. Soc, 121, 1723 (1900)
I -organ and Moss, J. Chem. Soc, 1ST, 2857 (1922)
. Elkins and Hunter, J. Chem. Sac.,~935 1598
• Ernsberger and Erode, J. Org. ChemTTS 331 (1941 )
I Haendler and Smith, J. Am. Chem. Soc 7 62, 1669 (1940)
I Drew and Landquist, J. Chem. Soc, 1938 292
I Beech and Drew, J. Chem. Soc, 1940rfoe.
I Drew and Pairbairn, J. Chem. Soc7~~i93g 823
I r;Tv1,rd,Dont°f1' J- Cne:n- aoo., 1940—T064: '
• Callis, ,U3. rhesis, University oTTliinois, Urbana, 1946
-3-
THE STRUCTURE OF THE SILICATES
October 15, 1946 G. K% Schweitzer
Introduction
Possibly the greatest contribution of crystal chemistry
to science in general has been the systematic classification
of the silicates. Attempts were first made at classification
by postulating a series of theoretical acids thru the hydra-
tion of silica,, Salts and mineral derivatives of a large num-
ber of these acids are known. Following is a table of these
hypothetical silicic acids?
TableJUSilicic Acids
Mono- Di~ - Trl- Tetra-
mHaOrSiQg QHaO-.gSiOa mHaQ~5SiO& mH20-4Si03
Ortho- HTtEU H^57~ intalT^ HlTsi^T"
Me to- Hs8i03 (H8Si03)8 (HsSi03)3 (HsSi03)4
;leso- - H;,S180B H4Si308 rdGSU011
lar*- ~ •=" HSS130, H4Si40^
Tertero- - H3Si4Og
This idea was widely held for some time; but since it is not
completely in accord with the chemistry of the silicates, it
has been abandoned*
There are several peculiarities making the study of the
silicates very difficult. They are:
1. Silicates are insoluble in the majority of solvent s„
2. Silicates have high melting points,
3. Silicates are chemically auite inert*
4. Silicates exhibit very complex structures, showing
many S1:0 ratio s«
5. In silicates, the. silicon nay be replaced by many ether
ionst Fe , Fe"% Al+++, Ca++
Jakob (1) and Wahl (2) attempted to relate silicate struct-
ures to Werner's coordination theory, but met with failure be-
cause of the uncertainty that they were dealing with single
molecules*
Brass's Principles
3n extensive X-ray study of the silicates by Bragg, hi s
coworkers, rnd his contemporaries (3,4,5,6, .7,8) suggested the
following conclusions which led Bragg to a system of structure:
1, Oxygen ions^ being the largest, form' the skeleton
of all silicate crystals*
26 Silicon always occurs in silicates surrounded tetra-
hedrally by four oxygen atoms*
3. The oxygen ions are shared by metallic elements;
the silicon-oxygen tetrahedra may be connected with
other groups thru these metallic ions,
4. The oxygens may be replaced by fluoride ions or hydrox-
ide ions.
5. The other cations tend to symetrically distribute'
themselves throughout the crystal, giving the max-
imum electrical stability.
6. When two or more silicons share the same oxyr;en, the
SiiO ratio varies accordingly.
7. The oxygen ions are always 1.62A from the silicons* the
oxygens themselves are separated by a distance of 2fi6 to
208A
"1 ' r:r t" \ ' i ■ . i.V') J'-'c-tt
ft fv:-..iv..-
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Pauling' s Principles
Pauling approached the subject of the silicates structure
by rssuming that each metallic ion (including Si ) lies at
the center of a polyhedron whose corners are occupied by an-
ions (9} • He says that the cation-anion distance is determined
by addition of the radii, and the coordination number is
determined by the radius ratio. The radius ratio (10) may be
defined as the ratio of the radius of the cation to that of the
anion. The following tables show the utility of this idea;
Table I I- Radius Ratios
Radius Ratio
Coord.
No. 1
Configuration
up to .15
, ... g
linear
.15 to .22
3
pl~ne triangle
.22 to .41
4
tetrahedral
.41 to .73
a
plane square
.41 to .73
6
octahedral
*73 and up
8
cubic
Table Ill-Coord
.« No.
of Ions in Oxides
loo Radius Ra
tio Coord.)
NIos Bond Strength
B^-r . 20
— 5=T
i£3/4 h *'
Be*' .25
4
1/2
S1ttt • 37
4
1
Al£+ -41
Zr++++ . 62
4-6
6
6-8
3/4-1/2
1/2-1/3
2/3-1/2
Pauling1 s ideas can be used quite successfully with the
following limitations:
1. The anions must not be easily polarized.
2. The bonds must be essentially ionic.
Classification
From the observations of these two scientists, we see
that we may consider the silicates as a close packed assembly
of oxygen ions, with relatively small silicon and other cations
fitted into the interstices so that each cation is coordinated
with its required number of oxygen atoms, Silicon^ having a
coordination number of fourp is invariably found at the center
of a tetrahedral arrangement of oxygen atoms. The following
classification is derived from the above principles and is in
general usage today:
1. Self-contained groups
a. Si04 single tetrahedra
Examples: ortho silicates
garnet (ll)
olivine (12) Mg3Si04
b. Si307 two tetrahedra sharing one oxygen corner
Examples: thorveitite (13)
hardystonite (14)
melitite (15) (Ca,Na)3 (Mg,Al) (Si,Al)307
c. Si30g three tetrahedra sharing corners with each
other to form a closed ring
Example: benitoite (16) BaTiSi30g
II i\ ■ •-. .
I: ., .1 ,
r '. ,. s>n/£i •':•■:■ l) ml ■■ Is. \.y;-^ :\ ::. ■
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2. Silicon-oxygen endless chains
a. Si03 chrins of Si04 tetrahedra each sharing two
oxygens
Example: diopside (17) CaMg(Si03)a
b. Si40lt double chains
Example: tremolite (18) Ca2Mgs (Si4013> ) (0H)S
3, Silicon-oxygen sheets
Si3Os groups
sheets of Si04 tetrahedra each sharing three oxygen
atoms
Examples mica s| muscovite (19) (0H)s(K,Na)Ala(Sl3A10lo )
chlorite s; talc (20; Mg3Si40lo(0H)3
4« Silicon-oxygen three dimensional networks (Si^MjOg
blocks of Si04 tetrahedra each sharing four oxygen
atoms
Examples: danburite (21) OaB23i208
tridymite (22) Si02
nephelite (23) NaAlSi04
Sharing of Corners , Edges, and Frees
In a stable coordinated structure, the electrical charge
of each anion tends to compensate the strength of the electro-
static valence bonds reaching to it from the cation's at the
centers of the polyhedra of which it forms a corner^ Thus in
beryl, oxygen may be shared by two silicon ions (l & 1 = 2) or
by one silicon^ one beryllium^ and one aluminum (l / l/2 / 1/2),
Other examples follow this idea quite coherently.
The presence of shared edges and faces in silicates decrea-
ses the stability. The loss of the stability is due to the
close approach of the cations.
Sharing edge Si to Si is 0,58 x shared corner value
Sharing face Si to Si is 0®33 x shared corner value
Properties
An interesting group of minerals known as the zeolites
form three dimensional structures*, They undergo a process known
as base exchange in which the metallic ions can be inter-
changed or the water removed and then readded without any
apparent change in the structure* They are used quite
effectively in water softening:
Na20-Al203-nSi03-mH30 / CaS04 —^ CaO-Al303 -nSi03 -mH30
general zeolite formula in H20
/ Na2S04
sol. in H20
Another base exchanger, similar to the zeolites, is
permutite, an artificially produced alkali metal aluminum
silicate of the general formula 2M0-iil303-3Si03-2Hs09 If
permutite is treated with water containing silver, calcium,,
magnesium^ manganese, iron, and many other salts, these take
the place of sodium.
The ultramarines form a series of sodium aluminum sil-
icates containing sulfur compounds and possibly free sulfur*
(24,25 )«. Their structure is still not well characterized,.
It is known that they consist of an aluminosilicate skeleton
in which exist alkali ions. The varied colors of the ultra-
marines are attributed to the presence of group VI elements
(26,27,28). An example of this series is sodalite, . * -, - lt-
Na8Al6Si6034Cl3. Others contain Sv, Se , Te in place of the CI.
Ki
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Many silicates contain water, which can be driven off
only at high temperatures showing that it is not water of
crystallization. They are attacked by acids in many differ-
ent ways. Some are readily decomposed by hydrochloric acid*
even in the cold, the silicic acid separating as a jelly.
Others are attacked slowly; still others not at all. In
general, the mere electropositive the metal in the silicate,
the easier the decomposition. Hydrofluoric acid" decomposes
all silicates with the formation of gaseous SiF4-,
G-eneral References
1. Emeleus and Anderson, "Modern Aspects of Inorganic Chem-
istry", Van Nostrand, New York, 1945, pp. 195-218.
2. Latimer and Hildebrand, "Reference Book of Inorganic
Chemistry", MacMillan, New York, 1942, pp. 300-310.
3. Pauling," Nature of the Chemical BondM, Cornell
University Press, Ithica, New York, 1945, ppB 386-400.
4„ Sphraim, "Inorganic Chemistry", Interseience Publishers,
New York, 1946, pp„ 825-831. .
5, Stillwell, "Crystal Chemistry", McGraw-Hill, New York,
1938, pp„ 286-306,
References
1. Jakob, Helv. Chim. Acta 3, 659' (1920).
2. Wahl, Z. Krist. 66, 175 (1927);
5. Bragg, Roy* Inst. Froc, 1927 3 121.
4. Bragg, Trans. Faraday Soc. 25, 291 (1929),
5. Bragg, Z. Krist. 74, 273 (1930 )«
6* Bragg, "The Structure of the Silicates", 1932,
7. Bragg, "The Atomic Structure of Minerals", 1937tt
8. Bragg and Bragg, "The Crystalline State", Vol. I, p. 131.
9. Pauling, J, Ami Chem. Soc, 51, 1010 (1929).
10. Goldschmidt, Ber, 60, 1263 "CT927)*
11. Menzer, Z„ Krist. 69, 300 '(1928),
12. Taylor and West, Pro'c. Roy. Soc, (London) A1I7, 132 (1928).
13. Zarhariasen, Z. KristB 7& 1(1930).
14. Warren and Trantz, Z* Krist « 75, 525 (1930 );
15. Warren, Z« Krist. 74, 131 (1930).
16. Zachariasen, Z. Krist. 74 139 . (1930),
17. Warren and Bragg, Z, Krist. _699 168 (1928).
18. Warren, Ind, ling. Chem, 24, 41'9 (1932),
19. Pauling, Proc* Natl. Acad. Sci, 16, 123 (1920 ).
20. Gruner, Z, Krist. 66, 412 (1934).
21. Dunbar and Maohat schki, Z. Krist. 76, 133 (1930).
22. Bannister, Hineralog. Mag, 22, 569~Tl93l).
23. Gunther-Schulze, Z. Electro chem* 27, 402 (1921).
24. Hoffmann, Za anorg.
allgern. Chem. 183, 37 (i929>.
25. Jaeger, Trans, Faraday Soc, 25, 320 (1929).
26,- Hofmann, Ber, 38, 2482 (19057*
27.. Ostwald and Auerbach, Kblloid Z. 38, 336 (1926),
28. Ostwald, ZP anorg. Chem, 135, 37 fl929)t
"'.■'.. ••
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- 7 -
October 22. 1946 -, ,_
' Robert A. Penneman
SOME APPLICATIONS OF ELECTRONICS TO EXPERIMENTAL CHEMISTRi
I- ^l^'Sls^a Electron Emission
a) Pure tungsten 8". 56 ma7cm27~tt
I b) Thoriated tungsten (1-2^ Th) ca 100 ma/cm2/watt
„,/°'2/;,°:?r0 °?"ted filaments, low work function, ca 100
fn{ £ !" Fxlaments are adversely affected by positive
rir°or;^et^t°?ninStTe.ntS ?aVing se^rate controls; it
Voltage if Golfed alsonth,tenia=t°Wednf hSat ^^ <3late
beforl filament voltage! ' °ltage 1S tUrned 2«
InaSJ?! v"iS8 h0ll°l oathodes. « is possible to heat them
indirectly by using AC coils imbedded in a ceramic insulator,
■, ,„:LjrV,the l3ter tube classification the numerical pre-fix
(6 3v? 6^7 a^T°f,mfte fllament voltage, e.g. six volte
5i f i volls Im* V°ltS' i2K?' 12Q7; fentyfive volts,
„X„ 4-"7 , volt»> 50Lo, hundred seventeen volts fo^n he
operated directly from AC line) lira?.
2-3famps.m°n reCtlfiei's have « "** volt filament requiring
II. Rectification
rvnlU^e 2* a d"10de i,valve", conduction only on oositive half
cycle, tnus converts AG into pulsating direct current'
AC
-1 DC
V
^^ ll-h-,
*■— -A—
time "
- X
-1-, . |, UJL1UC
turn over" the wasted negative cycle and achieve full
Nye rectification is obviously more efficient and ridges
pne nltering problem. i sauces
v
III
a r.i
dou
• , ^£^£I_Vol tas;e
;:i^;blrr3rCU1^-. Si!?-Dle rectification produces, ,3
Ki^ifTr inPUt Volt&Se; the following curcSfts
Die this value (at zero current drain).
V .,
. {
■1 - ..
"^ y
AC
h
- 8 -
-T
•DC
/
X
/
AC
\
x\ "t
^y-~
+
DC
A disadvantage. Both
sides of output are
different from grounc
potential.
Half wave doubler.
Common side can be
at ground potential.
B) Higher voltages are conveniently obtained from a
power transformer with AC input.
^* Filtering
The pulsation present in the rectified AC cannot, in
many cases, be used for plate or screen voltages. In
r -los it causes hum and can introduce error in measure-
ments etc. To smooth out this "ripple" various circuits
a r e a ppr o pr i a t e .
a) Condenser
Voltage =JTe wi
;vnere E is
the R:.I3 applied voltage.
The condenser charges to pea': applied voltage and nelps
to maintain that voltage during the V cycle until it is
aga.in charged. Trius the ripple is reduced.
b) In duct,-- nee and Capacitance
In this case, the voltage
is partially smoothed out
before reaching the con-
denser and filtering is
improved,
c) ouch sections can be multiplied until residual
ripple is reduced to an amount that can be tolerated.
Choke input, with VF"
section.
Condenser in ju t al 1 ow s
h i gh e r volt a ge s t ha n
choke input, for same
applied voltage. Gas
Rectifiers -re always followed by choke input to limit
current.
e) Obviously, with increasing current drain, the vol-
tage at which it is available decreases: For a 5^3 ) 350v
RMS per plate, approximate values are:
d) Condenser input.
idenser input: DC output, V:
Current, ma
Choke incut:
DC output, v:
current, ma :
450
20
290
20
390 340
60 120
27 5 250
60 120
V. Vacuum Tubes, On-Off Control
aT Triode " Jr ~ plate
^rid /I .
cathode
4
plate
eurrent
i
/
•
i tT filament
f i!
-f -
grid voltage (-')"'•-
- 9 -
1) Cathode is taken as the zero reference "Point from
Loh tube voltages are measured.
2) Grid, bias is the negative voltage difference be-
tween the grid . and cathode.
3) A tube is at ''cutoff" when the grid voltage is
sufficiently negative to reduce the plate current to a
very 1 o w ( z ero ) va 1 u e .
b) Example] of a simple relay circuit, using a 117L7.
This tube contains a rectifier and amplifier in same en-
velope, but for clarity of presentation they will be shown
as two tubes.
117L7
*-— Relay (contacts not shown)
1 C: 16 uf. 250 v.
117L7
-^V i AC
The relay is a Potter Bromfield relay of 1250 ohms re-
tance, and requires 20 ma to close.
An analysis of the steps in the calculation of the circuit
is given to illustrate the method used.
en tube is conducting, 20 ma required for relay, plus
10 raa thru "bleeder" (arbitrary value) - 30 ma current drain.
From manufacturer's charts of the tube characteristics, rec-
tifier out-out at 30 ma drain (117 volt input) is 136 volts'.
Voltage droo in relay is 20/1000 x 1250 ~ 25 volts; to nave
plate more positive than screen voltage add 5 volts. E]_ -
25 + 5 = 30 v,. •. Rt 3 30/10 x 1000 = 3000 ohms. Let Eg
(screen voltage) = 60 volts. (This is an arbitrary selection,
but once chosen fixes the rest of the values) Rg = 6000 ohms.
Again from tube characteristics, a grid bias of -4 volts will
allow the tube to pass 20 raa at a screen voltage of 60 volts.
Remembering that both the bleeder current and the tube current
is through R3, R3 = 4/30 x 1000 ~ 133 ohras, By difference
R.l - 1467 ohms (1500).
When the contacts at X are connected (by a Hg thermostat,
for example) the tube ceases to conduct and the relay opens.
This reduces the current drain and the voltage at the con-
denser will rise. Assume it rises to 150 volts; from the
tube characteristics we see that the rectifier will furnish
15 ma at this voltage. The bleeder current is 150/10630 =
14#1 ma. Under these conditions, Plate voltage = 127 v,
screen = 85 volts, grid —23 v. A check of the tube charac-
teristics shows that -23 volts will bias the tube to cutoff
at a screen voltage of 85 volts. If this were not the case,
the calculations would have to be repeated using slightly
different values. The contact current = E4/R5 = 23/10° =
23 ua (if R5 is 1 megohm). Thus 23 ua at the contact points
controls 20 ma plate current, which is turn operates the
relay which ca.n handle 5 amps. The "Sargent Zero Current
Relay" utilizes a similar circuit but uses the relay to
energize the coil of a 110 volt AC mercury relay which will
handle 15 amos.
J.
- 10 -
VI . Pro portioning_ Control , Thyratrons
aT~Tne thyratron is a triode filled with mercury argon-
's or some other inert gas at a pressure ca 1-2 err! In
this tube th grid serves only as a trigger. After the
tube begins tc conduct the grid has no further influence
Alternating current is usually applied to the anode, since
uhe ' bG c^ses 'co conduct 60 times each second, this allows
Kr?.d to regain control.
ibility of carry currents of
b) Of importance is
several amperes.
c) Relay., circuit.
( JT^ — v^^-
v^.nn^ — \r -••*\ Load
.heir
S
i__
AC
mattery
d) The critical grid voltag
conduction to begin varies with anode potential.
V
critical
Grid voltage
e) Phase shift.
rX
With S open, grid is at
cathode potential and
tube will conduct on every
positive half cycle. With
3 closed, grid is negative
"nd tube ceases to conduct.
which is necessary to allow
If we
choose the grid potential
so it intersects the crit-
ical voltage curve, at that
point the tube conducts
(shaded area). The conduc-
tion c-'-n thus be varied over
| the positive half cycle.
This offers a poor method
of control since the point
of intersection cannot be
closely controlled.
phase
^k
critical
i
In this method, the
of the alternating grid
voltage is varied and the
tube current can be con-
trolled over the complete
positive half cycle.'
- arid
The following circuit shows one
Uo^aT
1 nrr "v
Transformer
is con s t ' n t
method of accomplishing this.
If R - 0, grid and anode
are positive -^nd tube con-
ducts. If R. is large and
C is large, grid is at
opposite potential from
anode and tube will not con-
duct. By adjusting C and
R, conduction can be varied
over this entire range. ' If
verage anode current deer-eases as R inc.. eases,
C
R can be resistance thermometer" (Ptyto ^control furnace
temperature.
f) Thyratrons are useful to supply current to dual-field
reversible motor. By direction of current, the motor can
ma/.e adjustments to restore unbalance etc,.
-J.V: r :. i. '" .
^:u
- 11 -
References
1 . Strong, J . . e t . al . "Pro cedur es in Experimental Physics " ,
Prentice- Fall, I no "N,Y. 1944, Chapter X.
Ler. R " , -"... £r.rcan & M.E, Dros, "Experimental
21.^cjtronJ_cs ■'] ire.:::: -Hall, Ire, N.Y. 1944., Chapter 3,6
c- I 'cton, 0 ' .' H, '.? Maseer, -electronics, April 1934
4. " t 1. :-..:.: & R.R. Hancox, Rev. Sci. Instruments, 5, 28 (1934)
5. Kenney, K. "Electron Tubes in Industry", Second Edition,
McGraw-Hill, N.Y. , 1937
6. G-eorge, E.E. "Electronics I1 Aug.. 1937; p. 19.
7. Beaver and Beaver, Ind. Eng. Chem. 15. 359, 1923
8. Ferguson, Van Lente and Hitch ens, Ind. En:?. Cnem. Anal. Ed.,
4, 218, 1932.
9. Kawes, R.C., Ind.. Ens;. Chem. 11, 222, 1939.
10. Heisig and G-ernes, Ind. Enr;. Chen. 6, 155, 1934.
11. Huntress, E.H. and Hershberg, E.5. I nd . Eng. Chem. 5, 144, 3933.
12. Parks, Ind. Eng. Chem. 5, 356, 1933.
13. Serfass, E. J. Ind. £ng. Chem. 15, 262, 1941.
14. Waddel, H. Ii. , and Salman, YY. , Ind. Eng. Chem. 12, 225, 1941.
15. Yee and Davis, Ind. Sng. Chem. 8, 477, 1933.
-±£-
ELECTRODE REACTIONS IN LIQUID AIQ'ONIA
Jack Nyman October 29, 1946
Only recently have the electrode potentials of metals in
liauid ammonia been measured with a fair degree of accuracy. In
1907, Johnson and Wilsmore (l) measured the potentials of a series
of metals by making use of the cell MIMX Cd(N03)3.4H20( satd. ) |Cd.
Because hydrated cadmium nitrate was used in the reference elect-
rode, and also the fact that no special precautions were taken
to dry the ammonia, considerable doubt was thrown on these
results. The values obtained by Johnson and Wilsmore are recorded
below.
Electrode E.H.F. (-35°C)
Ag/Ag NO 3 n/10 -0.963
Ag/Ag NO 3 n/100 -0.932
Ag/Ag
Ag/Ag I n/10 -0.885
Ag/Ag I n/100 -0.827
Hg/Hg I3 n/10
Kg/Hglg n/100
Cu/Cu(N03)3.3H30 n/1
Cu'Cu(N03)3.3H30 n/10
Gu/Gu(N03)3,3H30 n/100
Pb/Fb(N03)3 n/10
Pb/Pb(N03)3 n/100
Ni/Ni(N03)3„6H30 n/10
Cd/Cd(N03)3.4H30 n/10
Cd/Cd(N03)2 4H30 n/100
Zn/Zn (N03)3.6H30 n/10
2n/Zn(N03)3*6H30 n/100
NH4(Hg) f\ NH4NO3 n/10
Mgillgl3xn/100
Ca/Ca(N03)3.4H30 n/10 +1,48
Na/NaN03 n/lO +1,56
Na/NaCl n/10 +1.58
K/KI n/10 +1,59
-0.895
-0.867
-0.68
-0.70
-0.58
-0.515
-0.495
-0.500
+0.047
+0.086
+ .353
+ .376
+ .91
+1.26
Johnson and Wilsmore also attempted to relate the electrode
potentials of metals in liquid ammonia to those in water by use
of a cell of the type
CdlCd(N03)a.4HsO ( saturated)! NH40H IHg8Cl3 + KC1 N/lO (aq)|Hg
(-35°C) 25°C
Measurement of potentials of cells of the latter type are without
meaning because of the fact that there is a liauid junction
potential and a temperature gradient in the NH40H bridge which will
cause indeterminate effects in the e.m.f.
Since 1935, Pleskov and 1'onosson (2,3,4,5,6) have carried
out very careful measurements in anhydrous liauid ammonia at -50°C.
Their results are recorded in the following table, on the basis
of the Rb ^ Rb+ + e~ electrode being taken as 0, At various points
in the progress of their work, they used FblPb and HglHg**"* as
reference electrodes. Tne Rb electrode was finally selected
(XI
) *• "• ..
-13-
because of the fact that rubidium amalgam gave a very steady and
reproducable potential in liquid ammonia, A table of electrode
potentials in anhydrous by hydra z in e as determined by Fleskov
(6) is also listed for corrroarison.
EN2H4 ENHa EHsO
+0.19 +0.31 +0.09
•+Q.01 +0,05 +0.01
+0.02
0 0 0
-0.10 -0.29 -0.16
-0.18 -0.08 -0.22
-0, 57
-1.60 -1.40 -2.1?
-1.91 -1.73 -2.53
-2.01 -1.93 -2.93
-2.23 -2.34 -3.45
-2.36 -3.28
-2.36 -2.25 -2.80
— - -3. 33
-2„68 -3.79
-2.78 -2.76 -5.74
-3.38 -3,51
— -3.76 -4.01
-3,96 -4.29
Several different methods were employed to obtain these
values. For the less active metals, cells of the type
M!H(N03)x 0.1N|KN0a (saturated)! Fb(N03)2 0.1 N I Fb were set up and
the measurements made directly using Pb|Fb(N03)2 0.1 N as a refer-
ence electrode. In the case of the more active metals, it was
necessary to measure the potential of an amalgam of known con-
centration, against the Pb half cell and then calculate the
standard potential of the metal. This calculation can readily be
made if the -ootential difference between the amalgam and the metal
is known. It was fortunate that for the alkali metals this
potential difference had been previously measured.
Element
LilU+
K\K+
Cs! Cs
Rb! Rb+
CalCa^
Nal Na+
N2iNH2"
++
2ni Zn
Cd 1 Cd++
H2 t NH4+
CulCu
^ ,« ++
CulCu
Pb\Fb++
O3IOH"
Hg 1 Hg*
Ag)Ag+
ru3
Br" \3r2
Cl"iCla
1 • ! V JLJ
% -\.
— JL^fc—
The e.m.f. of the hydrogen electrode was measured against
a lead electrode by Pleskov and Mo ho 8 son (7) and found to be
reversible. These authors (8; alSb used concentration cells in-
volving hydrogen electrodes to calculate the activity coefficients
of ammonium nitrate at various concentrations.
Fleskov (9) found that the nitrogen electrode was irrevers-
ible, but that a value could be obtained for the electrolytic
evolution of nitrogen. The evolution of nitrogen is shifted
toward the positive side in liquid ammonia in contrast to oxygen
evolution in water because of the small /\ £of formation of
ammonia. The theoretical "decomposition ootential of liauid ammon-
ia amounts to 0C082 V at -50°Ct"
Elliott and Yost (10) found the e9m.f„ of the cell at 25° C.
Zn(Hg) (s) \ ZnCla.6N^(s)./NH4Cl (a3 = 1)/T1C1(s) Tl(Hg)s to be
.9016 volts, and if the Zn and Tl were present as pure metals,
0.8293 volts. Garner, Green, and Yost (11) found that the e„m.f.
of the cell Zn(s) ZnCl3o6NK3,NH4Cl, (a3 = 1) CdCl3.6NH3)Cd(s) at
25°C. is 0.3605 volts. Ritchey and Hunt (12) using values of the
activity coefficients of ammonium chloride which they determined
at 25°C, and the experimental measurements of Yost and coworkers,
calculated the e.nuf. of the following half cells on the basis
of hydrogen = 0.
Tl(s) + CI"" > TlCl(s) + e~ E°
Zn(s) + 2C1~ + 6NH3(1) ^
298
0.0371
ZnCl3.6NH3(s)+ 2e 0.8664
Cd(a) + 201- + 6NH3 (1) CdCl2,6NH3(s) + 2e~ 0.5059
It was noticed by Palmaer (13) that blue streaks appeared
near the cathode when a liquid ammonia solution of tetra-
methyl ammonium chloride was electrolyzed. Schulbach (14)
observed a similar phenomenon with several tetraalkyl ammonium
ions. He also reported that the substitution of hydrogen for an
alkyl group decreased the stability of the ionse
Forbes and Norton (15) measured the oxidation potentials of "
several NR4 groups in the following manner. They first electroly-
zed a solution of NR4I in liquid ammonia at -75° between two
platinum electrodes and obtained at the cathode a blue solution
of NR4 radicals. Then using another platinum electrode in the
NPU solution and a Silver-sat. silver nitrate electrode, separated
by a ground gLass joint, they measured the potential of the
NR4 > NR4* oxidation.
Radical • E.M.F, E#M,F. con-
obs. (average) nected to .005 M
N(CH3)4 2.593 2.585
N °2H5 4 2.597 o#590
N(C3H7)4 2.602 2,596
N C4Hg 4 2.585 2.578
N C3Hl)3(C4H9)3 2.537 2.595
N(C3H5)C4Hq)3 2.601 2.599
N(CH3)3(C4H9) 2.592 2.590
v i ..■ T
>;;0 ■-.■■'•■. •- ■
■T-T'..
>* "" -.'"'"
,f J ->n/^ • I; •
• • ■•
*f
; J
ȣJ
.e ■ r
-15-
N(C3H5)iC4Hq) 2.600 2.595
N(C3H7)3(C4H9) 2.533 2*578
N(C4Hq)3(CH3) 2'i596 2.595
Li 2 4 606
Na 2*603 2.594
K 2.601 —
The potentials of the alkali metals was measured against
several NR4 groups by use of the cell
PtIK , MI \ NR4 , NIUI \Pt. It was found that all of the
oxidation potentials of these radicals and of the alkali metals
were within 25 millivolts of each other,, and that the Nernst
equation was not valid for these solutions. That is, a change
in concentration of the metal, salt, or radical did not effect
the electrode potential markedly.
It is apparent that the formation of this blue solution in-
volves a transfer of an electron from the cathode to the solvent,
or to the NR4+ ion to form an NR^radical. In view of the work of
Kraus (16,17) it appears that the best representation would be
NR4 ions and solvated electrons. - Kryus f°unme£&f£ when a
current is passed through solutions of alkali/ in tiouid ammonia,
the concentration of the metal ion is increased at the cathode,
as indicated by a deepening of the blue color. At the anode, the
reverse phenomenon occurs; the cone, of lr decreases and the blue
color in the immediate region disappears. There is no evidence
for an electrode process other than the transfer of an electron
from the solvent to the electrode,. Conductance measurements in-
dicate that the solution is composed of sodium ions and solvated
electrons.
On this basis it would appear that the reduction potential
of the NR4 groups and the alkali metal ions should be dependent
only on the electron concentration of the solution and should
obey the equation S = E° ~ RT In (C electron),
nF
BIBLIOGRAPHY
(1) Johnson, F.M.G. , and Wilsmore,N.T.M. , Trans, Faradi Soc.
3,70, (1907)
(2) Fleskov and Monosson, Acta Physico Chim. 2, 615 (1955),
'3) Pleskov and lionosson, Acta Fhysico Chim, 2, 628 (1955),
,4) Pleskov, Acta Fhysico Chim. 13, 659 ( 1940*7.
(5) Fleskov, Acta Physico Chim. 13, 662 (1940).
(6) Fleskov, Acta Fhysico Chim. 21, 235 (1946).
(7) Pleskov and Konosson, Acta Fhysico Chim. 1, 871, (1935).
(8) Fleskov and i'onosson, Acta Physico Chim. 1, 715, (1935).
(9) Fleskov, Acta Fhysico Chim. 20, 578, (19457.
(10) Elliott and Yost, J. Am. . Chem. - Soc 56, 1057, 2797, (1934),
(11) Gamer, Green, and Yost, J. Am. . Chem. Soc. _57, 2055, (1935),
(12) Ritchey and Hunt, J. Fhys. Chem. 43, 414, (1939).
(13) Palmaer, Z Electro Chem. 8, 729, Tl902).
(34) Schulbach, Eer. .53, 1689, "(1920 ).
[15 ) ^orbes and Morton, J. .Am. Chem. Soc. 48, 2278, (1926).
(15) .Kraus, C.A.,.J. Am. Chem. Soc. 30, 1323, (1908).
(17) Kraus, C.A. .J.'.Am. Chem. Soc. 36, 864, (1914)
\ !
1- rvr.- .. [ '■
. ■'-
,'•"1
. A #•
t..
'4 -
. ... v
'.)
* A
•16-
INORGANIC CHROMATOGRAPHY
Matheson, A0 R. November 5, 1946
I. Introduction
Inorganic chromatography is used herein as the term applied
to the process whereby solutions of inorganic substances are passed
through a column containing a finely divided solid material, the
"adsorbent", upon which solid the inorganic substances are retained
to a greater or lesser degree. The remainder of the solution
passes on through the column. The formation of zones of various
colors upon the body of the solid material is called a "chromato-
gram". In some cases it is necessary to "develop" the column after
the original solution has passed through the column in order to
produce a visible banding. Development is usually brought about
by various chemical means. Once the zones have been developed the
inorganic substances present may be identified by color or position
in the series, or both; the column may be physically extruded and
divided at the various zonal boundaries; or, by using a suitable
liouid the zones can be made to move ("elution") through the column
and the "eluate" caught fractionally and analyzed for components.
II. Historical
Tswett (25) in 1906 made the first chromatographic separation
when he poured a petroleum ether extract of driet leaf material
through a column of precipitated chalk and obtained a separation of
materials into several colored zones, The method was little used
until 1931 when an examination of carotene and xanthophyll material?
indicated its usefulness,
The first reference to the use of chromatography for inorganic
substances was made by Lange and Nagel (18) in 1936, who from
theoretical considerations, proposed that rare earths should be
capable of being separated by chromatographic adsorption. Schwab
and his co-workers (20-24) ma.de note of this proposal but did not
work with the rare earths. Instead in a preliminary communication
Schwab and Jockers (20) reported that the separation of inorganic
materials from solution, using alumina as sn adsorbent, was very
useful and that the resulting chromatograms exhibited bands or
zones containing the various components of the solution.
Schwab and his co-workers have contributed most of the basic
work on inorganic chromatography. In recent years the method has
been expanded by various means and the development is continuing
today.
III. Apparatus
The apparatus varies widely from a simple glass tube with a
constriction near one end, glass wool, rubber stopper and a suction
flask, to the complex apparatus developed by Tiselius (4) whereby
the properties of the eluate may be physically evaluated immediately
after passing through the adsorbent. Columns range in size from a
i few millimeters to several inches in diameter and a few centimeters
to several feet in length. Strain (6) and Zechmeister (7) have
many illustrations of special aoparatus.
VW ". f t-
-'0>
:■>?.■* iSj
J' • 'l >-■: -
. ! <> I
v
:q.~- . "J-f-n'j •■ e.1 ill -Xn.;;:. -7 1
..; i'.T->:>w3 i;s , 'j.i"r /.■?'"." )'. it-
.'..
;■ '"i 3- :.;•<■
.Vj >'K; '
M !
'CO
- . .
. • . ■ : i ; ■ •
— J. ( —
IV. Materials
Materials used may be divided into three general classes, i.e.
adsorbents, solvents and eluants, and developers.
A. Adsorbents
For inorganic chromatography activated alumina, silica
gel, 8-hydroxyquinoline, violuric acid, and some oxime deriva-
tives have been used. The preparation of the adsorbents is
an industry within itself. The nature of the adsorbent can
be varied to fit the problem. A good adsorbent should be
granular, reasonably even in particle size, inert (unless it
is desired to form a compound with the solute), and insoluble
in the liquids used,
3. Solvents and eluants
The solvent being used depends upon the nature of the
substances being investigated and the nature of the adsorbent
itself. A list of solvents of increasing polarity ranging
from petroleum ether to water solution of acids and bases is
used as a guide. Adsorption is greatest from non-polar
solvents. Eluants are in most cases the more polar solvents
of the series. The complete series is listed in Strain, and
Zechmeister. Water is the most frequently used solvent in
inorganic chromatography with acids as eluants.
C, Developers
The development of the zones is important, particularly
in inorganic chromatography. Addition of a more polar solvent
often widens the bands and moves them down the column and
sometimes serves as a development process. With a comparative-
ly weak adsorption from water acids cannot be used to develop
the column so some substance is added to the water which will
react with the adsorbed material and give a colored product,,
Solutions of H2S, (NH4)2S,NaOH,K4Fe(CN)6 have been used as
developers.
V. Applications
Host of the inorganic application of chromatography has been
carried out in Europe, although Bishop (8) has suggested the use
of inorganic chromatography for undergraduate work in the separa-
tion of various inorganic ions.
Schwab and his co-workers have carried out many experiments on
inorganic adsorption and as a result of their work they came to
the conclusion that the adsorption process is one of ion exchange
wherein the cation in question is exchanged upon the column of
alumina for a sodium ion. The sodium ion is contained in the alum-
ina as a basic sodium aluminate. For anions to be exchanged there
must be bound to the alumina an anion which the anion in solution
may displace. An alumina column treated with acid produces a
column whereupon certain anions may be exchanged. Hesse (3) divides
chromatography into two parts, (a) true adsorption in which only
surface forces between the solution and solid are considered, and
(b) exchange adsorption where ions in solution displace ions from
the column of adsorbent. Jacobs and Tompkins (17) consider in-
organic adsorption as part true adsorption and part ion exchange.
■>V '.-;
'■■■
. 1
-18-
They believe that inorganic ions' would be better adsorbed from
purely cation exchange material s«
A. Cation exchange.
Cations may be exchanged for a sodium ion or an alumina
column, or exchanged for a H ion in a compound such as 8-
hydroxy ciuinoline to form metal ouinolate*
Schwab and Jockers (20) investigated the adsorption of
various inorganic ions upon alumina both from aqueous solutions
and from solutions containing tartrate ion„ The use of ammonia
causes a definite alteration in the seauence of adsorption.
From an aqueous solution the seauence of ions from top to bot-
tom of the column is as follows:
r +Jr+ C ++
! A s+++ Sb+*+ , Bi+++ , Fe£+ , UO 2++ ,F b++ , Cu++ , Ag\ 2n++ , Ni++ , Tl+ , Mn++ .
Kg Cd++
++ ++ ++ JP.& +
With ammonia the series becomes Co , Zn , Cd ,,Ni ,Ag .
Cu++
Erlenmeyer and Dahn (14) used 8-hydroxy quinoline as the ad-
++
l
red-
orange. In an other experiment (15) violuric acid was used
as the adsorbent and a series of zones of the alkali and
alkaline earth metals complexes was formed. A rnicro-auantat-
ive determination of Na and K was made using violuric acid
and 5-oxo-4-oximino-3-pheny-isoxazoline in the same column
as adsorbents (16).
Clarke (l) reports that Venturello and Agliardi in 1940,
used an alumina column to separate a number of inorganic ions,
apparently similarily to the work of Schwab and others.
The first investigator to carry out Lange and Nagel' s
suggestion for the sepa.ra.tion of the rare earths appears to
be Er&metsa1 (11). A sample containing the rare earths and
yttrium was dissolved and the solution (neutral) was passed
through a column of alumina. The Y was less adsorbed than the
rare earths and some shifts in composition x^ere noted, although
no pure separation was claimed. A tartrate solution was also
used and resulted in a lesser amount of Y being adsorbed than
before and a larger amount of the yttrium earths being adsorbed
Yttrium does not appear to follow the true lanthanides as far
as basicity behavior is concerned in these experiments. A
second experiment (12) wa.s carried out with similar results to
that above. Citrate complexing caused some changes in the
sequences, and carbonate complexing permitted a better
separation of the cerium group for the yttrium group. Silica
gel was used for an adsorbent in one column. Croates (9)
has also studied the chromatographic adsorption of the rare
ea^fjfis. It is reported that a preferential adsorption of
Ce with respect to La and the formation of two zones
was brought about > but the details are unknown since the orig-
inal article has not been available.
-U..
iV.Y_
-19-
Era'metsa' (13) in an unsuccessful attempt to find a complexing
agent for the rare earths used diphenyithiocarbazone ("Dithi-
zone" ) to prepare dithizonates of several metals (antimony,
tin, nickel, manganese, copper, etc.,). The dithizonates
were in a CHC13 solution and this solution was poured through
an alumina column resulting 'in ouite sharp banding. CC14
solutions were also employed.
B. Anion exchange
Schwab and Dattlerj(21) separated some of the more common
anions such as OH , P04 ~, F , .Fe(CN)e , ~rC4~ etc., but
found it was not possible to separate all anions because of
the difficulty in forming colored compounds,
VI. Theory
Wilson (26) has proposed a theory for chromatography which has
been applied largely to organic processes. DeVault (10) has mod-
ified this to a certain extent. Meyers (19), and Jacobs and
Tompkins (17) have made some application of the theory to inorganic
processes.
General references
1. Alexander, J., Colloid Chemistry, Reinhold Publishing Corp*, New
York, (1944), Vol. V. 457-491 (Beverly Clarke- author),
2. Bottger, W. , Fhysikalischei I.ethoden der Analytischen Chemie,
Akad. Verlag-gesellschaf t, Leipzig, (1939), pp. 1-7, 30-73.
5. Hesse, C-. , Adsorption method en im Chemischen Laboratorium,
Gruyter and Co., Berlin, (1943), pp. 29-33; 107-113.
4. Kraemer, E. 0., Advances in Colloid Chemistry, Interscience
Publishing Inc. , New York, (1942, pp. 81-98; 333; 541
5. KacDougall, F. H. , Physical Chemistry. The MacM'illan Co., New
York, (1943), pp. 681-3.
6. Strain, H. H. , Chromatographic Adsorption Analysis, (1942) , pp. 1-8'
7. Zechmeister, L, and Cholnoky, L, Principles and Practices of
Ch roma tog raphy , (Trans. Bacharach, A.L. and Robinson, F.A.y"
John 'tfiley and Sons, Inc., New York, (1941), pp. 1-88; 304-24.
Special references
B, Bishop, J., J. Chem. Educ., 22, 524 (1945) 0^7
9. Croats, K. , C.A. , 37, 2680~Tl943; Ricerca Sci. , 12, 15^ (1941).
10. DeVault, D. , J. An, Them. Soc. 65 532 (1943).
11. Era'metsa", 0., Bull. Comm. C-eol. Finlande, 14, 36 (1941).
12. , Sahama, ^h. , and Kanula, V., Ann. Acad. Sci. Fennica,A,
5_7, No, 3, 5 (1941).
13. Erametsi, 0., Suomen Kemistlehti, 163, 13 (1943).
14. Erlenmeyer, H. and Dahn, H. , Helv. Chim. Acta. 22, 1369 (1939),
15. , and Schoenauer, 'vT. , ibid. , 24, 878 (1941*77
16. , and Sohmidlin, J., ibid, 24, 1213 (1941).
17. Jacobs, F.W. and Tompkins, F. ' :-. , C.A. 39 5156. 5157 (1945; Tram
Faradya Soc., 41, 338-94; 595-400; 400-5 (1945).
18„ Luige. E. and Magel, K,, Zeit. fur Elektrochem. , 42, 210 (1936).
rer*. K. Je , bastes, J,*'"., and Urauhart, D. , Ind. Eng, Chem(.
33', 12*: (1941).
L : -j
* %
" * \ 0 9
■N -■
\ " '
-SO-
SO. Schwab, G-.H. , and Jockers, K. , Zeit. fur Elektrochemie, 43 610
(1937); Naturwissenschaf ten, 25, 44 (193V); Angew, Chemie, 50_,
546 (1937).
21. , end Dattler, G. , Ibid. , 50, 691 (1937 )0
22. , , ibid., 51, 709 (1938).
23. , and Ghosn"T~A.N. , ibid, 52, 666 (1939).
24. , , ibid. , 53,159^(1940 ).
25. Tswett, 11., Ber. deut. bo 'tan. C-es., 24, 384 (1906).
26. Wilson, J.N., J. Am, Chem. Soc., 62, 1583 (1940),
I
<-.
- 21-
ION EXCHANGE
Starr, Donald November 12, 1946
^ • Introduction
Ion exchange has been described as the reversible inter-
change of ions between a liquid phase and a solid, involving
no radical change of the solid (29). The existence of such a
phenomenon was first noticed by Way in 1845 (31) when he passed
an ammonium chloride solution through a column of soil and
found calcium ions, in place of ammonium ions, in the effluent.
Thom-oson (26) is also given credit for the discovery.
Other materials, zeolites in particular, were found to
oosess this base-exchanging property. Technical application
of these exchangers to the softening of water dates each about
forty years. Many varied uses have been found for the process
since the discovery of the ion exchange capacity of organic
resins (1).
II. Types of Exchangers
A. Cation
Many natural materials, clays, zeolites, glauconites
for examples, have ability to exchange ions. Some treated,
naturally occurring substances have been used in treating hard
water. Synthetic "zeolites" have been produced from sodium
silicate and sodium aluminate. (29) Carbonaceous exchangers
are those produced by the action of 303 on coal (5). The
phenol-formaldehyde type of resins are widely used at pre-
sent (5) .
B. Anion exchange absorbents
Some inorganic exchangers have been mentioned out
their use is limited (12). (29) The most useful materials for
anion exchange or acid absorption are the basic resins (13).
IH • Ion Exchange Reactions
These reactions are reversible and represented thus:
Ca^ + 2 (Na+Ex-) --z-^ 2Na+ ■* ( Ca++ Ex2~)
where Ex represents the cation exchanger.
In this example the exchanger operates on the sodium cycle.
Operation according to the hydrogen cycle is analogous. Re-
generation of the exchanger is possible because of the rever-
sibility of the reactions.
Acid adsorption is represented as follows:
(R3N) + HC1 ^ (R3M.K4 CI")
or;
(R3NH+ OH"") * HC1 -» (R3N-H+C1-) * H20
where R^N represents an anion exchanger.
After an anion is attached to the exchanger it can be ex-
changed for another anion:
SO = * 2 (R3NH+CI-) ==r=^ [(R3NH*) 2S04=j +2C1-
Thus a combination of hydrogen cycle exchange followed
-
■-> i
..:i
■■a
- 22 -
by acid adsorption will result in co iplete removal of all
electrolytes from solution. This is referred to as deion-
ization or de mineralization].
Several workers (2) (4) (6) (12) (15) (30) nave examined
the reactions of exchangers in a static system. They brought
weighed quantities of dried materials into contact with various
solutions and determined the extent of exchange after equilib-
rium had been established. Likewise work has been done with
exchangers in dynamic systems by allowing solutions to flow
through columns of exchange materials (12) (13) (25). Gen-
erally ion exchangers are utilized in industry under such
conditions. Using this method, the usable, or "break-through",
capacity can be determined. This capacity is the quantity of
ion which is exchanged up to the point where it first appears
to a detectable amount in the effluent.
Ion exchange reactions have been shown to obey the mass
action law or closely approach such conditions (2) (7) (12).
|iost of the exchange occurs in a few minutes, but true equi-
librium is attained slowly (15) (16) (27). The reaction rate
of anion exchange is much slower than that of cation exchange
(13). Temperature has been shown to have little effect on
the reaction rate (16) or equilibrium (6),
Nacrhod and Wood showed the influence of anions on cation
exchange (16). Salts in the form of the acetate, formate or
bicarbonate were exchanged to a greater degree than the corr-
esponding chloride, nitrate, or sulfate. Correlation has
been seen between the size of the hydrated ion and the extent
of exchange (16) (29). In general, the larger the hydrated
ion, the smaller is the amount of the exchange. Increased
charge upon an ion produces more exchange. (16)
The pH is known to effect the exchange. Nelson and Walton
(17) explain the increased exchange of calcium ions in solution
for hydrogen ions in an exchanger at higher pH values, by
citing the existence of the very weakly acidic groups in the
resi:\, which will exchange in alkaline solution but not in
acid solution.
IV. A'o Plications
Ion exchangers have been used for a number of varied
purposes. Water conditioning has been the largest field for
technical application of ion exchangers. Water comparable to
distilled water can be produced in this manner at lower cost.
Myers (11) ;:nd Suss man and Mindler (23) have written re-
views on the uses of ion exchange materials in industry. These
apolications include removal of ionic impurities from sugar
solutions, (32) removal of formic acid from formaldehyde, and
removal of objectionable ions found in crude petroleum.
As well as removing undersirable ions, valuable materials
may be recovered from solution. HocGhromium, gold, iron, molybdenum,
[palladium, platinum and vanadium, in the form of anions (22).
(Copper ions have been recovered from ouprammonium rayon waste
liquors. Alkaloids (21) and tartrates (9) have been obtained
in pure form in this manner*
~ 23 -
Electrolytes can be separated or fractionated hy this
process. This has been applied to amino acid separation (28),
to rare earth separation by Pearce and Russell (18), and to
fractionation of lithium isotopes by Taylor and Urey (24) 4
Separations for analytical purposes have been used by Frizzell
(8) and Samuel son (20).
In industry ion exchange has the disadvantages of any batch
process, in that the exchanger bed must he regenerated at
intervals. Semi-continuous operation is obtained by the use
of several columns, one or more of which may operate while
the others are being regenerated.
Due to the capactities of the exchangers, the process is
limited to solutions of relatively low concentration. With
increasingly higher concentrations of ions, the volume of
solution which can be treated decreases until the volume of
exchanger required is larger than the volume of solution used.
This is seen in the demineralization of sea water to produce
drinking water. It has been estimated that two liters of
ordinary exchangers would be required to desalt one liter of
sea water. During the war, however, a high capacity ion ex-
changer, with silver ac the exchangeable ion, was used by the
Armed Forces for this purpose (23),
Thus, ion exchange is definitely out of the question for
some processes, but the versatility of the process can be seen.
It has been suggested that because of its general application,
it should, be mentioned with distillation and filtration as a
unit process of chemical industry, (28)
References
1. Adams, B.A. & Holmes, E.L., J. Ind. Chem. Soc. 54, IT (1935)
2. Aheroyd, E.I. & Broughton, G. , J.Phys. Chem. , 42, 343 (1938)
3. Applebaum, S.B. & Riley, R. , Ind. Eng. Chem. 30, 80 (1938)
4. Austerweil, G.V., J. Soc. Chem. Ind. , 53, 185T"Tl934)
5. Bauman, W.C., Ind. Eng. Chem. , 38, 45~Tl946)
6. Ferguson, J.B., Musgrove, J.R., and Patton,J.R. Can. J. Res, B.
14, 243 (1936)
7. Furnas, C.C., and Beaton, R.H., Ind. Eng. Chem. 33, 1500 (1941)
8. Frizzedl, L.D., Ind. Eng, Chem. , Anal. Ed.", 16, 615 (1944)
9. Matchett, J.R. , Legault,R.R. , Nimmo, C.C., & Motter, G-. K,,
Ind. Eng. Chem. 36, 851 (1944)
10. Morrison, W. S. , Monthly Rev. Am. Eleetroo^-aters Soc, 30,702 (1943)
C.A., 37, 6195 (1943)
11. Myers, R. J. , "Synthetic Resin Ion Exchangers", in E.O. Kramer
"Advances in Colloid Science", Interscience Publishers Inc.,
Mew York, 1942
12. Myers, R, J., Eastes, J.W. & Myers, F.J. Ind. Eng. Chem. , 33, 697(1941
14. Nachod, F. C. & Sussman, S. , J. Chem. Education, 21, 56^*1944)
15. Nachod, F C; , & Wood, W. , J. Am. Chem. Soc. , 66, 1380 (1940)
16. Nachod, F.'c , and Wood, W, , J. Am. Chem. Soc. , 67, 629 (1945)
17. Nelson, R, and Walton, H. P. , J. Phys. Chem. , 48, 406 (1944)
18. Pearce, D.W. & Russell, R; G. , J. Am. Chem. Soc. , 65, 595 (1943)
19. Ryznar, J.W. , Ind. Eng. Chem. , 36, 821 (1944)
BO. Samuelson, 0., Z. anal. chem. , 116, 328 (1939)
21. Sussman, S., Nachod, F. C. , and Wood, W. , Chem. Ind. , 57, 455,549
(1945) ~~
22. Sussman, S% , Nachod, F'CtI & Wood,W. Ind, Eng. Chem. , 37,618(1945)
23. Sussman, s! , & MindlerjA.5. Chem.Md., 56, 789 (1945)
|L3. Myers, R.J. , Eastes, J.W. & Urquhart, T7D. Ind. Ens:. Chem. 53,
*i
«'
n
» '— . i
...
r 24 -
24. Taylor, T.I%, & Urey, K.C., J.Chem.Phys, 6, 429 (1938)
25. Thomas, h'.C, J.Am.Chem.Soc, , 66, 1664 (1944)
26. Thompson, J., J.Roy. Agr. Soc. ingl. , 11, 68 (1850); 13, 123 (1852)
27. Tiger, H.L. , & Sucsman, S. , Ind.EngTtJhenu 35, 186 (T94o)
28. Walton, H.F., J. Chem. Education, 23, 454 (1946)
29. Walton, H.F., J.Franklin Inst. 232, 318 (1941)
30. Walton, K.F., J.Phys. Chem. , 47, 371 (1943)
31. Way, J.T., J.Roy . Agr. Soc. Engl. 11, 313 (1850)
32. Weitz, F.W. , Sugar, 38, Mo.l, 26 (1943)
p. 25 -
VALENCE STATES OF IRON
Weaver, Eugene November 12, 1946
I. Introduction
Iron, which is found to be the fourth element in abundance
on the earth's surface and the backbone of the so called "steel
age , is ;.lso important as a component of chemical compounds
We are familiar with the ferrous and ferric comoounds and need
to become more familiar with the higher valences of iron.
II. Iron's position in the Periodic Table.
Iron is found in the eighth group and is a transitional
element in the first long period. These • elements are grouped
in threes, which are called triads because of their similarity,
ihe similarity between iron, cobalt and nickel is due to the
fact that electrons are filling an underlying shell.
Similarities may be expected among iron, ruthenium and
osmium since the 3d, 4d, 5d levels are being filled in the
respective elements. Both ruthenium and osmium form tetra-
oxides so a similar compound might be expected for iron.
Sidgwick (7) points cut that according to the covalency
rule the highest valence for iron is six so it would not be
expected to form a tetra-oxide.
III. Suggested valence states of iron.
Using ruthenium and osmium as examples we can expect to
find the valence states which are listed in the table. They are
the valences which have attracted the most attention of investi-
gators.
Valence +2 +o +4 -*6 +8
Oxide FeO Fe203 FeOg* freOgJ $e0^
Acid Increasing ^_
properties **
Acid lH2Fe0g^ HFe02 <[H2Fe05] [HgFe04J [%Fe0^
Hypoferrous ferrous perferrous ferric perferric
acid acid acid acid acid
Represent ive
compound ^NaoFeQ^ NaFeOg BaFe03 BaFe04 ^KgFeOsl
Name Sodium Sodium Barium Barium Potassium
hypoferrite ferrite perferrite ferrate perferrate
-1-9 FeO 4=
-0.9 FeO 4=
0.55 Fc04=
Oxidation
potentials
(3)
equilibrium
Potentials
(15)
Fe
Fe
Fe
.44 . Fe"*"1, -.77
Fe-s-++
"*FeO?= ,68
.88 Fe(0H71? .56
-.86 ^ FeO:v= -.69
FeOg-
>Fe(0H
>
_^ Fe02~
>
— ->
\ •
■I ./.
- 26 -
The acid properties of the oxides increase with the valence
of the iron. The acids are named in the same manner as the
oxygen acids of chlorine were named. The compounds listed have
all been reported as having been prepared.
IV. Experimental work reported in the Literature.
The literature has many references to the formation of
salts of the acidic iron oxides. These references go back to
the early 18th century. The compounds will be discussed in
order of their valence states.
Iron also forms several interesting types of compounds of
lower valence.
Finely divided iron reacts with carbon monoxide to form the
pentacarbonyl Fe(CO)^ in which the valence of iron is zero according
to our usual idea of valence.
Fe(NO)oI has been prepared from FetCO^Ig and NO. In the
former the apparent valence of iron is one.
A. Hypoferrites
3-rube and Ghnelin (15) conducted an experiment in which
they dissolved an activated iron anode in 40$ sodium hydroxide
solution. They plotted the anode potential against current
density and obtained a curve containing two inflections. They
took this to mean the formation of sodium hypoferrite and sodium
ferrate.
B. Perrites
G-rube and G-melin found that ferrites could be prepared by
anodic oxidation of alkaline ferrous solutions or cathodic re-
duction of sodium ferrate if platinum electrodes were used.
Ferrites may also be prepared by fusing ferric oxide and so-
dium c -rbonnte at red heat.
Bernard and Chandron (8) found that they could prepare
the ferrites of cobalt, nickel, magnesium and manganese by
heating the oxides of these metals with magnetite at 800° in
a vacuum. Calcium, strontium and barium did not react, apparently
because their size was not near enough that of the ferrous ion.
Songuet (23) observed that ferrites of cobalt, nickel,
co-.rper and zinc could be prepared by heating together the
precipitated hydroxides. Calcium, magnesium, and zinc ferrites
are well defined crystalline compounds.
C. Perferrites
Pellini and Meneghini (20) observed that an alcoholic
solution of ferrous chloride reacted much differently with
hydrogen peroxide than ferric chloride and hydrogen peroxide
which showed very little reaction. These men assumed that
the product of the oxidation of the ferrous salt was iron
dioxide.
Moser and Borch (18) heated to dryness a solution of
ferric nitrate and strontium nitrate. The residue was heated
in b current of oxygen and strontium perferrite was obtained.
The perferrites are stable below 640°. Above this tem-
perature they evolve oxygen and the iron is reduced to the
ferric state.
- 27 ~
The perfcrrites are fairly stable in alkaline solution.
Bray and G-orin (10) have suggested that FeOXJ- ions
exist equilibrium with the ferric ion.
Another example of tetra-valent iron is found in FeSg
which is obtained when Fe^S^ is treated with KgS (15).
D. Pcnta-valent Iron
Manchot and Wilhelms (17) studied the reaction of hy-
drogen peroxide and potassiums iodide in the presence of ferrous
salts. Calculations based on the amount of iodine liberated
seem to indicate the formation of F0I5. Selwood (6) mentions
a similar compound, NH^FeFg, in which the iron would be penta-
valent,
E. Ferrates
G-rube and Ornelin (14) expanded on their work mentioned
earlier and built a cell in which they used superimposed
alternating current on direct current. They got good yields
of sodium ferrate in that manner.
Losana (15) prepared potassium ferrate by two general
methods :
(a) Iron powder was thrown into fused potassium nitrate.
(b) A rapid current of chlorine gas is passed thru a
suspension of ferric hydroxide in concentrated potassium
hydroxide solution.
The silver, barium, calcium, lead zinc, nickel and cobalt
salts may be dried without decomposition.
On heating, a stepwise decomposition occurs.
Ea Fe04 -1222, Ba Fe03 -i£i* BaO •+ Fe203
F. Perforates
G-oralevich (11) reported that he prepared a green com-
pound -:"AQn he fused together ferric oxide, potassium hydroxide
and an excess of potassium nitrate. He said that the green
pompound was a perferrate.
Petroo pnd Ormont (21) reinvestigated G-oralevich' s work
and came to the conclusion that the green compound was a
manganese compound rather than an iron compound.
Kulgina and Coworkers found that by first purifing the
ferric oxide they got no green compound.
G-. Summary.
It can be pointed out that the vertical relationship in
the periodic table is as important as the triad relationship.
The stability of the compounds containing higher valent
states increases with atomic number.
The acids of valences 3, 4 and 6 form stable compounds.
The ferrate ion is a powerful oxidizing agent.
References
1* : ,,] mdbueh der anorg; chemie" Vol. 13, part 3 2nd half
B 290, B 427 ^
2| TCav!n and Lander "Systematic Inorganic Chen." Blackie and Son
London, 1931, page 357 " '
3. Latimer and Hildebrand, "Reference Books of Inorganic Chemistry"
ulacmillan, Mew York 1940, p. 390
4. Latimer "Oxidation Potentials", Prentice-Hall New York 1938,
5. Mellor "Inorganic and Theoretical Chemistry" Longmans New York
ITol. 13, p 494, 905 '
6. Selwood "Magnetochemistry" interscience Publishers Inc.
New York 1943 p. 155
7. Sidgwick "Electronic Theory of Valency" p. 295 Oxford University
Press, 1929 J
6. Benard, J. and Chandron, Geprges Comet, rend. 204 766-8 (1937)
9. deBoca, Armando Anales farm bicqum 6, 65-9 (19357
10. rix-ay, .:.C. ana GorinM.H., J. Am. ChemTSoc. 54, 2124 (1^3?)
11. 3-o^l-V.Lck, D.K. Phys.Chem.Soc. 58, 1129-58 (1926); 5.1 22,
12' ^E°rishvili, Kulgina and Zoyagintsev; J.Gen.Chem. (USSR) 9
1961-6 (1939); C.A. 34 5011 (1940) -'
13. Griffith and Morcom j. Chem. Soc 1945 786-90
14. Gru.be, G. and Gmelin, H. Z. Elektrochem 26 153-61 (1920)
15. Grubc, G. and Gmelin, H. ibid 26 459-7l"Tl920)
16. Losana, L. Grazz. Chim ital 55 458-97 (1925); C.A. 20 156 (1926)
' ^S^I'ninS?4 Wilhelms> *• Ber 34 2479 (1901); Llebigs Ann
eoo 105 (1902)
18. Mbscr, L. and Borch, H. Ber 42 4279 (1909)
19. Orrmont Acta ohysicochim UR8S 11 1911-16 (1939); C.A. 34 4622
( 1 940 ) ~~ —
20. Pollini, G. and Heneghini D. Zeit. anorg. ohem. 62 203 (1909)
21- "°*r0I; |;n!nf1g;??nt' B- J- ?hys Ch^- ("S3R) 8 565-76 (1956);
22' C^A^3i,B83a9:1(l9S7^, B' J' ^ ^^ (U33R) ' Z> 1690"4 (1937>
33. 3cn-u;;t, Jackqueline, Co ipt. rend. 213 577-9 (1941)
-29-
C0I1PCUNDS OF METHYL SULFIDE WITH INORGANIC SUBSTANCES
November 19, 1946 William G-. 3ritton
Introduction
Sulfur has the property of exhibiting the greatest variety of
valence forms of any of the elements occurring in organic com-
pounds (l). This paper is a review of some chemical and physical
properties of methyl sulfide which makes readily available in-
formation needed to predict the course of hitherto unknown
reactions of this compound.
Description of Compounds
1. With halogens
Under anhydrous conditions sulfides react with the halogens
(except flourine) to form dihalide addition products which
might be considered as having a structure similar to that
of sulfonium salts. X
" t
R3R + X3 >[?SRl+ X~ „
The formation of dihalide s occurs- with great ease when
methyl or methylene groups are adjacent to sulfur; in fact,
the reaction with bromine takes place so readily that it
has been used as a quantitative method for the determina-
tion of sulfides (2T- The compound
B+
jHeSHe]4" 3r~ is a yellow crystalline solid (3)*
II. With platinum salts
When excess methyl sulfide is added to aaueous PtCl4, (4)
A„ PtCl3.2Me3S is formed
B. PtCl4«2I!e3S is formed on recrystallizing
C. PtCl3«2I'e3S is formed after evaooration in a vacuum de-
siccator.
Compound A appears to have one methyl sulfide molecule not
coordinated. When Pt3r4 acts on Me3S3r3 (5)
D. Pt3r4.211e3S, an orange red material, is formed on stand-
ing in alcohol,
E. Pt3rs (MegSBr )s, a dark red material, is formed when D
is washed with alcohol.
Compound S appears to have a bromine atom on one side of the
sulfur, the other side of which is coordinated with the
platinum^
More complex compounds are fo«ned (6) when He2S reacts
with K3PtBr4 and H3r yielding
F. IPt(!le3S)4]pt3r4.
PtCl3»2N;e3S + jP^NKa] Cl3 on shaking with water frrm (7)
G. [pt4NH3lptCl4 + [Pt4Me3SjCl3. + \?t (NH3 )4J [ptCl4jf
The ammonia complex has the form -of Kagnue* &Q.\t
[P^NHajPtCl^
* ,
-30-
A few years ago three chemists brought severe criticism
on themselves (l). It has long been known that the following
two modifications exist for PtCl2- (Et3S)3,
Et2S
CI
st3s
.CI
Ft
7/ x
Et3S
rsCWerner
/Ft
CI
,SEt
^5 We
rner
Angell, Drew and Ward law found that the reaction of the c^~di-
chloride with bromine and the /-- dibromide with chlorine yields
one and the same dibromo dichloride* They interpreted this as
indicating a tetrahedral structure for the dihalide.
Et3s gi ci
"EtsS ,L_, cl Et2S , ' --
+ /Ft/ 0i
■'Pt
Et2S<- j-~ Br + Cl3 — — ->^ ' /Pt/ { Br
Br
Obviouly, if planar
EtsS __ Cl
III/ + Br3
Et3S Cl
Et3S I Br
3r
Et2S
>
Et2S
Et2S
Et2S Cl
Et2S Cl
"~ Et2S
+ Cl3 ^
Et2S
As would be expected, the theorists were severely criticized,
so they decided that the 7- forms were really the i"> forms and
the reaction would proceed as follows:
Br
Et2S Cl E':2S I C1 Et2S Br
/ Ptv + Br2 > Ij&j / C1 + /pY/
SEt3 Cl f SEt8 * X2 +Br Z~-SEt8
Br 8
Cl
III. With mercury salts
A. General reaction
Organic sulfides combine with mercury salts according
to the type formula
R2S + Hgl3 = R-S — ^ Hgl3
liercuric chloride is used in separating sulfides from
petroleum distillates,, Treatment with hydrogen sulfide
regenerates the sulfides (2).
3. With mercuric halides
Loir discovered the ability of organic sulfides to
form compounds with certain heavy metal salts and assigned
the formula (CH3 )2S»HgCl2 to the mercuric chloride com-
pound i Phillips reported the formula of 3KgCl2»2(CH3)aS
(8). There is a possibility that the product is a mole-
cular compound made up of He3S'HgCls + He3S"2HgCl3 (8).
Smiles reports the existence of the mercuric iodide
compound He23HgI2 (8).
-?^:- ;r,/o: .
4 -s :•
. » .. . '■.
— .1
t- ,
I c* >: r: . S!
* >^
'. :f.
•; ■- '•r-\ • -f ■ a\<
. 7?
... .... .. ^
I
'■} * a. r- 7'
'<: ' - '■■' -'A ' »...■ . . :
oj
. . . ■ / -
-31-
f
C. With mercurous nitrate
R2S + Hg3(N03)3 > (R3S)3Hg(N03)a + Hg.
Mercury is oxidized to a higher valence state (8).
D. Effect of solvent
In some cases the solvent is en important factor.
He thy 1 sulfide does not react with mercurous chloride
unless water is present but reacts readily with mercurous
acetate or sulfate in the absence of water.
E. Comparison of methyl sulfide with other sulfides in
reactions with mercury salts.
All organic sulfides react with aoueous Hg3(N03)3
or with aoueous or anhydrous Hg3S04» Only methyl sulfide
reacts with Hg3Cl3 and then only in the presence of water.
Only methyl sulfide reacts with mercurous acetate in the
absence of water. Other sulfides require water.
IV. With gold salts
The general type reaction of alkyl sulfides with gold salts
is stepwise (9).
AuCl3 + R3S ^. AuCl3»R3S (a yellow complex)
AuCl3-R2S -r R2S + K20 > AuCl*R2S + R3S0 + 2HC1 (color-
less)
The compound Me333r3 acts on AuCl3
Me2SBr3 + AuCl3 =;—-> He3SBr+ AuCl33r"
V. With -palladium salts
Solid products that are obtained by reaction with palla-
dous chloride are used for the identification of sulfides (2),
VI. With trimethyl aluminum
i
j
toi
Me3S«AlMea exists. Methyl ether coordinates more strongly
>ward trimethyl aluminum than does methyl sulfide (10).
VII. Wi th iridium chloride
IrCl4 + Me3S -----*> Ir2Cl5'4He2S
iiiLUri
(heat)
The same reaction at room temperature gives
IrCl3-2Me3S (11)
VIII. With alkyl halides
R
RSR + RX -> R-S-R + X"*
The reaction is slow at room temoerature and -oroceeds more
readily on heating (2).
IX. Summa ry
The sulfides form sulfonium-like comoounds with halogens
and alkyl halides, coordination compounds with salts of
heavy metals as the result of the donor activity of sulfur;
and as would be expected, some of the more complex compounds
aren't adaptable to the Werner scheme but probably form
"hydrate like" structures.
* *
-2 C «f f '
r.
-32-
Physical Properties
It is interesting to compare some of the physical properties
of methyl sulfide with those of methyl ether and also to investi-
gate some physical methods of examining methyl sulfide and see
how the properties of the very resctive sulfur atom manifest them-
selves.
A. G-eneral observations Melting Boiling Solubil-
ity in /,£
Point Point T 'later '
Methyl ether - colorless gas -138.5° -23.65° 370Ccc/lO "r
llethyl sulfide - colorless liquid - 83.2° 37.5° insoluble
The low molecular weight sulfides have odors which, though
disagreeable, are not so objectionable as those of the mercap-
ta.ns (2)c Experiments carried out on fasting female rats in
a gas chamber show that dimethyl sulfide irritates the mucous
membrane, paralyzes the voluntary muscles, and finally the
respiratory muscles. A concentration of 5^ is fatal in 15
minutes* Dimethyl disulfide is more irritating while of/methyl
mercaptan is less (13).
B. Raman Spectrum
A beam of mono-chromatic light has its frequency altered
when scattered by a liquid in a way which depends on the nature
of the scattering molecules. The change in frequency is de-
pendent upon a characteristic frequency of the molecule. A
mechanical analogy with weights and springs agrees remarkably
with actual data. The Raman spectrum gives Pn indication of
the numbers of atoms in a molecule, the masses of the atoms, the
strength of the chemical bonds, and degree of ionization (14).
As ye'c, the Raman specturm for methyl sulfide has not been
developed to the extent that unknown information can be obtained
from it (15')
C. Barrier potential
Until recent years it was supposed that rotation of a methyl
group about the C-C bond was quite free, but the view of
restricted rotation is now generally accepted. Absence of iso-
mers does not conflict with this idea because the magnitude of
the barrier potential is 5 k« calories and it would have to be
of the magnitude of 20 k» calories to allefto isomers at ordinary
temperatures (16). The cause of this restriction to rotation
is mutual repulsion of the hydrogen atoms.
The barrier potential must be considered in calculating any
thermodynamic oroperty of a. substance at any temperature (16).
The barrier potential of methyl sulfide is smaller than for
methyl ether and larger than for methyl mercaptan (17). This
is to be expected because the oxygen atom is smaller than the
sulfur and therefore in ether the methyl groups are closer to-
gether than in methyl sulfide.
It can be shown that this hindering of rotation is mainly
due to the proximity of the methyl groups rather than to the
type of atom to which they are attached (18).
D. Bond ancle
C-3-C angle is 100 -110° (18)
H-S-H angle is 92° (16)
H-O-H angle is 105° (IS)
- f '
-33-
E. Dipole moment
The moment of sulfides Is higher than that of ethers, but
contrary to what would be expected, the moment of sulfides is
higher than that of (mercaptans even though the moment for
ethers is lower than for alcohols (19).
F . Ionization potential ( 20 )
Decreasing oocential
Me30 >It20 >H33 >EtSH^::e2S^Et3S
G-. Summary
Methyl sulfide differs from methyl ether in its boiling point,
melting point, and solubility in water as would be expected
from the difference in molecular weight, mhe odor and toxic-
ity are representative of sulfur compounds. The Raman spectum
offers little data; the terrier potential reflects the size of
the sulfur atom; the bond angle shows no striking peculiarity
but the dipole moments an interesting relation between ethers,
alcohols, mercaptans and sulfides is found.
F reparation and Purification
mi
:he general method of preparation for symmetrical sulfides
is shown by the type reaction (2)
RX + K23 > RSR + 2KX.
Hercaptans and water are the main impurities en6 removal can
be affected by re fluxing with copper and sodium, f ra.ctiona ting,
allowing to st^nd in vacuo to expel non-condensable gases, and
fractionating again. By this method sn impurity of only .00?
mole $ remains (17),
Summa ry
Methyl sulfide compounds with inorganic substances are listed
and seem to be divided into sulfonium-like compounds, coordina-
tion compounds; and more complex compounds difficult to classify v
Some physical properties of methyl sulfide are discussed and
interesting relationships between physical properties and
related compounds are shown. Finally methods of preparation and
purification are reviewed.
References
1. Gibson, D. T., "Significant studies in the Organic Chemistry
of Sulfur", Chem. Reviews 14, 431 (1934)
2. Gilman, H. , "Organic Chemistry", T\Tiley and Sons, 1943,
3. Kantzsik, A, and Hibbert H. , ;nAddition Froducts of Tri-Alkyl
FhosDhines, Arsines, and Stibines", Ber. , 40, 1503-19
(1907)
4. Prafulla, C. R. and Puma, C. 11., "Action of Bases on Com-
plex Compounds Derived from Organic Thio Compounds and
PlatinicChloride". J. of Ind. Chem. Soc, 6, 885-91 (1929),
5. Fietro, 7pinoglio and DeGs.sperl, Mario, "Structure of Ki-
halogenodialkjl Sulfides and of Dihalogenodialkyl Selenides
and Their Jorip.1 exes with Aerie Chloride and Platinum Tetra
bromic3:., Gaza, chim, ital. 67, 318-24 (1937).
6. Chugaev. Z. fend Praenkel, e), ."^COmolex Compounds of Flatinum
Bromide and Organic Sulfides", Cop.pt, rend, 154, 33-5 (1912)
VY I, <■
'X .
i .,!5
... .. -II
■' .- ■-■;
-34-
7. Tshugaev, L. and Suffotin, V#J "Isomeric Platinum Compounds of
Organic Sulfides", Per., 43, 120C-5 (1910).
8. Faragher, W, F. , Merrell, J, C., and Camay, S. , "Interaction of
Alkyl Sulfides and Salts of Mercury", J. Am Chem. Soc. 51, 2774-
81 (1929).
9. Ignacio Ribas y Haraues and. Joaouin de Fascual Terera, "Reaction
of Organic Sulfides with Aaueous G-old Chloride Solution", Ion.
4, 31, 73-8 (1944).
10. Davidson, N. and Brown, H. , "The Polymerization of Some Deriva-
tives of Trimethyl Aluminum", J. Am. Chem. Soc. 64, 316-24 (1942)
11. Prafulla, C. R. and Nadiabehari, A„ , "Complex Compounds of Irid-
ium", J. Ind. Chem. Soc. 9, 251-7 (1932).
12. Kodgman, C, D. "Handbook of Chemistry and Fhysics", Chemical
Rubber Publishing Co., 29th edition, (1945),
13. Ljunggren, G-ustaf and Norberg, 3., The Effect and Toxicity of
Dimethyl Sulfide", Acta Physiol. Scand. 5 248-55, (1943) Chem.
Zentr. 1943, II, 1979,
14. Reilly, J. and Ray, W. N. "physico-Chemical Methods", Hethuen,
and Co., Ltd., London, 2nd edition, 1933, Ch. 59.
15. Fonteyne, R. "Infra Red and Raman Spectra of Polyatomic Mole-
cules", J, Chem. Phye, 8, 56-9, (1940 ).
16. G-las^tone, S. , Theoretical Chemistry", Dc V>n No strand Co., N. Y. ,
(1944). d. 410-22.
17. Osborn, D. *V. , Doescher, R. N. and Yost, D. M, , "The Heat Capac-
ity, Heats of Fusion and Va-ooriza tion, Vapor Pressure, and
Zntropy of Dimethyl Sulfide", J. Am. Chem. Soc. 64, 169-73 (1942)
18. Osborn, D. W. Doescher, R. N. and Yost, D. H. , "The Entropy of
Dimethyl Sulfide from Low Temperature Calorimetric Measurements.
Restricted Rotation of the Methyl G-roups", J. Chem. Phys. <8,
506 (1940).
19. Hunter, S, and Partington, J. R. . "Studies in Dielectric Polariza
tion", J. Chem. Soc. 2820, (1932).
20. Sugden, T. M. , Walsh, A. D, , and Price, W. C, "Ionization
Potentials of Poly Atomic Molecules", Nature, 148, 372-3 (1941).
r. - i ■%
* ; ■ .. • .
\ * ■
r- (
e. f
*- * * t
» - x •
• - . f
:
J t
- 35 -
THE INTERHALOGENS AND RELATED COMPOUNDS
Elliot M. Marvell November 19, 1946
Introduction:
The halogens form an extensive series of compounds among
themselves and ako with the so-called halo genoias or pseudo-
halogens. Most of these compounds are not well known and have
not been intensively investigated. This is due perhaps to the
instability and extreme reactivity of many of them. The lit-
erature has been rather thoroughly surveyed and a general com-
pilation of their preparations are reactions is presented here,
A* The Interhalogens :
I» Type AB (References 1-25)
All the possible combinations of the halogens as
halogen monohalides have been shown to have a definite existence
exceot iodine monofluoride.
Preparations:
For the preparation of I CI, IBr, and BrCl equimolar
portions of the requisite halogens are mixed and allowed to
stand for varying oeriods of time. The reaction between iodine
and chlorine goes to completion, but the latter two reactions
oroduce only equilibrium mixtures. IBr has never been isolated
whereas BrCl has been obtained in an impure condition by frac-
tional distillation at low temperatures. The reactions be-
tween chlorine or bromine and fluorine form in each case more
than one compound and the desired products have been obtained
pure through distillation and fractional condensation.
Reactions:
With defines: - both IC1 and BrCl pdd to the double
bonds in defines with great ease.
substitutions in organic molecules: - IC1 is a well
known iodinating agent for sensitive organic compounds, while
IBr acts as a brominatinp; agent on the same type of compounds,
with water: - IC1 may be hydrolyzed in two ways with
the formation of HOI, or HI03 and iodine in the two cases, BrCl
forms a stable hydrate containing four molecules of water. The
fluorides of chlorine and bromine react explosively with water,
as oxidizing agents: - IC1 reacts as a weak oxidizing
agent with positive iodine atom being reduced to iodine or to
iodide ion depending on the strength of the reducing agent,
as acids: - IBr has been investigated as an acid in
iodine solution. Thus, neutralization can occur with the acid
ilBr and the base KI with the formation of solvent iodine and
salt KBr.
II. Type AB^ (References 26-32)
o
Preparations:
The only known compounds in this group are ICI3,
IBr3, BrF3 and C1F3» If the required halogens are mixed in the
- ". .
n 4
dSectlymornbv'di«till%^°Ve =™nds ^ ** "oiated either
preyed ?n the pure slate? ^^ ^ Whl°h h&S "0t yet been
Reactions;
As oxidizing agents: - IOU, C1F-, and BrF, are an
oxidizing agents. The trivalent halogen atofmay he reduced
either to free halogen or to halide ion. The oxidizing oowe-
increases in order T •/ n-n s n «rv,-i«i, a ■ ^imzmg power
their qtflhi i+v \Z tu x IT • ^ -T which is in reverse order to
xneir staoility m the trivalent state.
whii, nP Wl^ wJter: ^ BrF3 reacts with water to produce oxygen
wnile C1F3 attacks water explosively. ^y-en
three eomnnnS?^?1^?11^" Br!3 iS qUite stable while the other
III. Type ABft (References 33-38)
Preparations: -.
L 4. . F}Ll0rine, which is noted for its ability to force
ndmiSdiSneinIn ft*1* highT ValenCe St*tes' combines with bromine
ind iodine in the pentavalent condition. The reaction with
?n°theecoTd? ^ "^ at hlgh ^-atures whereiriodine'reacts
Reactions;
with alkalie: - aikalie reacts with the Dentflfinnn^e
Irming alkalie fluorides and bromate or i odaJ ^s^SsTma^ be,
nd - n„/4lth«rganl° comP°unds: - IF5 acts as both an iodinating
nd a fluormatmg agent on organic molecules. S
with halogen: -
BrF5 4 ci2 .3000^ BrP 4 2C1F
V Type IF7 (39,35)
Preparation:
IF? is the only compound of this group,
IF5 - F2 222=5360 IF? ^ y.eld
Reactions:
iy he eithir^odsS1!^" "^ ^ rSSCts With alkalie the Products
mditions. Ygen °r perlodate depending on the
: -eversef in 5hi°S~L: The/?actlon ^ which IF7 is produced
-cvtfxbea in tne presence of I9.
Ifte_Psondohalogen halides:
I- lkg__cyanogen halides: (References 56-68)
anc
nd:
Preparations:
]
:<
*ad AgF.
n,a.fl . ^ogens react with alkalie cyanides to produce all the
JfSJI&'iSrca 52.' FCN CM b8 f0™ed «*» anh^uf6
ry :...- ¥«.-' :;-..:. n-^rf. ;
. ci
* . 1
cr-:*-
;"; r ■ r
M . '* ' ■<: -iT'
v ■>:
.• .
r
liS-jt'O £
* ,.';•:..;- :;j 4
i ..t
Y£> . '■■■ . '- J <i
>
' ." J •
r *
.:.;.: *n : i
i ■,
»•■■';' i
"■**
■T
- 37 -
Reactions;
polymerization: - all the cyanogen halides except
FCN trimerize to form cyanuric trihalides.
with base: - t^Q cyanogen halides react with bases
with the production of alkalie cyanates and halides.
with ammonias - cyanogen halides and ammonia form
ammonium halides pnd cyanamide.
II. The halogen ozides (40,41,55,69)
Preparations;
Halogens react with silver and alkalie abides to form
halogen azides. The reaction requires anhydrous conditions.
Reactions :
With hydroxyl ion: - The reactions of halogen abides
with hydroxyl ions produce hypohalous acid and aside ione.
as oxidizing agents: - If the halogen atom of the
halogen azides is considered as a positive halogen it can act as
an oxidizing agent, being reduced in the process to halide ion*
III. 02£^_^j^aml_^lcno cyanogen halides (References 42-47; 50-53)
Preparations:
oxycyanogen halides can be prepared by the action of
halogens on silver cyanate, Thiocyanogen halides may be produced
from thiocyanogen or from lead thiocyanate*
Reactions:.
polymerization: - all the oxycyanogen halides form
iimers of the form 9
X2N - C - N a C = 0
oxidation: - these compounds may be considered as
possessing positive halogen atoms which can act as oxidizing agents,
C. The Interpseudohalogens (48, 49, 54)
Preo a rat ions:
BrTir"*rTTaN3 ^ NaBr + N„CN
ICN T AgCNS -> Agl + CN. ~ SCN
BrgC (CN)2 * 2NaN3 + H* sther_v c2N8
Reactions;
Dimerization: -
2 CN/N3 ZZZ^IZ NSC - N=C (N3)2 The general
pactions of cyanazile are those of the dimer.
References
. Cerdeiras, Anales soc. espan fis.quim. 13 » 460 (1915)
. Tarugi, Gazz. chi.m. ital. 481., 1 (1918)
. Fournean & Donard, Compt. rend. soc. biol. 81, 1192 (1918)
» Delepine & Ville, Bull Soc. Chem. 27, 673 (1920; Compt. rend. 170,
1390 (1920)
. Fourneau & Donard, Bull. 3ci. Pharmacol,, 27, 561 (1920)
i Lang, Z. avnorg. allgenu chem. 122, 332 (1922)
Eodenstein & Schmidt, Z. Physik, Chem. 123, 28 (1926)
Fillipov, Z. Physik 6, 1024 (1928)
Ruff, etal., Z. anorg. allgem--.. .hem. 176, 258 (1928)
Barratt & Stein, Proc. Roy. Soc lg2A,T5g (1929)
■ iX-.
I . i ^' t .
* ■ '■ U -i
...,.f
I V . - ■ r i
- o8 -
Ruff, etal., Z angev. Chem/ 41, 1289 (1929)
Gil lam & Morton, Proc. Roy. Soc. 124A, 604 (1929)
Loomis & Allen, Phys. Rev. 33, 63ITT1929)
Lux, Ber. 63B, 1156 (1930)
Taylor & Forscey, J, Chem. 3oc. 1930, 2722
Jost, Z. physik. .Chem. 14B, 413TT§31)
Cornog & Karges, J. Am. "Shem. Soc. 54, 1882 (1932)
Anwar-Ullahj J. Chem. Soc. 1932, XlWS
Ruff, etal,, Z, anorg, allgem. Chem. 207, 46, (1932)
Ruff & Braida, ibid 214, 61 (1933); ibid. 214, 91 (1933)
Vesper & Rollefson, J.Am. Chem. Soo. 56, 6^0^(1934)
Miltzer, J, Am. Chem. Soc. 60, 256 d§38)
Fialkov & 'Goldman, J. Gen, "Chem. USSR 11, 910 (1941)
Cornog & Bauer, JtAm. Chem. Soc. 64, 2^£o (1942)
Cornog & Olson, ibid. 62, 3328 (1940)
Lebeau, Ann. Chem. Phys*. [8,1 , 9, 241 (1906)
Hanzlik & Tar*. , J. Pharmacol 14, 221 (1919)
BirK, Z. angew, Chem. 41, 751 TT928)
Ruff & Krug, , Z anorg. allgen. Chem. 190, 270 (1930)
Truesdale & Beyer, J. Am. Chem. Soc. 53, 164 (1931)
Ruff, etal, Z. anorg, allgem. Shem. 2§S, 59 (1932)
Forbes & Faull, J. Am. Chem. Soc. 557T820 (1933)
Sidgewick, J. Chem. Soc. 125, 2672"Tl924)
Ruff & lienzel, Z. anorg. allgem. Chem. 202, 49 (1931)
Ruff & Braida, Z. angew chem. 47, 480 (T§34)
Ruff & Braida, Z. anorg. allgem. Chem. 220, 43 (1934)
Simons, Bond & McArthur, J. Am. Chem. Soc. 62, 3477 (1940)
Ruff & Kelo, Z. anorg. allgem. Chem. 201, 245 (1931)
Ruff & Keim, ibid 193, 176 (1930)
Audubert & Ralea, Sompt. rend. 208, 983 (1939)
Hantzsch, Ber. 33, 524 (1900)
Cornog, etal, J. Am. Chem. Soc. 60, 429 (1938)
Kaufmann, Oel, Kohle, ErdOel & Teer 14, 199 (1938)
Baroni, Atti acad Lin cei 23. 871 (T§36)
Kaufmann:, Ber. 60B, 58 (1927)
Lecher & Joseph7~"5er. 59B, 2603 (1926)
Kaufmann, Ber. 57B, 973~Tl924)
Ott & V/eisenburger, Ber, 70B, 1829 (1937)
Hart, J. Am, Chen, Soc. 50, 1922 (1928)
Birckenback & Linhard, Ber, 64B, 961 (1931)
Birckenback & Linhard, Ber. 6'3B, 2528 (1930)
Birckenback & Linhard, Ber. B3B,, 2544 (1930)
Birckenback & Linhard, Ber, 62B, 2261 (1929)
Waldon and Audrieth, Chem. RevV 5, 339 (1928)
Spencer, , J. Chem. Soc. 127, 216 (1925)
Perret & Perrot, Bull. Soc Chim. 7, 743 (1940)
Slotta, Ber. 673, 1028 (1934)
Oberhauser a Scnornuller, Ber, 62B, 1436 (1929)
Oberhauaer, Ber. 605, j.434 (1927T*"
Kle a?. e-np, & Wagner, Z. anorg. allgen. Chem, 2oo, 427 (1938)
Zappi, Bull Soc. Chim 47, 453 (1930)
oernagj,otto, Giom. Cniu. ind. apolicata , 3, 153 (1921)
'! ".^uin & Simon, lomrt, rendt 169, 474 (1919)
Ccrmaati, Anal e a aroc quim. argentina 27, 45 (1939)
?.appi & Labriola, Lull Soc. ' Chim. 5 [5] ,~27(1938)
".api, Analea avsoc, uim. argentina 21, 37 (1933)
"looney & Reid, J. Chen. Soc, 1933, 1518
CcssLett, Z. riiorg. aij.gem. Chem, 201, 75 (1931)
^'berberger, inorganic .Seminar, November 6, 1945
'i\fer Cc Wiig, J. Am, Cher, Soc. 67, 1441 (1945)
, . — ■ '•.. ft* *~
)
<•*■ ... r
.Or.- ,
- .•?:
S4 JJ
• ••■•.■•//■«.•>
l i.
.< v: ;
4»
•x±..-
" •:
«r '■ „ ..
T>-~'*r«
V- • ■■ •*■ .»
• •• > * • •
.".
- 39 -
SUPERCONDUCTIVITY
Carlyle E. Shoemaker - November 26, 1946
I. Discovery
As each new low temperature was reached, one of the easiest
and first measurements to be made was the resistance of various
metals. Kammerlingh-Onnes discovered superconductivity or the
phenomena of no resistance by measuring the resistance of mercury
at the temperature of liquid helium. The temperature at which
the metal loses its resistance is defined as the transition
temperature.
II. Super conducting Elements
A. Location in Periodic Table
Al
1.14°
Ti V Zn Ga
1.81° 4.3 0.79° 1,07°
Zr Cb Cd In Sn (white)
0.7° 9.220 0.54° 3.370 3.69
La Hf Ta Hg Tl Pb
4.710 0.35° 4.38° 4.120 2.38° 7.26
Th
1.3-1.40
B. Conclusions
1. All superconducting elements have 2-5 electrons in
the outer shell.
2. Mo superconductors have been found among monovalent
metals, transition metals of Group VIII {-sjwgpti La)
or the rare earth metalsle*--^ t-*0
3. Atomic volumes of superconducting elements lie in
a close range.
4. Nearly all types of crystal symmetry are found.
III. Alloys and Compounds
In addition to the above elements, various alloys and
compounds of other elements are superconducting. A few
examples are:
Alloys: AupBi 1.8°
Carbides: fioC 7. 70, M00C 2.4°, WC 2.8, WpC 2.05°
Sulfides: CuS 1.5°
Nitrides: Bi3N 3.6°
Alloys and compounds of superconducting elements are also
known. fcn general an alloy containing a superconducting
element has a lower transition temperature than the super-
conducting component. Eutectic alloys of Tl, Pb, Sn with
elements in VB have transition temperatures higher than those
of the constituents. X ray examination of Sn-Tl alloys
indicates that the lattice dimensions are a maximum at the
eutectic composition and the transition temperature is at
a minimum.
IV. Factors affecting the transition temperature.
A. A large current will cause a superconductor to resume
its normal properties. This is thought to be due to the
magnetic field which accompanies the current.
B. A magnetic field restores a superconductor to its
original state. The field necessary increases with de-
}& '.^"I'.'S^V
'.' iJI.
f t .'? '.
:.; a- , :>?;• rc
;..•;'
-)0 x~ *i J*tf* ;j.:i) 8fiw r •
,..f
Ls^r>^-'
. . i l j> •*• 2. .
ft C "•
" .4
J . •
rtrfi"
- 1
•,',■ ? ft ■■
I": >/.
:'-] ..:;.'
-■ .. .■ ■
V " * . ' • ' ■'■■ ' - '■ i ■
■ ■ ■
i
.
~ 40 -
creasing temper-, ture (below transition temperature). Meissner
and Ochsenfeld found that a residual magnetic field could be
"frozen" in a hollow superconductor. They also concluded
that no residual magnetic field could exist in a pure super-
conductor though this is not true for an alloy or an impure
element.
C. The shape and stresses cause slight changes in the
transition temperature.
V. Possible changes in structure aceompaning the transition.
A. X ray diffraction patterns of lead are unable to detect
any changes in the structure.
E. Discontinuous changes are observed in the specific heats
of tin and thallium.
C. Thcrmodynomically , a latent heat should be observed but
this point is controversial.
D. Thermal conductivity shows a change which is not general.
E. There is no theromolectric effect between two metals
when both are superconductors. Effects decrease until they
are zero at the transition temperature (within experimental
measurements) . There is a thermoelectric effect between a
superconductor and a nonsuperconductor of the same metal when
one is kept in the normal state by a magnetic field.
F. Mo changes observed in the photoelectric effect, in
the absorbtion of P; particles or slow electrons, no appreciable
change in the reflectivity for visible light, or in the air-
sorotion of long infra red radiation; experiments are limited
however,
G-. Several instances of a time lag at the transition
temperature have been reported. This may indicate that the
superconducting phase is different from the normal phase a_nd
that growth started from nuclei at the transition temperature.
VI. Conclusions
It is thought that changes at the transition temperature
affect only the conduction electrons, for the properties which
are significantly different in the superconducting and the
normal states ^11 depend on these electrons.
Bibliography
1. Burton, E. F. , Smith, H. Grayson, Wilhelm, J. 0.
"Phenomena at the Temperature of Liquid Helium'1 Remhold
Pub. Cora. (1940)
2. Koch, K. H. , Kolloid Z. 105, 89-97 (1943).
3. Koch, K. ::. , Z. Physik. 120, 86-102 (1942).
4. Andronikashvili. E. L. , Compt. rend. acad. sci. U.R. 3.3.
31, 541-2 (1941).
5. Alekseevskii, N., J. Phys. (U.S.3.R.) 9, 217-21 (1945).
6. Sharvin, J. Phys (USSR) 9, 350-1 (1945J.
7. Lazare?, B. , G-alkin, A., J. Exptl. Theoret. Phys. 14,
474-80 (1944).
8. Lazarev, B. , Kan, L. , J. Phys. (U. 3.S.R.) 8, 361-70 (1944).
9. London, F. , Nature 137, 991 (1936).
: >
I X
♦ ■? 1
-41-
THfi SILICON OXYKALIDES
Roy E. Dial November 26, 1946
Introduction
Frie
(hexachlo
MA1SI308,
pared a s
chlorine
tionable
by Rheinb
the oxyha
and Wisfi
del and Ladenberg (l), in 1868, first prepared Si?OCl6
rodisiloxane ) by passing SiCl4 over white hot feldspar,
in a porcelain tube. Troost and H&utetoille (2) pre-
eries of oxy chlorides in 1876 by passing a. mixture of
and oxygen over heated silicon. The results are oues-
except for Si20Cl6 and Si^O^Clg which were confirmed
oldt and Ttfisfield (o) in 1935. The investigation of
lides aTjoarently lav dormant from 1868 until Pheinboldt
eld revived it.
Oxy iodides
No evidence of formation of oxyiodides was found.
Oxy bromides
Rheinboldt and Wis field (o) determined the optimum reaction
temperature for the reaction of oxygen on SiBr4 (to form oxy-
bromides) to be between 670~695°C. "Higher temperatures than
395° result in the formation of SiC2. Si203rs and Si404Br8 were
prepared,
Schumb and Klein (5) prepared a series of oxybroinides as
follows :
A. Dry air was bubbled through a trap of bromine and this
..cture passed over silicon (97.5$! pure) which was contained ir.
a "cube in a furnace at 700°.
Oxygen was passed ever SiBr4 at 670 - 695° „
i
-4
n
r
t
14
I
IS a.
°ro duces Yo Products'
in A m 3 M.P.
SiE03rd V0.5
Vo023^ 49,4
O . . /,. L 4 *3 1 i
■J A... \J 3 0.0} 0
I
3-1 sC i :°, r
n
y r c
3.P
iOther Fror 5C
14.4
2^.9°
29.6
17,5°
50.4
123°
1C.4
■
-91°
9.6
-32*
•5.3
^-78°
118°(l5n.m. )
159° ( 12m. m. )
155° (7a.m. )
122°«.bm.ni.)
150'- (<.5m.m.)
160-180°
(<.5m.m. )
Colorless lie
11 cyrsts4
Colorless 15 q.
" cyrsts.
Colorless lie
white solid
Colorlers lie
lassy so lie
Colorless i*o.
glassy s:>:.id
Colorlers
heavy oil
glassy solid
!,;'•
y ' '.'
» <■
-42.
Oxyohloricl.es
Schumb and Holloway (4) prepared a series Of oxych
Eissing a mixture of two volumes of chlorine and one
of oxygen over silicon (98$ pure) heated to a red hea
pyrox tube, slanted so that the tube could be moved as
reaction proceeded along the tube. The mixtures were f
ted in a Fodbielniak type distillation column.
The compounds obtained all had the following prope
increased viscosity with increased complexity* miscible
CC14, C32, CKCI3 or SiCl4; incombustible; they hydrolyze
moist air, the lower ones more readily*
lorides
volume
t in a
the
raetiona.
rtios:
with
in
ii.r
3, Pi
Other Fro 'OS,
- — 1
SiCl4
Si2OCl6
Si 3C3 CIq
Si404Cl8
Si403CllO
Si504Cl12
Sis0.c5L/ll4
3i706Clls
-70
-28.1
-70
77
57
137
Colorless liquid
Colorless, oily liauid
76(15m.m. ) Colorless, oily liauid
9l(l5mim; )
109-110 (")
130-131 (" )
153-141 (")
145-147 ("")
Colorless, crvst solid
Colorless , oily liauid
Colorless, oily liauid
Colorless, oily liauid
Colorless, oily liauid
Schumb (5) shows that SiCl4 (diluted with anhydrous ether)
can be hydrolyzed by a moist organic solvent (like ether) to
form appreciable amounts of oxy chlorides.
Latimer and Hildebrand (3) give the following reactions:
2SiCl4 + 2S03 - Si20Cl6 + S305C13
SiCl4 + 3S03
Si02 + 2Sa0sCl8
Oxyfluo rides
^ooth and Ost
SbF3, using up to
low pressure. Oxy
obtained. The mix
then distilled in
all of the silicon
led at atmospheric
to obtain a distil
by a Uicromax reco
distilled several
en (7) fluorinated 3i20Cl6 with an excess of
15$ SbF5 as catalyst, at room temperature and
fluorides and a large amount of SiF4 were
ture was sublimed from one ampule to another,
a low temperature distilling column to remove
fluoride; The rest of the liauid was distil-
pressure to separate it into fractions and
lation curve, which was automatically recorded
rding potentiometer. Each fraction was then
times at pressures between 100 mm, and 1 atm.
-..) .i
< ',. '
' ',
-45-
■ ■"
Si2OF3Cl3
in I
Si20F4Cl2
Si20F6
B.P., °C
42,9
16.8
-tOg O
M.P., °C
-100 .0+. 05
-60.0+.05
-47. 8*. 05
Lia. range, • r!
145
76,8
25.5
■Liq. density
1.467
1.4,32
1.553
Hoi. wt., obsd.
256
252
184c5
Mol, wt., calcd.
255
219
186.0
^Hvap«> oal. , calcd.
7500
6770
5150
Trouton const,
25.1
dO# O
20.6
3i20ClF5 and Si302F8 were also believed to have been ob-
tained. The presence of SiF4 is believed to be clue to the
hydrolysis of Si20Cl6.
The general properties of these compounds are as follows:
they hydrolyze in water or alkaline solutions; their odors are
similar to that of SiF4; they do not attack mercury, copper or
nichrome at ordinary temperatures; they are clear liquids
white solids; and the liquidus ranges for the chlorofluorides
are greater than for the fluorides*
Since F3SiOSiF3 is an anolog of ethers, it might be
expected to have the properties of an ether and to coordinate
with BF3, but the analogy is only formal.
Zachariassen (11) determined the structure of titanite,
CaTiSi05. The 22 oxygen atoms of the unit cells are in three
different kinds of positions (Oj, Ott, nn& Ottt), where 0T is
not connected to any Si04 group. Zachariassen and Strunz pre-
dicted that water (OH) and fluorine play a noticeable role in
the lattice, and that they are substituted for 0T®
Sahama (12) determined the fluorine content of titanites
from six different localities. The fluorine is probably bound
as CaF3, because no fluorine is given off when the sample is
heated with CaF2 and quartz. He investigated titanite under
the Tic-u scope, and could find no fluorite, CaF2, even though
:.:n>- sample was rich in fluorine. Therefore, he explained
fluorine as oeing in the titanite structure itself.
Machin and Vaneoek (15) showed that additions of.smal]
•Kiounts (1-4$ of fluorspar is ^rery effective in reducing file
diameters of mineral wool produced from melts of HgO, CaO.
: •. a03 and 3i02o Mechanism of the action of fluorspar in
i.jwering the "iscosity of molten slags is explained on the
work theory of Zachariassen.
the
n 3"o-
■ * '* I • !*■».,<' »"»<,-..■ ■ ■ • -
-»■*- ■ ■■ -,%T<
i '■ r"' J h -« ". \j , "I „
,'; '' !
r f ••■
- • ?
> »■ • K VJ .J f
«'^'
'J1''?
»*'»fj
*. i
X a •
1.-.: '
.. <•
■ ' . .:
■- *
_44-
113 soellaneous,
isolation of higher members is difficult due to the 3ma3 L
ru.:.:r, .ties obtained,, the difference between the boiling points
of u./'-cent members and the percentage difference in c'cimoCsi-
on becoming smaller, and viscosity and decomposition on
Soillation becoming greater.
Compounds of the form SiOXs have not been isolated ann
probably do not exist, because the Si=0 link polymerizes
spontaneously to form the Si-O-Si linkage.
The Si-O-Si bond is the only stable type of bond formed
by the loss of water from the poly hydroxy compounds,,
In general, the insertion of pn oxygen atom between two
silicon atoms modifies the volatility to only a slight extent.,
Pauling says that the Si-Cl bond is partially double bond
in character (about 50$)', and that the Si-F bond is partially
triple bond in character.
References
1. Friedel and Ladenberg, Conrot. Rend, 66, 539 (1853).
2. Troost and Hautef euille, ~nnt Chim. Phys. 5j Zj 452 (1876).
3. Rheinboldt and Wisfield, Ann. 517, 197 (1935).
4. Schumb and Holloway, J. Am, Chem. Soce 63, 2753 (1941 ).
53 Schumb and Klein, J. Am. Chem. Soce 59, 261 (1937).
6. Schumb, Chem. Rev. 51, 537 (1942).
7. Booth and Osten, J. Am. Chem. Soc* 67, 1092 (1945 ).
8. Latimer and Hildebrand, "Reference Book of Inorganic Chemist r;
Chap, XIV Macmillan and Co., New York (1940).
9. hauling, "Nature of the Chemical ?ond"s pp. 53, 228-235
Cornell Univ* Press, Ithaca (1945).
10. ?h.D, Thesis, James Hartt, Western Reserve University, (1945)
11. Zachariassen, Zeit. Krist. , Abt.A, Bdtf 73, 7 (1930).
12. Bahama, "Bulletin de la Commission geologinue de Finlande"
No. 158, pp. 88-120, (1940).
13. Ma chin end Vanecek, Illinois State G-eol, Survey, Rept,
Investigations No . 68 , 15 pp. (1940),
14. Origorev and Iskyul, lull. acad. sci U.R, S. S„ Classe,
scife math. nat. , Ser. geol. 1937, 77-106 . C.A. 33, 3726
(1939).
15. G-rigorev, Mfem. soc, russe mineral 66, 118-23 (1937)
C.A. 33. 37269 (1939),
i" Oj ,■•. ■
t..\.
.■ )
I )
,f . . ..-..■,■«'." ; >..
t- - - l
,4- - i * <
— 45 ~»
P> EPARATION OF SOLID ELEMENTS IN A STATE OF PURITY
December 3, 194.6 Karl LL Beck
Introduction
During the last fifteen or twenty years considerable progress
has-been made in methods of obtaining solid elements in a high
state of purity. Most of these processes have been designed°for
use on a laboratory scale so that purity of product was the prime
Consideration rather than exoense and yield. These developments
have made possible many refinements, corrections, and additions
to studies of the properties of the elements. The high decree of
purity has been described by such terms as "suoer-nurity metals"
and is usually -ell over 99,2. The determination of purity is by'
difierence. The impurities are determined spectroscooically and
subtracted, so the impurities oresent must be known.
The most concise manner of summarizing this work is by con-
sider? ting methods which have been used with aoorooriate exa-oles.
More detailed data are readily available in a book^ by van Arkel
(1) in which each element is considered.
Thermal decomposition of compounds
This has not been one of the most applicable methods in the
past, Dut it is becoming more important because of its simplicity
and small requirements on apparatus.
1. Na, K, Rb, and Cs (4) liD.ve been orepared by decomposition
of their azides in high vacuum at 275-3950. The metals can be
further purified by distillation in the same apparatus, and are
obtained spectroscooically pure and gas-free-
2. Pt, Pd, and Ir of about 99.995$ purity can be obtained by
decomposition of their ammonium chloro-metallate salts, (MHa)q
MClg; Rh from (MK4)3Rh(N02) 6, Ru from RuNOCl^.NH^Cl, Os from
H20SC15 to). " 0 4*
3* Ductile Ta can be prepared by heating rods of TaOp to a
high temperature with electric current (6).
4. Spectroscopically pure Ge can be prepared by decomposition
of Ge3*»4 a* 1000°. The nitride is obtained from GeCl4 plus NH,
to get the imide, which with nitrogen at 350° forms the nitride??).
5. Pure graphite crystals 10 x 30 x 30 ft, can be prepared by
•heating sucrose in a stream of hydrogen at 1000-1100° for 10 hours.
'"ork is now being done on the decomposition of organometallic
compounds as a possible source of many metals.
riot -wire methods
Perhaps the most outstanding modern development in this
field of pure elements is the invention of the hot-wire tech-
nique, it was used successfully in 1925 by van Arkel and de
3oer, and has been expanded rapidly since by these two men and
3everal other investigators.
In this method a volatile compound is decomposed or re-
luced at the surface of a wire which is heated by an electric
current. The wire is preferably made of the element being de-
"r'i ' :
: : . ■ .
:t ( ,:
-48-
leads connected to the wire, a connection to the vacuum ev-teS
vol,'tiS0;;rod^t^8)?m?OUnd t0 bS *•"*»-. «- a trafloT
1. Cu, Ti, Zr, Hf, Th, V, Cr, Mo, W, Re, Fe, end Ni can be
5T?»tr?pnJ ^composition of their halides at 600-2000°. These
it wh'ch EL ^r61^ g^tioularUy well to "continuous reaction",
in whicn one liberated halogen reacts with a supply of the metal
m oowderod form prepared fairly pure by another metnod* * '
mlJ' Bc',^ V> a,nd B h"ve been prepared by reduction of
volatile nalides by hydrogen.
3r c»?wi Sidf1!tt.Can be 'or!rj2red °y decomposition of halides,
)i caroonyi naliae in the case of Pt.
This method has its greatest value in preparing hish melt-
ing elements winch are difficult to obtain oure by other m"'fn^
such *s Ti (rhir-M-?^ 7v» u* m -.. nx. m „■ ie u/_oLner metnous,
There are
in ampere to a final several hundred amperes. Aooaratus
iimple yields are often low, and only small quant of the
fed ,Ta* SFS^t* a ^^ S° tMS ^^^ ln ™* «»"
eduction methods
nP n?0^^!01? °; °Xi?eS rnd halides t0 obtain pure elements is
ne of tne oldest methods, but there have been some interesting
rogress in techniques and some novel reducing agents.
1. e, Co, and Ni can be prepared by reduction of their
tides with hydrogen. Ferric oxide is reduced this way Corn-
wall y bo produce Fe which is 99.994^ pure (9), MoO? is re-
uced oy nydrogen at 900-1200° to pure Mo. Ammonium per-rhenate
s readily reduced to metallic Re, and 99.85^ Pure V can be made
Y reduction of VC13 with hydrogen. aae
2. Chromic oxide can be reduced to Cr in two ways (10)
Lth hydrided tantalum at 1000° a good product results. Or'
!#^5oPur? C^ ca? 5? obtained by heating the oxide with CaHo
t 470°. In the latter case the Ca liberated reacts with the
>ter produced, so the reduction is complete inabout 30 miziutes,
_ 3. Th, Be, V, and B can be prepared by reducing their
tides with calcium hydride.
| 4. Cr, Th, U, and V can be prepared jy reduction of their
Idea or chlorides with metallic calcium. Pure ductile Ti and
can oe prepared by reduction of their dioxides with Ca in a
*ed oath of CaCl2-BaCl2. Rb and Cs halides can be reduced with
by using special techniques, but the reaction is not very use-
5. Zr has a high affinity for oxygen and the oxide formed
very refractory, so Zr is a good, although expensive, reduc-
agent. Rb, K, Cs, and Li can be obtained by reduction of
eir chrornates or sulfates with zirconium (25), and the products
r
- 47 -
pre very pure. The reductions go at aoderate te noerstures wiv-
ing no volatile products. • "" °
Elec^r-l_mm_c_;ethods
trolv^yn; ^ lllC ?^me?ta can bs conveniently prepared by elec-
trolyses 01 tneir salts In aqueous or fused salt solutions.
1. C-a is best prepared by electrolysis of G-a(CH)^ in NaOH
solution using Pt electrodes (11). The temperature is kept "
ibove 300 so the liquid ar formed CftR be coilected JiVcSp be-
low the cathode.
2. Pure Th can be prepared by electrolysis of an aoueous
solution of thorium sulphamate.
s of
■ 3- d» :^> fa, and Co can all be prepared by electrolysis
lelts containing complex fluorides of the metals. U obtained
rom^JFg is deposited on a Mo cathode, and is 99.88/6 oure. t,
>otaming Ta pnd Cb from &2MF7 some pentoxide of the metnl
■posited is added to overcome the anode effect.
4. Cr, La, Nd, Pr, 3m, and Gd have been ore oared by el°c-
folysis of their fused chlorides (13) in ourities of 94-9si
rcfn 'd which is obtained 99^ cure. Tnis coupled with re-
liction oi oxides ay alkali or elmalme earth metals and with
fcalgam formation has permitted isolation of most of the rare
j^rtn elements in a fairly pure state.
I 5. So hnn been prepared oy electrolysis of a fused KCl-Li C1-
'CC1„ mix cure using a tungsten cathode (14).
•?o-r-- ticn of similar elements by chemical means
Certain closely similar elements can best be separated by
nemical metnods to obtain one or more of them in a pure state.
1. Sc can best be separated from the rare earths and thorium
I Qa-:;r^0n °? rn "Cid sclution of the mixture containing"
I^SCN with ether. A large quantity of 75-80;* '6c2Q"> ore after,
[icn treatment had 90fo of the 3c extracted in soectroscooically
ure ic
2. Eu, 5m, and Yt c.^n be separated from the othe^ rare
artns by shai'ing a solution of the acetates with sodium amalgam
uj, the Eu, on, and Yt being concentrated in the amalgam layer
i Has oeen removed from Nd-Sm and Sm-Gd mixtures this ^ay and
D and Eu can successfully be removed from a Sm-Eu-Gd mixture
/ sociium amalgam. There is >lso an electrolytic method of
formation (16, 25).
nvestigations of separating rare earths bv means of
:. Zr and Hf nre still best separated by fractionation.
tcrr Purification by recrystallization of pnosohates, ferrocy-
ides, or oxysulfates followed by a couole of recrystallizatiom
the oxychloride, Zr salts which are soectroscooically free of
have been obtained.
- 48 -
Purification methods
jiany metals can be prepared in "commercially pure" states
methods? ^^^ °Urified °n a laboratory scale by" one ofsevlral
t ^h ?y dlstillation— Many solid elements can be purified bv
distillation in high vacuum. Cr, Al, Si, Be, Fe, Cu, Ni Sr and
Pb nave been purified thus (19), the'Be being only 99.69^ pSre
but tne otnors in higher purity. Be which is 99.95.^ cure can be
•btained by soecial distillation methods at 19000 from a sinte^ec
5e0 crucible Zn which has less than 0.0001^" total" impurities
is obtained by distillation purification (20). Te containing
a
punrication (2 :>nt,iining"
Se, Cu, i-e, and some oxide is purified by distillation in vacuum.
2. 3y sinterin-; or fusion in vacuum— Sintering and vacuum
^ 4rLenTC^lly ^?efUl f°r removi^ volatile impurities
from metals of nigh melting point. Ductile Ta and Cb" can be
intTb'r,^,3 ^ i21)> 3ither by -^"sing th* Powdered metal
into bars and sintering in vacuo just below the melting ooint
or oy mailing the hydride and decomposing it at 1500°. Catnodic
ILnl 3urif?-ea °y annealing in H2 at 10500 to remove C and 3, and
Unending ln vacuum in magnesia crucibles to get 99.94,:* pure Ni.
3. 3y electrolytic methods— Cu which is 99.999,-2 cure is
?u30 XbT?hC°m^r^ally Pre C°PPer by e^otrolysis inV HgSoJf
tin! u'o ?ir-fowinf *° remove 3, and finally electrolysis
ping CuU03)2 as an electrolyte. Indium which is 99.999 6 cure
I prepared from commerically pure indium by electrolysis us in?
iS? ^ifhv^f11?1^6-- Zn' ?b' ^ and AS «e prepared espec-
ally 'ell by 3lectrolysis.
Lpi^i S?^ m2th°d?:r Certain difficult elements require
fecial methods oi purification. Iodine is ourified of other
ve? -tS4n700Ogr-? ^fV* *ublirtion in S CUrrent of °x^
ver .t at ^00 (22), The Fe and silica are removed from Si by
fecial^ acid treatment. American sulfur is freed of organic
Rter oy a metnod using HgO and redistillation.
:r^r ' ''^QIL^LJLlQJ^nM^^LJ^ec^l allotrooic forms
it is interesting to note that of the" twelve~diamonds "ore-
red oy Hannay (23) in 1879-1880 from oa raff in, bone-oil and
■onls?' eleven hevc been sh0'vn °y ^ray analysis to be true dir
Recently black phosphorus was prepared from the white
te?Der-taPPliC tl0n °f pressure of lc°,000 kg./sg. cm. at
.lotrone
JME,<
-49-*
References
U939)Van Arke1, Heine Wet*lle Herausgegeben, Springer, Berlin
Wright et al, Proc Araer, Soc Test. Hat., 37 I, 531, 538 (193?)
welch, Ann, Reports on Frogress of Chem. , 40~8 (1943)
buhrmann and Clusius, Z. anorg. Chem., 1527~52, (1936)
En 76 (>602hFiSt,)and Swnnger' Tr'?ns-^e^ Inst. Min. Met.
C. W. von Bolton, Z. Electrochem, , 11, 45 (1905)
Schwars, Die Chemie, 55, 45 (1942) —
Laubengayer, et al , J. Am. Chem. Soc, 65, 1924 (1943)
Adcocit, J, Soc. Chem, Ind. ( Transactions! , 59, 28, (1940)
Alexander, Met. and Alloys, 5, 37 (1934) T
Sebba and Pugh, Ja Chem, Soc,, 1937, 1371
2. Lloyd and Pugh, ibid, 1943. 8 ~~ —
3. Trombe, Ann. Chin., 6, 349 (1936)
4. Fischer, et al, Z. anorg. Chem,, 231, 54 (1937)
5. Marsh, J4 Chem. Soc, 1942, 398,523"
6. McCoy and Hammond, J Am. Chem. Soc, 64, 1009 (1942)
\>ill?rd and Freund, ind, Eng. Chem. (Anal.), 18, 195 (1946)
Russell and r-earce J. Am. Chem, Soc, 65, 1924 (1943)
-roll Metal Ind. (London), 47, 3, 29, T03, 155 (1935)
^llT'l^T^U^ ***** ^^^ Hln* ***' Eng" InSt- MetalS
SmithelTsT Metal Ind. (London), 38, 336 (1931)
Baxter and Lundstedt, J. Am. CheraT Soc, 62, 1829 (1940)
Hannay, Proc, Roy, Soc (London), A30, 1887'450 (1880)
Suntiier, et al, Z. anorg, Chem.. 250, 373, (1943)
de Boer, Broos, Emmers, ibid, 1917T13 (1930)
Inorganic Syntheses, I, page 15, McGraw-Hill, New York, (1939)
JuKKola, -udrieth and H0okins ' K±*°^}
■•' .'*
.
i
i 'l ' "
-50-
STRUCTUHES
0. F. Hill
PHOSPHATES
December 3, 1946
Introduction. The chemistry of the phosphoric acids end their
salts is very complex &nd., even now, not very well understood*
The evident confusion in the literature has reached a. stage where
a thorough understanding of the structure of the phosphates is
most desirable and where a logical approach and a new working
hypothesis are necessary* It has only been during the last
two decades that such phosphate structure studies have been under-
taken and only in the last few years that any extensive studies
have been reported; Though advances in a practical and a
theoretical way have been made, there is still much work to be
done to bring order into this chaotic fields
Phosphates cm be grouped into three major classes: ortho-
phosphates, polyphosphates, and metaphosphates. These have
been listed in Table 1. Phosphates of composition varying all
the way from phosphorous (V) oxide to the orthophosphates have
been reported, though many of these are subject to question*
Indeed some of higher phosphorous content than required for the
met phosphates have been reported, as for example? Ca0«2P»0s
and 2CaO*3F205 the existence of which has been established beyond
doubt (1).
TABLE 1
The Phosphates
Class of
Phosphates
[Formula of
the acid
nemarks
0 r thopho spha t e s
iA3- u4
Kost stable of all phosphates*
Structure fairly well established.
Hay be prepared by dissolving
P30* in water,.
Pyrophosphates
K4P3O7
Undergo slow hydrolysis to ortho-
phosphates,, Structure well
established^ The sodium salt
may be prepared by igniting
Na3H?04.
^polyphosphates] H5P30lo
( Tri oho sphat e s )
Undergo slow hydrolysis to ortho-
phosphates. Structure fairly
well established, ^he sodium
salt may be prepared by fusing
mixtures of a) NaH2F04 and
Na3H?04 or b)(Na?03)x and
Na4P307.
Tetrapho sphat es
T-J "o n
Existence ouestionable
Iletaphosphates
(HP03)x
Undergo hydrolysis to ortho-
phosphates with pyrophosphates
as intermediate products. Struc-
ture nuite complex and. not well
understood. See Table 2 for
added information
♦'#■■
4
-51-
Structures,
Phosphorous (V) Oxide, P40lo. ?40lo is the product obtained
upon complete oxidation of phosphorous. Inconsistent data were
obtained in the early studies of the vapor pressure of ?40lO (2).
Subsequent studies (3,4,5,6) led to the conclusion that at least
two crystalline modifications exist, as well as a glass. Later
experimenters (7) showed that actually there are three distinct
crystalline modifications which differ, not only in their physical
properties, but also in their chemical properties* These three
forms ore the hexagonal, m.p. 4 '■' 2±_ 6°C. ;' ort ho rhombic, m.p.
558^6° C.; and tetragonal (? ) , m.p. 580+ 5° C.
The hexagonal form is metastable with respect to both the ortho-
rhombic and the tetragonal (?) forms and is the form widely known
to chemists. It reacts vigorously with water. The ortho rhombic
form is metastable with respect to the tetragonal (?) form and is
surprisingly resistant to water, a suspension dissolving only
slowly, even at stean-bath temperatures. mhe tetragonal (?)
form is the stable form and reacts with water ouickly with the
liberation of much heat to be converted into a stiff gel which
shortly liauefies to a limpid liquid. This difference in reactiv-
ity is undoubtedly due to differences in structure.
The crystals of the hexagonal form (8) consist of agglomerates
of ?40-^ molecules whose structure is the same as that of the
F40xo vapor phase as determined by Hampson and Stosick (9)
from electron diffraction data. The four phosphorous atoms are
bound together through oxygen atom linkages to form a regular
tetrahedron. Each phosphorous atom is then tetrahedrally
surrounded by four oxygen atoms.
_h~ orthohombic form is vn infinite sheet polymer containing
interlocking rings (10). Crystal structure determinations have
not been made on the tetragonal (?) form, though indications are
that it is an infinite polymer of either a three dimensional type
or a sheet type. The tetragonal symmetry makes the sheet type
improbable.
C r t h o ph o spha t e s - It is pretty well established that the ortho-
pia a pna- 1 e s t rue cure consists of a phosphorous atom tetrahedrally
surrounded by four oxygen atoms. (11,12,13). The crystal struc-
tures are such that the coordination number of the cations, as
well as that of the phosphorous, is satisfied by bonds to oxygen*
For example, the crystal structure of KH3r04(l4,15) may be regardet
as consisting of H02,F04, end K0a groups interconnected so as to
satisfy the valency relations*
?y ropho sphat es. The pyrophosphate structure may be regarded as
consisting of two P04 tetrahedra sharing an ox^^gen atom at one
corner as in the Si307 group (11,12,16). The structure of ZrP20T
consists of four molecules per unit cell (11,18)
Tripolyphosphates. The tripolyphosphate structure may be consid-
ered as an extension of the pyrophosphate structure, three P04
tetrahedra joined through corners into a chain (13).
?ige 1
Q Q O O Q
P04 3 P2C7 4 ?a0lo"*5
1 ■ •••
-52-
Metaphosphates. Less is known about the structures of the meta-
than any of the others. It is highly probable that
monomeric form. However, oolyraers ranging from dimers
php spha t e s
there is no
to hexamers
Many of the
ful. The t
and hexamer
heating NaH
of preparat
are listed
and even higher have been reported (13,19^20).
se seem fairly certain and others are somewhat doubt-
rimer is established with certainty. A dimer, tetramer,
probably exide a A higher oolymer is obtained by
rr04 below fusion for a long period of time. Methods
ion and properties of the different metaphosphates
in Table 2.
TABLE 2(20)
The Sodium lie tapho spha tea
Name
Probable
Folvmer
Methods of i- reparation Properties
Pascal' s Salt
Sodium dimeta-
phosphate
di
(CgKsFOaJx + C3HB0Na
in ether so In
Maddrell » s
Salt
Knorre1 s Salt
cr
Sodium t rime ta-
pho spha te
Sodium tetra-
met a. phosphate
G-raham' s Salt
or
Sodium hexa-
me ta pho spha t e
Y
lurrol's Salt
tri
tetra
1. Heat K3PO4 a short
time at ce« 300°,
neutralize cold soln
2, Heat NK4N03(l pt, ),
NaH3F04(5 pts9 ),and
KHaCKI -ot. ) at 250°
Heat KsH3F04 at 300-
400° for several hrs,
l0Heat "H4N0o(l pt. )
and NaH3P04 (2pts. )
at 300°.
2. Heat NaH2F04 at
500 500° for several
hrs,
3. Heat fused G-raham « s
salt at 300-400° for
several hrs.
T,.Thite deliouescent
solid; sole in
water; ppts.with Ag
Fb++. Cr++:
es albumin,
coa.gula-
Sol. in water but
hydrolyzes rapidly
t o pyropho spha t e ;
opts, with Fb
but does not coagu-
late albumin.
Crystalline, insol.
solid; two crystall-
ine modifications.
White, sol, cryst.
subst., m.o. 62£°;
no ppt- with Ag
or Pb in low cenen
no ppt. with Ca++,
'coagulates albumin.
Heat CuO and H3P04 up White' sol
to 400°. Treat Cu salt pots. Fb++ and
with H8S and neutral-
ize.
subst;
a++ but not Ag+
hexa?
;nexa
NaK3?04, Na3H3F307, or
NaNH4KP04 fused and
auenched.
coagulates a.lbumin,
Hlasily sol. £lass;
ppts
Pb++
wi en Ag p nd
but forms
stable complex ion
with Ca++
Obtained sometimes
on heating NaH2P04
below fusion for long
periods of time. Po-
tassium salt made
readily by heating to
50 ~
above
so no
Insol. in water
but dissolves in
solns of pyro-and
hexame tapho spha t e s
to give highly
viscous solns*
Melts at 809° to
fcive lie. distinct
from C-r.?.hamfs ealt.
The co&led melt is
an insol. glass.
" ' ,-•
J2? SS?t likely structural configurations for th 'metabhosphates
Ul, 22) Pre- given by the structu 1 formulae in Fig/ 2* These
structures are-'' those which best fit the known chemical oroperties
Fig. 2
0.
\
A /O
A>^
0' ^0
dimetaphosphates
(21) ...
0 yO
09 w-
-0-: x0 X0
-P-
i
-o
?
0
Q 0 I
0 O-P-O-P-0
I
0
0 P- O-P-O-P-0
I ob I
hexametapho soha te
(22)
0-F-IO-
I
0
0
0
-0-P-0
0— F— 0 — F— 0
i i
te^rametaphosohate
(25)
- Ql v 0
H5.gher polymers
o :? me t a -oho spha t e s
(23)
holecular weight determinations on the glassy polymers have
indicated values from 10,000 to 20,000, th,e exact' molecular
weight being a function of the length of time of heating and the
temperature of heating (13,23,24)
A1(P03)3 is the only metaphosphata the crystal structure of which
has been determined (26). The unit Sell consists of 15 Al (P03)3
molecules, .It has a tetrametaphosDhate structure, that is,
there are four P04 tetrahecra in a ring. A106 octahedra share
the remaining oxygen atoms of the P04 tetrfihedra.
Theoretical. With the knowledge of the structure of ?40lo and
of the phosphates we are now able to examine the reactions which
occur when the bonds in these structures are broken. A
theoretical treatment should prove to be ver.r illuminating and
helpful in the interpretation of available d^ta.
For example, if a statistical analysis is mad« of the bond
ruptures which may occur when water reacts wi^h F40lO, one may
make some predictions a s to the composition o*' the resulting acid.
Ir is possible to calculate theoretically concentrations of ortho-
phosphoric, pyrophosphoric, tripolyphosphoric, and meta-ohosohoric
acids which might be expected for products of varying plOiolHgO
ratios. This has been done and the data compared' with analytical
results obtained by Bell (27) of the Victor Chemical Works. The
agreement insofar as the more complex acids is concerned is not
good, but it is , certainly in the right order of magnitude for
the orthophosphoric acid, which might be expected to be present
in such equilibrium mixtures. The disagreement which is noted
between calculated and observed components of such Fa0iO:H20
mixtures may not be real in that it is not known how "the 'composi-
tions subjected to analysis were obtained. Whether true equilibr-
ium is attained in any P4010:H20 composition between various com-
ponents has not been established. Furthermore, a statistical
treatment, such as outlined above, assumes eoual bond energies
fldsdo-ia- Til airf* taa sJbios aJJ^.oriqaon'a -r-la nl fcnocJ q-0-3 eiW icrt
.ojjTd" J" on
yld
■
' ■ » '•' - 1
. ;.
BIBLIO&RAPHX
1. Hill, 7. L. , Faust, G. 7. , and Reynolds, D. S. , Am. J. Sci,
242, 457, 542 (1944). *
2. Smits, A. end Rutgers, A. J. f J. Chem. Soc. 125, 9573 (1924)
3. Smits, A. and Dernura, N. W., Z physik. chem.~PQl49, 337 (1930)
4. Smits, A Ketelaer, J. A. A., end Heyering, J. L. , Z. physik,
Chem. (3)41, 87 (1938).
5. Hoeflake, J.M.A. end Schef'er, F.E.C., Rec. trav. chim. 45
191 (1926). —
6- ^m^1^* J-c« am* Nelson, R. A., J. Am. Chem. Soc. 59, 911
v 1937 ).
7. Hill, W. L. , Faust. G. 7. , end Hendricks, S* 3., J. Am. Chem.
Soc. 65, 794 (1943).
8. deDecker, H.C.J, and Me.cC-illavry, C.H., Rec. trav. chim. 60,
153 (19411. —
9. Hampson, a. C. and Stosick, A, J. , J0 Am. Chem. Soc. 60,
1814 (1938). — '
10. deDecker, H.C.J. , Rec. trev. chim. 60, 413 (1941).
11. Pauling, L. , The Nature of the Chemical Bond, Cornell Univers-
ity Press, Ithaca, New York, 1945, p. 249.
12. Wells, A.F., Structural Inorganic Chemistry, Oxford Press,
London, 1945, p. 417.
13. ^uinby, O.T., Chem. Rev. (submitted for publication).
14. Hendricks, S.3. , Am. J. Sci; 241, 269 (1927).
15. West, J., Z. Krist. 74, 30S (T§30).
16. Schweitzer, G. K. , Inorganic Seminar, October 15, 1946.
17. Levi, G, R. end Peyronel, G-. , Z. Krist. 92, 190 (1955).
18. Peyronel, G. , Z. Krist. 94, 311 (1936). ~~*~
19. Kerbe, K. end Jander, G. , Koll. Beihefte 54, 1 (1942).
20. Yost, D.M. and Russell, N. , Jr., Systematic Inorge.nic Chemistry
Prentice-Hall, Inc., New York, 1944, p. 211.
21' ??QaoYell> W-D* and Leutwyler, F. , Helv. Chim. Acta 21, 1450
\ 1938 ) . ~~~~
22. Rudy, H. and Schloesser, H. , 3er. 73, 484 (1940).
23. Samuelson, 0., Svensk Xem. Tid. 56, 343(1944); C.A. 40, 4613 4
(1946).
24. Ifelgren, H. and Lamm, 0., Z. enorg. Chem. 252, 255 (1944).
25. Nylen, P., Z. anorg. e.llgem. chem. 229, 30~TT936).
26. Pauling, L. end Sherman, J., Z. Krist. 96, 48 (1937).
27. 3ell, Victor Chemical Works (unpublished data).
.* » '
.'.-r.
-A. ,'!
J^p—
- 55 -
COIiPLEX FORMATION WITH H:GH MOLECULAR WEIGHT AMINES
Higgins, Morton A; December 10, 1946
I. Introduction
There are many literature references on the general sub-
ject of complex compounds involving amines and metal s.tlts; how-
ever until this year no reports have listed compounds of high
molecular weight aliphatic amines (1). Only within the past
few years have these amines been available, and a study *#s in-
stigated by the Research Laboratory of Armour and Company because
oi the great difference in oroperties between the low and high
molecular weight amines.
II. Preparation
The methods of preparation necessarily differ from those
in use for the preparation of complex compounds containing low
molecular weight amines. Most metal salts are insoluble in
organic solvents, while on the contrary, the high molecular
weight amines are in all cases insoluble in water. Furthermore
the amines are unable to displace water from metal-salt hydrates
and tiie salts employed must therefore be carefully dried before '
use. The preparation is usually carried out by mixing an alco-
holic solution of the metal salt with an alcoholic solution of
the amine. The complex precipitates and is recrystallized,
when this method fails, other procedures such as" heating the
reactants in absence of solvent may be used.
III. Properties
Several high molecular -v eight amine complexes have been
prepared. Variations of the metal have included: copper, silver
zinc, cadmium, and mercury. Variations of the amine^ have in-
cluded: dodecylamine, octadecylamine, and dioctylamme. T||e
complexes are low-melting (750,1550) solids, insoluble in Sold
water. They are decomposed by hot water to yield free amine,
metal oxide or hydroxide, and probably amine hydrochloride and
basic metal salt. Thus about one-half of the amine may be re-
covered by steam distillation from a mixture of water and bis-
(dodecylammino) cupric chloride.
IV. Amine-metal Ratio
Every complex prepared has been found to have an amine-
oetal ratio of 2:1. It is possible with copner salts to obtain
ibstances of a deeper blue color than the 2:1 complexes, but
phese cannot be obtained in the crystalline state. The ex-
planation for the failure of the amines to fill the coordination
sphere probably lies in their great bulk.
In addition to the complex compounds, two double salts
'ere prepared during the course of this study; cupric dodecyl-
Lmmonium chloride and cupric octadecylammonium chloride. They
Resulted when an excess of cupric chloride was added to the
[mine. In this case the blue complex was not formed; rather
ihere precipitated a yellow product with a Cu: Amine: CI ratio of
I 2; 4, which proved to be CUCI2" 2AHC1 (A represents amine). The
alts differed strikingly from the complexes since they melted
- 56 -
above 200° and were soluole in water. The amine: cu ratio in
the salts, as in the complexes, is 2:1, but for a different
reason. The yellow-brown color of anhydrous CuClg, its con-
centrated alcoholic solution, and its hydrochloric acid solution
have been ascribed (2) to the presence of the (CUCI4)- ion»
By analogy the yellow alkylammonium double salts may be con-
sidered to contain this grouping. Thus the 2:1 ratio is
necessitated by the 4-coordination power of copper: (CUCI4) (AH)g.
V, Dissociation 01 Complexes
Broome, Ralston, and Thornton (3) desired to apply the
Method of Continuous Variations as expanded by Vosburgh and
Cooper (4) to the amine complexes to determine whether any
ratios other than 2:1 were to be found. In the course of this
investigation it was found that the complex dissociated to an
extent of about 10 per cent at room temperature in 0,04 molar
chloroform solution. This dissociation prevented the use of
the Method of Continuous Variations. Thus while ratios higher
than 2:1 may exist, the question is still an open one.
References
1. Broome, Ralston, Thornton, J. Am. Chem, 3oc. , 68, 67 (1946).
2. Moeller, J. Phys. Chem. , 48, 111 (1944).
3. Broome, Ralston, Thornton, J. Am. Chem. Soc. , 68, 849 (1946).
4. Vosburgh, Cooper, J. Am. Chem. Soc, 63, 437 (1941).
STABILITY OF CHELATE COMPOUNDS
I. Introduction
Although a great deal of work has been done in the prep-
aration of chelate compounds and upon their structure, no attempt
has been made until recently to determine quantitatively how
structural factors of the organic residue other than simple
geometry influence the stability of chelates. Calvin, along
frith Wilson, Bailes, and Duffield, in a recent series of three
papers (1) (2) (3) has brought to light several factors which
play an important role in the stability of chelate complexes,
II. Factors Influencing Stability
A. Acid Strength of Chelate Group
Experiments involving the equilibrium Cu"*"1" + 2Ke~ ~rzr^
CuKoq have indicated that the acid strength of the chelating
Irganic residue influences the stability of the complex in an
indorse sense. Thus complexes of weakly acidic organic groups
Ire more stable than those of strongly acidic organic groups,
B, Possibility of Enolate Resonance
The chelate ring involving the central metal atom is
thought to exist as a resonance hybrid. If another resonating
structure, such as the benzene ring, be fused to the chelate
ring, the chelate resonance is to a greater or lesser extent
hindered (as in salicylaldehyde, for example). Any interference
with the resonance of the chelate decreases proportionately the
stability of the complex.
- 57 -
C. Joining Together of Chelate G-roups
The joining together of chelate groups exerts a pro-
nounced stabilizing effect on the comolex. Studies involving
oolarograohic reduction have shown that comoounds of the tyoe
.M \ pre more readily reduced than those of the typei .-M \,
The half-wave potential for the first type is about -*0.02v.,
«'hile that of the second type is -0.75 v.
D, Availability of the Coordinating: Electron Pair
A. /0^
An investigation of comoounds of the type'/ . Cu. ) has
OO
A
shown that as constituent A is changed in the order NOg, SO Na,
ohenyl, H, CH3, OH, and OCH3 there is an uniform increase in
the stability. This is just the order of increasing base
strength of the corresponding aniline and the order of avail-
ability of the electron pair on the coordinating nitrogen, -
References
1. Calvin, Wilson, J. Am. Chem. Soc, 67, 2003 (1945).
2. Calvin, Eailes, ibid, 68, ■ 949 (1946*]7
3. Duf field, Calvin, ibid, 68, 557 (1946),
T. M. vial
- 68 *
ALKALINE EARTH AND HEAVY METAL SOAPS
December 17, 1946
Metallic soaps are salts of complex monobasic organic acids,
pne soaps of the alkali metals, except lithium, are water soluble,
Uiile tnose of the alkaline e^rtha and heavy metals are water in-
soluble, but usually soluble in non-polar solvents.
T: organic raw material may be animal or vegetable fats or
che free fatty acids derived therefrom, naothenic acids,
°r 1G- Napthenic acids are found in certain petroleum crudes.
arboxylic acids of vaf; ing molecular weight, usually
a five-membered ring in the carbon chain* Rosin gives
-sin acids and rosin oils, both of which find use in
soaos for special uses.
1 LIS.
inorganic raw materials are salts of the desired' metal.
uch iess variation n properties in th^se than in the
Organic material. The commonly used salts include oxides, hy~
lroxiass' carbonates, acetates, chlorides, sulfates, and nitrates.
aps nay be of oither the precipitated or the fused
e; er, a solution of the sodium so£ d xe allowed to
t.W1^ s solution of appropriate metallic salt. &f (FA) reo-
Btnl fatty acid radios? , the reaction may be represented'
!>S iOlloWS'
2Na(FA) -v CoS04 -,+---> :o(FA)2 r Na2S04
T.;: 3 sodium soap shown ata^e may arise directly from tiie
ysis of fat or oil, or by the neutralization of the free
"atty acid.
ni? SOa^s are P^e ) w L V)y the same type of reaction ch«?m-
y, but the physical tecr.m>.que is quite different. Either an
acid is al?o l to react with an oxide, a hydroxide,
e, or ,- carbonate . heating the two to a relat>.v'elv high
:;;-:u;re in tn^ *Dsenc? of aided water. With free fatty acids
fie -eaction may be repre^frTed'
K(OH)g - 2H(F\) > w!(FA)2 + 2H0H
-t is so chosen that the cecond product of the reaction
this case) will be volatile at the temperature q* the
i^*a c ,; i c n .
'or convenience, the uses to which soaos are ;ut mav be.
ed into three classes— uses depending on trie available petal
, uses eased or th.:.r ability to influence the era -yc cter-
liquids, and -..us based on physical characteristics of
>s0 The largest quantities of soaos are used for ourposes
gti depend on the available metal ©resent. The ^cid anion"
tryes to make tne metal most readily available under the con-
its use. Catalysis requires a high degree of §ub-
-visic: so as to obtain r large surface area. Soaos offer sol-
in organic solvents, jiving almost molecular subdivision.
of the use of soaos as cat lysts to date has been m the
Ijnt and the oetroleum industries. In tne oaint industry me-
■ilic soaps are used to catalyze the oxidation (and poDymeri-
Jtion) of drying oils. In the petroleum industry soaos are
5d as addition agents to lubricating oils. They were once
idered anti-oxiuants, but there are indications that t ^ey
* 39 *p
catalyze the total oxidation of the lubricant to volatile pro-
ducts, leaving the lubricant sludge-free. Some; napthenates
for example, have been shown to act as antioxidants at atmos-*
pheric temperatures and as prooxidants at engine temperatures*
Other uses based on the metal present include fungicides,
ceramic glazes, and analytical agents.
Uses based on ability to influence characteristics of liquids
Include applications as wetting and dispersing agents, detergents
(in nonaqueous solvents, e.g. in the dry cleaning industry),
lirulnif iers, and in greases. The uses based on the physical
ore Gerties of the soap include flatting and anti-cnalking agents
for >aint3. means of applying monomolecular films, special lub*-
llcants, po. cosmetics*
References
I. B. Ellictt, The Alkaline-Earth and Heavy-Metal Soaps, Rein-
iola Publishing Corp., New York, N. Y. , 1946
\, Z, S„ iiavr-Siice, Trans. Faraday Soc. , 34, 660 (1938)
I L, Shipp, Oil Cas J., 34, (44) 56 (1936); J. Inst. Petroleum
Pech. 22. bc?A fi9«55). (Napthenic acids)
I ' G-eorgi) J, Chenu Education 10} 415 (1933) (Rosin acids)
- 60 -
CONTACT CATALYSIS
January 7, 1947 Agnes McDonald
Prior to 1920 many technological processes were based upon
the ability of prepared solid surfaces to induce chemical reac-
tions between -rases. Theoretical knowledge of the processes,
however, was limited almost entirely to the observations made by
Faraday in 1834 (1). Langmuir's concepts of contact catalysis
bad been published, but they attracted very little attention at
firs to These concepts prjoved to be the stimulus for the inves-
iticrs which brought contact catalysis out of the realms of
-.
he development of the theories of contact catalysis can
be o.\ :ded into four phasjes of study (1).
\ L.tngmuir's concepts of unimolecular adsorption and the
kin ;-ic treatment of catalytic reactions:
r.grauir states (2,3,4) that all forces involved in the
of solids and liquids are chemical in nature. Not
orly ical combinations, but the phenomena of condensation,
'■>' Lon, condensation, etc. are manifestations of primary
'..Irry valences. The valency of the atom is divided
the surrounding atoms. Thus, there is an unbalanced force
on the s- -"ace of a catalyst and the atoms are loosely bound,
ince chemical forces are of short range, the unsaturated crystals
the s'J ice ''ill adsorb a monolayer of gas. The amount of
d depends on a kinetic equilibrium between conden-
'. evaporation. Probably every molecule hitting the
vrf ce ?ondenses and evaoor^-tes. Adsorption might be considered
between condensation and evaporation. At first, these
:-e considered as sacculation, but experimental investi-
ions proved them to be essentially correct (5-11).
Br Heterogeneity of the catalyst surface and the concept of
f.oaivity centers:
auir's concepts could not be applied unaltered to
\t :enous surfaces (12-16). There is a wide range of effic-
iency in reactions. In some reactions every atom will be active,
in other reactions relatively few are active. It is evident that
adsoroticn is dependent upon factors other than available sur-
Lce atoms. Taylor suggested. (5) that only a small portion of
the c-l lytic surface is necessarily active. Catalysis may be
fined to certain active centers. Interaction apparently
?s place -/Lea molecules of two cases are adsorbed on adjacent
litems of the catalyst.
0. inner nature of adsorption:
Tee concept of activity centers could not be fully developed
until a distinction was made between chemical and physical ad-
rptr.on, This distinction was necessary to help explain why
;ood adsorbents are poor catalysts and some poor adsorbents
l.re zeoi catalysts. 3enton and White (28) observed that at cer-
lin or; ssures the adsorption of hydrogen on nickel increased
jfitn increasing temperature. These observations were plausible
the lower temperature adsorotion were physical and the higher
"emoe-e ture adsorption were chemical. The isotherms indicated
Ft three reactions -'ere involved (a) chemical adsorotion, (D)
hysical adsorption, (c) solution of gas and metal. The chemi-
ciotion of ~ases requires an activation energy which is fur-
Ashed by the rising temperatures. Quantum mechanical calcul-
ations (52) indicate that this energy of activation is a fune-
ion of the r:roup spacing .
• ■
* •*. ,.
D. Extent of surface area of the catalysts and the signifi-
cence of the several kinds of, crystals on catalytic activity:
A comprehensive study of contact catalysis has been pre-
sented by Brunauer and Eramett (38, 41). Their studies are lim-
ited to the synthesis of ammonia but "their methods rave become
p norm for expressing numerically the accessible surface of a
solia boay" (l). Other methods have been used to verify this
method.
rpl-
he vecmetric arrangement of a surface has a definite re*
-tion to the activity of the surface. A surface activited for
one reaction may not be activated for another; Beeck and ©c-
workers (59,44) have shown that there is a definite relation be-
tween the efficiency of the catalysts and ootimum spacing of the
atoms.
Tracer elements, magnetic characteristics of the catalysts
?nd the p;ases adsorbed, and the rate of adsorption at various
oressures are used to study the process of making and breaking
bonds at a prepared surface.
References
L. Taylor, Am. Sci,, 34, 554-72 (1946)
I. Langmuir, Phys. Rev., 6, 79-8 (1915)
Langmuir, J. Am. Chem. Soc. , 38, 221-95 (1916)
Langmuir, Proc. Nat. Acad. Sci., 3, 251-7 (1917)
Taylor, Proc, Roy. Soc. (London), 115A, 77-86 (1922)
Bos -.veil and McLaughlin; Tran. Roy Soc. (Canada), 17,SectIII 1-20
(1923) —
r. Pease, J. . Am, Chem, Soc. ,. 45, ■ 2298-2305 (1923)
>. Beebe and Taylor, J. Am, Chem. Soc. 46, 435 (1924)
I Pease and Yung, J. Am. Chem. Soc. 46, 390-4G3 (1924)
). Taylor, J. Phys. Chem. 28, 898-942 (1924)
.. Henshelwood and Prichard; J. Chem. Soc. 127, 17-36,1546-52,1552-9,
2395-2900 (1925) '
>. Almqulst, Caddy, Bronam, Ind. Errc Chem. , 17, 599-603 (1925)
5. Pease and Stewart, J. Am. Chem. Soc. , 47, 17535-40 (1925)
■ Taylor and RussellL J. Phys. Chem. 29, 1325-41 (1925)
). Almquist, J. Chem. education, 3, 385-9 (1926)
). Almquist and Bl^ck, J. Am. Chem. Soc. ,48 2814-6(1926)
'. Tweedy, Chem.andlnd. , 45 157-9; 177-80 (1926)
I Tweedy, Proc. Roy. Soc . Tlondon) , 112A 296-303 (1926)
>. Beebe, J.Phy. Chem. , 30, 1538-44 T1926)
I ?I£2£ an4 ^iffin, J. Am. Chem. Soc. 49 25-81 (1927)
- Pec.se and Stewart J. Am. Chem. Soc. 49-2763-7 (1927)
!. Rideal, Chem. Reviews 5 67-84 (1928)
*. Taylor. md.Eng.Chem. 20 439-443 (1928)
I Langmuir, Chem. Reviews 6 451-79 (1929)
>. Taylor and Lavin, J. Am. "Chem. Soc. 52 1910-18 (1930)
>• Taylor, J. Am. Chem. Soc. , 52 5298-9HT1930) ;53 578-97 (1931)
'. Taylor and McKinney.; J. Am.. Chem. Soc. 53 3604-24 (1931)
!- ?2^:o;a 9nd White:, J.Am.CShem.Bbc. 52 2523-36(1930)5^,2807-8,
^301-14(1931); 54 1373-90 (1932) —
I Taylor, Trans. Faraday Soc. 28 131-8 (1932)
. Rideal, Trans. Faraday Soc. 28 139-47 (1932)
. Taylor and Long, Phys . Rev. 40 463-4 (1932)
■. Taylor, Eyring and Sherman, TTChem. Physics 68-76 (1933)
| Russell and_Ghering> J. Am, Chem. Soc. 57,2544-52 (19351
I Palmer ana Clark, PPoc.HBySoc. (London) AI49 360=84 (1935)
. Rideal, Proc. Roy. Soc London. A- 155 684~W~( 1936)
' ToS^S'l aSd Elefcprc-c.Roy.3oc. "(London) A178 429-5 (1941)
. xaylor, Trans. <E1 e ctro chem. Soc . 71, 37tr=-S£l (1937)
. Emmet t and 3runauer.> Tran. Electrochem Soc. 71 383-394 (1937)
. Beecii, J. Chem. Phys. 4 680-9 (1936) 5 268-73 (1~937)
. Taylor o J. Chim.ohvs. 34 529-35 '1937)
I ^l^^^^^H'^M^300' & 2682-9 (1937)
-
- <r
THE ROLE OF THE CATALYST IN THE SANDMEYER REACTION
John Speziale
January 14, 1947
The Sandmeyer reaction is the replacement of a diazonium
grouo by a halogen atom using cuprous halide and a nalogen acid.
PZO
Side
com^oun
reactions usually give rise to phenols, biaryls an
nds0 Hodgson (1) has postulated separate mechanis
ms
for halogen substitution and the side reactions, whereas Waters
(2) has postulated a single mechanism.
Cuprous halides react with diazonium salts mainly by:
1. The formation of a complex anion with halogen acid;
attraction of the complex anion to the diazonium cation;
release of an electron from the halogen to the nitrogen
via the significant carbon atom followed by separation of
neutral chlorine and evolution of Np; linkage of neutral
chlorine to the aryl radical followed by rehabilitation
of the ccmolex anion by corrdination with an external
chloride ion.
2. Oxidation of Cu4, to 0wy-*- by diazonium ion, which in-
volves relepse of an electron by the copper to the
nitrogen with subsequent linkage of the aryl radicals
oroduced to form biaryls.
4.
A. Cu+ + Ar-
NsN
Cu
4.4-
4 Ar. * N2
3. 2Ar. > Ar- Ar
But if the reaction is
then Waters submits th<
tution:
carried out in an acid medium
following for halogen substi-
C. Ar* + Cl~ > ArCl + e
D. Cu** T e ) CuT
Waters and Hodgson are in agreement only on equations A
i.nd B. This mechanism differs from that of Hodgson for the
ipndmeyer reaction in that Hodgson postulates that electron
;ransfer takes place in reverse of phase C and that there is
slectron release at the significant carbon atom of the aryl
touo from a chlorine atom of the complex anion (CuCl4)s«
Mechanism 1
ilain the results
s postulated by Hodgson also serves to ex-
in a mixed Sandmeyer reaction* Eight aryl
jnines '.'ere diazotized and then decomposed in two ways,
(a) CuCl dissolved in concentrated HBr
(b) CuBr dissolved in concentrated HC1
an
A:Tdne
-nitroaniline
-nitroaailine
-nitroaniline
-"oh .?:- ;: 1 en ediamine
enzidine
-chloro aniline
-bro :-ocniIine
Treble I
Mixed Spndmeyer Reaction
CuCl in HBr
iBromo
^Chloro
90
10
96
4
96
4
96
4
93
7
(b)
CuBr
in HC1
,;?Bromo
/oCTqlorO
31
69
32
68
36
64
31
69
35
65
i
65
63
• s
— >"C ~* "
.
•- 63 ~
in (^)htnTf(lren°\ln thf ?ercent^ of ^romo to chloro compounds
in la; and (b) can be explained on the basis of the complex In
thn? fnf f?S K -^ jHfe*"' ^he mechanism" is siSilS'to^
that for (CuCl4)». In similar experiments, using Cul in HC1 and
ThuV nW?l^°Wn ^at the i0d0 ^™?ound was formed predominantly.
iVBrs CI. cooper complexes, the order of reactivity is
tvQ* J-^0rdner t0 test the intention of Hantzsch and Blagden (3)
diazoni!mn^??^ °^l ^J1 *he inorganic salt and not from the
cunrnn* h V V ' n0d^son (U treated a diazonium salt with
cuprous nalide m aqueous suspension and in methyl sulfide solu-
tion in tme absence of acid. The results showed that when (1)
£S *?*Cted w1*? P^omobenzene-diazonium bromide? the main
r bf P-chlorobro.mo-benzene and (b) when CuBr reacted with
I nffl °enf nediazonium chloride, the mam product was p-dibromo-
benzene. According to his mechanism, a complex anion is formed
or ^??vlh'?^fUS ft11?* "* the ^dmating solvent in water
or metnyl sulfide. The halogen from the diazonium salt will re~
S-^p %nlie depfftinS ^logen from the anionoid complex, and give
rise to a small amount of the other halogen derivative.
, , J" gqpeoys solu^on, hydrofluoric acid is assumed to be
lately H2Fo (ionized as H+ + HP-g) and a small amount of HF
fn0o°"iZf' T1^se Properties account for the ineffectiveness
II cooper as a catalyst since the affinity of fluorine for hv~
irogen and stability of the HF~Q anion apparently SrSven? ooL
Dlex cuprous formation. The small yield of fluoro comoound
\l L/Vn difzo.tizf m-nitroaniline) would, therefore/ aopear to
due to attack of cationoid carbon by nonionized HF, the HF""?
Lon being unreactive like chloride and bromide ions.
i ii nS*e+l however' a dpy borofluoride is decomposed by heatins
lrN2BF4 the same Kind of process occurs as in the cuorous salt
pcrianism - a polarized fluorine atom in BF4~ ion attacks the
tetionoid carbon like CI in the (CuCljE comolex with the re-
citing evolution of N2 and BF3 and subsequent replacement of
;ne diazonium grouo by fluorine.
Hodgson (4,5) found that cupric salts were ps effective as
suprous salts in the Sandmeyer reaction. The Sandmeyer reaction
ipears to be dependent upon the degree of positivitv of the
lazomum ion, which when of sufficient magnitude enables the
^ore epnemeral cupric halogen complexes to react like thej r cu~
rous analogues. The complex cupric anion is postulated as hy-
rated [ CuX4)~. 2H20 which serves to activate the otherwise stable
lalide ions.
The reaction of cupric chloride is general for oroperly
Instituted aryl diazonium chlorides. When the significant carbon
torn has only a relatively small postive charge (as in diazotized
jruline and toluidines) cupric chloride is oractically ineffective.
ior those amines which have a nitro or halogen group in the
ing, the significant carbon atom will bear a relatively high"
Dsitive charge due to the (+1) inductive effect. In these cases
Joric chloride is as effective as cuprous chloride.
Most of the decompositions of diazonium halides hitherto
,udied have been in acid solution and found to vary greatly in
n cent rat ion of acid. It appeared of interest to ascertain
aether chloride ions take part in the decomposition (6).
- 64-
The acid solution of p-nitrobenzenediazonium chloride was
jxpctly neutralized with the avoropnate base and the corres-
xmding metallic chlorides added in equivalent amount to secure
fcrsllel sets of decompositions*
Table II
affect of chloride ion on p-NapCfiH4NpCl
Base Salt jgYield - p •♦ H0pC6H4Cl
nil nil 28
CaC03 nil 6
ZnO nil. 5
CaC05 CaCl 12
ZnO ZnCl§.2HP0 6
MaHC03 NaCl 3
K2CO^ KC1 6
CaCOg CuClp.2H20 85
In the foregoing tpble, the addition of metallic chlori5.es
auses no significant rise in .yield of the chloro compound,
he only exception is when hydra ted cupric chloride is added to
he neutrrl solution of the diazonium salt. According to Hodgson
his indicates the presence of the complex cupric anion (CuCl^.)-
eld to exist in acid solution. These results ere claimed to
how thrt the chloride ion plays little, if any, part in the
jubstitution of chlorine for the diazo group, since the only
ases of appreciable substitution are those in which there is
'he possibility of the existence of covalent chlorine (or partly
fcarised) with HC1, CaCl.? and CuClo.
Reactions were carried by decomposing diazotized m- and
j-nitroaniline in concentrated HC1 using metallic chlorides whose
letals are prone to form complex halogen anions (7).
All decomposition were carried out under identical conditions
Table III
Effect of metallic chlorides on jD-NapCgr^NgCl
Addition ^Yield
p- HO 2 C 5H4 CI
HC1 54.4
A1C13 60.7
SbCl3 37,1
CaClo 54.4
CrCl^ 54,4
C0CI2 blue sol. 70,9
Co CI o nink sol. 10.2
BlanK without CoClo 10.2
CuoClo '" 77*6
uClp .77.6
eCl3 77„6
•Clp 54.4
. LClp 60„?
3nCl4 60*7.
ZnCl 54.4
It is seen that both cupric chloride and ferric chloride
i as efficient as cuprous chloride.
The experiments with cobaltous chloride have an interesting
Jaring" on its ionic state - when anhydrous or in a solution of
*!.-
. J'->
iktyx
- 65 -
high chloride ion concentration, cobalt chloride is blue owing
to the presence of (C0CI4)- anion and such a solution affords
a 70.9/0 yield of the chloro compound. The more aqueous pink
solution containing (Co(HgO) 6)Cig gives about 10/o yeild,~the
ssme dilution but with no cobaltous chloride present. These
experiments with CoClg support the interpretption that the de-
composition is due to (CUX4)-.
Sandmeyer was unable to isolate any intermediate complex,
Hod-Tson suggests that the complex salt (ArN2)2 CoCl4 existed in
his experiments with cobaltous chloride. Tne efficiency of ferric
chloride in concentrated HC1 was due to the formation of the
com/olex ferric salts ArNpFeCl^. Several double salts of diazonium
chlorides have been reported (8).
Hodgson and Sibbald (9) have reported eight examples of
these complex ferric salts. They decompose when heated with
concentrated HC1, giving the aryl chloro compound. This is fur-
ther evidence for the Hodgson mechanism. These complexes are
yellow-orange crystalline solids, soluble in water. Cold solu-
tions are stable but decompose upon heating* The dry solids
can be kept from a few days to one year without decomposition*
Hodgson summarizes his work on the Sandmeyer reaction as
follows:
1. Cuprous salts do not possess unique characteristics
as claimed by Sandmeyer and Waters,
2. In cases where the diazonium cation possesses suffic-
ient positivity, cupric salts can function with efficiency
comparable to those of cuorous salts.
3. Metals other than copper can form anionoid complexes
with halogen which decompose in like manner to the
copper salts,,
4. There are no fundamental differences in the mechanism
of formation of halogen compounds during the decom-
position of complex diazonium chlorides with cuprous
chloride, cupric chloride, zinc chloride or any other
chloride (including HC1) in aqueous or other media.
Such differences as do occur are due to differences in
stability and concentration of the complex anion whereby
the competing action of anionoid water can become
negligible (cuorous salts) or predominant (zinc salts).
5. All the reactions can be interpreted by the single
anionoid mechanism already proposed*
BIBLIOGRAPHY
1. Hod '-son, Birtwell cc Walker, J. Chem. 3oc , 1941 770*
P. -. s, J. Chem. Soc, 1942, 266.
. :-:■ . zsch & Blagden*, Ber. , 33, 2544 (1900).
I. Hodgson, Birtwell & Walker, J, Chem. 8.0c, 1942, 720,
5. Hodeson, J. Chem. Soc, 1946, 745.
6. ] -on & Sibbald, Jt Chem. Soc. , 1945, 545,
. Hodgson, Birtwell & Walker, J. Chem. Soc, 1944, 18.
|. Schmidt & Meier, J« prakt. Chem. 132 153 (193T7.
Sau] s, The Aromatic Diazo Compounds. Longman & 3-reen,
London 1936, pp. 37, 154.
I. Hodgson & Sibbald, J. Chem. Soc, 1945, 819.
-.
Rov D. J»hnson
I. Introduction (l)
February 11, 1947
Although early workers believed that °rgano metallic compounds
could not be formed by the metals in B™up« six end seven of
periodic chart, a very ^^e^^? fries nf orgs no-ohromiu^ ^
■oounds has been prepared and sidled by He In ana nis oompounds
basic reaction for the preparation of tnc "^"^"hiorlde with
v,, boon the reaction of c ™°" ^^ ^vf compounds closely
e. cold aryl Grignard solution. uie resulting * , t*ivelv unstable
resemble the inorganic dichromates in color - relative! lnstance
thermally, and are quite sensitive to oxygen ana ngni.
oY^kyl-Chromium compounds being isolated was found,
II 0 Fhenyl-Chromium Compounds,
• ,i „«v,v (9) *in the field was in the synthesis and
Hein's original work 12; in tne i icxu * -product
s? Afffaarsrti^B s-s.'tS'.ss a-
Fh4CrBr and Ph3CrBr are also formed J.
CrCl3 + 5PhHgBr H£°. PhsCrEr ♦ 3CrCl3 * 3MgCl3 * ZMgBr,
| Cr03Cl3 + 5FhligBr ?^ Ph5CrBr ♦ ZHg.OBr, + KgCl,
pormation of Cr« compounds has been g^jf^g^L'SS*?
^r^odlum**^
of univalent Cr in the following manner:
4CrCl3 * 4PhKgBr , Ph.CrCl + 3CrCl + ZKgCl. + SMgBr,
then CrCl + H,0 4 Cr(OH)3Cl + H3
The crude product was purified by the formation and subs equent
decomposition of an H^ addition product It s apical yji
r-p pnnnound as it is orange in coior cuu. bx
cipitafe of AgBr on treatment with AgN03 in aqueous alcohol.
PhgCrOH (5) is best prepared as follows:
I Fh5CrBr + KOK ^ Kbr + Ph5CrOH
Tt . „„,„„. oranee verv slightly soluble in water, gives strongly
*;>*-%?= aolutClt'abeorbs C03J and replaces ammonia in.ammomum
^aTt The nydroxide retains four mols of water over 33^- KO H, two
:,;.,:;, over Caoi„ and becomes f*£°»» f er F305 f it ^ lon
(t. „ for a considerable period, there is * aeeP ^ea^eu f
:, the f-mation of diphenyl Constantly .the ^«ot«r.f x^
believed to be Fh5Cr(H30)30H.2,.30. Men a aii precipitated
^drcxide in alcohol containing, soaewtcr is P"^* ^°°lp,n or.ange
1;rj 3ther, the filtrate « *g»6 ot^suU^io a previously obtained
substance of the same composition as Me ainy aL / -,0S.
over Caol3. However, this substance loses no water over P3 5.
»
etr'wucKiro:
O:',, n rr <->.
- %
;.'•;
•67~
nein calls it "beta haRP1' "n^i- ^-p-p
enoc in behavior! The dihydrate ^7 *Z *xPlanation f°r the differ-
melt ouite sharpiy at 104^10^ ' °etrei>*****°. «d beta form all
salts^oTto^form SrtfaSrtfilSffSSl" **J}Ct" *"h a°lds or
Phenyl group, though the S.^^oSS0?^^1* 2"1"?
the reaction mechanism (n>\ v,*„ - ,°V maintained Study of
Sri £°s- e™ -~» * -- s^"l
uj.x^ loaine, die periodide shows no lo<*n ~^ < ^-
m standing over 3o£ KOH in vacuo for several hours. ^
acchouVta^V^Sf ^ueoT be PvP?PTea ^ t^8ting thC
instable when dry, exploding in >" ™ Perehl»ric acid. It is
^ming, or on sllghf peSsi™! " ""^ *" ^^ dayS' on Sentl«
a simple tetra phenyl chromium compound FH.Cr (ft q^ vao
atho-r^n ^ri^rKo'tjSxS-L?^^ &^r°n *•
SOor Tf- 4- u tieciioiyzea in liquid ammonia at -40 to
volving ^odor^f T£Zl arte°°am SHirf' f^f "S ^
ive a blue solution "7? £,?etallic luster, form amalgamator
stio iX'SSSSrV.iS'lLS^^i^tS' metalli0 iharacter-
Fh4CrOH (5,10) has been prepared bv the electrnlv^ic «f i-v,„
EHslFV fir- - s^rsA'srass-
ired. Pr°V ldentl°al w«h the halides previously pre-
lutinr fhS^iS °fange comv°und PhaCrOK (11) was obtained bv
lluting the notner liquor after thFTSpaTktion of (PhsCr).CO. 6H-P
V^Tol^TlTtZt 'r rn°entra;l0n Sclutlon> gives re,ctton;6'^*
pioal of solutions of bases, ma ls a stronger base than either of
«■-.
-
di ■•■ . .■ .<* • «•--
■ '. ,-
-se-
the other polypheny 1 bases. The trlphenyl base is decolorized by
H202 and very dilute K^nG^
Fh3CrI»Et80 (11) may be prepared by treating the aqueous trl-
phenyl base with KI or HI. Its behavior is similar to that of the
penta and tetra phenyl halides.
Ffr-aCr (10) can be prepared by the electrolysis of Fh3Cr I in
anhydrous liquid ammonia or by treating the iodide with a solution
sodium in liquid ammonia. This brownish yellow deposit is less
stable than Fh4Cr readily splitting off diphenyl. In air it is
converted to Ph3CrOHf
Since both brown Fh2CrX and green FhCrO (1) have been identified
among the decomposition products of the tri, tetra, and penta phenyl
series of compounds, the phenyl series includes five types of corn-
bounds. They are as follows? ?h5CrX, Ph4CrX» Fh3CrX/?h3CrX,
id FhCrX2.
III. Substituted Phenyl- Cr Compounds
' ' ■ ■ i i*T m*m, m , | ,., nail i«n« ,«j»^. ■ ».««
An idea of the substituted phenyl compounds which have been
prepared may be gained from the following table (12,13,14).
Toly1 p(CHa-CsH4)5,.„,3,CrX, o(CH3-C6H4)5,4,3CrX
Xylyl 1,3,4- [(CH3)2CsK3]5,4CrX
Naphthyl alpha (C1BH* )3Cr3r
p-3r phenyl p(Br-C6H4)4CrBr, p(?r-C6H4-C6H4-C6H4 )5CrBr
m-Cl phenyl B(CX.0#H4^0eH4)8nr(06H4)x,f Cr(CsH4-CsH4Cl )3,
In working with the above compounds it has been found that the
tability of the C-€r bond depends to a large degree on the organic
adical. Stability decreases with increasing saturation of the
iidical. The yield is very poor with the halogen substituted phenyl
impounds where very complex mixtures are the chief product,
-V. Relation of Organo-Cr Compounds to the Complex Chemistry of
Chromium " ' ' ' — *" —
3 in and his coworkers studied the formation of organo-Cr
impounds using many complex Cr compounds (1,15,16,17). The
[suits of this work may be stated in the following general rule:
nly those complex derivatives of CrCl3 and CrBr3 (probably also
pJ3; in which at least three halogens are connected directly
1« e, not ionizable) with Cr and do not contain any ions in the outer
3 permit the introduction of the organic radical in place of
he nalogen atoms-' It may be noted that this corroborates the
leumption that CrCl3 and Cr3r3 are unionized. A similar inference
ay be drawn from the fact that chromous salts such as CrCla and
r(0Ac)3 will also react with PhligBr.
-69-
3I3LI0GRAFHY
1*
p
- •
5*
4.
5.
3.
74
8.
9.
0.
u
2.
5.
/;.
--•
5.
6.
7.
He in
He in
He in
He in
He in
Hein
F. -Hein
F. Hein
Hein
Hein
Hein
Hein
Hein
Hein
Hein
Hein
Hein
F«
F,
F.
F.
F.
F„
F.
F,
F.
F.
F*
F.
J. Frakt. Chcmie, 152, 59 (1931)
Ber,, 52B, 195 (1919)
Ber., 543, 1905 (1921)
J, Rescnke, end F. Fintus, Ber., gOB, 749 (1927)
3er\, 54B, 2708 (1921)
et al,, Ber., 613, 730 (1928)
et al*, Ber., 623, 1151 (1929)
and W. Eissner, 3er,, 593 a 362 (1926)
and E. Harkert, 3ei\, 613, 2255 (1928)
and 0„ Schwartzkoof, Ber. , 573, 8 (1924)
, Ber., 54B, 2727 "(1921)
and R. Speete, 3er, , 573, 899- (1924)
pnd R. Spaete, Ber., 593, 751 (1926)
and W, Retter, Ber., 713, 1966 (1938)
and F. Fintus, Ber., SOB, 2388 (1927)
, J. Reschke and F. Fintus, Ber. , 60S, 679 (1927)
, Ber., J, Frakt, Chem. 153. 160 (1939)
* 7C -
Methods of Measuring Aqueous Vapor and Dissociation Pressures
Philip Faust _ ,
February 18, 1947
accurate Knowl°to lot the ™ °r delitescent depends on an
^aKt OI Ine vapor pressure of hydrates.
Early Investigations
i-ie work on vpoo^ nrp^curio f, + ,,ji„„ , ,
to 1075 has little qnip?i?f studies which was done prior
lynamic and indirect. ?ressuj,es 01 salt nydrates; static,
1. Static Methods
an ordLl,rvrbptrome?er8tSubee,nfrdU<3?i0n °f the !™te ^to
mere--. This -v»s uLfl w t recording the lowering of the
mis .as usea by Leseoeur (1) and Pareau (2).
Prowein (3) made some improvements b» w! *.v,
J c- tuoe lined witn olive oil.
.dv-nts^o? !n^i!8ed =°ttonseed oil as his liquid. -he
BreSoea iS heSt? "^ 1S tfet they glve heater dil-
A scheme used by Leseoeur (1) consisted in determining
dew point of air above the hydrates. aetermiuin6
amic Methods
The first dynamic method was develooed bv Mupiip, r^v ,
5) -o assumed that the vapor oressures of t™^i«? Zbach
re oro-oortional to the relstivp S!t« t • ? substances
fussed out of Bimilflp fiTaVa iJ % S at wnicn water va:)0^
Ushs werellaced^n l^etl^^1^ th9 ^^ ^ ^
l!:!"6^ introduced by Tammann (6) consist
- 71 -
3. Indirect Methods
In these, the vapor pressure is determined by bringing
the hydrate into equilibrium with some liquid whose aqueous
vaoor pressure is known.
leller-Erzbach (5) determined the concentration of sul-
furic acid over which a pair of hydrates neither gained nor
lost weight.
Linebarger (7) suggested obtaining equilibrium by shak-
ing the hydrates with an excess of a liquid in which they
were insoluble, but hich would dissolve small amounts of
water. He used ether and measured the water content by
change in boiling point,
Foote and Scholes (8) used ethyl alconol as a reference
liquid and determined the water content by density measurements.
Factors G-overning the Selection of Methods
The static methods are not very good for measuring the
vaoor pressure of hydrates.
First many solid hydrates approach equilibrium very
slowly.
Second the equilibrium is ordinarily approached from
one side only.
Third the presence of absorbed gases on the hydrate :
raises large errors.
Fourth no entirely satisfactory confining liquid is
avail abl e .
The principal objections to the ordinary d^mamic methods
are similar to those for the static methods.
The. indirect methods of shaking up with some anhydrous
solvent offer the advantage of permitting the equilibrium to
be approached from both sides.
Ether takes up such small amounts of water that its
accurate determination is difficult and ethyl alcohol suffers
from the opposite effect.
The answer to the above difficulties is to find a sol-
vent intermediate in oroperties between the two just mentioned.
Cne such solvent is iso-amyl alcohol, chosen by V/ilson (9).
Several methods are proposed for determining the amount
of water in the alcohol: the addition of MggNg to liberate
ch could be titrated, a colorimetric method using co-
balt c iloride, a conductivity method using coualt chloride,
and finally a conductivity method using potassium thiocyanate
(10). This last method is the best-.
j 0 n e d y n a m i c me t ho d
A dynamic method used by Bonnell and Burridge (11) con-
sists in passing dry air over a salt hydrate, through phos-
phorus pentoxide tubes, through a water saturator and finally
- 72 -
through another phosphorus ^entoxide tube. The vapor pressure
can be calculated by the weights of water absorped. The ap-
paratus for this is somewhat complicated.
An o ther I nd i re c t me t ho d .
Collins and Menzies (12) have used the method of allow-
ing sulfuric acid of known concentration to alter its own con-
centration until its aqueous pressure matches that of the ma-
terial under investigation* This is a simple accurate method.
Collins and Ivlenzies have attempted to explain earlier
discrepancies and difficulties by saying there are not always
just two crystalline and one vapor phase present. There m
be a layer of non-vaporous water present on the surface of
the "active points" (points where the two crystalline phases
are in contact). This alters the phase rule prediction.
tzies and Fetter (13) found that dehydration of a hy-
drate may be more raoid and thorough in the presence of in-
cr.^ s 0 d pr e s sur es of wa. t e r va po r .
low -re some conclusions reached by Collins and jlenzies
in their work:
?':±»y found (1) that the difficulty due to this water
layer at the "active points11 becomes less apparent, the higher
the t ?ature. (2) that material which has for purposes of
measurement, previously been in contact with a higher pressure
of water vapor at a higher temperature is prone to yield
ores sure values which are too high in comparison lower temper-
ature measurements which immediately succeed them. (3) that in
cert- in cases, a genuine equilibrium pressure appears to pre-
sent itself in experiments of customary duration, which Tar's
in value only slowly with time. (4) that with different hy-
ftrate Dairs, the abnormality is the greater the lower the dis-
sociation pressure for the same temperature. (5) that, if the
mat. . for investigation must be prepared by efflorescence,
liscrepancies ere best avoided b~r preventing undue access cf
water vaeor to the material orior to measurements.
References
1. Lescoeur, Ann. chim. ohys. 'fi] 16 578 (1869), 21 511 (1890),
2. ? • -a . 1. ann. 1 55 (1877).
3* Frowein, 2. physik chera. 1 5, 362 (1887).
4. Menzies, J. Am. Chem. Soc. 42 1951 (1920).
5. Mueller-Erzbach, Ber. 14 1093 (1881).
6. Ta ann, Ann. chim. phys. 53 15 (1897).
7. Linebarser, Z physik Chem. 13 500 (1894).
■8. Foote and Scholes, J. Am. Chm. Soc. 33 1309 (1911).
1. 7ilson, ibid. 43 704 (1921).
C. Moyea and Westbrook, ibid 43 728 (1921).
.1. Bonnell and Eurridge, Trans. Faraday Soc. 31 473 (1935)
2. Collins and henzies, J. Fhys. Ghem. 40 379 (1936),
3. Licnzies and hotter, J. Am. Chem. Soc. 34 1452 (1912).
-73-
SULFUR MONOXIDE
J. B, McFherson, Jr.
!• Introduction
February 25, 1947
^ho observed a flint Titl'T descrlbed *» 1883 by Heumann (l),
heating sulfur ^o 200°C ^n" t ^f'T806"00 fnd PecuH« odor on
He najaed the comoound fA™ „ the dark and In the presence of air.
sulfur-oXyg:„°0ra?io of on:1oSoUne"r """^ SlnCe " Sh°Wed *
roderfr8olu??on* was eSLYrV rP£ta?\1?nl? acid *" "^e„-
8 expJ-amed b, the following equations: (2)
2. H20 + 5so 4 H3SsOe
*cid JroceeSdfthuI:°?3)ea *"* *" deooraPOsition of thiosulfurio
H3S203 4, 2S0 + H20
»t .^TtE^R^" j^ We K?5f ?*>¥*'
:-nndd ajs.^^r ssiB"-2 p* ffi^-s?£&
.uthor also tried the act?Sn 0? tM SOdl™ hyp°SUlflte' The la"er
lagnesium. sodium and !?„.! tnionyl chloride on silver,
«eEpted'to Jre^a" l?t?«nU?h°r'"0rlde1- Staudin^ "d Kreis (6)
■romide. P r°m tne formal decomposition of thionyl
■
., * significant observation was madp in iq<jq k, it
?). They reported the forms "w i- = 9 by Henrl and *olff
ange of 2500 to 39M 1 T » ' "eW emlsslon spectrum in the
Iternating electric Ja'J ^^ WSS subJocted to an
alculation of t£ dlsaociatfoVef * red"ced P-ssure. Their
ulfur and o^n^tltTltl^ToT/l^ltZ S^' **
f sulfur dioxide Thno « for the dissociation
onoxiae. # TnUS tne neW *>««t™» was attributed to sulfur
t. Methods of Preparation
LosiSngeankmSLrr00r8Sf^ a11So°xieenaSnrlf1U? *"**»■ *
Lectrlc dischare-e at „uc aloxide and sulfur vapor to an
k reactions wore given^o^w 11*%** °^ ™' Hg* The follow-
&ivcn G0 sriow 10s formation:
S02 + s ± 2S0
2S03 > os0 + q2^
t74-
The sulfur monoxide was detected by its absorption spectrum which
was found to lie in approximately the same range as the emission
soectrum. to ° u"
Schenk and Flatz (9) obtained sulfur monoxide by heating
silver sodium, antimony, tin or stannous chloride with thiony]
cnloride in accordance with the reaction
SO CI 3 + 211 ^ 2HC1 + SO.
Thermal decomposition of thionly halides, preferablv the
bromide, proved successful for Schenk and Triebel (10) "More re-
cent preparative methods include the slow oxidation of h"<?roeen
sulfide (9,11,12) or carbon disulfide (17,18) with oxygen and the
pnotocnemical decomposition of sulfur dioxide (13). But the
best methods remain the reaction of sulfur dioxide and sulfur
vapor in an electric discharge and the reduction of thionyl
cnloride with a meta]. Schenk (3) gave convenient directions
for these # in a review article. He has also given directions for
a metnod involving the direct combination of sulfur and oxygen
1/2 S2 + 1/2 02 £ SO,
III. Physical Properties
?here has been some disagreement concerning the molecular
■/eight of gaseous sulfur monoxide, however it is now generally
accepted that it exists as a dimer S202.
Kondratteva and Kondrat i ev(U') found that the absorption
spectrum calculated from the known emission specturm differed from
,ne known absorption spectrum, indicating that the absorption
carrier must be S202 rather than SO, Schenk (15) however claimed
,nat they had misinterpreted their data and believed the gas to
3e monomeric. This contradicted his own earlier statement that
sulfur monoxide was a mixture' in which approximately 64$ of the
$as was associated as a dimer,
Jakovleva and Kondrat'ev (is) reported that under the
conditions of their experiment only S202, and net SO, could be
ormed from the photochemical decomposition of sulfur dioxide.
Sulfur monoxide gas condenses on cooling in a Liquid air
)ath to an orange-red solid which is soluble in carbon tetrachlor-
ide (19). The molecular weight of the dissolved product varies
:'rom 300 to 800.
The most important property of sulfur monoxide from a research
standpoint is its absorption spectrum, which makes possible the
•etection of SO even in extreme dilution. There has been disagree-
ment on the carrier of this absorption, which in general paralleled
jne molecular weight controversy.
Cordes (20) believed the carrier to be a metastable S2 molecule.
jut most investigators (13,14,.?1) consider the carrier to be S.C*.
.75-
IV. Chemical Properties
Gaseous sulfur monoxide is stable to decomoosition at mnm
temperatures and at low pressures. It decomposes to sulfur and
sulfur dioxide on increasing the pressure and temperature. (22,23,
The above-mentioned condensed form is thought to be a poly
"^ r,°f f WUh a variable sulfur-oxygen ration of 2-1-1 ( 19)
The solid decomposes to sulfur dioxide and sulfur on warming ' ''
It snows many of the reactions of sulfur monoxide gas and if*
onougnt to contain SO units in a polymeric chain.
fl^vJiJV^f??8 f0rl? )S deC(?mP°secl readily to sulfur end sulfur
plStS.S1 £&<?&$• silver sulfide (25) an* °n — *
the ^ss.si2a54r(S?r iG obtainea by teating so with
/oovdoes not react with rubber (23) or ethylene (3) B S
Rao (28) reported the dehydrogenation of liQuid paraffin cr'del
calin as well as methanol and ethanol with the liberation of
nydrogen sulfide. The following reaction was suggested?
2 SO + CH3OK ± K3S + HCHO
y »3w -r nuiiu -r DW2,
SO:
oyidp SoUq? X e \S Stable With oxygen (24> and with Citric
oxide U',29) at room temperature and low pressure. However at
increased temperature and pressure it reacts with oxygen to give
sulfur, sulfur dioxide and sulfur trioxide. (30, 31, 32)
Wilkins and Soper (29,55) have studied the effect of sulfur
monoxide on nitrous acid, nitric acid and nit rosyl sulfuric acid.
On passing SO through either imoz or HN03 solutions, nitrogen is
evolved in accordance with the following equation:
3S0 + N303 3 3S03 + N2c
With nitrosylsulfuric acid, nitric oxide rather than nitrogen is
evolved. &
Sulfur monoxide reacts with water to give hydrogen sulfide
sulfurous acid and polythionic acids. (3) Thiosulf ites, sulfite;
and sulfides are formed when it is passed into a basic solution
3S0 + H80 ^ H2S + 2H3303
S303 + H30 + H3S303.
Stamm and Wiebuaoh (39) recently reported the oxidation of
aydrogen iodide to free iodine in a carbon tetrachloride solution
oy sulfur monoxide.
A
-73-
V. Uses
The main use of sulfur monoxide remains that of a research
hP°L1^P?«ViS6,S?a?tion raechanisms> Emanuel, Semenov, and Pavlov
U^, 34 ,35,36,37,38) nave recently made an extensive study of the
oxidation of hydrogen sulfide with oxygen in which sulfur monoxide
nas been snown to be an intermediate product.
BIBLIOGRAPHY
1. K. Heumann, Ber. , 16 139 (1883 )
2. Fritz Ephraim, "Inorganic Chemistry", Nordeman Publishing Co.
. Inc., New York, 1943, 4th ed. rev., p, 562. b
o. P. tf. Schenk, Chem. Ztg., 5? 251, 273 (194 3)
4# C340°(l9301)eS ?nd ^ El8tner' Z' 8norZ° allSem. Chem., 191,
: 5. S. Grun^r, ibid, 212, 393 (1933)
o. H. Staudinger and V. Kreis, Helv. chin. Acta, 8, 71 (1925)
7. V. Henri and F. Wolff, J. Phys. et Had., 10, 81 (1929)
8. F. W. Scnenk, Z. anorg. allgem. Chem. ," 2lI7 150 (1955)
9. F. f Scnenk and H-. Platz, ibid, 215, 113 (1933)
u0o P. rf. Sohenk and H. Triebel, ibid, 229, 305 (1936) '
1942,' 22inUGl' 3Ul1' aCad' SCU U-R-S-S-' Classe sol, chim.,
-2- ^uS!SS'sS-e& alio]: N- "• Seraenov' Compt- rend- acad-
-o. a Jakovleva and V. Kondrat'ev, Acta Physicochim. U.R.S.S.,
Am ?! K?^ooaK^?vand V« Kondrattev, J. Phys. Chem. (U.S.S.R.),
•5. P. W Schenk, Z. Fhysik, Chem., E52, 295 (1942)
|. P. W. Schenk, 2, anorg. allgem. Chem. 222, 177 (1935)
>v. P. IV. Schenk, ibid, 220, 268 (1934) ~
Qm yo,n0n^t,eV' 3ul1- aCad' scU U^R.S.S., Classe sci. chim.,
ly4u , 501
[9. P. TvT. Schenk, Z. Elektrochem. , 47, 855 (1941)
:0. H. Cordes, Z. Fhysik., 105, 251~Tl937)
"". P. 'tf. Schenk, Z. Fhysik. Chem., £51, 113 (1942)
. C. W .Montgomery and G. 3. Kassel, J. Chem. Phys.. 2, 417
(1934) ' -' "
1.
2
t. H. uordes and P, W. Schenk, Trans. Faraday Soc, 30. 51 (1934)
g. ri. Cordes and P. TV. Schenk, Z. Electrochem. , 39, 594 (1933)
5« 3. S. Rao and M. R. Ra.o, Current Sci., 12, 323 (1935)
5. H. Cordes and P. W. Schenk, Z. anorg. allgem. Chen., 214,
33 (1933) ' '
?. P. W. Schenk, ibid, 233, No* 4, 385 (1937)
o. B. S. Rao and H. R. Rao, Current Sci., 4, 406 (1935)
9. C. J. Wilkins, J. Chem. Soc., 1940, 115T
0. E. Kondrat'eva and V. Kondrat* ev, Compt. rend. acad. sci.
U.R.S.S., 31, 128 (1941)
1. E. Kondrat'eva and V, Kondrati ev, J. Phys. Chem. (U.S.S.R. ),
g. E. Kondrat'eva and V. Knodrat* ev, ibid, 18, 102 (1944)
p. C. J. Wilkins and F. G. Soper, J. Chem. Soc, 1939, 600
P oo No,oei??o?'\and N" H- Smanuel* co^-Pt. rend. acad. sci. U.R.S.S.
££, <ol9 ^1940).
p. N. N. Semenov, ibid, 35, 145 (1942)
. .
4 • '•■'■•
-77-
36. D. A. Pavlov, N. N, Senenov, K. M. Emanuel, Bull. acad. sol.
U.R. S. S0 , Classe soie chim«, 1942, 98
37. N. M. Emanuel, J, Fhys* Chem, (U..S.S.R. ), 19, 15 (1945)
36. N. N, Semenov, Bull. acad. sci. U.R. S.S., Classe sci. chim. .
1945, 210 '
39a H. Stanm, K. D. Wiebusch, Naturwissenschaf ten, 32, 42 (1944)
Miscellaneous References
H. M, Hulbert, Js 0. Hirschf elder, J. Chem. Fhys., 9, 61 (1941)
H. Lessheim, R. Samuel, Fhila Hag., 25, 667 (1938) ~"
R, Chereton, Bull. soc. roy. sci, Liege, 11, 54 (1942)
N. M. Emanuel, Compt rend, r.cad. scie, U.R. S.S. , 5P 250 (1942)
K. K. Kelley, U.S. Bur. Mines 3ull., No. 406, 16 Tl937)
C. E. H. Bawn, J. Chem. Soc., 1953, 145
* . ■ — m mm*
-77-
Crystal Chemistry
A. R. Llatheson March 4, 1947
I. INTRODUCTION
Stillwell (27) defines crystal chemistry as "the study of (1)
■he laws governing the arrangements of atoms in solids and (2)
the influence of the arrangement and the electronic structure of
the atoms inon Physical and chemical orooerties of the solid".
Bocks 3tilwell (27), Pauling (19), Weils (31), and Dsvey (4)
ieal 'vith various chases of crystal chemistry and with the more
orecise and comolex phases of the subject.
The study of crystals began over 150 years ago, but until the
bginning of the 20th century no hypotheses were brought forward
&x-olaming the interior arrangement of crystals. Barlow (1) and
Sollas (26) visualized atoms as soheres and having certain
arrangements in crystals. The use in 1912 of x-rays to produce
a diffraction pattern of a crystal w s a major advance in the
levelopment of atomic structure knowledge. However, not until
the work of G-oldschmidt (6,7,8,9,) and Pauling (16,17,18) during
the 1920 rs was there any real correlation between size and prop-
erties of materials. Stillwell consideres this work by Gold-
schmidt and Pauling as the beginning of crystal chemistry,
:i. ato::ic size
The size of atoms or ions is important in determining the
tructure of the elements or compounds, or vice versa, and this
size relationship is in turn manifested in certain determinable
)hysical values.
The concept of atoms or ions being definite, more or less
solid, spheres was used in early discussions of atomic size,
)ut with the advent of wave mechanics this viewpoint is no longer
fcnsidered accurate. While we speak of atomic and ionic radii
fcese are used only in a relative manner and it is realized the
Jralu.es obtained for the various radii are dependent uoon the
nethod of measurement, the nature of the association of the atom
/ith other atoms, the fundemental constants used, and assumptions
)f some "base" atom's dimensions. Distinction must be made in
Jferticular as to the conditions of the application of the terms
fctomic and ionic radii. Pauling (19) gives the limits of accuracy
'or the three mam methods of determining radii as, (a) spectro-
fcico ->ic-0.Gl-0.001 A.U. ; (b) electron diffraction of gases'- 0.01-
;>.0o A.U. ; X-ray diffraction of eases-0.1-0.2 A.U. ; (c) X-rav
r.laysis- 0.001 A.U. .
II. ATOMIC RADII
Interatomic distances may be divided into two main clashes,
fovalcnt and ionic. Distances in covalent compounds may be used
In the determination of atomic radii and such radii agree with
Ihe radii of the same atoms as found in the elemental~forms.
Juggins (10) published a series of articles containing the first
lobulations of atomic radii values for a series of elements for
Jse in -crystals containing homopolar or electron-pair bonds.
Juggins used the method reported by Bragg (2) whereby the inter-
[tonic distances for the alkali halides are tabulated and the
Jifferonces in values between the horizontal and vertical members
|n a series are listed. A constant difference is found as you
pienge either the metal or the halide. This constant-difference
^- 78 -
alue may bfeu£g comoute the interatomic distance in some other
compound. Huggins used the oxides, sulfides, selenides and tell-
jrides of zinc, osdmium and mercury for the determination of the
atomic radii of seme 19 elements. The radii of carbon, silicon,
germanium, and gray tin were taken as half the interatomic dis-
tance m crystals of these elements. He furtner usee a sulfur
radius of 1.04a. mhe tetrahedral structure was proposed for zinc,
sadmiu.r, divalent nercury and monovalent cooper in combination
vith the group VIB elements.
In 1926 he revised his earlier works because the additivity
|rls-;-c.y.T ereby the -adii of two atoms ar?i added together to obtain
;neir interatomic c'.i stance in a compounl, was found not to be
jorrect unde-r all conditions of use, anl secondly, as shown by
lycKoif ,52), ohe < or.cept of constant r.adii for any one atom in
wide series of crm'.ounds was no longe.T valid.
The next co-p: --hensive uece of work on covalent radii was
by Pauling and Huggi.-is (20). Tiey discuss the covalent
end from a quantum mechanical standpoint* From their calculat-
ions tney show tfcs formation of the new common dsp2 and d^sp3
pids as vfell as tie strength of these bonds. The dsp2 bonds are
ound in bivalent nickel, palladium anc platinum compounds where
:ere are eight electrons in the outer d shell* When these elec-
rons are placed *.Wo in an orbit there is one d orbit left to
orm a oond through combination with tht3 sp3 orbitals of the next
per shell. Four strong ortitals can be formed in this manner
nd have been found to be directed towar-ls the corner of a Square,
?nce are called square bond orcitals* For six or less d elec-
rons there are ^wo d orbits available for bond formation^ which
n combination with s,px,py, und pz are lound to give six equi-
lent d^ep° orbitals directel towards the corners of a regular
Itahedron. An additional si::*- bond type is formed with the or-
itals somewhat un symmetrical and directed towards the corners
a trigonal prism. The bonU strength here is the strongest
f all the covalent bond type's.
The tetrahedral form on Itemding occurs when the tetrahedral
trbitals sp° are used. These bonds form at an angle of 109° 28»
ath each other and justify the tetrahedral carbon atom and other
ptrahedral atoms.
Thus we may classify aton.ic radii uoon the above basis into
irahedral, normal valence, octahedral, trigonal and square
ppes.
Many of the values listed by Pauling and Huggins for the
!ftrahedral and normal covaler.t radii are the same as given by
?ins in his earlier papers^ In general the additivity rule
lis found to hold for the values they give, and they did not
llieve the partial ionic character of a bond would cause too much
the deviation observed in certain interatomic distances.
For normal valence compo undc of non-metallic atoms each
torn forms a number of covalent bonds equivalent to its valence.
le normal valence values fo* carbon, silicon, germanium and
in are the same as for tetrahedral crystals since the tetra-
Idral crystal is the normal form of these elements. For those
lements capable of forming nultiple bonds the radii are found
t> decrease as the number of bonds increases.
Octahedral radii are found mainly in transition elements
-79-
such as group VIII, but also include tin, lead, selenium and
tellurium in the quadrivalent state. For the group VIII ele-
ments the bonds are d^sp3 type, whereas for elements like tin
Ithey are the so^d^ type. The octahedral form of a crystal is
usually of the pyrite form of structure. The octahedral form
of a crystal is usually of the pyrite form of structure. The
ictahe&ral radius of iron for example can be calculated by sub-
tracting the tetrahedral radium of sulfur from the Fe-S distance
observ3d within the crystal.
The trigonal prism is found only in MoS2 and W3o, where the
metal atom is surrounded by six sulfur atoms at the corners of a
|rigonal >rism.
Square radii are found in compounds such as K2PdCl4 and K9
PtCl4 where the Pd or Pt atom is surrounded by four chlorine
atoms at the corners of a square. For group VIII elements the
square radii are the same as the octahedral radii for the same
slements.
In 1941 Schomaker and Stevenson (24) orooosed certain re-
/isions for the work of Pauling and Muggins in confuting atomic
eadii. From more recent measurements on interatomic distances
lp. F2 (23), HpOg, and N2H4 they believed the covalent single
oond radii of F, C, and M should be increased in value- They also
found it necessary to apply a correction which would account for
;he partial ionic character of various bonds; The length raD
fctween two atoms with normal covalent radii ra and rv,, and
|Lectronegativities xa and x^, is given by
rab = ra-j rb - B(xa-Xfc). B = 0.09
'he expression -B(x -x^) is associated with the extra ionic
shar-\cter of the bond A-B.
V. IONIC RADII
Bragg (2) made one of the first tabulations of ionic radii
sing x-ray data in his calculations. The absolute value used
■ Brag as a reference value was later proven inaccurate and he
id not realize the possibility of variation in ionic radii in
ifferent compounds of the same element.
Tlie major advances in ionic radii determinations aave been
ade by "/rsastjerna (30); Golds chm id t (6,7,8,9), Pauling (16,17,
;8,21), and Zachariasen (33).
sastjerna calculated a number of ionic radii from optical
telationships within the molecule and his values of 1.33 ft for F"
jnd 1.32 & for 0= '-'ere later used as absolute values by Goldschmidt
Goldschmidt during the 1920' s published a great series of
Hides upon the geocheraical laws of distribution and crystal
tructure. As a result of his experiments and using the above
lues of Wasast jerna for fluorine and oxygen, by empirical means
calculated the radii of a large number of ions: being careful
use only crystals considered to be essentially ionic in nature-
In 1927 Pauling (16) published a set of ionic radii calcv*-
|ted from wave mechanics relationships between ions. His values
Feed reasonably well with those of Goldschmidt and served to
Jtrblish a firm basis for crystal chemistry. From the atom con-
■••V -otf
xr .* »• '
-80-
sidered by Pauling we no longer find the concept of a solid
sohero, but a nucleus surrounded by a cloud of electrons. The
atom is considered to be spherically symmetrical, with electron
density greatest at the nucleus and decreasing exponentially as
r, the distance from the nucleus, increases. The electrons in
the outer shell of the atom are considered to have the greatest
influence of the inner electrons upon the positive charge, Ze, ■■
where Z is the atomic number and e the charge upon the electron,
is known as the screening effect, Se. The effective nuclear
charge which determines the attraction exerted upon the outer
electrons is given by (Z-S)e. Tables of screening constants, S,
are given by Pauling (18,21), The radii are obtained by dividing
the observed interionic distance of a compound in the inverse
ratio of the effective nuclear charge. The univalent radii ob-
tained in this manner represent the relative extension in space
of the outer electron shells and may be cons-dered the relative
sizes of the ions. These univalent radii are the ones which
when added together reproduce the observed interionic distances
in the crystal, if the crystal is of the NaCl type. For multi-
valent ions it is necessary to apply a correction factor.
Za.chariasen (33) calculated a set of univalent radii which
parallel in most cases those of Pauling. Zachariasen made cor-
rections for coordination number, coulombic or valence forces,
and radius ratio effects.
Thus we see that the interactions between an ion and its
neighbors are what largely determine the equilbrium interionic
iistances in ionic crystals. Radii have been determined for
ions which radii when added together give the distances between
the ions in a compound. Tfte effective size of an ion is not
constant and varies with coordination number, valence forces, and
the ratio of the cation and anion radii. For proof that certain
compounds possess ionic bonding, and thus have ionic radii, Fried-
nan and Shuler (5) offer seven proofs to be applied.
/. SIZE RELATIONSHIPS TO PR0PERTII3 OF MATTER
An important property of the elements is atomic volume
l*hich may be obtained by dividing the atomic weight of the ele-
ment by its density in the solid state. If atomic volume values
>re plotted against increasing atomic number a curve is obtained
ifhich closely parallels a curve of atomic radii plotted against
.ncreasmg atomic number. I.ioeller (14) has plotted the atomic
'olum;- of the elements going across the periodic table and ob-
tained a series of curves sloping towards the middle of the table
'rom both ends of a series, When atomic volumes are calculated
'or some other st^te besides the solid state an error is introduced,
In group IIIA an interesting relationship is observed in
he ate .lie volume values. From scandium to lanthum there is the
kpected increase in atomic radii and atomic volume, but in going
Tom lanthanum to lutecium there is a ganeral decrease in atomic
pdii and atomic volume. Klemm and Bommer (12) examined the
tomic volumes of the rare earth metals and found excessively
large volumes for eurooium and ytterbium which they explain as
robably due to the fact that these two elements crystallize in
jhe cubic system, ;'r".iereas, the other rare earths crystallize in
1 hexagonal system. Deviations from the curve by several ele-
ments is attributed to the forna tion of ionization states within
jhe metal by the element in question. The metals in general show
jhe lanthanide contraction effect, but to a lesser degree than is
Iho w n i n t.h r o x \ d p. a
m r
- 81 -
If we consider the molecular size relationships among com-
pounds of these elements we find a somewhat similar relation-
shio as with atomic volumes. The size of an ion is larger or
smaller than the size of it.? oerent element depending upon
Whether electrons have been gained or lost in the ionization
process- For two edjaeent positive ions in a horizontal series
the ions are iscalectronic but the increase in nuclear charge Z,
causes a. decrease in size as the atomic number increases. In
the rare earth series we do not obtain an iscelectronic series
as the -tomic number increases still a decrease is noted in the
ionic radii of the ions. While the outer electronic structure
remains the eame additional electrons are added into the 4f shell
but fail to nullify the increased nuclear charge and a decrease
in size is noted. Grimm is reported (15) to have predicted such
a decrease in size among the rare earths and also a parallel de-
crease in ra ~.: 3ul».ar volume and basicity..
Golds chmid": (7,9) was the first to clearly show the decrease
in size in the rare earth oxides and to realize the effect of
such a contraction upon the elements immediately following the
rare earths. From x-ray data lattice constants were obtained
for the various oxides and when thesu lattice constants were
blotted -gainst increasing atomic number a regular decrea.se was
noted. Goldschmidt called this decrease in size the "lanthanide
contraction1''. Molecular volumes of the octahydrated sulfates of
the ra.re earths show a corresponding decrease in value with in-
creasing atomic number (15).
From these volume relationships Gold senmidt calculated the
ionic radii which we have discussed above. Here again we find
an increase in ionic radius from scandium to lanthanum, but a.
plecrease from lanthanum to lutecium.
A large cation would be expected to have less attraction
for electrons or anions than one of smaller size, and if basicity
is considered as a function of the relative ease with which elec-
trons or anions are held or given up, we would then expect a
decrease in basicity with a decrease in cation size. If we con-
sider the rare earths we find that we have a decrease in basicity
with increasing atomic number, but with decreasing ionic size,
thus " have lutecium hydroxide less basic than lanthanum hydroxide.
To more precisely consider the effects of both charge and
size upon basicity Cartledge (15) used the relationship 0 =»
cation charge, where a hydroxide will be basic, amphoteric, or
cation radius
acidic as the square root of 0 is less than 2.2, between 2.2
and 3.2, or greater than 3.2 respectively. Sun (28) reca.lcula.ted
the values given by Cartledge. By using more accurate ionic
radii Sun found that a hydroxide was basic, amphoteric, or acidic
Is 0 varied from below six, around six, and above six respec-
tively. Sun and Li (15) used the relationship AV/n3, where A
is atomic number, V the valence, and n the principal quantum
number of the highest quantum level in the neutral atom. There
nda.rd values were, less than 1.44, around 1.44, and greater
than 1.44 for basic, amphoteric, and acidic behavior- Any of
these calculations may be used an still show the relative decrease
in basicity of the rare earth series with increasing atomic
number.
Other effects of the lanthanide contraction are apparent
In the elements which immediately follow the rare earths. As
- 82 -
a result of the lanthanide contraction the chemical properties
3f oairs of elements such as Zr-Hf , Mo-W, Cb-Ta, etc are very
similar and it is difficult to seoarate them. Physical prop-
?roioS Sh°W thiS similarity- For example, in the titanium
At. No, Compound Density Molecular volume
f2 Ti02 4.20 ie.8
4° Zr02 5.73 21.5
72 Hf02 9.68 21.7
If, as has been recently proposed, we have a second rare
:artn series designated as the actinide series (25), from analogy
'e should also expect an "actinide contraction". Considerable
vidence (3,13,22,25,290) has been accumulated in the literature
0 show the resemblance between the rare earths and the transur-
mc elements. Quill (22) states that there should be a "shrink-
ge in atomic and ionic sizes of these elements (transuraric)
nalogous to the 'lanthanide contraction' in the rare earth
roup * At the time however, he was considering a group of
lements of atomic number 95 to 108. There is insufficient data
vailaple to verify such an expectation, but a decrease in size
1 atomic volume is noted between thorium and uranium (15).
Thus we have seen a few of the many unique properties of
atter which may be explained in terms of the size of atoms,
References
' ?ono?V'' W" Scientific proc. Royal Dublin Soc, 8, 527 (1895-
1898) •
, Bragg, W. L., Phil. Mag., 40, 169 (1920).
. Curie, I.^and Savitch, P., Compt. Rend. 206 905 (1938)
' uney' uNf"/^-5^ ~ Crystal Structure and Its Applications,
McGraw-Hill, (T934TChap XTtT. ^ "'
Friedman, H. B> and Shuier, K. 2., J. Chem. Educ. , 24, 11 (1947).
Golo.sc midt, V. M. , Skrifter Norske Videnskap. Akad7~0slo, I.,
Hatn.-Nat. Kl. (1926) No. 7; Trans. Faraday Soc. 25,253 (19295,
Goldscnmidt, V. M, , Barth, T, and Lunde, G. , Skrifter Norske
VidenskaD. Akad. Oslo, I, Math. -Nat. Kl. (1925) No. 7.
Goldscnmidt, V. M., and Thomassen, L., Videnskap. -Skrifter, I.
Matn. Nat, Kl. Kristiana, (1924) No. 5»
Goldschmidt, V. M,, Ulrich, F, and Barth T. , Skrifter Norske
Videnskap. Akad. Oslo, I, Math, Nat. Kl. (1925) No. 5.
onFo??' ^.L;AoPhr- R?v',Ser, 2, 19, 246 (1922); ibid, 21,
205,211, 379,509, (1923); ibid., 267*1086 (1926). ~
Hume-Rothery, W. Phil. Mag. 10, 217 (1930).
!??•??■ H*' and Bommer, H, , Z. anorg. Chem., 231, 138 (1937).
McMillan E. and Abelson, P., Phys. Rev., SerT"2, 57, 1185 (1940),
Moeller, T., J. Chem. Educ, 17, 44 (1940).
Moeller, T» , and Kremers, H.,™TJhem. Rev., 37. 97 (1945).
Pauling, Lv J. Am. Chem. Soc, 49, 965 (1927),
Pauling, l:, ibid., 50 1036 (1928).
Pauling, L. , Proc. Roy. Soc. (London) A, 114,187 (1927).
t^^V ^r Na*u£g 21 *M Chemical Bond,. Cornell Univ. Press,
Ithaca, N.Y.,HnL93oTT2*cL Ed. , Chaps. V £nd~X,
Pauling L. , and Huggins, M. L. , Z. Krist. , 87, 205 (1934) (in
English) . —
Pauling L;, and Sherman, J,, ibid, 81. 1 (1932) (in English).
iuixl, L. L. , Chem. Rev., 23, 87 (1938).
Rogers, M. T. Schoraaker, V., and Stevenson, D. P., J. Am. Chem.
Soc, 63, 2610 (1941).
!> ■ . f
. as , I .■ ; v
1 i * T - - -
■ :' ■:;*. D 'V.'. f: - ;
•'•■• "■'-•
. . -A
' '
- 83 -
4. Schomakcr, V., and Stevenson, D. P, , ibid. 63 37 fiq*n
5- nil^&Ttl S&Sztr »• k9° (l6jf; "-• S; u93
F ibid!f'2V6; 286 (r899)ROy' B°°' ^^ ' ®' 27°' 286 ^1898^
[ ifanrili.0" W'' Crystal Chemistry, McGraw-Hill, (1938) Chaps.
i' ftil S' ?"/• Chinese Chom. Sots;, 5, 148 (1937).
5'lioii: °,-Aru-' 3J5° ("^TAnn. acad. brasil. Sol.,
if' (1944) ; • Educ" ^' 286> 3S9 (194s:|; lbid-. 21.
!)* a923*JNo?a38f* A" S0C' SOi- Fennlca> Comm- phys. Math. I,
f offord/h^oJ-^fp^T^^SS^Sl-istri, Clarendon Press,
■ WycXoff, R.W.G-. , Proc. Natl. Acad. Sci. , 9 33 (1923)
| Zacharxasen, W,Z. Krist. , 80, 136 (1931$ fin E^lishh '
•tine with line 5, page 80 should read: -
electrons in the outer shell of the atom are considered to have
greatest influence upon the size of the atom or ion? However
inner electrons absorb a large portion of the charge of the '
eus before it can reach the outer electrons. This influence of
inner electrons upon the oositive charge, Ze, where Z is t°e atomic
ber ana e the charge upon the electron, 'is known as the screening
-84-
THE POISONING OF CONTACT CATALYSTS
J. 0. Richards terch u> lg4?
I. HISTORICAL
has been oHnn^f »°E, 0f+uhe Poisoning of catalytic reactions
s?nce P I n'i derable theoretical and technical importance
earlv „ 18i< v^V°ntaCt oatalysis wa* first discovered. As
""V, ; ' Faraday» recognizing the importance of poisoning
tion (?o^ th/?°ti0nS'/t!ted that :the only essential condi-6
clean and ^.n? CG10n,t0 $«*« Plaoe) appears to be a perfectly
clean and metallic surface". However, it was not until the 1920's
poisoninTofU?nT*anding °f the caWic reaction and ol the
poisoning of that reactr.on, was obtained.
II. TECHNICAL IMPORTANCE
™ ™!!° tactora are responsible for the emphasis which is Placed
on poisons in industrial practice. The first is the high cost
of almost all contact catalysts, and the second is the fact that
lufficientT^ ^antitiea of «* «" a variety of materials are
Etalvs? rLh?a ?♦ f6 alm0St coraPletely the ordinary contact
ClttXl J Inability to remove the last traces of poisonous na-
trL 1 Lfi\the reactants "I" spell the failure of anv indus-
e f0f ,1 ,^ProCef; f°r examPle> the "modern" contact pro-
IaeLS to „St friC/°ld Wf* Patented in 1831 and attempts were
t^tt llr. k-, 3° Practlce shortly thereafter, but the opera-
Sal inuTce^ysV0 C°P6 W"h the Pr°blen 0f P0^"^ «f She*
[II. TYPES OF POISONS
Lv n^lySt poisons, may be divided into two categories, tempor-
ary and permanent. Temporary poisons are those which may be re-
ipvea under the conditions of the reaction merely by excluding
if'™^?! reactants and running the system for a few minutes.
to example of this type is water vapor in the synthesis of amm-
mxa over an iron catalyst. In this reaction, no difficulty is
experienced unless the partial pressure of the water vapor is
illowed to become too high in the reaction mixture.
Permanent poisons are those which cannot be removed from the
aoalyst unaer the conditions of the reaction, and in fact usually
an be removed only under drastic conditions. While most tempor-
ry poisons are nerely preferentially adsorbed on the catalytic
l,ve?Ce'rnSerSan2n,t poisons form st*ble compounds with the cat-
il fides n examples of Permanent poisons are the
V. ADSORPTION AND CATALYSIS
Two types of adsorption may take place on the surface of
catalyst van der V/aals adsorption, and activated adsorption.
d^n™??™ !tl0nK Thf f°rmer' a Physical Process with a heat of
dsorotion corresponding to the heat of liquifaction of the Ras
oes not lead to any catalytic activity. The latter, on the
nddopf nrtin ,a0c*e!?lcal Process with a high heat of adsorption
nd does often lead to catalytic activity. The fact that adsoro-
t0;,,^/? ™t enough to cause catalysis has been demonstrated
Y numerous investigators, among them Pease (1) and Maxted and
1
-So-
lon (2). Both of these papers showed for different svgtpmo th.t
flecf o1n1i?s°tfolsnrfdi0i?0n t0 deactivate the^alysf hal JJ&.
iiect on its total adsorptive capacity. This obviously means thst
il though the power of adsorption is common to a Urge part of 2
mall'pert of "thi f ' t^ "^ °<"<*W activfty^f l^mUef tTt
man part of this total surface.
A quantitative determination of the ratio of active to 1b-
ImZUVt^ $.**<%***? °f a Pr°m0tnd lrCn <*t£ysrwas made by
Fpoison tee ea^v^'^y+raSUrinf the amount of ox^en need^
„ i i ''he cata. vs - -or ohe ammonia synthesis, they v.-ere able
..^calcula:, that only one surface atom cut of 200 was ca?alytlcally
; DISTRIBUTION OF ACTIVITY/ OVER THE CATALYST SURFACE
I =^St °f °"r kn°wledse about the distribution of activity among
..e active centers has come from studies of the effect of poisons
Icti^fylTtaken" ? ""f* °l 00mm°n cata^st- ^is varUUon
LJniJiuf a f advantage of m the use of selective poison-
tion ThlUm«vhr "" r?ac"ons "ith°«t affecting the main "e-
lich will ieac?yorlvaw^hPthe mnJ" "^ °aSeS by addinS a material
: WJ"Lf --ec.ee only with The most active centers on the cat«lv<*t
►face without interfering with the less active ones. An ex- *
■okel ion*?^™* t?1SiS 3h! treatment of a nickel catalyst with
ickel ion to prevent ring hydrogenation in the catalytic reduction
aaded lurfn^ t° ^'T U) ' In a *°tte* kno™ example wa?er
added during the denydrogenation of alconols to aldehydes in
der to prevent further reactions of the latter
rerriefiMtHfa?*?? ^ f2r haVe den>on6trated that there is
« ™n?5i? n% i ♦ J!^0!? °f activlty amone ^e active centers
a contact catalyst, but have not indicated what type of distri-
xlri onH1^1^-/^ !eries of experiments by Maxted (5 & 6) and
xted and Morrish (7 demonstrated rather conclusively that the
Ttc ters of a Platinum catalyst can be classified in two or
fcans three groups, the members of each group all having aoorCxi-
i-^oo w^Same d6gree .°f activ"y- The evidence for this con-
'"?" ^ b'°sed on *e fact ^at a plot of catalyst activity vs.
I0",'0"™ on *e catalyst yielded straight line graphs rath
:-, and in some cases two, inflection points. The straight line
-un°oS ^t6Sent ^ adsorption of the poison on the molt active
fc? =L IZ t' and the inflections indicate, saturation of this
•ur and the star-, of poison addition to the set of next lower
j j. v i t y •
OHSMICAL STRUCTURE vs. TOXICITY
.^l+*f'i%rts *° ?bJain further indirect information about the
•'^d Snr^v, ^ytJC/urface» Ivlaxtea t0Sether with Evans, Mars-
. and Morrish conducted a series of investigations aimed at
hi wpi£g ^emical structure with toxicity (7-13). Their experi-
'L8awf all <rajried out by measuring the effect of the poison
pie rate of hydrogenation of crotonic acid in glacial acetic
a Dver a platinum catalyst. The activity of the poison was
,-b.yTed cy calculating the "poisoning coefficient" a from the
J owing equation: -
Kc = X0(l-ac)
c = concentration of poison
K0 = rate of unpoisoned reaction
Kc ~ rate of poisoned reaction
s*«
• :5.- :-;,:■ .. ■■■ ■• . ;>,r?j ";" \
.': ; '.':-,- ' ., r - V-'
*s •- ;.• ;-■ -- < *
" ' ' •■■ .i .■ 'i
'"■■ • •. ...
■
*
3
?
; . ••
.
* i . ■
«
•
•
. •
■■-,
- 86 -
This equation fits the straight-line plot of rate vs, quantity
poison until the first inflection in the curve, which usually
1 found at about b0% of the original rate.,
The first compounds investigated were sulfides, thiols di~
llfides, and dithiols. The following conclusions were drawn:
1. Alkyl sulfides and thiols- Toxicity per unit of sul-
fr increased with increasing chain length. The rate of increase
iclmed as chain length increased
. „< ,2\?he rati0 of toxicities of alkyl thiols to the corre-
londing dialkyl sulfides was 1 / 2.5, regardless of chain length
3. Addition of a second thiol group at the far end of
|e hydrocarbon chain decreased the toxicity, presumably by de-
ceasing the mobility of the chain.
4. Disulfides were only slightly more toxic than corre-
ronding monosulfides
5. Chain branching cut down the toxicity slightly: in-
duction of a terminal double bond had little or no effect
The next group of compounds tested was made up of the hydrides
l phosphorous, arsenic, antimony and bismuth. The toxicities of
I J uS\ f? Were approximately equal; that of bismuth was one-
Iird higher than the others, probably because of its larger size,
|C. SHIELDED DERIVATIVES OF TOXIC ELEMENTS
Some derivatives of phosphorous, selenium, tellurium, and
i fur were tested for toxicity under the same conditions as those
Dlined above^ The results are tabulated below;
TOXIC NON-TOXIC
sulfide sulfate
sulfite sulfonate
tetrathionate
phosphite phosphate
hypophosphite
tellurite tellurate
selenite selenate
It may be noted that the toxic derivatives all contain
.her unshared electron pairs or pairs shared with hydrosen.
Jarently either of these conditions allows the toxic atom to
let with the metal catalyst.
It was found that the activity of a platinum catalyst ooisoned
&im°Tod a8Uac^ by oxidizing
METALS AS POISONS
h
The toxicity of a number of metals (in the form of the ace-
tV Wn? ^termined with the same system and catalyst mentioned
1 2 , he elements of the first four groups of the Bohr Table
te tested was toxic, with the exception of aluminum, '
i The toxic elements could be divided into three groups with
ktive toxicities of one, two and four. Toxicity increased with
reasmg atomic size and with the number of covalent bonds th*
^nent might be expected to form with platinum.
IT* i - . • ^* •
. «> ... „• *•••-..• i ■■■: >: ■» . • •
j -..^t,;-» :
r v - s. •**
...r
r -'-
IT,
."' ' "f • '
^ -:■./: -;c
•y - * : • \i ■■ ■ • •
.•-'.-•; r- ..if .. . - "- '-y • ? >• ,--
- 87 -
References
Pease, J. Am. Chem. Soc. 45, 2296 (1923)
Maxted and Moon, J. Chem. Soc, 1936, 1228
Almquist and Black, J. Am. Chem. Soc. 48, 2814 (1926)
Yoshikawa, Bull, I:i«t. Phys, Chem. Research (Tokyo) 13, 1(H2,
(1954) C.A. 29, 5005 (1935)
Chem. Soc. 119, 225~Tl92l)
Chem. Soc. 119, 1280 (1921)
M0rrish, J, Chem. Soc. 194C , 252
Evans, ibid, 1957, 6C3
Evans, ibid, 1957, 1004
Evans, ibid, 1958, 455
Marsden, ibid, 1958, 839
Marsden, ibid, 1940, 460
Maxted, J.
Maxted, J„
Maxted and
Maxted
Maxted
Maxted
Maxted
Maxted
Maxted
and
end
and
and
and
and
Morrish, ibid, 1941, 152
-88-
USES OF THE IOx\TIC POTENTIAL
George K. Schweitzer Karen 18, 1947
I. The Ionic Potential (3)
Quite freouently we Pre reminded that the ninety-six known
chemical elements are too complex to be classified by reference
to any one atomic characteristic. The periodic classification
gives us only qualitative ideas and many attempts heve been
made to place the elements on a Quantitative scale.
Two important factors influencing ionic behavior are ionic
radius and oxidation number; increasing ionic radius and ionic
charge acting in opposite directions. In view of these considera-
tions, Cartledge has proposed that the ratio of charge to radius
(of a cation) should be an important property. Hence he defines
the ionic potential {</>) as:
fi = _Z = charge
radius
Some actual values of the ionic potential are given in the
following table:
Ion
Z
1
r
0
7fi
:cs
1.69
0.61
0.78
Rb
1
1.48
0.67
0.82
K
1
l.oo
0.71
0.89
Ne
1
0.98
l.OC
1.00
Li
1
0.60
1.30
1.14
3a
2
1.35
1.40
1.18
Sr
2
1.13
1.60
1.26
Ca
o
0.99
1.90
1.38
La
3
1.15
2.50
1.58
Kg
o
0.55
2.60
1.62
Sm
3
1.11
2.70
1.64
V
JL
3
0.93
2,80
1.67
Lu
3
1.00
3.00
1.74
Sc
3
0.81
3.60
1.90
Tn
4
1.10
3. 70
1.92
Ce
1
1.03
3.90
1.98
2r
4
0.80
4.60
2.15
Al
3
0.50
5.30
2.30
re
2
0.31
5.90
2.43
Ti
4
0.68
6.30
2.51
Cb
5
0.70
7.3
2,75
Mo
D
0.62
9.7
3.11
Si
4
0.41
1Q.0
3.16
s
3
0,20
15.0
3. 88
F
5
0.34
15. C
3.88
S
6
0.29
20.0
4.46
C
4
0.15
27,0
5.20
N
5
0.11
45,0
6*70
f
to
'f
\°-
Ir
J
T
o
0
Ft
X,
0
IIA HE IIF IIIA IIIC
II. Chemical Applications (3)4,5,7)
A. Acid and basic character may
1
< 2.2
>3.2
.2-3.:
Mature of hydroxide __
ba sic
acidic
a mono t eric
be related to j6
examole
NaOH
P(0K)B
A1(0H)3
1.00
3.88
2.30
s follows
• . «■•■■ ■ .'
-89-
B0 "he heats of solution (evolution) of salts with a common
anion increase with the i> of the cation.
Crr.od.
Heat of So In,
$ cation
LiCl
8.37kcal/mole
1.47
NaCI
-1.2
1.33
KC1
-4.4
0,75
RbCl
-4.5
0.68
CsCl
-4.75
0.60
C. The discharge potentials of cations in fused electrolytes
decrease regularly with increasing fi.
Cation Dischg. rot.
Arr_r"r 1.00 v.
Mgt 1.45 v.
Ca++ 1.90 v.
KaJ 2.45 v.
Cs1" 2.95 v.
i
cation
6.
,0
o
,82
o
,04
1.
,02
0,
,60
D. The ionization cotentials of metals decrease with decreasing
Element Li Na K Rb Cs
loniz, 5,37 5.12 4.32 4.16 3.88
i 1.30 1.00 0.71 C.67 0.61
E. If the "» ^ of the cation of a chloride is greater than
2.2, the chloride is volatile and non-conducting in the
liouid state. ,A ..
Element Si+'* Ge+4 Ti*4 Fb'4 Th+*
i:.F* Cl~ -70 -49,5 -30 -15 820
)'6 3.16 2.74 2.51 2.18 1.92
Cations with Yfr greater than 2 do not form stable normal
carbonates or nitrates. T.tfhen £ is between 2V2.5, basic
carbonates may be precipitated in solution. They are then
soluble in &n excess of ammonium or alkali carbonate.
Cmcd . T-rof; <t> cation
Sc2(CC3)3 stable 1.90
Th(CC3)3 stable 1.92
Zr(CC3)2 unstable 2.15
A13(C03J3 unstable 2.30
Binary crystals increase in hardness es the ^' s of their
constituents increase.
Cmot.
NaF
MgO
ScN
TiC
}i8 rd .
3.2
6.5
7-8
8-9
Yjfon
1.00
1.62
1.90
2.51
Y?a
0.86
1.19
1.32
1.24
H. When the ^ of a cation is less than 1, its salts are seldom
hydra ted and it does not form complex compounds. If the
fa lies above 1.9, the salts are almost invariably hydrated.
Ions with a fi above 2.4 are readily ammoniated and those
with i> above 2.5 may form ammines and inner complexes.
The following table lists some of the common complexing ions
and shows how these rules work*
-90-
Ion
Rb*
Be
+*
Cd*+
Ca++
Zn+*
Co**
Ni++
Fe+++
Co+++
Cr+++
A1+++
Ft
t-t-;- :
0.61
0/67
0.71
1,00
1.4
1.8
1.9
1.9
2.4
2.4
2.5
4.5
4,5
4.6
6.0
6.0
Complexin^ Ability
L
*
/^.
3
*
H/
3« Geological Apj^J_a£^l2^1 (1,2,6)
A" "l^CatLn^w^^f id6d lnt° three grou?s geologically:
1. Cations witn i less tnan three-these cations re-
Z^tn'trae i°^iC solution during the processes of
weatnering and transoortation.
Cations with j* between 3 and 6-these cations are pre-
cipitated by hydrolysis.
Cations with i> greater than 6-theee cations form
complex anions containing oxygen and some of them
ere soluble.
N^!fal,xfe0llte,S Collect and easily exchange cations
wnose 0's are less than 2.
2.
3.
^lements with nigh values of £ enrich in pili.
Goldscnmidt says that the dividing line is at fi ea
:ates;
ual
Conclusion • '
8 conven^nt^T-^V6 !?e thPt the ionio potential is
a convenient aid for instruction and understanding of various
is not.infalliole and may fail in some cases. It is used
to greatest advantage in trend oredictions; but at tines other
lrizscZiiT4e b^nvalld' chief *™ng tA-e bein^ ^ «"«t
1.
2.
3.
4.
5.
6.
7.
References
joldschnidt
Go Id schmidt
J. Chem. Soc.
19_5Z,
655.
ueocnemiscne Verteilungsgesetze der Elemente
iv v ^engfnverhaltnisFe der Element und der Atom-Arten
Vid-Akad. Oslo, Mat. Natwiv. Kl, , No. 4 1937
2855 (1928).
3076 (1930).
Skr. Norske
Cartledge, J. Am. Chem. Soc.
Cartledge, J^ Am. Chem. Soc, 52
Sun J. Chinese Chem. Soc, 5,T48 I(1937)J
nankama, Suomen G-eol. Toiailcunta, Bull
Finland?, 126, 24 (1941)
^meleus andVXnderson, "L'odern Aspects of Inorganic Chem
Comm. geol.
• • 5 .. - . ,; • - :•■' .
•
.
kw -n
.
- 91 -
TETRAVALZNT NICKEL
Elliot N. Marvel ROLL CALL March 25, 1947
Tetraval.ent nickel is not very stable or well characterized.
The oxide NiOo does exist perhaps, but has never been obtained
-cure and with constant composition. Hall (1) has obtained some
heteropolyacida of molybdenum and nickel with Mi+4^ Reasonably
complete analytical data and oxidative studies substantiate this
claim. His salts have the formula 3MO NiOg-QMoOy xKgO where M
may be K?, (NH4J0, or Ba. All are purple-black insoluble solids
which give very dilute but deep purple solutions.
Ray and Sarma (2) have submitted Hall's complexes to magne-
tic studies. All are diamagnetic showing that the Ni*4 is the
central atom of an octahedral complex with d sp3 hybrid bonds
resembling Co3. These authors have also prepared some tetra-
valent nickel complexes as M(I)|NiIO§}. Both Hall and Ray and
Sarma found that the only effective oxidizing agent was an al-
kalie persulfate. The treatment of a boiling NiSO^ and McIOg
solution with alkalie persulfate precipitates the insoluble
purple-black complexes as microcrystalline solids. Analytical
data are not presented but would not serve to distinguish the
Nia4 from Ni+2. Tetravalent nickel having four unpaired elec-
trons should hpve a magnetic susceptibility of 4.9 Bohr magnetons
The complexes however have a susceptibility of only 1.2 magnetons
Dissociation of the diamagnetic complex as shown would account
for this abnormality.
M
NilO
6j
..===^ MIOA + KiO.
Lly quantitative oxidation
Ii 4 this series falls in ■
However until fully quantitative oxidation studies can confirm
the presence of Nl 4 this series falls in the same category as
the higher oxides of nickel.
References
1. Hall, J. Am. Ohera. Goc. 29, 692 (1907)
2. Ray and Sarma, Nature, 157, 627 (1946)
Si. I".i
1' :
-92-
THE BUILDERS* by Vannevar Bush
Leon 5. Ciereszko ROLL CALL March 25, 1947
The process by which the boundaries of knowledge are ad-
vanced, and the structure of organized science is built, is a
complex process indeed. It corresponds fairly well with the
exploitation of a difficult quarry for its building materials
and the fitting of these into an edifice; but there are very
significant differences* First, the material itself is exceed-
ingly varied, hidden and overlaid with relatively worthless rubble
and the orocesc- ; uncovering new fact? and relationships has
some of the attrl '.v.tes of orospecting and exploration rather
than of mining o* -.'Tarrying. Second, the whole effort is highly
unorganized. Therv; 5 re no direct orders from architect or
ouarryma ster. Individuals and small bands proceed about their
businesses unimpeded and uncontrolled, digging where they will,
working over their material, and tucking it into place in the
edifice.
Finally, the edifice itself has a remarkable property, for
its form is predestined by the laws of logic and the nature of
human reasoning. It is almost as though it had once existed,
and its building blocks had then been scattered, hidden, and
buried, each with its unioue form retained so that it would fit
only in its own peculiar oosition, ^nd with the concomitant
limitation that the blocks cannot be found or recognized until
the building of the structure has progressed to the point where
their position and form reveals itself to the discerning eye
of the talented worker in the ouarry. Farts of the edifice
are being used while construction proceeds, by reason of the
applications of science, but other parts are merely admired
for their beauty and symmetry, and their possible utility is
not in question.
In these circumstances it is not at all strange that the
workers sometimes proceed in erratic ways. There are those
who are ouite content, given a few tools, to dig away unearthing
odd blocks, piling them up in the view of fellow workers, and
apparently not caring whether they fit anywhere or not. Un-
fortunately there are also those who watch carefully until soms
industrious group digs out a particularly ornamental block, where-
upon they fit it in place with much gusto and bow to the crowd*
Some groups do not dig at all, but spend all their time arguing
a s to the exact arrangement of a cornice or en abutment. Some
spend all their days trying to pull down a block or two that a
rival has put in place. Some, indeed neither dig nor argure,
but go along with the crowd, scratch here and there, and enjoy
the scenery. Some sit by and rive advice, and some just sit.
On the other hand there are those men of rare vision, who
can grasp v/ell in rdvance just the block that is. needed for
rapid advance on a section of the edifice to be possible, who
can tell by some subtle sense where it will be found, and who
;ach
,.iip and
delve, industriously, but with little grasp of what it is all
about, and who nevertheless make the great steps possible.
-93-
There ere those who can give the structure meaning, who
can trace its evolution from early times, and describe the
glories that are to be, in ways that inspire those who work
and those who enjoy. They bring the inspiration that all is
not mere building of monotonous walls, and that there is
architecture even though the architect is not seen to guide and
order.
There are those who labor to make the utility of the
structure real, to cause it to give shelter to the multitude,
that they may be better protected, and that they may derive
health and well-being because of its presence.
And the edific-e is not built by the ouerrymen and the
masons alone, There h:?e those who bring them food during
their labors, and cooling drink when the days are warm, who
sing to them, and pie se flowers on the little walls that have
grown with the ~jer. pB
There are also the old men, whose days o£.evJ.gorous
building are done, whose eyes are too dim to/the details of the
arch or the needed form of its keystone; but who have built a
wall here and there, and lived long in the edifice, who have
learned to love it and who have even grasped a suggestion of
its ultimate meaning; and who sit in the shade and encourage
the young men.
* Reprinted by permission of The Technology Review. Copyright,
1945, The Technology Review.
r.r •■ ,
; i. i J
: ■ ■ ' < ,:• . .
■■■
=31 -3.1 i.
-94-
SEPARATION OF RADIOISOTOPES
0. Pi Hill ROLL CALL March 25, 1947
Radio chemistry involves the handling of extremely small
amounts of material (for example, one microcurie of an element
of atomic weight 100 and of hal f life 1 day consists of only
7.7xl0~1^gm. ) so that the normal techniques of chemical separa-
tions do not apply. This material, however, has the same chem-
ical properties as the stable isotopes of that element and those
properties are brought into use in its sep-rr tion. A qualita-
tive outline is presented of the different methods of separation
employed.
I . Separation by means of Carriers .
Frequently it is advantageous to separate a radioelement
by "diluting" the radioisotope with a stable Isotope. The stable
isotope is called a carrier. Carriers are used, for example,
when it is desired to determine which of several possible' nuclear
reactions may have occurred in a particular bombardment. Accord-
ingly, in the nuclear reaction.
Za + 1 -«. V
.'7
Za -r n '--— -> (Z-l)a 4 p
'V(Z-2) *-3 *•<
About 10 mg of each new element which might be formed (e.g.,Z-l
and Z-2) are added and the usual chemical separations carried
out, the radioactive product thus following its isotope in tre
separation.
II. Separations without carriers
A* Precipitation HeacTtions"
After the bombardment, Cu65(a, 2n)Zn65 , the target
may be dissolved and the copper precipitated as the sulfide,
Heaving the zinc in solution. Similarily, "scavengers" can be
employed. Precipitates such as IvInOg or BaS04, which pick up
■ubstances present even in macro amounts, may be utilized to
remove certain of the fission products from solution, leaving
others in solution.
B . electroplating and chemic al plating
After the bombardment, Zn^3(n,o) Cu^4, the target may
be dissolved and the copper plated out on lead.
C . Volatility Methods
After the bombardment, Ga71 (D, 2n)?e71, GeCl, mav be
volatilized from hydrochloric acid solution without carrier
)ther than vapors from the solution.
Element 85 has been separated from bismuth after the
Dombardment Bi^uy(<X , 2n) 85^-1 by heating the target to 400°C, at
vhich temperature element 85 readily volatilzes and which is well
Delow the boiling point of Bi(1470°C).
Hahn and Strassmann passed a current of air thru
solutions of uranium compounds to remove kryoton and zenon activ-
ities from among the fission products.
D. Mori Aqueous Extractions
ETxer the bomoardment Zn6?(d, n) Ga68, a6N hydrochloric
icid solution of the target may be shaken with ether, extracting
>9.5> of the gallium into the ether layer, just as with macro
.mounts.
hj. Adsorption
Adsorption is a source of trouble more than an aid.
For example, in the determination of the solubility of RaSOA,
low values were obtained because > 98:3 of the RaS04 from its sat-
urated solution was adsorbed on filter paper. Glassware picks
up large amounts of radioactive materials and is a frequent source
of contamination.
F. Leaching;
After the bomb-rdment, Mg-4(d, --')Na22, the sodium may
be leached from a magnesium oxide target.
1 1 1 • Sep e ration by Re c oil - The S z i 1 ard-Chal me rs Method
When the radio element formed is on" isotope of tne target,
a special technique is employed to increase the concentration of
the radioisotope in the element. For example, in the reaction,
Br'y(n, ^)Breo, the *r recoil causes disruption of molecules such
as CgHeBr and CgH^Br and the active bromine can be collected
(usually with bromine carrier) free from the organic molecule.
Bimilarily, ueon bomb i 3 nent of Br03~, the active bromine can be
collected as silver b .c.
Necessary conditions are
(1) The radio atoms must be liberated during the bombard-
ment reaction.
(2) The radio atoms must not exchange with the unchanged
atoms.
(3) The radio atoms must be separable from the remaining
atoms.
IV. The Hahn precipitation rules
Frequently, it is necessary to employ as carrier on el-
ement which is not an isotope of the radioelement which is to be
separated (e.g., the separation of RaS04 with BaSO ). in 1913
Fajans formulated the rule that the lower the solubility of the
compound formed by the radioelement with the anion of the pre-
cipitate, the greater the amount carried by the precipitate. For
example, RaC (Bi isotope) precipitates with BaCO„ and' with Fe(OH),
but not v/,th Ba304 or Pb304, in agreement with the known sol- °
ability of the bismuth salts.
Hahn has divided coprecipitation into four types of
processes :
(]-) Isomorphous replacement is the precipitation process
when true isomorphism of the components occurs. The amount of
carrying is independent of temperature, acidity, order of addition
reagents etc. , as would be expected.
(2) Surface adsorption is the coprecipitation of an
3lemen t on the active surface of a freshly formed precipitate,
it is favored when the precipitate forms with a surface charge
Ipposite to that of the ion to be carried. Such things as tem-
perature, acidity, order of the addition of the reagents, etc.
featly influence the efficienty of this method.
(3) Anomalous isomorphous replacement is similar to (1)
iccept that it is not observed in macroscopic amounts of the two
jonroonents. It has been suggested that a very narrow range of
solid solution of the compound of the radioelement in the 'compound
)f the carrier element may be formed.
(4) Int e rn a 1_ a d s o r \ > t i o n s y s terns are poorly understood.
?he crystals appear as if the mother liquor or a radio-colloid is
lechanically enclosed within the crystal. X-rays indicate spotty
listribution of tne tracer element.
Source of Material: Series of lectures presented by G-.T.Seaborg
it the Metallurgical Laboratory, University of Chicago, July, 1942.
I few general references;
Ihn, Applied Jipdiocnemistry, 1936-Hevesy&Paneth, Manual of Radio-
activity,2nd ed., 1938. -Seaborg, Artificial Radioactivity, Chem Jlev
-96-
ELEKENTS 85 AND 87
Caryle Shoemaker April 1, 1947
The gaps in the periodic table have been filled one by
one until at the present time there seems to be few undiscovered
elements. The unknown as well as many of the rare elements
are found in the lower part of the periodic table. Many of the
elements with high atomic numbers, especially those whose
number Is greater than 83 have radioactive isotopes. Because
of this and the fact that elements 85 and 87 are very rare if
they exist naturally at all, it was widely suspected that these
elements would *be radioactive with comparatively short half
lives.
Hulubei and Cauchois (l) in 1939 were among the first to
report some experiments which they interpreted as evidence for
the existence of 85 in the decay products of radon.
Minder (2) also proposed that element 85 was among the
products of radium A (Fo; by a branched reaction.
2
222 /(^-):.io £fa£cM) at« , £
,T 2KI .
3
O
Their conclusions for evidence of 85 are based on the ioniza-
tion of shielded gas chambers (to stop^x particles). It was
found in this connection that Rn would coagulate starch.
The first to actually report the properties of element
85 were Carson, KacKenzie and Segre who bombarded Bi with 32
mev. alpha particles at the University of Cplifornia in 1940.
As a result of the bombardment the following radioactive phenom-
ena were observed.
1. Alpha particles of 6.55 cm. range (60$ of the total).
2. Alpha particles of 4.52 cm. range (40$ of the total).
3. G-fmma rays with an energy of about 0.5 m.e.v.
4. An X-ray or soft gamma ray with an energy of
about 80 k.e.v.
5. A soft X-ray.
6. a few low energy electrons.
7. All exhibit a. half life of 7.5 hours.
Further evidence and the basis for their conclusions on the
nuclear processes are as follows.
1. Alpha tracks always appear singly.
2. Nuclear isomerism was ruled out because the G-eiger Nut-
tal rule would predict a half life of 10~3 seconds in-
stead of the obseroed 7.5 hours. It would be most
reasonable to assume that the 4.5 c m appeared first.
■'i ■-.' ' ' .:
u« a X'c"-- -•
',". i
-97-
3. A right angled tube was arranged so that the nuclei
recoiling from one alpha, disintegration would be collec-
ted in front of a counter. The alpha particle from a
second disintegration would be detected. None were
found. This would indicate that a t ranching reaction
has occurred.
4. The fact that both alpha particles have the same
half life suggest that both groups originate from the
same species through some intermediate process.
5. The X-rays were characteristic of Fo and had a half
life of 7.5 hours.
6. No positrons were found. The nuclear reactions were
concluded to be,
7.5 hr.
f
V-
* 3
Though element 85 was separated from 3i in ten sec., no
evidence was found for the reaction
207 / 207
Bi ^-§l§5^ron_captJIL p^
83 ^82
Fission was ruled out because of the simplicity of the
radioactive phenomena and elements of low^r number occuring
as a result of fission would probably no'C be alpha emitters*
The reactions of element 85 were studied by the tracer
method using carriers and are reported as follows:
1. If the target of bismuth was scraped and the filings
heated almost to the melting point in an inert atmosphere,
the active residue was found to collect in an invisible layer
on a cooled plate. The target was dissolved in nitric acid and
diluted to 0.25 N (H*) for the following reactions.
2. HC1 does not precipitate 85 using Fb or Tl as a carrier
(useful for seoarating Hg, Fb, Tl )
3. 85 does not ppt. ouantltatively from (NH4)2S solution
using Ag or Hg as a carrier. Hydrogen sulfide will pre-
cipitate 85 Quantitatively in acid solution uo to 6N HC1 using
Bl,H3>Ag, Sb.
4. Ammonium hydroxide or fixed alkali precipitates 85,
perhaps due to absorption (not quantitative).
5. Fractional hydrolysis of bismuth nitrate by dilution
enriches 85 in the first fractions.
6. Reducing agents such as sulfur dioxide, zinc or stann-
ous chloride in hydrochloric or sulfuric acid solution pre-
cipitate 85 quantitatively, Precipitation with sulfur dioxide
in 3N HC1 ofiers a means of seoarating 85 nuantitatively from
Polonium which etayd in solution. "odiu^ stannite does not
precipitace 35 and this reaction affords a good method for
Rpnarptin^ 1 '•* fi'oin b i fiiiuith tn'\. Luriurn selenium mPT.urv ot^
8.9 x 10"
10
■ 5 gms
mo mi
525 (deliauescent)
8.9 x 10"
"6
0.81
3 x 10
0.003
-98-
7. Silver nitrate does not precipitate 85 from a slightly
acid solution using iodide as r carrier. When Agl, Zn and
sulfuric acid are mixed the activity collects on the zinc.
Compound Solubility
AgCl
AgC103
AgC104
AgBr
AgBr03
Agl
AglO 3
8. KI and dilute nitric acid were heated and the liberated
iodine distilled. The recovery of iodine was practically
complete while the recovery of 85 was variable and poor.
Polonium does not distill.
9. Extraction of 85 and iodine with carbon tetrachloride
gave a poor but definite yield.
10. 85 is deposited on a copoer plate from a 0.25 N nitric
acid solution containing bismuth and mercury. Cautious
heating removed the mercury leaving 85 behind.
Hamilton and Mayo (4) used some of the element 85 as
prepared by Carson, HacKenzie, and Segre to inject into
guinea pigs.. It was found that 85 was concentrated up to 100
times in the thyroid gland.
Recently Carson, HacKenzie and Segre prooosed the name
astatine (At) meaning unstable, for element 85. (5,6).
Leigh, Smith, and Minder (7) (1942) have reported that they
detected an isotope of 85 in the decay products of radio-
thorium. The nuclear reactions were interpreted as follows.
?i Si /A C » ^ 1 h L
I 9 i (3 (,0 mii
) \
oL li% , . , < < i '^ct» 2°lTL , ^
I O 5 re
The element 85 was separated from Rd-Th by blowing
the Th between two copoer electrodes. 85 was collected on the
negative electrode and sublimed at 180° onto a cooled silver
wire. After Ij min. the wire was placed in a Wilson expansion
chamber. Alphs and beta tracks began to appear after 10-20
minc These \r\ -tks originated from the gas and the walls,
continuing fo- Jbout 2 days. A beta ray often started at
the 33me poir" as an alpha particle. No reactions were given.
fli I K
':-■•■
.9v:
-99-
In 1942 (8) Karlik and Bernest at the Vienna Institute
for Radium Research disputed the earlier results Hulubei,
Cauchois and Kinden. They could find no evidence of wfpk
beta radiation from radium A.
Lrter in (1943) they continued the work of Leigh, Smith
and Kinden and concentrated the emanation from Rd-Th. Alpha
radiation of 6.84 cm. range and half period 54 sec, was found,
They believe this to be due to ^n alpha radiating isotope
216 of element 85. The branching ratio compared with the
alpha disintegration of Th A was determined as 1.35 x 10~4.
They could not duplicate the work of Leigh, Smith and Kinden
concerning the separation of element 85.
In a third paper they claim to have found 85 in the
products of An. Alpha rays reaching beyond the longest radia-
tion of the active precipitate (6.6 cm) were observed in en
ionization chamber with 4-step electrometer and oscillo-
graph. An alpha radiation of range 8.C cm. in the ratio
5 x 1C~6 to the Act A radiation was found. This value corres-
ponds to an extrapolsted energy for element 85 of mass 215
resulting from beta decay of Act A.
■•)
The following isotopes of 85 have been reported.
Experimenter
Hulubei, Ca uchlis, Hinder
Leigh, Smith, Kinder
Karlik and Bernert
Karlik and Bernert
Corson, KacKenzie, Segre
60$
Kuch less is known, (or reported) on Element 87
In 1939, Ferey (9) found evidence of a weak alpha
radiation from actimium. The following nuclear reactions
were advanced.
10 i| r j
V7
"ii
■ - <«_
,. ,o-a
*«c
2.11
4 y,)
•
c
•6"
;1. i
\
A)
C&.I i-
f
1
■■■■L
<<
,0 c ■
No
chemi
cal
react!
ons
were
given
«
Isotope
Radiation
218
(?)
216
3
216
LcL
215
(?)
211
«L (4.5 cm.
40f. )
kelectron crot.
* '**-,
' 7 , X (
ll.«d
2 1 *■ . > ,^ -^
4 a"3 .
, ((illcw)
f- ^_
y>
X - —
t. .
--, ,*• '
-100-
This new element w?s not carried down by orecipitates
of lead sulfide, barium carbonate or ceric hydroxide. It
was found to react, w3 th cesium as a carrier, to form an
insoluble perchlorate. Recently the name francium (Fr)
was proposed for this element (5,6).
BIBLIOGRAPHY
1. Hulubei, H. , and Cauchois, Y. , Comptes rendu. 209, 39 (1939).
2. lander, W. , Helv. Fhys. Acta. 13, 144-152 (1940T~
3. Corson, D. R. , KacKenzie, K. R. , and Segre, E.
Fhys. Rev. 5_7, 459, 1087, 58, 672 (1940).
4. Hamilton, J. G-. and Sole y, E, H. , Froc. Natl. Acad.
Sci. U. S. 26, 483-9 (1940 ).
5. Fareth, . F. A. Nature, Jan. 4, 1947.
6. Chem. and Engr. News. 25, 431 (1947).
7. Leigh-Smith, A. and Minder, V . , Nature 150, 767-8 (1942).
8. Karlik, Berta and Bernert, Traude Naturwlssenschaf ten
30, 685-6 (1942); 31, 492 (1943); 32, 44 (1944).
9. Ferey, M, J. Fhys. et le Radium 10, 435, 438 (1939).
10. Ferey, M, Compt. rend. 208, 97 (1939); 212, 893 (1991).
11. Ferey, M, end Lecoin, M. , Nature 144, 326 (1939)
( '
, *
-i r
f.~- ;.■
-\
-101-
METHODS OF DETERMING THE ADSORPTION OF
G-ASFS AMD VAPORS ON SOLIDS
\7. G-. Britton April 8, 1947
I. Introduction
Volumes have been written on the topic of adsorption.
This discussion is confined to the methods used to measure the
adsorption of vapors by solids with only a brief discussion of
the theory involved.
II. Theory
A. Variables to consider
If we consider, for example, the adsorption of vapors by
charcoal, the pressure of the vapor, according to the phase rule,
should be determined by the type of charcoal, the type of vapor,
the concentration of the condensed phase and the temperature,
Coolidge (l) has shown additional variables which are listed
below.
1. The temperature of the charcoal during outgassing
2. The time for outgassing.
3. The efficiency of the outgassing pump.
4. The previous exposure of the charcoal to trie same or
other vapors.
5. The direction from which equilibrium is approached.
6. The time elapsed since the last change in concentration.
This last variable is unusual. An equilibrium between the
charcoal and gas phase is quickly reached, after which the pres-
sure decreases in a few hours because the vapor slowly penetrates
to the interior of the charcoal. Sometimes the pressure increases
again, probably because traces of gas which remain in the char-
coal after outgassing are replaced by the penetration of more
powerfully adsorbed vapors,
3. Adsorption Isotherms
When the amount of gas adsorbed is plotted against pres-
sure, an "S" shaped curve usually results. Allmand and Burrage
(2) have shown that if a sufficient number of points are ob-
tained, some adsorotion isotherms show discontinuities. Tnese
breaks escaped the notice of other investigators because an
insufficient number of points was obtained experimentally, and
the deviation of a particular point from the smooth curve was
attributed to experimental error.
C. Character of the Interaction
When a gas comes in contact with a solid, it may be ad-
sorbed on the surface of the solid, it may be absorbed by di-
ffusion into the solid or it may react with the solid. Benton
(3) has shown that absorption may be distinguished from adsorp-
tion by study of the plot of pressure of tne gas against time.
Since gases diffuse into or through solids slowly, the pressure
decreases rapidly till adsorption equilibrium is reached, then
slowly till absorption equilibrium is reached. A chemical re-
action may be distinguished only by a knowledge of the tendency
of a particular gas to react with a particular solid. G-enerally,
a gas will act in all three manners simultaneously.
D. Mathematical Treatment
Even though the process of adsorption is a complicated
one, several mathematical equations have been proposed.
-102-
Freundlich has proposed a simple equation v/hich is faulty
because it does not recognize a maximum saturation for a definite
area of adsorbing surface (4).
Langmuir has proposed an equation which assumes that an ad-
sorotion maximum or surface saturation may be obtained (4). Lang-
muir described the mechanism of adsorotion as a dynamic equilibrium
between condensation and evaporation. When the surface b2cornes
cover ed with an unimolecular thickness of adsorbed gas, the sur-
face is saturated,
Brunauer, Emmett, and Teller (5) have modified the Langmuir
concept. They suggested that a multi-molecular layor may be
built up, and they derived two equations patterned after the
Langmuir equation for a mono-molecular layer. Pickett changed
the equations (6) by modifying the assumption that the final
layer of va oor on an element of surface is fully exposed re-
gardless of the number of layers on any adjacent element of sur-
face. He has suggested a decrease in the probability of escape
from an elemental area covered with a number of layers when the
number of layers on adjacent areas increases, and has derived
an equation which is verified over a greater range than the
Brunauer, Emmett, and Teller equations.
Recent investigators have applied mathematical treatment to
the discontinuities in the isotherms (7). Most changes in phase
are of the first order, i.e. posess a latent heat of transfor-
mation and a discontinuous change in volume. In a first order
change the volume changes without a corresponding change in
oressu::e; in a second order change there is a discontinuity in
(^'V/^P)rp and in a third order change there is a discontinuity in
( :>2v/}p2)ip. The order of the change of phase accounts for var-
ious types of discontinuities in experimental data. Such a com-
ol3x problem as this entails careful work in experimental veri-
fication.
III. Methods
There are three general methods for measuring adsorption.
The static method involves passing a known quantity of vapor
into a vessel containing the adsorbent and comparing the ob-
served pressure with that v/hich would have existed had there
been no adsorption. The dynamic method involves saturating
the solid with the adsorbent, passing another gas over the sat-
urated solid at a given rate and measuring the decrease in
weight of the solid at intervals. The sorption balance method
deoends on the sain in weight of the solid as determined by
the lengthening of a spring to which it is attached. Otner
methods involving the cnange in the floating level of a hydro-
meter, the use of an ultra-violet photometer, and the determina-
tion of adsorption of mixed gases will be presented.
A. The Static Method
A simple and rapid technique has been described by Porter
(8). The solid was placed on a micro-filter tube and the filter
tube was placed inside a larger tube wnich was connected to a
vacuum line and evacuate;!. Vapor was introduced into the tube
and the region around the solid was cooled so that the vapor
condensed on the solid. The filter was removed and the excess
liquid was centrifuges off. The filter was weighed to determine
Ithe weight of the solid saturated with vapor. The filter was
(returned to the tube; the tube was evacuated to a desirable
[pressure, and the filter was removed and reweighed. From the
-1C3-
data obtained, the oressure was plotted against the volume
adsorbed.
'.".rork on the adsorption of sulfur dioxide has been described
by McGavack and Patrick (9). The quantity of gas introduced
onto a weighed quantity of solid was determined with a gas buret
and the quantity of gas withdrawn was determined by the°gam in
weight of a tube of soda lime into which some of the gas°was
allowed to escape,,
A complicated apparatus for static measurements has been
described by Coolidge (l). All valves were mercury seals. Pres-
sures were measured with a McCleod gauge and a quartz fiber gauge
and volumes were measured with calibrated measuring bulbs, Dur-
ing a run, the quantity of gas in the aoparat.ua was never altered
Out tne fraction adsorbed by the solid was obtained from the
pressure reedinsre. The weight of the solid was obtained by
sealing off tne evacuated tube, weighing, and subtracting the
weight of the glass,
B. The Dynamic Method
The dynamic method of Allmund and Burrage (10) consisted
of passing air saturated with vapor over the solid, weighting
it then passing dry air at a known rate over the solid°(as
determined by a flow meter) and removing it at various intervals
and weighing. The weight of tne adsorbed vaoor was -clotted
against the volume of air passed. The tangent to this curve rep-
resents the rate of. loss of sorbed vapor and is orooortional to
the pressure of the vapor.
In a more recent article, Burrage has shown a source of
error in their earlier determination (11). When the air oassed
through tne tube of solid, the adsorbed vapor at the lower end
of tne tube passed into the air first so that there was a grad-
ient set up within the tube. A modified tube which had a volume
oi less than one centimeter was then used because here (Burrage
calculated) the pressure length effect was insignificant. The
data obtained from both of these investigations showed discon-
tinuities m tne isotherms. Some of the criticisms of this
metnoc, and the replies Burrage gave are interesting.
Criticism: It is unlikely that equilibrium was reached
between the adsorbed vapor and the air stream.
Reply: It was shown that the results were independent of
the velocity of the air stream.
Criticism: True equilibrium was not attained. If more time
were allowed the adsorbed material would "sink in".
Reply: The vapor was allowed to stand over the solid for
«Iinkfn5°?nn h°*UxS \ithout a Preemptible change in the pressure so
sinking in" did not occur with the materials used.
. . Criticism: Breaks m the isotherms might be connected with
interruptions due to the necessity of weighing.
Reply: a determination was carried out with purposely long
and snort periods between weighings and breaks occurred at the
same pressures as before.
Bohart and Adams (12) used a dynamic method for determine:
the effect of moist air on the adsorption of chlorine by char-
COai* .pAir Was Passed through a flow meter, then through sulfuric
acid of Known concentration to give it a definite vapo? oressure.
Chlorine was passed through a flow meter, then mixed" with the
^oAi 4?G mi*ture was Passed through the chaircoal, then through
solution of potassium iodide and starch. The appearance of
-104-
chlorine beyond the charcoal was detected by the starch coloration
Titration of the ootassium iodide solution with thicsulfate gave
the amound of chlorine that the cnarcoal did not retain. Tne
hydrogen chloride that was formed by catalytic action of tne
charcoal was determined by titrating the potassium iodide solu-
tion with sodium hydroxide.
C. The Sorption Balance Method
HcBain and Baker (12) have described a sorption balance.
The solid was placed on a pan attached to a spring which was
sealed along with a small tube of volatile liquid into a larger
bulb which was then evacuated. The tube of liquid was broken
and the weight of vapor adsorbed was proportional to the elonga-
tion of the spring. The pressure of the vapor was regulated by
regulating the temperature of the liquid.
Application of the sorption balance to high pressure
measurements has been described by McBain and Britton (13) . The
balance was made of glass covered with a sheet iron screen.
The balance was connected by cooper tubing to a cylinder of
compressed nitrogen. Thirty atmospheres pressure was handled
by the apparatus. when it was desired to reduce the pressure a
valvo vras loosened to permit some of the nitrogen to escape..
The pressure was measured by a pressure gauge..
D. Miscellaneous Methods
A new technique has been described by Chambers and King
(14) . Their apparatus was essentially a modified sorption
balance. A hydrometer floating in mercury held the solid and
the change in weight of the solid was determined by the change
in the level of the hydrometer*
Hurst and Rideal (15) have described a method for deter-
mining the selective adsorption of mixed gases. The com-
position of the gas was determined by measuring each pure gas
in a gas buret, then mixing. The gas was then passed over the
solid and the change in composition detected by thermal con-
ductivity measurements.
Recent work on an automatic recording ultra-violet photo-
meter has been described by Klotz and Dole (16). This device
measured the rate of adsorption of a gas. The device works
for any gas that adsorbs ultra-violet light. A concentration
of one part per million has been detected.
-105-
REFERENCES
1. Coo]idge, A. S., J. Am. Chem. Soc. 46, 596 (1924),
2. Allraund, A. J. and Burrage, L. J., Froc. Roy. Soc. (London)
A130, 610 (1931).
3. Benton, A, F. f J. Am, Chcm. Soc. 45, 887 (1923).
4. Rid al, ''Surface Chemistry", Cambridge University Press,
Cambridge, England, 1926, p. 132.
5. Brunauer, S. , Emmett, P. , and Toller, E. , J. Am. Chem. Soc.
60, 309 (1938).
6. Pickett, G. , J. Am. Cnem, Soc. 67, 1958 (1945).
7. Jura, G, ct al., J, Chem. Phys. 14, 117 (1943).
8. Porter, J. L. , J. Phys. Chem. 37, 361 (1933).
9. McGavack, J. Jr. and Patrick, W. A., J. Am. Chem0 Soc. 42,
946 (1920).
10. Allmund, A. J. and Burrage, L. J., J. Soc. Chem. Ind. 47,
372T (1928).
11. Burrage, L. J., J. Phys. Chem. 34, 2202 (1930).
12. fcloBain, J. V,'. and Baker, A. M. , J. Am. Chem. Soc. 48, 690 (1926)
13. McBain, J. '.V. and Britton, J. T. , J. Am. Chem. Soc. 52, 2198
(1930).
14. Chambers, K. K. and King, A., J. Chem. Soc. 139 (1939).
15. Hurst, W. V;. and Dideal, E. E. , J. Chem. Soc. 125, 696 (1924).
16. Koltz, I. IvI. and Dole, M. , Ind. Eng. Chem. (Anal. Ed.) 18,
741 (1946).
G-LNIRAL REFERENCE
Deitz, V. R. , "Biblio^raohy of Solid Adsorbants" Wasxiington, D.C.y
1944.
-106-
ADDITION COHFOUNDS OF SULFUR DIOXIDE
Carl Weatherbee April 15, 1947
Sulfur dioxide is generally assumed to exist in the
following resonance forms: (11)
- +
:0: :S:£:
I
f » :.Q:S:0:
II
< ^ :0:S::0:
III
If the above is accept
then one cm readily s
for both the sulfur at
donors and for the sul
sulfur atom of II havi
shell should be able t
whereas the sulfur a to
or III should be able
over, evidence will be
atom can act as an ace
ed as the structure of sulfur dioxide,
ee that it is theoretically possible
om and the oxygen atoms to act as electron
fur atom to act as an acceptor. The
ng only six electrons in its outer
o react by accepting a pair of electrons,
m and the oxygen atoms of either I, II,
to serve as electron pair donors. More-
presented later indicating an oxygen
eptor.
Liouid sulfur dioxide is a fair solvent for many inorganic
compounds and en excellent solvent for many organic substances;
such solutions are good electrical conductors, while sulfur
dioxide is not. It may be that linuid sulfur dioxide Gissoci-
a tes :
2S0;
fi-ZZ-^
so
+4-
Iik — ^ III
I <___.> II
0:
IV
++
so
..II «___^ III
:0:
V
or it may dissociate as Wickert (8) has pointed out:
0"""
so 3 ^"z_ so++ +
I 4 > II <r > III
:0:
:S
-4/
+4- "
0: +
VI VII
Even if sulfur dioxide should dissociate to any appreciable
extent according to either of these mechanisms, there are
good possibilities of the sulfur atom acting as an acceptor
and the oxygen and sulfur atoms acting as donors.
.
-107-
Booth and Martin (13) have shown that boron trifluorlde
and sulfur dioxide form a 1:1 addition compound with sulfur
dioxide. This was indicated by plotting temperature against
mole fraction of boron trifluoride and obtaining a maximum
a t 50 mole percent of boron trifluoride.
The question arises - what is the structure of this com-
pound? If Wickert's theory of the dissociation of liouid
sulfur dioxide is true, the boron trifluoride may react with
VI and VII to form
0:
:F:
:0 : B : F
:F:
in which the boron atom acts as an acceptor and the oxygen
anion acts as a donor. This structure is analogous to that
of the monohydrate of boron trifluoride:
H+
H : 0
: F;
However, the structure ma'y be similar to that of the addition
compound between Hyirogen sulfide and boron trifluoride Villa
in which the sulfur c^j\2 acts as a. donor:
H .
H
.0.
S : 3F3
» •
'■?.
Villa
S : 3F;
VHIb
Moreover, although it is not mentioned in literature, it
seems that it should be theoretically possible for the sulfite
anion V to form
: 0
: 0 : S
: 0
3F-
which being negatively charged would then combine with IV to
form:
0
Since no 2:1 addition compound, 25C3-BF3, has been noted to
date this might be used as evidence that liouid sulfur dioxide
dissociates as Wlckert has oointed out.
"' ■ "
— _
• •
++
• »
: 0 :
• •
•
0
• •
: S :
• •
: 0 :
BF3
v I -
-108-
Th e system A1C13-S03 has been studied by vrrious investi-
gators who have indicated that a 1:1 addition compound is
formed. G-erding and Smit (l?. ) prepared the compound and pro-
posed three structural formulas:
ci^i
I
CI
/y
0
i
Al
CI ^Cl
but experimental evidence seems to be best in agreement with
a double molecule, A13C16-2S03,
0
Ammonia (l) and various nitrogen containing compounds (2)
form complexes with sulfur dioxide. Ephraim and Fiotrowski
(1) have shown that three different compounds are formed by
the interaction of sulfur dioxide with ammonia, depending on
the conditions and relative amounts of reactants.
With an excess of sulfur dioxide, a compound S03-NH3, which
may be represented a £ amidosulf inic acid. NH3S03H, is always
formed. The reaction might be represented as:
H:N:+:0:S:0: > : 0 : S : 0
H
excess
H : N : H
H
and it may be assumed that the sulfur atom acts as an acceptor
and the nitrogen atom as a donor, followed by rearrangement
of the addition compound to the amido sulfinic acid by simple
proton migration:
H-H-
H
^ H8 N SO 3 H
With an excess of ammonia two products are formed, one a
white compound with the composition S03-2NH3 end the other a
red compound with the same percentage composition but double
molecular weight, 2S03-4NH3. The white product has been shown
to be ammonium amido sulfite, NH3S03NH4, and the red compound
triammonium imidosulf inate, NH4-N: (S03-NH4 )3. That one of the
nitrogens of the red compound has a different link than the
other three is shown by the preparation of a silver salt,
AgN: ( S03Ag)3, which is also red in color, such colored salts
often being obtained when metals are directly combined with
nitrogen.
:• r.rn
-109-
When amidosulf inic acid is heated under dry carbon di-
sulfide in a reflux apparatus, decomposition with ^h^ evolution
of 8mmonia is noticed, and e dark red crystalline sublimate of
the composition 3S03-4NH3 is obtained,
When sulfur dioxide is passed into an anhydrous alchollc
solution of hydrazine, a white, crystalline precipitate is formed
whose structure may be represented as
H3N ± NHa
J I ?==== (HOOS) NHNH ('SOOH)
bU 3 bU 2
Here again the sulfur atoms are electron pair acceptors.
Hydroxylamine react s..with sulfur dioxide to form sulfamic
acid. NH3OH + S03 -^2_> NH3S03H
Sisler and Audrieth (9) have shown that the yields are better
and the reaction time shorter if the reaction is carried out
under pressure. The mechanism of the reaction is essentially
as follows: The sulfur atom may act as an acceptor, the nitro-
gen atom as a donor ,t,o form H0NH3S03
H :0ml . . pH ; 0 ;
H : 0 : N : + V : £ H : 0 : N : S :
* H : o : • # k : o :
t * • «
The HONHgSOa may then undergo a ^eckmann type rearrangement;
that is, the hydroxyl group forms sn ionic bond leaving the
nitrogen with a positive charge:
n \ 0 4 n ♦ 0 "
0 : N : 3 :
0
S ± H
H
N
•'■ k" : o : " h :p#;
but since the nitrogen atom ha s a greater Vffinity for electrons
than sulfur, the free electron pair on the sulfur may shift to
the nitrogen, the sulfur acting as a do.npr assuming a positive
charge H ; 0 i
O ....
ho h3n: s > w + : N : s
+
s.
:o :
The negatively charged hydroxyl group unites with the possitlvely
charged sulfur atom which acts as an acceptor forming the
sulfamic acid
H : 0
H : 0 '.
* •
N
• •
H
S
• «
0 :
* •
0
H
±,
N
S
0
0 : H
H
N — ±
H
-AOHi
Thus, here is a compound in which the sulfur atom acts both as
a donor r nd as an acceptor.
Various organic compounds containing nitrogen form co-
ordination compounds with sulfur dioxide. Hoffman and Werf (20 )
in 1946 showed that oyridine, /% , forms a single stable
compound, S02-C6H5N, ' m.o. -7,4°f L
110-
alpha picoline,
C
J-CH3> forms two stable compounds with S03
1. 3S032CH3CBH4N, melts 8t -17.8°
S, SO3-CH3C5H4N, melts at -19.4°
A -CK3
bete oicoline, I L , forms one stsble compound
XN~ S03-CH3C5H4N, melts at -15.0°
gfmma picoline, CH
t
forms two compounds with sulfur dioxide
1. S03-CH3CsH4N, melts at 5°
?.. 2S03-CH3CBH4N, undergoes transition
N-
et its melting point at -26,5'
This
may be the result of the 1:1 compound
undergoing solvation.
Unlike most addition compounds, those resulting from the addit-
ion of sulfur dioxide to pyridine and picolines gives colorizes
compounds. Burg (17) presents evidence that trimethyl amine
and sulfur dioxide form a 1:1 addition compound simply by
electron sharing between the nitrogen and sulfur atoms - the
sulfur atom acting as an acceptor.
(CH3)3N: + S02 ^ (CH3)3N — > 30 3
He offeree.
I(CH3)3N-
formula
evidence
S0++SQ
that it does not exist
.To
as Bn ionic dimer
Jander and Wickert (7) advocated the.
|JC3H5)3N gj S0++ S03 , for the addition oroduct of
sulfur dioxide and triethylamine.
Burg points out that the 1:1 addition compound of trimethyl-
amine is soluble and is apparently solvated in liquid sulfur
dioxide; this could be due to a possible tendency for the sulfur
atom of the trimethylamine addition compound to act as a donor
with the sulfur atom of sulfur dioxide acting as an acceptor,
*. 0: :0: 0 0
(CK3)3N : S : S- or (CK3)3N — ±> S — » p
:0: :0: 0 0
It is interesting to note that trimethylamine forms a 1:1
addition compound
pound has much les
probably indicati
sulfur atom of sulfur trioxide.
with sulfur trioxide; this 1:1 addition com-
s solubility in sulfur dioxide than (CH3)3N'3D3,
ng the lack of free electron pairs on the
Trimethylamln
oxide at low temoe
(CH3)3N0S03, indie
ion (OK) has stro
tion comoound adds
not known whether
as a donor or if a
the amine oxide ac
that the crder of d
to be (CH3)3N0 >(
:o:
• •
s
• •
0
0
e oxide, (CH3)3N— *0, reacts with sulfur di-
ratures to yield the 1:1 addition compound,
a ting that the amine oxide as the hydro xyl
ng electron donor properties. This 1:1 addi-
another molecule of sulfur dioxide; it is
the free electron oair of the sulfur acts
free electron oair on the oxygen atom of
ts as the donor. However, Burg indicated
ecreasing attraction for sulfur dioxide appears
CH3)3N >(CH3)3NCS03 >(CH3)3NS03 >(CH3)3NS03
Bright and Fernelius (15) have shown that dimethylaniline,
CH3
, forms en addition comoound with sulfur dioxide.
OH.
i> V
• • j
-111-
Unlike Burg, they propose a N-O-S linkage instead of a
N-S-0 linkage., They oropose 5 oossible structures*
(R»= CGK5 ; R = CH3)
. R '.0'"., 4R 0.- ,
R*N ; S Vo: R*:ii : S :0:
R
R
R
o :
R
• a
:N r
R
• • ^
s:
• •
:o:
III
R'
+R
:'N :
0 ;
S :
-.0
• <
I II
\r # ~
r':n : o : s :0T
R
IV V
From experimental data the parachor of the addition compound
measures 405.4, which is within 2$ of 396.8, the value obtained
from the sum of the atomic and structural parachors for struc-
tures I and IV. However, Bright and Fernelius state that
structure I is unlikely because of adjacent positive charges, and
II, III, and V are unlikely because the sulfur atom has more
than an octet and because the double bonds makes the sum
of the additive parachors too high over the value obtained
from experimental results. Thus, they conclude that structure
IV seems the most probable. Although not stated in their arti-
cle, if this is true, then the oxygen atO'T, is acting as an
acceptor for the free pair of electrons from the nitrogen.
3right and Jasper (l6)+for similar, reasons assigned the
structural formula (C2HS)3N : 0* : S : P.r for the 1:1 addition
product of triethyajnine with s'ulfur dioxide, and the structure
(C3H7)3N+ : 0 : S *P.: for the addition compound with tripropyl-
amine. (19) '* "
Albertson and Fernelius (18) point out that various oxygen
containing compounds form addition compounds with sulfur dioxide.
They believe the 1:1 addition compound between sulfur dioxide
and dimethyl ether is best explained by assuming that the ether
oxygen atom shares a pair of its electrons with the sulfur atom
of sulfur dioxide:
« •
■^3^ . ,# H3C , . ', C#*.
; 0. + S02 -> '0*: S:
•
If this is true note the adjacent positive charges in the sense
that Bright and Fernelius assigned them in case of formula I
above. Thus it seems that either the existence of a N-S-0
link in R3K-S03 compounds cannot be ruled out as unlikely
because of adjacent like charges, or that a different type of
linkage exists between the oxygen atom of dimethyl ether and
sulfur dioxide than is explained above; to be similar to that
proposed by Bright and Fernelius in case of tertiary amines,
would reauire an oxygen-oxygen-sulfur link,
H»G + .. .. :0:-
> : 0 : S '*
H3C" " "
• J ;:
J..
■< -
T C\ l'1 \ '
■
■ » l_
-112-
It is interesting to note no reference has been found in which
Fernelius measured the parachors of such oxygen cSntalnU o™
pounds as dimethyl ether ~ sulfur dioxidefbCt Sas proofed
tnat tne oxygen atoms of anesole, dioxane, acetone donate
electrons to sulfur atoms of sulfur dioxide. aonc?^
th*t ^Q^1 sulfide forms an addition comoound similar to
that of hydrogen sulfide:
Hs^s
X
S- :
^5^2^
SO;
HsCg .. . +
> t ^..S > SO;
^ 5 C 2'
n5^2 . . .
- s
HRC
5^3
c
S '!
'he work of Ha gg (5)
of sulfur dioxide to sulfur trioxide may be
the sulfur atom of sulfur dioxide acts as a
0
0
In regard ;he ease of oxidation
interpreted to mean
■donor:
0 : ^ : '0
a
0
Sulfur dioxide
most evidence is in
sulfur atom acts as
y. m - -
has been reported to form various hydrates:
favor of S03-6Ha0. It is probable that the
m acceptor for a free electron oair from
one molecule of water, or of a hydroxyl ion, forming
[
0
s
K
0
H,0
the balance being associated
through hydrogen bonding.
Since sulfurous acid ionizes
it may be a hydrate of the type:
H30 +
Ha SO 3 ^=^ H30 + HSO
0
S
0 ;
H
0
• 1-
H,0
J
'» ' ", '! o ; '/ ^
-113-
1. Eohraim and Fiotrowski, Ber. 44, 379 (1911)
2. ibid. 44, 386 (1911)
3. Silberhead, Froc. Chem. Soc. 121, 1015 (1922)
4. 3-ermann and Booth, J. Fhys. Chem. 30, 369 (1926)
5. Hagg, 2. physik. Chem. 318, 199 (1932)
6. Hill and Fitzgerald, J. Am. Chem. Soc. 57, 250 (1935)
7. Jpnder and Wlckert, Ber. 70B, 251 (1937"]""
8. Wickert, Z. Electrochem. 44, 410 (1938)
9. Sisler and Audrieth, J. Am. Chem. Soc. 61, 3389 (1939)
10. Bright and Jasper, ibid. 63, 3486 (l94lT~
11. G-ur'yanova, Fhysicochem (T37S.S.R. ) 16, 181 (1942)
12. herding and Smit, Z. Fhysik, Chem. 351, 200 (1942)
13. 3ooth and Martin, J. Am. Chem. Soc. 64, 2198 (1942)
14. Fischer and Burger, Z. Anorg. Algem. Chem. 251, 355 (1943)
15. Bright and Fernelius, J. Am. Chem. Soc. 65, 637 (1943)
16. Bright and Jasper, ibid. 65, 1262 (1943)
17. Burg. ibid. 65, 1629 (19437
18. Albertson and Fernelius, ibid. 65, 1687 (1943)
19. Bright and Jasper, ibid. 66, 105 (1944)
20. Hoffmann and Werf, ibid. 68, 997 (1946)
-114-
THEORIES CONCERNING THE PASSIVITY OF METALS
Aoril 22, 1947 Peter C-. Arvan
The phenomenon of passivity of metals was discovered by
Keir (l) in the year 1790. He observed that iron, after treat-
ment with concentrated nitric acid, lost the property of pre"*
cipitating silver from solutions of silver salts, and was no
longer attacked by dilute nitric acid. The name passivity is
due to Schdnbein (2), who made many important contributions
to the knowledge of the subject. Faraday's (3) name is also
closely associated with the early history of the phenomenon.
For a number of years after 1840, little progress was
made in this field, but about 1900 a new era of advance set
in. This stage was initiated by the experimental investiga-
tions of Hittorf (8), who worked chiefly with chromium. Other
investigators of this time are Le Blanc (9, 17), Foerster (15),
Haber (4, 5), liililler (7, 11), Schmidt (16), and Krassa (6).
Since 1918 the predominating names have been U. R. Evans (19),
Tronstad, W. Hughes, and E. S. Hedges (20).
The Theories of the Passivity of Hetals
1* The oxide film theory (3, 4, 5, 6, 7, 20)
The mode of action of a film of oxide or other insol-
uble substance in causing passivity is presumably that
it coats the electrode c?nd mechanically hinders metallic
ions from entering the solution. Current can only pass
when the anode potential is increased to such an extent
that anions are discharged. This theory was proposed by
Farady (3), generally accepted until about 1900, and
then abandoned only to be revived in 1926 by U. R. Evans
(19).
£• The valence theory of passivity (10)
This theory, first brought forth by Finkelstein (10), is
based on the assumption that the modifications of a metal
with different valencies are all present in the solid
metal, in proportions depending on temperature and other
factors, and that the electrochemical behavior of metals
depends on the relative concentration of these modifi-
cations.
The main point of the valence theory is that the cause
of passivity is to be sought in the metals themselves.
This theory met with very little support and has been
almost discarded.
3 . The reaction-velocity theory ( 9 )
This theory was proposed by Le Blanc and in its most
general form states that passivity phenomena are due to
slow rate of change (electrochemical or purely chemical)
at the anode. This theory is little more than the state-
ment of the facts, and several special hypotheses have
been put forward as regards the mechanism of retardation
of the reactions at the anode.
(a) The oxygen charge hypothesis (12, 13)
The cause of passivity is to be sought in the slow
rate of reaction between the anode and the oxygen
liberated, with the result that the anode becomes
-115-
charged ,-rith gas, or, alternately, a metal-
oxygen alloy is formed. The sudden changes
from the active to the Passive condition are
ascribed to the transition from a non-homogen-
eous state of polarization into a continuous gas
charge covering the electrode uniformly.
( b ) The anion di s charge h y oothe s i s (14)
According to this hypothesis, the main change at
the anode is not the formation of metal ions but
the discharge of anions; the slow reaction of the
discharged anions v/ith the metal produces Passivity.
( c ) Th e hyd rogen aotiva tion hypothesis (15, 16)
This theory is based on the assumption that the
aure metal is passive and becomes active only
under the influence of a catalyst.
( d ) The retarded ion hy po the sis (l 7 )
In this theory the "assumption is made that the
active metal sends out ions into the electrolyte,
and that in the case of metals which tend to be-
come passive, these ions combine only very slowly
with water.
Ion + water p---£ ion hydrate
• Bibliography
"Transactions of the Faraday Society," 9, 203 (1914)
McKay and V/or thing ton, Corrosion Resistance of Metals and Alloys,
Reinhold Publishing Corporation, Mew' York, (19367"
Evans, U. R. , The Corrosion of Metals, Arnold and Co., London, (1924)
1. Keir, Fhil. Trans., 80, 359 (1790)
2. Schdnbein, Pogg. Ann., 37, 390 (1836); 43, 103 (1938)
3. Faraday, Fhil. Mag., 9, 53 (1836)
4. Haber and Goldschmidt, Zeitsch. Electrochem. , 12, 49 (1906)
5. Haber and Ma.itla.nd-- ibid; 13, 309 (1907)
6. Krassa, Zeitsch. Electrochem., 15, 490 (1909)
7. Mililler and Spitzer, Zeitsch. anorg. chem., 50, 321 (1906)
8. Hittorf, Zeitsch. physikal. Chem. , 25, 729 (1898); 30, 48,
(1899) ; 34, 385 (1900)
9. Le Blanc, Zeitsch. Electrochem., 6, 472 (1900); 11, 9 (1905)
0. Krillger and Finkelstein, Zeitsch. physikal. Chem., 39, 104 (1902)
1. LKtller, Zeitsch. physikal. Chem., 48, 577 (1904)
2. Fredenhagen, Zeitsch. physikal. Chem., 43, 1 (1903); 63, 1 (1908)
3. Muthmann and Frauenberger, Sitzungsber. der Kgl. Bayrischen Akad.,
34, 201 (1904)
(1908)
8. Russell, Mature, 115, 455 (1925)
9. Eva.ns, Nature, 118, 51 (1926)
D. Hedges, Chem. and Ind. , 50, 750--1 (1931); 1219 (1927)
- 116 -
ZIRCONIUM
Roy D. Johnson April 29, 1947
I. general (1,2,3,4,5,6)
Zirconium is raoidly emerging from its obscure position as
"one of the less familiar elements" through greatly expanded
commerical interest and usage. In spite of tne fact that zir-
conium is one of the twenty most abundant elements and is more
plentiful than nickel, tin, copper, lead, and zinc combined,
its use up to 1892 was severely hampered by the stability of
ZrSi04, its chief ore. The discovery of baddelyte, a zirconium
oxide ore, in nature has made zirconium and its compounds much
more readily available.
II. History (1,2)
Klaproth in 1789 found a new earth which he called "Zirconia"
in analyzing the precious stone from Ceylon known as jargon.
Berzelius (1824) was the first to obtain the element zirconium
in impure form. Ke obtained amorphous zirconium by reducing
KgZrFg with potassium. This method is still one of the best for
reducing zirconium to the elemental stage. After many false
'discoveries' of new elements in zirconium ores had been re-
ported, the element hafnium was found in zirconium ores by Cos-
ter and v. Hevesey in 1923. Since hafnium is very similar to
zirconium, no attempt to separate the two is made in indus try.
III. Zirconium- the element
Elemental zirconium' has been prepared as a fine black or dark
gray powder and as the lusterous ductile metal.
Zirconium powder (2,6,7) is generally prepared from the
purified oxide by a thermit reaction with Ma, Mg, Al, or Ca,
and purified by special methods. While the powder is stable
and relatively inert at ordinary temperatures, it ignities in
air when heated to 210-275°C The heat of combustion is approx-
imately 1956 calories/gram. These properties make it valuable
in primer mixtures as it doesn't deteriorate, react with the
other components, or form an amlgam with mercury on standing.
Above 200° the powder is an excellent getter. When it is used
in vacuum tubes for this purpose, the powder is mixed with a
binder and sprayed on the anode assembly. The good black sur-
face obtained by this method allows the use of smaller plates
by reason of its high heat of radiation. The powder has been
pressed into bars, sheets and wire, but these in general have
been brittle and unsatisfactory. Zirconium powder has also
been used in blasting caps, pyrotechnics, tracer ammunition,
end X-ray tube filters.
Ductile zirconium (2,6,9,10,11) is prepared by the method
of de Boer. Somewhat inrnure zirconium powder is placed in a
pyrex container with a little iodine. After the vessel is evac-
uated, it is heated gently to about 400° thus vaporizing the
iodine and forming Zrl4« A hairpin tungsten filament is then
heated to about 1300°, and very pure crystalline zirconium de-
posits on the filament :,'ith the liberation of the iodine. The
powder used must be free of other elements having volatile
iodides (e.g. Ti, 3n) as the iodine carrier action would cause
- 117 ••
thsm to codeposit and greatly decrease the ductility of the
product. When deposited at 1300°, zirconium crystallizes in a
body centered cubic lattice (beta-Zr) while at room temoereture
it has a closely packed hexagonal lattice (aloha-Zr). On cool-
5, the transformation takes place at 865°* The external form,
'ever, remains beta thus giving an interesting example of
seudo morohism.
Ductile zirconium possesses a white metallic luster which
does not tarnish on Jong standing. It is attacked by concentre
sulfuric acid at 100° C. ur by KF, but not by b0% Ho304 at IOC/--
any concentre tion of^HCl or HN0«i aqua regia at room temperatu:
10 fa NaOH at 100°, 50^ NaOH at lt)0°, or H2S.
The use of zirconium as a getter depends on its great affin-
ity for oxygen, nitrogen, carbon monoxide, carbon dioxide, hy-
drogen -aa water vapor. It aosorbs none of tae rare gases.
Definite compounds possessing crystalline forms different from
■conium are formed with oxygen, nitrogen, and hydrogen (ErOo,
ZrN, and Z1-H2) . When one starts with the pure metal, it seems"
rhat large amounts of these three gases can be absorbed without
:he formation of a new phase. Absorption of hydrogen is rever-
sible but that of oxygen ; nd nitrogen is not. Oxygen is ab-
rbed above 700° 3nd nitrogen above 1000°. Hydrogen is ab-
sorbed fairly readily at 500° and more rapidly at 1000°, but
at 1500° ZrH2 is completely decomposed.
Formation of the oxide raises the melting point, electric
JSistivity, and atomic distance but decreases ductility. The
>ehavior of nitrogen is similar except for the fact that the
nitride is a better conductor than the metal itself. ' Zirconium
rendered brittle by hydrogen becomes ductile again on heating
to a high temperature in vacuo.
When zirconium wire is used as a getter in vacuum tubes
(11), it is usually wound around a core, since the zirconium
alone is relatively weak. A companion wire serves to prevent
creepage and the formation of liquid zirconium globules around
the core. Ductile zirconium is also used as a getter for metal
evaporation on ceramics, glass and metals; as a welding flux,
grid emission inhibitor, and vacuum accelerator; and for rayon
spinnerets, sutures, surgical repair plates, and ceramics and
glass decoration.
IV. Zirconium alloys (6)
Interest in zirconium alloys arose chiefly from its use in
the steel industry as a scavenger where the addition of 0.15$
zirconium is reoorted to markedly decrease nometallic inclusions
and to counteract the effects of a high sulfur content - ZrSo
in steel does not cause brittleness.
Zirconium alloys with many metals including Si, Al, Ti, Mh,
Fe, Cu, and Mi. The solubility of zirconium in these metals
seems to be very small. As the amount of zirconium is increased
beyond a few tenths of a percent, definite compounds are formed.
Approximate formulas for some of these compounds are as follows:
Al4Zr3, (Fe3Zr2 or Fe2Zr) , Cu3Zr, Ni3Zr and Ni4Zr. An uninter-
rupted series of solid solutions is obtained with hafnium. Per-
haps the most interesting alloy -from the industrial viewpoint is
one of copper, containing 0.1 - b% zirconium. The electrical
conductivity of the cooper remains essentially unchanged, while
tne tensile strength and hardness are increased up to 50%. Tie
alloy will not soften up to 450° and is suitable for use in
'■••.trie leads and in spot welding electrodes.
- 118 -
V. Zirconium compounds (1)
Zirconium forms three general types of compounds, the normal
salts, Zr4"4; zirconyl salts, ZrO4*2; and zirconates, Zr03~2. Of
these, the zirconyl compounds are far in the majority as the
ormal salts are generally stable only in strong acids while
strong bases are required to obtain zirconates.
ZrSi04 (4, 12, 13) is the most abundant zirconium compound.
Zircon's melting point of 2550° is quite high, and, in addition,
it is extremely inert being insoluble in all acids except hy-
drofluoric. These properties coupled -with the low coefficient
of thermal exoansion of zircon, lead to its chief uses in, spec-
ial oorcelains and refractories. Zircon-silica glass is less
sensitive to temperrture change and more resistant to acids and
alkalies than ordinary glass. Zircon also finds some use in
enamels, cements, in the preparation of zirconium alloys, and as
an inert white pigment. Artificial zircons as well as the nat-
ural stones are now available commercially. It has been re-
ported that a mixture of ZrOg and silica heated to 1460° is con-
verted to a zirconium silicate identical with the mineral.
Zirconia (3, 14) is perhaps the most important zirconium
compound commerically because of its large us'e as an opacifier
in ena.nels. It is a white talc like powder which melts at
2950-200 and is a good, insulator for heat and electricity. Its
stability is indicated by the high heat of formation (264K cal-
ories/mol). The coefficient of expansion of 8 x 10"7 is slightly
higher than that of silica. Three crystalline forms have been
reported. The monoclinic form, which is precipitated under
ordinary conditions, changes over to the tetrsrronal with a
marked shrinkage in volume on heating over 1000°. This change
is reversible on rapid cooling. It is reported that a trigonal
or pseudo hexagonal rhombic form is obtained when ZrOg is fired
above 1900° for long periods. Some workers believe that this
is the stable crystalline form although it has not been found in
nature. Taking these facts into account, there are two methods
for making satisfactory zirconia refractories: A. by preparing
the "stable" trigonal form, and B. by adding 4 to 40 mol percent
of magnesium oxide to the zirconia and heating above 1700 •
In this region the two oxides form a series of solid solutions
giving a stable homogeneous cubic phase. Refractories made
in the latter manner are unusable above 2000°. Zirconia is also
used as a -oaint pigment, in glass, for safe and vault walls,
and as a catalyst in the preparation of gasoline from olefins.
Zirconium hydroxide (2) is obtained by precipitating a salt
solution with caustic soda or ammonia. It comes down as a bulky
gelatinous mass which retains a great deal of water. The anhy-
drous compound may be obtained by drying in vacuo over sulfuric
acid. Zirconyl hydroxide, ZrO(OH)g, is obtained at 100° or by
precipitation from boiling solution. Zirconyl hydroxide is am-
photeric as it forms zirconyl salts in the presence of mineral
acids and zirconates on fusing with a suitable alkalies. Organic
ialpha hydroxy acids give soluble complex compounds with zircon-
ium in alkaline solution. Thus, when tartaric acid is present,
izirconium is not precioitpted by caustic soda. Only when the
solution is exactly neutralized does the hydroxide come down.
JThe same effect is obtained with 1,2 dihydroxy alcohols and 1,2
aromatic phenols.
- 119 -
Zirconium sulfate (1,2) is prepared by the following re-
action: Zr02 "♦ cone. H2S04 _>_IQQ?___4 Zr(S04)2
It is useful in the detection of potassium as Ma+, NH4+ Cs4",
Rb"1", Li*, and Mg4-* do not interfere. The normal sulfate reacts
with water to give ZrOS04- The zirconyl sulfate finds consider-
able use as a tanning agent (15,16,17) for the best white leather.
Leather tanned with this agent is white all the way through,
stable, washable, unaffected by shoe cleaners, resistant to hot
water, and absolutely fast to light. A wide range of basicity
has been found permis sable in the tanning process, making it
easy to control under practical conditions. It can also be
used with chrome for tanning as a substitute for part of the
chrome or as a retan on chrome tanned leather to give additional
weight.
Zirconium carbide, ZrC, (1,18) is of interest because of
its extremely high melting point, 3532°C. It reacts to a small
extent with dilute nitric acid but immediately and violently
with concentrated nitric acid or aqua rogia. Caustic potash
dissolves it readily. T.ie carbide finds some use in cutting
tools because of its low heat conductivity, hardness, and re-
fractory nature. When the oxide is reduced with an insufficient
amount of carbon, a mixture of ZrC and Zr02 suitable for use as
an abrasive is obtained.
Zirconium^ halides (1,2,4) are quite similar so the dis-
cussion here will 15e confined primarily to the chlorides. The
normal chloride sublimes at about 350° • On cooling the vapor,
the chloride condenses to well shaped white needles which fume
in air with hydrolysis to ZrOClg* Zirconyl chloride crystallizes
in well shaped colorless n.edles with eight molecules of water
of hydro tion. It cannot be completely dehydrated without decom-
position.
Some facts of interest on other zirconium compounds (19)
are given in the following table.
VI • Bibliography
1. F. ?. Vsnable, "Zirconium and its Compounds," Chemical Catalog
Co., N.Y., N.Y. (1922).
2. J. H. deBoer, Foote Prints, 3, No. 2, 1 (1930).
3. J. D. Fast, Foote Prints, 10, No. 2, 1 (1937).
4. 3. S. Hopkins, "Chapters in the Chemistry of the Less Familiar
Elements, "Chap. 12, Stipes Pub. Co., Champaign, 111. (1939).
5. A. S. van Arkel, "Reine Lie tall e, "191, Edwards Brothers, Ann
Arbor, Mich. (1943).
6. :■!. :■:. Raynor, Foote Prints, 15, No. 2, 3 (1943).
7. &. H. Chambers, Metals and Alloys, 4, No. 12, 199 (1933).
8. US Pat. 17S0 413 (1930).
9. H. W. C-illett, Foote Prints, 13, No. 1, 1 (1940).
10. J. D. Fast, Foote Prints, 13, No. 1, 22 (1940).
11. C-. A. Eperson, Foote Prints, 18, No. 1, 3 (1946).
12. H. C. Meyer, Foote Prints, 9, No. 1, 1 (1936).
13. G-. C. 3etz, Foote Prints, 9, No. 2, 15 (1936).
14. E. Preston, Foote Prints, 11, No. 2, 1 (1938).
15. I. C. Sommerville, J. Am. Leather Cnem. Assoc. 36, No. 8,
381, (1942). ~
16. H. G. Turley and I. C. Somerville, J. Am. Leather Chem. Assoc.
36, No. 8, 391 (1942).
17. 1. C. Somerville and H. G-. Turley, J. Am. Leather Chem. Assoc. ,
38, No. 9, 326 (1943).
18. Agte and Alterthum, Zeit. tech. Physik, 11, 182 (1930).
19. Rahm and Haas advertizing literature.
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