NOTES
2086
sample. The sealed tube runs on the 10 and 70% gallium oxide mixtures gave results identical with those obtained in open foil envelopes. No compounds of gallium oxide and Si02were encountered in this study. The 50, 60 and 70% Ga203compositions were heated a t solidus temperatures, and also a t 1550 and 1450" for 24 and 48 hours, respectively. Only @-Ga203and cristobalite were present in the runs. Thus no gallium analogs of mullite (3A1203.2Si02)or the A12SiOspolymorphs are stable a t high temperatures. The high temperature liquid immiscibility in the Ga203-Si02 system is another feature not found in A1203-Si02.4
1800~
Vol. 63
The observed electromative forces and values of the activity coefficients are recorded in Table I . TABLE I THE ACTIVITYCOEFFICIENT O F HYDROCHLORIC ACID CADMIUM CHLORIDE SOLUTIONS T = 25"; pT = p1 pp = ml 3mg = 5
+
IN
+
ml
E
log. Yl
5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5
0.09519 ,10906 ,12359 ,13859 ,15390 ,16935 .18529 .20253 ,22245 .25009
0,3766 ,2896 ,2001 .I102 ,0224 - ,0600 ,1574 - ,2114 ,2822 - .3550
-
This contribut,ion was supported in part by The Atomic Energy Commission under Contract AT (30-1) 1375
I
1500-
c n JIW2
2o
40
60
Mde % Ga,O,.
-
80
r
,-.
b o Z "3
Fig. 1.-Phase relations in the system Ga2O3-Si02. Solid dots represent the temperature of critical quench runs.
Phase relations in the Fe203-Si02 systems are not known a t liquidus temperatures because of the difficulty of maintaining the iron in the ferric state, so that no direct comparisons can be made with other M203-SiO2 systems. An extrapolation of data obtained at oxygen pressures of 1 atmosphere and less6 indicates that extensive liquid immiscibility exists in the Fe2O3-SiOa system. It may be suggested, therefore, that melting relations are similar in the systems Ga2O3--SiOzand Fez03Si02. (4) N. L. Bowen and J. W. Greig, ibid., 7 [41,242 (1924); with corrections by J. F. Schairer, ibid., 26, 243 (1942); further revision suggested b y N. A. Toropov and F. Ya. Galakhov, Doklady Akad. Nauk S.S.S.R., 78 [2],301 (1951). ( 5 ) A. Muan, J . Metals, 7 [9],965 (1955).
THE ACTIVITY COEFFICIENT OF HYDROCHLORIC ACID IN CADMIUM CHLORIDE SOLUTIONS AT 5 M TOTAL IONIC STRENGTH BY HERBERTS. HARNED AND ROBERT GARY Contribution N o . 1669from the Department of Chemistry of Yale University, NEWHaven, Conn. Received June 66,1959
As a further contribution to the st.udy of the systems containing two electrolytes in water, the activity coefficient of hydrochloric acid in cadmium chloride solutions a t 5 M total stoichiometric ionic strength has been determined at 25' from measurements of the cells H 2 lHCl
(mi), CdClz
(mz)lAgC1-Ag
ELECTRON PARAMAGNETIC RESONANCE STUDIES ON CARBON DISULFIDEINSOLUBLE SULFUR BY A. G. PINKUS A N D L. H. PIETTE~ Department 01Chemistry, Baylor University, Waeo, Texas, and Varian Associates, Palo Alto, California Recez'ved J u l y l.$?1969
Recently,2 a close-packed helical structure was uggested for crystalline polymeric carbon disulfide -insoluble sulfur obtained from the slow cooling of a purified sulfur melt in order to explain the similarity of its X-ray diffraction pattern to that of orthorhombic sulfur.3 A more extended helical structure also had been suggested recently for the fibrous constituent of stretched plastic s u l f ~ r , ~ , ~ Dads white sulfur,6.6 and for "supersublimation" It was pointed out2 that stereochemical considerations exclude a macrocyclicS structure for the close-packed helical configuration and suggested that electron paramagnetic resonance determinations on the insoluble sulfur would distinguish between the biradical (I) or three-electrori bond (II)9 structures on the one hand and the ionic structure (111) on the other. In their classical paper,'O Gardner and Fraenkel previously had re(1) Varian Associates.
(2) A. G. Pinkus, J. S. Kim, J. L. McAtee, Jr., and C. B. Concilio, to be published. (3) A. G. Pinkus. J . S. Kiln, J. L. McAtee, Jr., and C. B. Concilio, J . A m . Chem. Soc., 79, 4566 (1957). (4) L. Pauling, Proc. Nat. Acad. Sei., U . S.,35, 405 (1949); J. A. Prins, J. Schenk and P. A. M. Hospel, Physica, 22, 770 (1950); A. R i m monti and C. Vacca, Ricerca Sei., 28, 1880 (1958). ( 5 ) S. R. Das, Indian J . Phys., l a , 163 (1938). (6) J. A. Prins, J. Sohenk and L. H. J. Wachters, Physica, as, 746
(1957). (7) Product of Stauffer Chemical Co. having the registered trade name of "Crystex." ( 8 ) H. Krebs and E. F. Weber, Z. anorg. allgem. Chem., 272, 288 (1953). (9) F. Fairbrother, G. Gee and G. T. Merrall, J . Potymer Sei., 18, 459 (1955); G.Gee, Science P r o g ~ e s sNo. , 170, 193 (1955). (10) D. M. Gardner and G. K. Fraenkel, J . A m . Chem. Soc., 18, 3279 (1950).
6
