COMMUNICATIONS TO THE EDITOR
Aug. 5, 1961
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a t this temperature until no more olefin distilled (3 hr.). The distillate was fractionated through a semi-micro spinning band column to give 8.3 g. (76%) of mixed octenes, b.p. 46-47’ (48 mm.). (5) National Science CoBperative Graduate Fellow, 1960-1961.
DONALD B. DENNEY SCHOOL OF CHEMISTRY vi-. CARLJ. ROSSI RUTGERS, THESTATEUNIVBSITY JOHN J. VILL~ Fig. 1.-Expansion NEWBRUNSWICK, N. J . us. d8 for solutions of sodium in RECEIVED JUNE 26, 1961 ammonia at -45’.
ON THE VOLUME EXPANSION OF SODIUM-INAMMONIA SOLUTIONS Sir :
mate that the maximum error in A V in our experiments does not exceed three per cent.; most certainly i t is less than this normally. We shall present additional data and describe our experimental method in detail in a paper to be presented soon. Support for this research from the Office of Ordnance Research, U. S. Army, is gratefully acknowledged.
We have investigated the expansion accompanying the dissolution of sodium to form dilute solutions in ammonia. The extraordinary results obtained are shown in Fig. 1, where A V is defined as, A V = (volume of solution - volume of constit- JOHN HARRISON LABORATORY OF CHEMISTRY uents)/g. atoms Na. E. CHARLES EVERS UNIVERSITY OF PENNSYLVANIA M. FILBERT 4, PENNSYLVANIAAUGUSTUS We offer a qualitative explanation for the be- PHILADELPHIA havior of AV. At infinite dilution dissociation RECEIVED JUNE 26, 1961 of metal is complete into “solvated’’ or “trapped” electrons and metal ions, and the expansion is large. As the concentration is increased, ions and electrons associate forming “atoms” and “molecules,” and A V decreases. This would suggest that the latter CONDUCTIVITY IN species may not be the highly expanded types sug- MECHANISM OF ELECTRICAL FUSED SALTS gested by Becker, Lindquist and Alder.’ The minimum in A V occurs in the concentration range Sir: where the conductance also passes through a miniWe wish to make a preliminary report on some m u m 2 This result, together with measurement recent work pertinent to the mechanism of elecof transport numbers3, indicate that incipient metal trical conductivity in fused salts. The attempts properties are commencing to show up in this re- to correlate diffusion, electrical migration and gion. I n essence, electrons are now being released fluidity data, and isotope separations by electrical to solvent, and A V increases again. migration in fused salts may all be affected by Prior to this study reliable data for A V were not these findings.’ available much below 1 X where A V is approxiMixtures of LiN03 and KN03 were placed in the mately 42 C C . ~In making estimates of the size anode compartment and pure hTahT03 in the cathof the trapped electron, i t had been assumed ode compartment of a U-shaped the compartthat this value of 4 V probably would not be too ments being separated by ultrafine Pyrex or in different from its value a t infinite d i l ~ t i o n .Judg~ some cases quartz porous plate. Electrolysis was ing by our results, the value for infinite dilution allowed to proceed and the total amount of cation appears to be approximately 41.5 cc. It is in- and the ratio of Li :K passing from anode to cathode teresting to note that the two values of AV, taken compartment were measured. The results, listed where the states of the system are vastly different, in Table I, show that within experimental error the are very nearly the same. ions move a t the same rate in all mixtures. The In our study, volume changes were measured transport number of the cation is indicative of directly using a dilatometer technique. We esti- which ion the mixture resembles most. The transport numbers of the cations in pure KNOa and (1) E.Becker. R. M. Lindquist and B. J. Alder, J . Chcm. Phys., 26, 971 (1956). LiNOs are 0.60 and 0.84, re~pectively.~
(2) C. A. Kraus, J . A m . Chem. Soc., 49,749 (1921). (3) J. L. Dye, G. E. Smith and R . F. Sankuer, ibid., 82, 4803 (1960). (4) C . A. Kraus, G. S. Carney and W. C. Johnson, ibid., 49, 2206 (1927). ( 5 ) W N Lipscomb, J. Chem. Phyr., 21, 52 (1043).
(1) G. J. Janz. C.Solomons and H. J. Gardner, Chcm. Reus., 68, 461 (1968). (2) P. R . D u k e and R . A. Fleming, J. Ekclrochem. SOC.,106, 130 (1959). (3) F. R . D u k e and B. B. Owens, ibid.. 106, 548 (1958).
