iodide can only be explained by assuming some solubility of foreign cations in the solid (K + or H + ). These ions can enter from the solution and seem to have a mobility (diffusion coefficient) in the solid comparable to that of the silver ions. Detailed data cannot be obtained from the present results; it seems worthwhile to study the solubility and diffusion coefficient of such foreign ions by more direct solid-state methods.The main difference between the behavior of the two compounds Ag3SI and Ag19115P~O7 may stem from the different degree to which replacement of Ag + by other ions is possible in the interface. In Ag2SI only a very small part of the silver is exchangeable and the compound remains insoluble. With AglgI15P207 depletion of silver leads to new, water-soluble phases. ABSTRACTThe activity of Li~N dissolved in molten LiC1 at 923~ in the range of molar fraction between 0.101-1.6 X 10 -3 has been determined by using the following galvanic cell Fe, Li (1)/LiC], Li~N/N2 (g, 1 arm), Fe (I)) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 132.239.1.231 Downloaded on 2015-08-24 to IP

The free energy (Gibbs) of formation of Li2C2 , CaC2 , and Li3N and their activities in molten salt solutions at temperatures between 823° and 973°K have been determined by using the following galvanic cellsnormalFe,normalLi‐normalCa )(normalalloy|normalLiCl‐CaCl2 normaleut.CaC2|C)(normals,normalFe ][IandnormalFe,normalLi )(normalc|normalLiCl‐normalLiF eut.Li3N|N2 )(normalg,1 normalatm,normalFe ][IIThe nitrogen electrode used in cell (II) has been proved to have a Nernstian behavior by studying the dependence of emf on the partial pressure of nitrogen. The activity coefficients of CaC2 and Li3N in molten salts have been found to decrease with increasing concentration.

An exploratory study concerning the solubility and electrolysis of normalAlN in molten salts has been carried out in view of the development of a new process of electrowinning of aluminum with lower energy consumption than the Hall‐Herault process. Aluminum nitride appears soluble in molten Li3N‐normalLiCl and the existence of solubility is supported by thermal analysis, electrical conductivity, and galvanic cell measurements. Chemical analysis of the melt indicates the possibility of existence of aluminum chloride‐nitride complexes of the type Li3N·3normalAlN·4normalLiCl . Pre‐electrolysis or argon treatment of the bath could reduce Li3N content to about 0.1 w/o in the melt without observing decomposition of the solution. These melts with low Li3N content appear suitable for the electrowinning of aluminum. The Faradaic efficiency has been estimated to be about 83% from the amount of aluminum forming an alloy with the iron cathode. The cell voltage necessary for the electrolysis is in reasonable accord with the thermodynamic value.

Aus Löslichkeits‐ und elektrochemischen Untersuchungen geht hervor, daß AlN sich in Li3N‐ LiCl‐Schmelzen auflösen läßt und daß dieser Elektrolyttyp geeignete Zusammensetzungen und Eigenschaften f eine neuartige elektrolytische Al‐Gewinnung aufweist.

Die Freien Bildungsenthalpien und die Aktivitäten von Li,C2, CaC, und Li3N in den betreffenden Salzschmelzen konnten über die galvanischen Ketten: Fe, Li‐Ca(Legie‐ rung)/LiCl‐CaCl,‐Eutektikum, CaC,/C(fest),F e und Fe,Li(c)/LiCl‐LiF‐Eutektikum, Li3N/N,(p),Fe gemessen werden, von denen die erste auf der Basis der Carbidbildung zwischen 873 und 973 K und die zweite auf der Basis der Nitridbildung zwischen 823 und 973 Karbeitet.