A galvanic cell study of the Ca+CaC12 system is reported. By proper allowance for electronic conduction in the electrolyte phase, the thermodynamic properties have been determined. These data are in good agreement with a vapour pressure study and phase diagram determinations. A model is proposed based upon non-stoichiometric compound theory involving an electron pair exchange equilibrium (Ca2)2+ +2CaZ+ + e2 at low Ca concentration. As the Ca concentration approaches saturation, electron pairs are increasingly dissociated and the solution may be described by the equilibrium (Ca2)*+ +2Ca2+ + 2e.

The principal constituents in molten solutions of calcium carbide in calcium chloride have been determined. The analytical results were generally within order of magnitude agreement with calculations from thermodynamic data based upon a model in which the calciumcarbideis thought to be dissociated according to the equationOn a Btabli la nature des principaux constituants des solutions fondues de carbure de calcium dans le chlorure de calcium. Les rdsultats analytiques sont g6nCralement en accord tt I'intQieur d'une ordre de grandeur-avec les donnks thermodynamiques basks sur un modkle dans lequel on croyait que le carbure de calcium est dissociB suivant 1'Bquation