Thermodynamics of solutions of cadmium in cadmium chloride: activities and molar volumes

Abstract

Thermodynamic data for solutions of cadmium in molten cadmium chloride have been obtained at 600 and 700° using the cell: C(graphite)|(CdCl₂+Cd)∥(CdCl₂+Cd)| Cd(1). a_Cd<1 a_Cd= 1 The strong positive departures from ideality in the system have been interpreted using a model in which the free energy of mixing is separated into two parts, the formation of a hypothetical subchloride Cd₂Cl₂, containing the ion Cd²⁺₂, and the mixing of this with the normal halide. The thermodynamic properties of this subchloride have been estimated and compared with those for mercurous chloride. Volumes of mixing have also been measured using a pyknometric technique and are consistent with the same model.