Transpiration vapour pressures and activities in the molten salt systems ZnCl2 + NaCl and ZnCl2 + KCl

Vapour pressure measurements were made by a transpiration method for molten zinc chloride and molten mixtures of this salt with sodium and potassium chlorides, respectively. Activities of zinc chloride in the mixtures were calculated and from these values, those of the alkali chloride were calculated by Gibbs-Duhem integration. For this purpose a convenient computer method has been devised. Although the large deviations of activity and activity coefficients qualitatively support independent evidence that complex ions are formed in these systems, the results cannot quantitatively be explained using a calculation due to Braunstein in terms of interactions in the melt to form complex ions of a unique type, e.g. ZnCl3- or ZnCl42- etc. This indicates that the departure from ideal behaviour needs to be explained by a more detailed theory.

Molten salt mixtures. XI. Integral and partial molar volumes in the molten salt systems PbCl2 + NaCl, PbCl2 + RbCl, PbCl2 + CsCl, CdCl2 + RbCl, and CdCl2 + CsCl

The densities of molten PbCl2, CsCl, and RbCl and of the molten salt systems PbCl2 + NaCl, PbCl2 + RbCl, PbCl2 + CsCl, CdCl2 + RbCl, and CdCl, + CsCl have been measured to an accuracy of �0.1% by an Archimedean method over a considerable temperature range. Integral and partial molar volume isotherms have been constructed for the above binary systems and are interpreted to show that complex ions are formed in all but the PbCl2+NaCl system.