Volumetric Behaviour of Molten Salts and Molten Salt Hydrates

The volumetric behaviour of molten salts and salt hydrates depends on their measured densities as functions of the temperature at ambient pressure. Ultrasound velocities are also needed for obtaining compressibility data. The methodology employed for these measurements, as it is applicable at elevated temperatures, is briefly described. The densities, expansibilities, compressibilities, and molar volumes of molten salts are compiled and presented in extensive tables. The internal pressures of molten salts, deduced from these data, are presented. Correlations of these quantities with other properties of the salts, such as the sizes of the ionic constituents and the cohesive energies of the salts, are described. In the case of molten salt hydrates the molar volumes of the melts are discussed in terms of the electrostriction of the water.