Measurements on the Densities and the Surface Tensions of Molten Alkali Metal and Alkali-Earth Metal Fluorides

Abstract

Densities and surface tensions of molten alkali metal and alkali earth metal fluorides were measured by Archmedean method and maximum bubble pressure method, respectively. The results showed that the properties of the fluorides, such as surface tension, temperature coefficient of surface tension and coefficient of thermal expansion, depended on the Coulomb force experienced by foreign ions. Isothermal compressibility and coefficient of thermal expansion of fluorides calculated by application of the scaled particle theory, developed by H. REISS, agreed well with the experimental results. From the relation between surface tension and molar volume, it has been supposed that structure of liquid surface is similar to that of solid cleavage plane.