Structure of molten alkaline-earth halides; SrCl₂ and CaF₂

Abstract

Recently de Leeuw has reported Monte-Carlo simulations for solid and liquid SrCl₂ and CaF₂ based on the rigid ion model. In the absence of adequate diffraction experiments for these liquids, his results form effective experimental information in this respect. We therefore thought it of interest to test the predictions of the ‘general primitive model’ of electrolytes—mixtures of oppositely charged hard spheres of unequal diameters, for these molten salts. For the solution of this model we have employed the mean spherical approximation using the procedure developed for arbitrary diameter ratio by Abramo et al. The overall agreement of the calculated radial distribution functions and the coordination numbers with those obtained by de Leeuw is fair. This correspondence improves when the ratio of ionic diameters is taken to be the same as in the pair potential used in the rigid ion model.