Thermal Expansions of Some Alkali Halides

Abstract

A simple model is presented for the calculation of the equilibrium nearest‐neighbor separation R 0 of the alkali halides as a function of temperature at atmospheric pressure. Theoretical values of R 0 are compared with the experimental data for NaCl, KCl, KBr, KI, CsCl, CsBr, and CsI for the temperature range from room temperature to the melting point. Excellent agreement with experiment is obtained for the potassium halides by using a central‐force two‐particle potential composed of the Coulomb interaction and a nearest‐neighbor exponential repulsive potential.