New theory of repulsion and structural stability in ionic crystals

Abstract

An ionic crystal is viewed as a collection of compressible ions in polyhedral, spacefilling cells. Repulsion arises solely from the increased compression energy at the cell faces. Eighteen parameters (two per ion) are determined from the lattice spacings and compressibilities of the twenty alkali halides. These explain for the first time the observed structures of all these crystals as well as their thermal and pressure transitions—a significant advance over previous semiempirical theories