A simple model for calculating the bulk modulus of the mixed ionic crystal: NH4Cl1−x Br x

Abstract

The ammonium halides are an interesting systems because of their polymorphism and the possible internal rotation of the ammonium ion. The static properties of the mixed ionic crystal NH4Cl1 − xBrx have been recently investigated, using the three-body potential model (TDPM) by applying Vegard’s law. Here, by using a simple theoretical model, we estimate the bulk modulus of the alloys NH4Cl1 − xBrx, in terms of the bulk modulus of the end members alone. The calculated values are comparable to those deduced from the three-body potential model (TDPM) by applying Vegard’s law.