Simulation of the Local Structure and Properties of the CaO-SrO and SrO-BaO Solid Solution

摘要

As was mentioned in [1], phenomenological theory [2-4] has been used for a long time to calculate the thermodynamic functions of mixing and the stability limits of solid solutions extended in composition (continuous). According to this theory, the mixing enthalpy △H_(mix) of solid solutions such as MO-M'O with the NaCl-type structure can be determined by the formula △H_(mix) = 9/4x_1x_2VK(△R/R)~2 = 1/4x_1x_2VK(△V/V)~2. (1) Here, x_1 and x_2 are the molar factions of the components; V is the molar volume; K is the compression modulus; △R = R_2 - R_1 and △V = V_2 - V_1 are the differences of the interatomic distances and molar volumes in the pure-component crystals, respectively; R is the average interatomic distance additively depending on the composition according to Vegard's rule R = x_1R_1 + x_2R_2, (2) and V is the average molar volume satisfying the Retgers rule V = x_1V_1 + x_2V_2. (3)