Solvus of KCl: Sr2+ solid solution by density measurements of single crystals with the flotation method

Abstract

The solvus of the KCl‐SrCl2 system is constructed in the region of concentrations of SrCl2 from 1 × 10−2 to 3.4 × 10−1 mol% and temperatures from 300 to 560 °C. The decomposition of solid solutions after various heat treatments is marked by change in the single crystal densities determined by the flotation technique. A thermodynamic analysis of these experimental data yields the impurity solution energy ((1.02 × 0.15) eV) and vibrational entropy (S/k = 4.2 × 2.8). The solution energy thus obtained is compared with the estimates found in the Mott‐Littleton ionic model, from an analysis of distribution coefficients, and from electrical conductivity measurements. All estimates are in reasonable agreement with each other.