Heats of solution/substitution of Tl+, Rb+, K+, Br−, I− in crystalline CsCl from heats of solid phase transition by differential scanning calorimetry

Abstract

Measurements of the change in heat (enthalpy) of transition in crystalline CsCl effected by the presence of guest ions K+, Rb+, Tl+, Br−, I− using differential scanning calorimetry are reported. The nature of each mixed-ion solid, ‘mixed crystal’ or ‘crystalline solid solution’ is discussed. The limits of solubility of each guest ion are found to be consistent with the subsolidus region described in its respective phase diagram. The quantitative heat of transition values are used to calculate some fundamental solution quantities, viz. slope ΔHt/x or ΔH̄solute,χ, ΔHS0, ΔHL0—apparent partial molar heat of solution, partial molar heat of solution at infinite dilution, the heat of solution, recovered lattice energy, respectively.