Heats of solution/substitution and of fusion of Cs(1−x)KxCl compositions 0<x<0.57 by differential scanning calorimetry

Measurements of the change in heat (enthalpy) of solid-solid transition ΔH_t and of fusion ΔH_fus in crystalline CsCl effected by the presence of guest ion K⁺ up to 56.5 mol% using differential scanning calorimetry are reported. The range of K⁺ solubility is found to be higher and at variance with the subsolidus region described in earlier reports. Novel features of ΔH_t and ΔH_fus dependence on solute composition are in contrast to parallel binary systems, viz. CsNO₃-RbNO₃, CsNO₃-TlNO₃ and RbNO₃-TlNO₃. Some fundamental solution quantities are calculated from heat of transition, viz. slope ΔH_t/x or and χ-apparent partial molar heat of solution and partial molar heat of solution at infinite dilution, respectively.