Calorimetric Investigation of PrBr₃-MBr Liquid Mixtures (M = Na, K, Rb, Cs)

Abstract

The molar enthalpies of mixing (Δ mix H m ) in liquid alkali bromide-praseodymium(III) bromide mixtures have been measured with a Calvet-type high temperature microcalorimeter over the entire composition range at 1070 K. All of the melts are characterized by negative enthalpies of mixing with a minimum value shifted toward the alkali bromide-rich compositions that are located in the vicinity of x(PrBr 3 ) ∼0.4. The magnitude of the mixing enthalpy depends on the ionic radius of the alkali metal, radius of the common halide ion, and the ionic radius of the lanthanide(III) cation.