Thermodynamics of Tl(2)PrBr(5) Compound and Re-examination of Phase Equilibria in the PrBr(3)-TlBr System.

The PrBr(3)-TlBr phase diagram was first established in the 1970s. Due to some inaccuracies, it was redetermined using differential scanning calorimetry. The results obtained differ significantly from those in the literature, which has been discussed in this paper. Only one congruently melting Tl(2)PrBr(5) was confirmed, and the thermodynamic characterization of molar heat capacity temperature dependence was carried out for this compound. The compatibility of the obtained data was examined by using the CALPHAD method. The dependences of mixing enthalpy and mixing entropy of the liquid phase on the mole fraction were estimated.