Investigations of BaF2–ThF4 System

Abstract

The standard molar Gibbs energy of formation of BaThF6(s) has been experimentally determined using a solid electrolyte galvanic fluoride cell: (−)Pt, NiO(s) + NiF2(s)│CaF2(s)│ThOF2(s) + BaThF6(s) + BaF2(s), Pt(+), with CaF2(s) as solid electrolyte. From the measured emf values, the Gibbs energy of formation has been calculated as \( \Delta_{\text{f}} G_{\text{m}}^{\text{o}} \) (BaThF6, s, T) {±5.1} (kJ mol−1) = −3379.9 + 0.5411 (T/K). Using the experimentally obtained data, the both axis potential diagram of Ba–Th–F–O system has been calculated and binary phase diagram of BaF2–ThF4 system has been computed.