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.