Determination of the thermodynamic properties of yttrium oxyfluorides by the EMF method using solid fluorine-ion electrolyte

High temperature Gibbs energies, enthalpies and entropies of yttrium oxyfluorides formation using the e. m. f. method with a solid fluorine ion electrolyte are determined. Thermodynamic functions of reactions of YOF formation from simple substances are the following: ΔH12500 = 1199.6+-2.2 kJ-mol-1, ΔS12500 = 150.7 +-1.1 Jxmol-1xk-1, ΔG12500 = 1011+-2.2 kJxmol-1. It is established that crystal lattice of rhombic oxyfluorides YOF, YOsub(0.87), Fsub(1.26), YOsub(0.78)Fsub(1.44) in the energy ratio are practically equal