Gibbs free energy of formation of the LnMnO3 (Ln = Yb, Ho, and Er) phases determined by the e.m.f. method

The Gibbs free energies of formation of the solid YbMnO3, HoMnO3, and ErMnO3 phases in the (Ln + Mn + O) systems were determined by employing electrochemical cells with zirconia solid electrolyte in the temperature range (1150 to 1450) K. The results obtained in this study were used to derive the Gibbs free energy of formation of solid phases from the oxides. The respective equations took the following form:for YbMnO3: (ΔfGm∘ ±410)/(J · mol−1) = −29,189 + 0.021(T/K),for HoMnO3: (ΔfGm∘ ±730)/(J · mol−1) = −28,557 + 2.28(T/K),for ErMnO3: (ΔfGm∘ ±480)/(J · mol−1) = −25,324 + 4.265(T/K).