Abstract The enthalpy increments for the GdBaCo2O6-δ double perovskite were determined by means of drop calorimetry in air in the temperature range between 365.4 K and 1272.4 K. The heats of orthorhombic I→orthorhombic II phase transition at 347.2 K and orthorhombic II→tetragonal transition at 745.8 K are equal to (2.95 ± 0.07) kJ·mol−1 and (2.40 ± 0.09) kJ·mol−1, respectively, as measured with differential scanning calorimetry for GdBaCo2O6-δ. These calorimetric data were used to determine the heat capacity of GdBaCo2O6-δ and the high-temperature ‘chemical’ contribution to the enthalpy increments, caused by the oxygen exchange. The differentiation of the ‘chemical’ contribution with respect to oxygen nonstoichiometry yielded the partial molar enthalpy of oxygen in the GdBaCo2O6-δ, which agrees well with the previously reported results. The enthalpy increment data of nonstoichiometric oxides have proven itself as a valuable source of redox energetics information.

中文翻译：

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GdBaCo2O6-δ 的氧化还原能量和焓增量

摘要 GdBaCo2O6-δ 双钙钛矿的焓增量是通过在空气中在 365.4 K 和 1272.4 K 之间的温度范围内滴量热法测定的。正交 I→正交 II 相变的热量在 347.2 K 和正交→四方相转变 II 745.8 K 下的 GdBaCo2O6-δ 分别等于 (2.95 ± 0.07) kJ·mol-1 和 (2.40 ± 0.09) kJ·mol-1，用差示扫描量热法测量。这些量热数据用于确定 GdBaCo2O6-δ 的热容量和高温“化学”对由氧交换引起的焓增量的贡献。关于氧非化学计量的“化学”贡献的差异产生了 GdBaCo2O6-δ 中氧的部分摩尔焓，这与先前报道的结果非常吻合。