Molar heat capacities of La₂Mo₂O₉ and La_1.9Sr_0.1Mo₂O_9-δ

Baijun Yan, Jianhua Liu, Yunduo Dai, Qifeng Shu, and Zhihua Ren Metallurgical and Ecological Engineering School, University of Science and Technology Beijing, Beijing 100083, China

摘 要：The molar heat capacities of La2Mo2O9 and La1.9Sr0.1Mo2O9-δ were obtained using the differential scanning calorimetry （DSC） technique in a temperature range from 298 to 1473 K. The DSC curve of La2Mo2O9 showed an endothermal peak around 834 K corresponding to a first-order monoclinic-cubic phase transition, and the enthalpy change accompanying this phase transition is 5.99 kJ/mol. No evident endothermal peak existed in the DSC curve of La1.9Sr0.1Mo2O9-δ, but a broad thermal anomaly existed in its heat capacity curve at around 832 K. In addition, the heat capacity values of La2Mo2O9 and La1.9Sr0.1Mo2O9-δ began to decrease at 1196 and 1330 K, respectively. The non-transitional heat capacity values of La2Mo2O9 and La1.9Sr0.1Mo2O9-δ were formulated using multiple regression analysis in two temperature ranges.

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