Abstract

The apatite-like Pb₉Pr(GeO₄)₃(VO₄)₃ and Pb₉Sm(GeO₄)₃(VO₄)₃ compounds were prepared by solid-phase synthesis using oxides as starting chemicals: PbO, Pr₂O₃ (Sm₂O₃), GeO₂, and V₂O₅. The successive annealing was carried out at 773–1073 K in the air. The effect of rare-earth elements on the structure of the Pb₉R(GeO₄)₃(VO₄)₃ (R = La, Pr, Nd, Sm) apatites and basic thermodynamic functions was investigated. The temperature dependence (350–1050 K) of the heat capacity of the Pr(Sm)-containing apatites has been determined by differential scanning calorimetry. It has been established that the C_p = f(T) curve for the Pb₉Pr(GeO₄)₃(VO₄)₃ compound has an extremum associated with a polymorphic transformation in the region of 978 K.

中文翻译：

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Pb 9 R（GeO 4）3（VO 4）3（R = La，Pr，Nd，Sm）磷灰石的高温热容

摘要

通过以氧化物为起始化学物质：PbO，Pr ₂ O固相合成制备磷灰石状的Pb ₉ Pr（GeO ₄）₃（VO ₄）₃和Pb ₉ Sm（GeO ₄）₃（VO ₄）₃化合物。₃（Sm ₂ O ₃），GeO ₂和V ₂ O ₅。连续退火在空气中于773–1073 K进行。稀土元素对Pb ₉ R（GeO ₄）₃（VO₄）₃（R = La，Pr，Nd，Sm）磷灰石和基本的热力学函数进行了研究。含the（Sm）的磷灰石热容的温度依赖性（350-1050 K）已通过差示扫描量热法测定。已经确定，Pb ₉ Pr（GeO ₄）₃（VO ₄）₃化合物的C _p = f（T）曲线在978 K范围内具有与多态转化相关的极值。