Abstract Weberite-type oxides are a family of oxides with A3BO7 stoichiometry that can adopt different space groups depending on chemical composition. There is a discrepancy in previous studies as to whether Y3TaO7 is the orthorhombic C2221 or the Ccmm space group. Here, we describe the short- and long-range structural properties of weberite-type Y3TaO7 using neutron total scattering data, which has a high sensitivity to the oxygen sublattice. Simultaneous analysis of both short- and long-range structural data via conventional Rietveld and small box modeling demonstrates that Y3TaO7 is best modeled as C2221. While the Ccmm describes equally well the long-range structure, pair distribution function analysis revealed that the local atomic configuration can be best modelled as C2221. This is corroborated by first-principles calculations that confirm the energetic preference of the C2221 over Ccmm. Neutron total scattering data are reported for the first time for the Y3TaO7 weberite-type ceramics.

中文翻译：

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由中子总散射和密度泛函理论计算确定的正交方晶石型 Y3TaO7 的局部有序性

摘要 Weberite 型氧化物是一类具有 A3BO7 化学计量比的氧化物，可根据化学成分采用不同的空间群。Y3TaO7 是正交晶系 C2221 还是 Ccmm 空间群，以往的研究存在差异。在这里，我们使用对氧亚晶格具有高灵敏度的中子总散射数据描述了韦伯莱特型 Y3TaO7 的短程和长程结构特性。通过常规 Rietveld 和小盒建模同时分析短程和长程结构数据表明 Y3TaO7 最好建模为 C2221。虽然 Ccmm 同样很好地描述了长程结构，但对分布函数分析表明，局部原子配置可以最好地建模为 C2221。第一性原理计算证实了这一点，该计算证实了 C2221 对 Ccmm 的能量偏好。首次报道了 Y3TaO7 weberite 型陶瓷的中子总散射数据。