Double molybdates of indium and scandium with alluaudite structure are prepared by the solid-phase synthesis method. The crystal structure of the indium containing compound is refined and optical characteristics of Na5R(Mo04)4(R = Sc, In) are determined. Electronic structures of Na5R(Mo04)4(R = Sc, In) molybdates are studied within the ab initio method taking account of Na/Sc(In) positional disordering. Calculations of the imaginary part of dielectric function predict the optical gap of ~3.8 eV, in accordance with absorption spectroscopy data. It is established that formation energy of sodium vacancies strongly depends on sodium position and Sc(In) concentration. As a result, various diffusion mechanisms may be activated in alluaudite-type compounds with high and low contents of metal R.

中文翻译：

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钪铟双钼酸盐的晶体和电子结构

采用固相合成法制备了铝矾土结构的铟钪双钼酸盐。对含铟化合物的晶体结构进行了细化，并确定了 Na5R(MoO4)4(R = Sc, In) 的光学特性。Na5R(MoO4)4(R = Sc, In) 钼酸盐的电子结构在考虑到 Na/Sc(In) 位置无序的 ab initio 方法中进行了研究。根据吸收光谱数据，介电函数虚部的计算预测~3.8 eV 的光学间隙。已确定钠空位的形成能强烈依赖于钠位置和 Sc(In) 浓度。因此，可以在具有高和低金属 R 含量的铝矾土型化合物中激活各种扩散机制。