High-temperature behaviour of the CuMo3O10 ⋅ H2O compound
Ismagilova R. M., Zhitova E. S., Zolotarev A. A., Shilovskikh V. V.
Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2021. V. 150. N 2. P. 92-105
https://doi.org/10.31857/S0869605521020076
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Language: Russian
Abstract
CuMo3O10 ⋅ H2O crystals have been obtained by hydrothermal synthesis as a result of reaction between (NH4)6Mo7O24 ⋅ 4H2O and Cu(CH3COO)2 at 220 °C during 7 days. The Xray powder diffraction data in wide range of temperature have shown that the studied phase is stable within the range from –180 to 300 °С. Its thermal expansion is anisotropic, thermal expansion coefficients, calculated at Т = 100 °С, are: αa = 28.5, αb = 6.1 and αc = 13.3 °С–1. Structural changes have been analyzed by the structure refinement method based on the single-crystal X-ray diffraction data at different temperatures. Thermal expansion anisotropy is connected with the chain-structure type and the angle deformations caused by changes in inter-atomic angles in the CuO6 octahedra and in inter-polyhedral angles between copper octahedron and trimolybdate chains. The high-temperature behavior of CuMo3O10 ⋅ H2O is compared in the paper with behavior of chemically close copper molybdates – lindgrenite, szenicsite and cupromolybdate.
Keywords: copper and molybdenum compounds, trimolybdates, thermal expansion, dynamics of crystal structure
