Crystal Structure and Physical Properties of Ternary Phases around the Composition Cu5Sn2Se7 with Tetrahedral Coordination of Atoms

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• 作者：Jing Fan ; Wilder Carrillo-Cabrera ; Iryna Antonyshyn ; Yurii Prots ; Igor Veremchuk ; Walter Schnelle ; Christina Drathen ; Lidong Chen ; Yuri Grin
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：September 23, 2014
• 年：2014
• 卷：26
• 期：18
• 页码：5244-5251
• 全文大小：469K
• ISSN：1520-5002

文摘

A new monoclinic selenide Cu₅Sn₂Se₇ was synthesized, and its crystal and electronic structure as well as thermoelectric properties were studied. The crystal structure of Cu₅Sn₂Se₇ was determined by electron diffraction tomography and refined by full-profile techniques using synchrotron X-ray powder diffraction data: space group C2, a = 12.6509(3) 脜, b = 5.6642(2) 脜, c = 8.9319(4) 脜, 尾 = 98125(4)掳, Z = 2; T = 295 K. Thermal analysis and high-temperature synchrotron X-ray diffraction indicated the decomposition of Cu₅Sn₂Se₇ at 800 K with formation of the tetragonal high-temperature phase Cu_4.90(4)Sn_2.10(4)Se₇: space group I4虆2m, a = 5.74738(1) 脜, c = 11.45583(3) 脜; T = 873 K. Both crystal structures are superstructures to the sphalerite type with tetrahedral coordination of the atoms. In agreement with chemical bonding analysis and band structure calculations, Cu₅Sn₂Se₇ exhibits metal-like electronic transport behavior.