Four New Actinide Chalcogenides Ba2Cu4USe6, Ba2Cu2ThSe5, Ba2Cu2USe5, and Sr2Cu2

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• 作者：Adel Mesbah ; Jai Prakash ; Jessica C. Beard ; S茅bastien Leb猫gue ; Christos D. Malliakas ; James A. Ibers
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：September 21, 2015
• 年：2015
• 卷：54
• 期：18
• 页码：9138-9145
• 全文大小：657K
• ISSN：1520-510X

文摘

Four new actinide chalcogenides鈥攏amely, Ba₂Cu₄USe₆, Ba₂Cu₂ThSe₅, Ba₂Cu₂USe₅, and Sr₂Cu₂US₅鈥攚ere synthesized via solid-state methods at 1173 K. Single-crystal X-ray diffraction studies show that Ba₂Cu₄USe₆ crystallizes in a new structure type in space group C_2h⁵鈥?i>P2₁/c of the monoclinic system, whereas the three other compounds are isostructural and adopt the Ba₂Cu₂US₅ structure type in space group C_2h³鈥?i>C2/m, also of the monoclinic system. These Ak/Cu/An/Q structures (Ak = alkaline-earth metal; An = actinide; Q = chalcogen) have no short Q鈥換 interactions and, hence, are charge-balanced with Ak²⁺, Cu¹⁺, An⁴⁺, and Q^{2鈥?/sup>. Crystal structures of all these compounds are two-dimensional and feature layers that are separated by Ba2+ cations. The compositions of these layers differ. In the structure of Ba₂Cu₄USe₆, the _{鈭?/sub>2[Cu4USe64鈥?/sup>] layers comprising USe6 octahedra and CuSe4 tetrahedra stack perpendicular to the a-axis. These 鈭?/sub>2[Cu4USe64鈥?/sup>] layers show short Cu鈥揅u interactions. In the three isostructural Ak2Cu2AnQ5 compounds, AnQ6 octahedra and CuQ4 tetrahedra are connected along the c-axis in the sequence 鈥?..oct tet tet oct tet tet...鈥?to form the 鈭?/sub>2[Cu2AnQ54鈥?/sup>] layers. Resistivity, optical, and DFT calculations show semiconducting behavior for these compounds.}}