Anion鈥揂nion Bonding and Topology in Ternary Iridium Seleno鈥揝tannides

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• 作者：Benjamin A. Trump ; Jake A. Tutmaher ; Tyrel M. McQueen
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：December 21, 2015
• 年：2015
• 卷：54
• 期：24
• 页码：11993-12001
• 全文大小：751K
• ISSN：1520-510X

文摘

The synthesis and physical properties of two new and one known Ir鈥揝n鈥揝e compound are reported. Their crystal structures are elucidated with transmission electron microscopy and powder X-ray diffraction. IrSn_0.45Se_1.55 is a pyrite phase which consists of tilted corner-sharing IrX₆ octahedra with randomly distributed (Sn鈥揝e)^{4鈥?/sup> and (Se鈥揝e)2鈥?/sup> dimers. Ir₂Sn₃Se₃ is a known trigonally distorted skutterudite that consists of cooperatively tilted corner-sharing IrSn₃Se₃ octahedra with ordered (Sn鈥揝e)₂4鈥?/sup> tetramers. Ir₂SnSe₅ is a layered, distorted 尾-MnO₂ (pyrolusite) structure consisting of a double IrSe₆ octrahedral row, corner sharing in the a direction and edge sharing in the b direction. This distorted pyrolusite contains (Se鈥揝e)2鈥?/sup> dimers and Se2鈥?/sup> anions, and each double row is 鈥渃apped鈥?with a (Sn鈥揝e)_n polymeric chain. Resistivity, specific heat, and magnetization measurements show that all three have insulating and diamagnetic behavior, indicative of low-spin 5d6 Ir3+. Electronic structure calculations on Ir₂Sn₃Se₃ show a single, spherical, nonspin鈥搊rbit split valence band and suggest that Ir₂Sn₃Se₃ is topologically nontrivial under tensile strain due to inversion of Ir-d and Se-p states.}