Anion-Anion Bonding and Topology in Ternary Iridium Seleno-Stannides

作者：Trump Benjamin A^*; Tutmaher Jake A; McQueen Tyrel M

来源：Inorganic Chemistry, 2015, 54(24): 11993-12001.

DOI：10.1021/acs.inorgchem.5b02387

The synthesis and physical properties of two new and one known Ir-Sn-Se compound are reported. Their crystal structures are elucidated with transmission electron microscopy and powder X-ray diffraction. IrSn0.45Se1.55 is a pyrite phase which consists of tilted corner-sharing IrX6 octahedra with randomly distributed (Sn-Se)(4-) and (Se-Se)(2-) dimers. Ir2Sn3Se3 is a known trigonally distorted skutterudite that consists of cooperatively tilted corner-sharing IrSn3Se3 octahedra with ordered (Sn-Se)(2)(4-) tetramers. Ir2SnSe5 is a layered, distorted beta-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-Se)(2-) dimers and Se2- anions, and each double row is "capped" with a (Sn-Se)(n) polymeric chain. Resistivity, specific heat, and magnetization measurements show that all three have insulating and diamagnetic behavior, indicative of low-spin 5d(6) Ir3+. Electronic structure calculations on Ir2Sn3Se3 show a single, spherical, nonspin-orbit split valence band and suggest that Ir2Sn3Se3 is topologically nontrivial under tensile strain due to inversion of Ir-d and Se-p states.

• 出版日期2015-12-21