TY - GEN A1 - Knies, Maximilian A1 - Kaiser, Martin A1 - Lê Anh, Mai A1 - Efimova, Anastasia A1 - Doert, Thomas A1 - Ruck, Michael T1 - Low-Temperature Ordering in the Cluster Compound (Bi₈)Tl[AlCl₄]₃ T2 - Inorganics N2 - The reaction of Bi, BiCl₃, and TlCl in the ionic liquid [BMIm]Cl·4AlCl₃ (BMIm = 1-n-butyl-3-methylimidazolium) at 180 °C yielded air-sensitive black crystals of (Bi₈)Tl[AlCl₄]₃. X-ray diffraction on single crystals at room temperature revealed a structure containing [Tl(AlCl₄)₃]∞12− strands separated by isolated Bi₈²⁺ square antiprisms. The thallium(I) ion is coordinated by twelve Cl⁻ ions of six [AlCl₄]⁻ groups, resulting in a chain of face-sharing [TlCl₁₂]¹¹⁻ icosahedra. The Bi₈²⁺ polycation is disordered, simulating a threefold axis through its center and overall hexagonal symmetry (space group P6₃/m). Slowly cooling the crystals to 170 K resulted in increased order in the Bi₈ cluster orientations. An ordered structure model in a supercell with a’ = 2a, b’ = 2b, c’ = 3c and the space group P6₅ was refined. The structure resembles a hexagonal perovskite, with complex groups in place of simple ions. KW - bismuth KW - cluster compounds KW - hexagonal perovskite KW - ionic liquids KW - low-valen KW - low-valent compounds KW - order–disorder transition KW - orientational disorder KW - polycations KW - pseudosymmetry Y1 - 2019 UR - https://opus4.kobv.de/opus4-UBICO/frontdoor/index/index/docId/24132 VL - 7 IS - 4 SP - 1 EP - 9 ER -