Structure cristalline du composé Hg3-x Sb x (S+Se)2+x I2-x (x ≃ 0.1)
Abstract
Single crystals of the mercury chalcohalide Hg3-x Sb x (S+Se)2+x I2-x (x ≃ 0.1) (mercury anti-mony sulfide selenide iodide), were grown by a chemical transport reaction. The structure contains three independent A (Hg/Sb) atoms; each atom is strongly covalently bonded with two X (Se/S) atoms to form approximately linear X-A-X units. The X-A-X units link to form A 4 X 4 rings, which are combined into infinite crankshaft-type bands running along the [100] direction. Four equatorial E (I/X = Se,S) atoms at relatively long distances complete the distorted octa-hedral coordination of A (Hg/Sb). The crystal under investigation was twinned by non-merohedry with a refined twin domain fraction of 0.814 (6):0.186 (6). The structure is isotypic with Hg3Se2I2 [Beck & Hedderich (2000 ▸). J. Solid State Chem. 151, 73-76], but the current determination reveals a coupled substitution, with partial replacement of Hg(+2) by Sb(+3), balanced by the equivalent substitution of I(-1) by S(-2) and Se(-2). Bond-valence calculations are consistent with this relative substitution model