Structure cristalline du composé Hg(3-x)Sb(x)(S+Se)(2+x)I(2-x) (x ≃ 0.1)

Single crystals of the mercury chalcohalide Hg(3-x)Sb(x)(S+Se)(2+x)I(2-x) (x ≃ 0.1) (mercury anti­mony 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 octa­hedral 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 Hg(3)Se(2)I(2) [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.