Hydrothermalsynthese und Kristallstruktur der Münzmetall‐Quecksilber‐Chalkogenidhalogenide CuHgSeBr,AgHgSBr und AgHgSI

Hydrothermal Synthesis and Crystal Structure of the Coinage Metal Mercury Chalcogenide Halides CuHgSeBr, AgHgSBr, and AgHgSI The hydrothermal reaction of CuBr and HgSe in concentrated aqueous HBr as solvent at 285 °C yields red crystals of CuHgSeBr, the hydrothermal reaction of AgX (X = Br, I) and HgS in half‐concentrated aqueous HX (X = Br, I) as solvent at 300/400 °C yields yellow crystals of AgHgSBr and AgHgSI. The compounds crystallize isotypically (orthorhombic, Pmma, a = 1020.1(3) pm, b = 431.2(1) pm, c = 925.6(3) pm for CuHgSeBr, a = 964.8(8) pm, b = 466.1(4) pm, c = 942.6(6) pm for AgHgSBr und a = 1015.9(2) pm, b = 464.77(5) pm, c = 984.9(2) pm for AgHgSI, Z = 4). The structures consist of plane folded Hg–Y chains connected by pairs of distorted Y₂X₂ terahedra sharing the X–X‐edge (M = Cu, Ag; X = Br, I; Y = S, Se). Atoms of the monovalent metals M have a strongly distorted tetrahedral coordination of two halogen and two chalcogen atoms. The new structure type shows distinct differences in the arrangement of the Hg–Y chains in comparision to the already known CuHgSeCl, but represents the superposition structure of the order‐disorder phase γ‐Hg₃S₂Cl₂.