Darstellung und Kristallstruktur des Quecksilber(II)-thiodiphosphats Hg2P2S7

Preparation and Crystal Structure of Mercury (II) Thiodiphosphate Hg₂P₂S₇ Hg₂P₂S₇ crystallizes monoclinic with a = 10.887(8); b = 5.827(3); c = 8.132(6) Å und β = 103.83(6)° in space group C2.The crystal structure was determined from four-circle diffractometer data by means of the heavy atom method and refined by least squares to R = 0.094 for 1119 intensities. The structure contains P₂S₇ group which are arranged in layer parallel to the (001) plane and connected by Hg atoms to form a three-dimensional network. The Hg atoms are surrounded by four S atoms in a deformed tetrahedral arrangement (means distance Hg? S: 2.591 Å). The P₂S₇ group are composed of two PS₄ tetrahedra sharing one corner (mean distance P? S: 2.048 Å; ? P? S? P: 108.6°). According to the structural data Hg₂P₂S₇ may be interpreted as mercury(II) thiodiphosphate. The bond distance and the structural relationships between Hg₂P₂S₇ and Ag₄P₂S₇ are discussed. Hg₂P₂S₇ represents a new defect tetrahedral structural type.