Synthesis and structure of dichlorobis(thiosemicarbazide)mercury(II)

Abstract

The reaction between mercury(II) chloride and thiosemicarbazide (1:2 molar ratio) in ethanol–water (1:1 by volume) gave, almost quantitatively, dichlorobis(thiosemicarbazide)-mercury(II), HgCl 2 (tsc) 2 . There was a trace of unidentified black material as a side product. The crystals of HgCl 2 (tsc) 2 are orthorhombic with a = 8.675(7), b = 8.123(6), c = 15.786(11) Å, Z = 4, and space group Pbcn. The HgCl 2 (tsc) 2 molecule in the crystal has a twofold axis and the mercury atom is bonded to two chlorine atoms at 2.841(3) Å, and two sulfur atoms at 2.417(3) Å, in a highly distorted tetrahedron. The bond angles are: S—Hg—S = 160.7(1)°; Cl—Hg—Cl = 96.6(1)°; S—Hg—Cl = 89.5(1)° (twice) and 103.4(1)° (twice). However, if the close contacts, [Formula: see text] were counted, the coordination around the Hg atom would be an approximate octahedron.