Crystal structure of bis-(piperazin-1-ium-κN4)bis-(thio-sulfato-κS)zinc(II) dihydrate.

In the title compound, [Zn(C4H11N2)2(S2O3)2]·2H2O, two thio-sulfate ions coordinate to the zinc(II) atom through the terminal S atoms. The tetra-hedral coordination around the ZnII ion is completed by ligating to two N atoms of two piperazinium ions. The remaining two N atoms of the piperazinium ions are diprotonated and do not coordinate to the metal centre. In the crystal, however, they are involved in N-H⋯Owater and N-H⋯Osulfato hydrogen bonds. Together, a series of N-H⋯O and O-H⋯O hydrogen bonds, involving the O atoms of the thio-sulfate ions and the water mol-ecules as acceptors and the hydrogen atoms of the piperazinium ions and the water mol-ecules as donors, form a three-dimensional supra-molecuar structure. Within this framework there are a number of intra- and inter-molecular C-H⋯O and C-H⋯S contacts present.