trans-Diaquabis(thiosemicarbazido-kappa2N,S)nickel(II) dimaleate dihydrate.

In the title compound, [Ni(CH(5)N(3)S)(2)(H(2)O)(2)](C(4)H(3)O(4))(2).2H(2)O, the Ni atom lies on a center of symmetry and is coordinated by N and S atoms from two thiosemicarbazide ligands and the O atoms of two water molecules in a distorted octahedral geometry. In the asymmetric unit, the three components are linked together by one O-H...O and two N-H...O hydrogen bonds. The packing is built from molecular ribbons parallel to the b direction, stabilized by intramolecular hydrogen bonds, and by one N-H...S and two N-H...O intermolecular hydrogen bonds. The ribbons are further connected into columns by N-H...O interactions and then into a three-dimensional network by three O-H...O hydrogen bonds.