Diaqua-(2,2'-bipyridine-6,6'-dicarboxyl-ato)nickel(II).

In the title compound, [Ni(C(12)H(6)N(2)O(4))(H(2)O)(2)], the Ni(II) atom (site symmetry 2) displays a distorted cis-NiN(2)O(4) octa-hedral coordination geometry with two N atoms and two O atoms of the tetra-dentate 2,2'-bipyridine-6,6'-dicarboxyl-ate ligand in the equatorial plane and two water mol-ecules in axial positions. The complete dianionic ligand is generated by crystallographic twofold symmetry. In the crystal, a two-dimensional supra-molecular structure parallel to (001) is formed through O-H⋯O hydrogen-bond inter-actions between the coordinated water mol-ecules and the O atoms of nearby carboxyl-ate groups.