Bis(1H-imidazole-κN)bis-(2-oxidopyridinium-3-carboxyl-ato-κO,O)nickel(II).

In the crystal structure of the title Ni(II) complex, [Ni(C(6)H(4)NO(3))(2)(C(3)H(4)N(2))(2)], the Ni(II) atom is located on a twofold rotation axis and is chelated by two oxidopyridiniumcarboxyl-ate anions and further cis-coordinated by two imidazole ligands in a distorted cis-N(2)O(4) octa-hedral geometry. The C-O bond distance of 1.2573 (19) Å found for the non-coordinating O atom of the carboxyl-ate group indicates significant delocalization of π-electron density over this residue. Similarly, the C-O bond distance of 1.260 (2) Å in the heteroaromatic ring indicates delocalization between the deprotonated hydr-oxy group and the pyridinium ring. The uncoordinated carboxyl-ate O atom links with the imidazole and pyridinium rings of adjacent mol-ecules via N-H⋯O and C-H⋯O hydrogen bonding, leading to a two-dimensional array parallel to (100).