Hexakis(1H-imidazole-κN (3))cobalt(II) triaqua­tris(1H-imidazole-κN (3))cobalt(II) bis­(naphthalene-1,4-dicarboxyl­ate)

The asymmetric unit of the title compound, [Co(C(3)H(4)N(2))(6)][Co(C(3)H(4)N(2))(3)(H(2)O)(3)](C(12)H(6)O(4))(2), contains two halves of crystallographically independent Co(II) complex cations, each assuming a distorted octa­hedral geometry, and one uncoordinated naphthalene-1,4-dicarboxyl­ate dianion. One Co(II) cation is located on an inversion center and is coordinated by six imidazole mol­ecules, while the other Co(II) cation is located on a twofold rotation axis and is coordinated by three water and three imidazole mol­ecules. The uncoordinated naphthalene-1,4-dicarboxyl­ate dianion links both Co(II) complex cations via O—H⋯O and N—H⋯O hydrogen bonding. One imidazole ligand is equally disordered over two sites about a twofold rotation axis, while the coordinated N atom of the imidazole is located on the twofold rotation axis. One water O atom has site symmetry 2.