Diaqua­bis(2,2′-biimidazole)cobalt(II) 4,4′-dicarboxy­biphenyl-3,3′-di­car­boxylate

In the title compound, [Co(C(6)H(6)N(4))(2)(H(2)O)(2)](C(16)H(8)O(8)), the Co(II) cation and the organic anion occupy different crystallographic inversion centres and, as a consequence, the asymmetric unit comprises two half-mol­ecules. The benzene groups are coplanar. The four coordinating N atoms of the two bidentate biimidazole ligands define the equatorial plane of a slightly distorted octa­hedral CoO(2)N(4) geometry, and the water O atoms lie in the axial coordination sites. Translational (a,[Image: see text]) and inversion-related symmetry operations link the Co complex mol­ecules and the negatively charged carboxyl­ate anions via inter­molecular N—H⋯O and O—H⋯O hydrogen bonds into sheets parallel to ([Image: see text]01). The coordinated water mol­ecules connect the sheets through O—H⋯O hydrogen bonds, forming a three-dimensional framework. In addition, two intra­molecular O—H⋯O hydrogen bonds are observed between the carboxyl and carboxyl­ate groups.