Poly[[tetraaqua­bis(μ(3)-1H-benzimidazole-5,6-dicarboxyl­ato)dicobalt(II)] trihydrate]

The title complex, {[Co(2)(C(9)H(4)N(2)O(4))(2)(H(2)O)(4)]·3H(2)O}(n), was synthesized hydro­thermally. The unique Co(II) ion is coordin­ated in a distorted octa­hedral coordination environment by two water mol­ecules and three symmetry-related 1H-benzimid­azole-5,6-dicarboxyl­ate (Hbidc) ligands. The Hbidc ligands coordinate via a bis-chelating and mono-chelating carboxyl­ate group and by an imidazole group N atom, bridging the Co(II) ions and forming an extended two-dimensional structure in the ab plane. In the crystal structure, inter­molecular N—H⋯O and O—H⋯O hydrogen bonds connect complex and solvent water mol­ecules, forming a three-dimensional supermolecular network. One of the solvent water mol­ecules lies on a twofold rotation axis.