catena-Poly[[[diaqua(1,10-phenanthroline-kappa N-2,N')cobalt(II)]-mu-1H-benzimida-zole-5,6-dicarboxylato-kappa N-2(3):O-6] sesquihydrate}

In the title compound, {[Co(C9H4N2O4)(C12H8N2)(H2O)(2)]center dot 1.5H(2)O}(n), the Co-II atom is hexacoordinated by one N atom and one O atom from two symmetry-related 1H-benzimidazole-5,6-dicarboxylate ligands, two N atoms from one 1,10-phenanthroline ligand (phen) and two water molecules. The dihedral angle between the 1H-benzimidazole-5,6-dicarboxylate and 1,10-phenanthroline ligands is 74.41 (4)degrees. The crystal packing is governed by intermolecular O-H center dot center dot center dot O and N-H center dot center dot center dot O hydrogen-bonding interactions. All water (coordinating and lattice) molecules take part in the hydrogen-bonding interactions. In addition, there are pi-pi stacking interactions between inversion-related phen ligands, the shortest centroidcentroid distance being 3.7536 (16) angstrom. One of the two lattice water molecules shows half-occupancy.