catena-Poly[[[diaqua(1,10-phenanthroline-κ2N,N′)cobalt(II)]-μ-1H-benzimidazole-5,6-dicarboxylato-κ2N3:O6] sesquihydrate}

In the title compound, {[Co(C9H4N2O4)(C12H8N2)(H2O)2]·1.5H2O}n, the CoII 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)°. The crystal packing is governed by intermolecular O—H...O and N—H...O hydrogen-bonding interactions. All water (coordinating and lattice) molecules take part in the hydrogen-bonding interactions. In addition, there are π–π stacking interactions between inversion-related phen ligands, the shortest centroid–centroid distance being 3.7536 (16) Å. One of the two lattice water molecules shows half-occupancy