Experimental

R factor = 0.027; wR factor = 0.063; data-to-parameter ratio = 12.2. The title compound, [Co(C4H3N2O2)2(H2O)2], contains a Co II cation on a twofold rotation axis, exhibiting a distorted octahedral coordination geometry. The equatorial plane is formed by two N,O-bidentate 1H-imidazole-4-carboxylate ligands and the axial positions are occupied by water molecules. The crystal packing consists of a three-dimensional network stabilized by O—H O and N—H O hydrogen bonds, together with weak – interactions [centroid–centroid distance = 3.577 (2) Å] between the imidazole rings. Related literature For the isostructural zinc(II) and cadmium(II) complexes, see: Yin et al. (2009); Shuai et al. (2011). For related homolepti