trans-Diaquabis(pyridazine-3-carboxylato-kappa N-2(2),O) cobalt(II) dihydrate

The title compound, [Co(C5H3N2O2)(2)(H2O)(2)]center dot 2H(2)O, contains a Co II ion on an inversion center, exhibiting an octahedral coordination geometry. The equatorial plane is formed by two trans-related N, O-bidentate pyridazine-3-carboxylate ligands and the axial positions are occupied by two water molecules. The Co-II complex molecules are stacked in a column along the a-axis direction by an O-H center dot center dot center dot N hydrogen bond between the non-coordinating pyridazine N atom and the coordinating water molecule. These columns are further connected into a layer parallel to the ac plane by additional hydrogen bonds involving the coordinating and non-coordinating water molecules, and the non-coordinating carboxylate O atom. The crystal packing is completed by interlayer weak C-H center dot center dot center dot O interactions.