Crystal structure of trans-diaquabis(1H-pyrazole-3-carboxylato-κ2N,O)copper(II) dihydrate

In the title compound, [Cu(C4H3N2O2)2(H2O)2]·2H2O, the CuII ion is located on an inversion centre and exhibits an axially elongated octahedral coordination geometry. The equatorial plane is formed by two N,O-bidentate 1H-pyrazole-3-carboxylate ligands in a trans configuration. The axial positions are occupied by two water molecules. The mononuclear complex molecules are arranged in layers parallel to the ab plane. Each complex molecule is linked to four adjacent species through intermolecular O—H...O and N—H...O hydrogen bonds that are established between the coordinating water molecules and carboxylate O atoms or protonated N atoms of the organic ligands. These layers are further connected into a three-dimensional network by additional hydrogen bonds involving solvent water molecules and non-coordinating carboxylate O atoms.