A new two-dimensional cadmium coordination polymer with 1H-imidazole-4-carboxyl­ate and oxalate

The title compound, poly[aqua­([mu]₂-1H-imidazole-4-carboxylato-[kappa]³N³,O:O')hemi([mu]₂-oxalato-[kappa]⁴O¹,O²:O^1',O^2')cadmium(II)], [Cd(C₄H₃N₂O₂)(C₂O₄)_0.5(H₂O)]_n, exhibits a two-dimensional network. The Cd^II cation is coordinated to one N atom and two carboxyl­ate O atoms from two 1H-imidazole-4-carboxyl­ate (Himc) ligands, two carboxyl­ate O atoms from the bridging oxalate anion and one ligated water mol­ecule; these six donor atoms form a distorted octa­hedral configuration. The oxalate anion lies on a centre of inversion. The Himc ligands connect the Cd^II cations to form -Cd-Himc-Cd-Himc-Cd- zigzag chains, with a Cd...Cd separation of 5.8206 (6) Å along the b direction, which are further linked by tetra­dentate oxalate anions to generate a two-dimensional herringbone architecture in the ab plane. These layers are extended to form a three-dimensional supra­molecular framework via O-H...O and N-H...O hydrogen bonds and [pi]-[pi] stacking inter­actions. The solid-state photoluminscent behaviour of the title compound has been investigated at room temperature.