Poly[diimidazole-μ(4)-oxalato-μ(2)-oxalato-dicopper(II)]

The title compound, [Cu(2)(C(2)O(4))(2)(C(3)H(4)N(2))(2)](n), was obtained as an unexpected product under hydro­thermal conditions. The Cu(II) atom is in a Jahn–Teller-distorted octa­hedral environment formed by one imidazole N atom and five O atoms from three oxalate anions. The two independent oxalate anions are situated on centres of inversion and coordinate to the Cu(II) atom in two different modes, viz. bidentate and monodentate. The bidentate anions bridge two Cu(II) atoms, whereas the monodentate anions bridge four Cu(II) atoms, leading to a layered arrangement parallel to (100). These layers are further linked into a final three-dimensional network structure via inter­molecular N—H⋯O hydrogen bonds. The title compound is isotypic with the Zn analogue.