The X-ray crystal structural characterization of dipotassium bisoxalato copper(II) tetrahydrate, [K2Cu(ox)2·4H2O] (ox=oxalate dianion)

Dipotassium bisoxalato copper(II) tetrahydrate, [K2Cu(ox)2·4H2O] (1) (ox=C2O4 2−, oxalate dianion), was first characterized structurally by X-ray crystallography. The compound crystallizes in monoclinic, space group P21/n with a=3.7770(10), b=14.819(3), c=10.756(2) Å, β=93.180(10)°, V=601.1(2) Å3, Z=2, Dcalc=2.154 g cm−3, M=389.84, R=0.0301 based on 940 observed reflections with I>2σ(I). The results of structural analysis indicate that the complex formed by CuO and KO coordination bonds has a two-dimensional network structure which was further linked by hydrogen bonds to give a three-dimensional structure. The Cu(II) atom has square-planar geometry with two bidentate oxalate ligands. Each K+ cation is coordinated by eight oxygen atoms from one bidentate and two unidentate oxalate groups and four water molecules.