Tetra-kis(aceto-nitrile)copper(I) hydrogen oxalate-oxalic acid-aceto-nitrile (1/0.5/0.5).

In the title compound, [Cu(CH3CN)4](C2HO4)·0.5C2H2O4·0.5CH3CN, the Cu(I) ion is coordinated by the N atoms of four aceto-nitrile ligands in a slightly distorted tetra-hedral environment. The oxalic acid mol-ecule lies across an inversion center. The aceto-nitrile solvent mol-ecule is disordered across an inversion center and was refined with half occupancy. In the crystal, the hydrogen oxalate anions and oxalic acid mol-ecules are linked via O-H⋯O hydrogen bonds, forming chains along [010].