Quantum density functional theory (DFT) results are reported for the adsorption of H2CO2 on the Cu (111) metallic surface as modelled by a Cu-30 cluster. The calculations suggest that the H2CO2 species stabilises in the cross-bridge site with the two oxygen atoms located at different distances from the surface. The H2CO2 species prefers an orientation with the OCO plane normal to the surface. Mulliken population analysis in the adsorbed species shows that there is charge donation from the copper surface to the double radical. The internal geometry of the adsorbed species is very different from that of the free molecules and this is the result of the strong interaction with the metal surface. The bonding of this adsorbate to the copper surface is essentially ionic.