Octaammonium diaquahexa-μ2-oxalato-dioxalatotetracopper(II) tetrahydrate

In the structure of the title compound, (NH 4 ) 8 [Cu 4 (C 2 O 4 ) 8 (H 2 O) 2 ]·4H 2 O, isolated tetramers of [Cu(ox) 2 ] 2+ (ox is oxalate) are present. Each Cu II ion coordinates to four O atoms in two oxalate ligands and to two more distant O atoms in a neighbouring oxalate ligand or a water molecule. An extensive hydrogen-bonding network connects the tetramers to two unique solvent water molecules and four ammonium ions.