Transition metal oxalate complex

[1] As a small, symmetrical dinegative ion, oxalate commonly forms five-membered MO2C2 chelate rings.

Oxalate is often a bridging ligand forming bi- and polynuclear complexes with (κ2,κ'2-C2O4)M2 cores.

[13] Metal oxalate complexes are photoactive, degrading with loss of carbon dioxide.

The iron centre is reduced (gains an electron) from the +3 to the +2 oxidation state, while an oxalate ion is oxidised to carbon dioxide: The redox reaction has been used to access unusual complexes.

[14] The minerals moolooite and antipinite are examples of naturally occurring copper oxalates.

Structure of hydrated ferric oxalate, a coordination polymer . [ 9 ] Color code: red=O, white = H, blue = Fe, gray = C.
Potassium ferrioxalate crystals.