The formula for the compound aluminum oxalate is Al2(C2O4)3.
Aluminum oxalate is a coordination compound formed from aluminum ions and oxalate ions. In this compound, each aluminum ion (Al3+) is coordinated by oxalate ions (C2O42-). The oxalate ion carries a -2 charge, and since there are three oxalate ions needed to balance the charge of two aluminum ions (+6 charge from Al3+), the resulting formula is Al2(C2O4)3.