Thorium oxalate is the inorganic compound with the formula Th(C2O4)2(H2O)4.

It is a white insoluble solid prepared by the reaction of thorium(IV) salts with an oxalic acid.

Each Th(IV) center is bound to 10 oxygen centers: eight provided by the bridging oxalates and two by a pair of aquo ligands.

Two additional water of hydration are observed in the lattice.

[2] The solubility product (Ksp) of thorium oxalate is 5.01 × 10−25.