Thorium oxalate is the inorganic compound with the formula Th(C<sub>2</sub>O<sub>4</sub>)<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub>. It is a white insoluble solid prepared by the reaction of thorium(IV) salts with oxalic acid. The material is a coordination polymer. 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 waters of hydration are observed in the lattice.
The solubility product (K<sub>sp</sub>) of thorium oxalate is 5.0110<sup>âÂÂ25</sup>. The density of anhydrous thorium oxalate is 4.637 g/cm<sup>3</sup>.