Holmium(III) oxalate is the oxalate salt of holmium, with the chemical formula Ho2(C2O4)3.

It exists in anhydrous and hydrated forms.

Holmium(III) oxalate decahydrate decomposes in heat to obtain the dihydrate, which is further heated to obtain the anhydrous form, and finally holmium(III) oxide is obtained.

[1] It reacts with hydrochloric acid to obtain H[Ho(C2O4)2]·6H2O.

[2]