Copper(II) oxalate


Copper oxalate is an inorganic compound with the chemical formula. The value of x lies between 0 and 0.44. One of these species is found as the secondary mineral moolooite. The anhydrous compound has been characterized by X-ray crystallography. Many transition metal oxalate complexes are known.
Copper oxalate, whether anhydrous or hydrated, is practically insoluble in all solvents, as it is a coordination polymer.

Synthesis

Copper oxalate can be produced by precipitation from acidified aqueous copper salts and oxalic acid or an alkali metal oxalate.

Reactions

Upon heating to 130 °C, the hydrated copper oxalates convert to the anhydrous cupric oxalate. Further heating at higher temperatures under an atmosphere of hydrogen gives copper metal, suitable as a reagent.
The hydrates bind Lewis bases.
Hydrated copper oxalate reacts with alkali metal oxalates and ammonium oxalate to give biscuprate:

Uses

Copper oxalate is used as a catalyst for organic reactions, as a stabilizer for acetylated polyformaldehyde.

Related compounds

  • Cuprous oxalates.