CuC2O4

Copper(II) oxalate, with the chemical formula CuC2O4, is an inorganic compound. It is a salt formed from the cation copper(II) and the oxalate anion. Copper(II) oxalate typically appears as a pale green or blue-green solid. It is poorly soluble in water but can dissolve in acidic solutions.

The synthesis of copper(II) oxalate can be achieved through various methods, often involving the reaction of a soluble copper(II) salt with a soluble oxalate salt, such as sodium oxalate or ammonium oxalate. For example, mixing a solution of copper(II) sulfate with a solution of sodium oxalate will precipitate copper(II) oxalate.

CuSO4(aq) + Na2C2O4(aq) -> CuC2O4(s) + Na2SO4(aq)

Copper(II) oxalate has found some limited applications. It has been used as a catalyst in certain organic reactions and has been investigated for its potential in pigment production due to its color. However, its practical use is not widespread. Like many oxalate compounds, it should be handled with care, as oxalates can be toxic. The thermal decomposition of copper(II) oxalate yields copper(II) oxide, carbon monoxide, and carbon dioxide.