Copper peroxide is a hypothetical inorganic compound with the chemical formula CuO2.
One highly cited analysis concludes that gaseous CuO2 is a superoxide, with copper in a +1 oxidation state: Cu+O−2.
[1] Species claimed to be "copper peroxide" have been claimed, e.g., by the reaction of cold solutions of Schweizer's reagent—a source of copper(II)—and hydrogen peroxide..[2] The Schweizer's reagent used must not contain excess ammonia.
[2] It was once claimed to result from the very slow reaction of finely divided cupric oxide with cold hydrogen peroxide.
[3] Several molecular copper peroxide complexes have been reported, but these species always feature supporting organic ligands.