Copper(III) and copper(IV)

Copper(III) is a lot of artlessly begin in oxides. A simple archetype is potassium cuprate, KCuO2, a blue-black solid. The best advised copper(III) compounds are the cuprate superconductors. Yttrium barium chestnut oxide (YBa2Cu3O7) consists of both Cu(II) and Cu(III) centres. Like oxide, fluoride is a awful basal anion and is accepted to balance metal ions in top blaze states. Indeed, both copper(III) and even copper(IV) fluorides are known, K3CuF6 and Cs2CuF6, respectively. 
Some chestnut proteins anatomy oxo complexes, which aswell affection copper(III). With di- and tripeptides, purple-colored copper(III) complexes are counterbalanced by the deprotonated amide ligands.
Complexes of copper(III) are aswell empiric as intermediates in reactions of organocopper compounds.