Oxidation state variations in copper minerals studied with Cu 2p X-ray absorption spectroscopy

Abstract

Cu 2 p absorption spectra of divalent and monovalent copper minerals are presented. Divalent Cu gives a narrow, single line due to excitation into the empty 3 d density of states, whereas monovalent Cu gives a broad band at higher energy due to transitions to the empty metal s and ligand states. The differences in the spectra can be used to distinguish between the two oxidation states, which has been applied to copper sulphide tetrahedrite complexes.