Two factors contributing to the high binding energy asymmetry of the S 2p X-ray photo-electron spectroscopy peak for virginal chalcopyrite (CuFeS2) surfaces were identified. The Cu, Fe and S 2p spectra of freshly fractured surfaces of chalcopyrite were found to display a loss feature at ≈2.6eV that was attributed to an interband transition S 3p → Fe 3d, from occupied S levels to unoccupied Fe levels. For leached chalcopyrite systems, intensity on that side of the S 2p peak sometimes was interpreted erroneously in terms of oxidized species such as polysulphides. A second prominent S 2p component was determined at a binding energy of 161.9eV and identified as the sulphide dimer S22-. With supporting evidence, a simultaneous surface reconstruction and redox reaction model was developed for the fracturing of chalcopyrite, leading to an exposed surface phase of about two layers thick with a 50% pyritic content. The pyritic nature of the fractured chalcopyrite surface had implications for understanding the leaching chemistry of chalcopyrite.

Fracture-Induced Reconstruction of a Chalcopyrite (CuFeS2) Surface. C.Klauber: Surface and Interface Analysis, 2003, 35[5], 415-28