Electron energy-loss spectroscopy (EELS) as a technique for determining transition-element oxidation states offers several advantages over other methods. Chemical shifts as a function of oxidation state were determined for Ti3+-Ti4+ (2 eV), Mn2+-Mn4+ (3 eV) and Fe2+-Fe3+ (2 eV). The edge energies remain the same for a particular oxidation state, irrespective of the sample, confirming that EELS can be applied to oxidation-state determinations. Several experimental problems were encountered: poor edge resolution at low transition-element contents, difficulties in detecting mixed oxidation states, and in situ oxidation of hydrous minerals, probably through hydrogen loss.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics