title: Determination of the iron oxidation state in earth materials using XANES pre-edge information.
abstract: Fe K-edge XANES spectra have been measured in more than 35 Fe(II) and Fe(III)-bearing minerals. The separation between the average pre-edge centroid positions for Fe(II) and Fe(III) is 1.4 +/- 0.1 eV. Examination of calculated pre-edge features of mechanical mixtures of phases containing different proportions of Fe(II) and Fe(III) reveals that different trends of pre-edge position vs. pre-edge intensity can be observed, depending on the coordination environment. Both pre-edge parameters have been used to estimate the ferric/ferrous ratio in 12 natural minerals.
authors.affiliation: European Synchrotron Radiation Facility, Grenoble, France. ppetit@esrf.fr
authors.forename: P E
authors.initials: PE
authors.lastname: Petit
authors.forename: F
authors.initials: F
authors.lastname: Farges
authors.forename: M
authors.initials: M
authors.lastname: Wilke
authors.forename: V A
authors.initials: VA
authors.lastname: Solé