Article ID Journal Published Year Pages File Type
6305856 Chemie der Erde - Geochemistry 2014 9 Pages PDF
Abstract
Chromium L3,2 energy loss near-edge structures (ELNES) of nine chromium compounds were measured in a transmission electron microscope to study the effect of valence state and site geometry of chromium on spectral features. The compounds studied represent a set of standards with given valence state and coordination. The chromium coordination is either octahedral or tetrahedral with different degree of distortion. The distortion of polyhedra results in a loss of the fine detail of spectral features in Cr L3,2 ELNES spectra. The effect of valence state manifests in a systematic chemical shift of the ELNES spectra by about 2 eV per oxidation state for octahedrally coordinated Cr and 0.4-1.4 eV per oxidation state for tetrahedrally coordinated Cr. On the basis of collected Cr L3,2 ELNES spectra we propose a simple quantification technique for the determination of chromium oxidation state in oxidic compounds which is independent of the coordination.
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Physical Sciences and Engineering Earth and Planetary Sciences Geochemistry and Petrology
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