Apparent Chemical Shifts at X-ray Absorption Edges of 3d-, 4f-, 5d- and 5p-elements for Empirical Chemical State Analysis

Abstract

X-ray absorption spectra of 3d transition elements at K-edge, lanthanoides and the other period 6 elements at L-edges for 105 compounds were recorded by a laboratory-type X-ray absorption spectrometer to elucidate the chemical shift comprehensively for empirical oxidation state analysis. Apparent absorption edge energies were determined at a half of the normalized XANES, and each the chemical shifts were estimated by a slope of the edge energy plotted as a function of the oxidation number. Evaluated apparent chemical shifts, linearity of the valence dependency, and the deviations were discussed based on chemical element groups, each element being within the group, and absorption edges. The apparent chemical shifts for K-edge of 3d transition elements lay within 2 ± 0.5 eV/valences except for Cu. The chemical shifts for L-edges of lanthanoid compounds were about 2-4 times larger than those for K-edges of 3d transition elements, and shifts for Pt, Pb and Bi of the same period elements at L-edges were at most 1.3 eV/valences. Chemical shifts for lanthanoid elements at L1-edge were 1.5 times larger than those for corresponding L3-edges.