Application of High-Energy-Resolution X-ray Absorption Spectroscopy at the U M edge to Assess U(V) Electronic Structure in U(V) compounds

The oxidation state of uranium (U) largely controls its migration behavior in the environment. Recent studies have evidence the
importance of minor chemical
species of U(V), especially when interacting with minerals such as magnetite. Recently, the HERFD-XANES method has been used to detect U
(V) species, but there are a few U(V) compounds used as standard spectra. To establish a more accurate U(V) speciation method,
measurement of other U(V) compounds is indispensable.
We will conduct HERFD-XANES analysis at the U M-edge to clarify the spectral differences between U(V) oxides with different crystal
structures, such as monouranate compounds, isostructural mixed oxides and U adsorbed on Fe-oxides. These results will allow us to clearly
define the U valence and to discuss the difference of electronic structure of U(V) in each compound. Furthermore, the suitable speciation
method for U(V) compounds can be determined by discussing the results in combination with the U L-edge HERFD-XANES.