Application of M_V-edge XANES to determination of U oxidation state in zircon

Abstract

We examined three natural zircon samples with different amounts of radiation doses (1.9 × 10¹⁵–6.8 × 10¹⁵ α-decay events/mg) using M_V-edge and L_III-edge U X-ray absorption near-edge structure (XANES). Analysis of XANES spectra at both M_V-edge and L_III-edge suggested that the oxidation state of U in the zircon sample with the highest radiation dose is tetravalent. The XANES spectra of the two other samples with lower radiation doses suggested a mixture of U(IV) and U(VI), while the possibility of U(V) was not excluded. This is the first work on the application of M_V-edge U XANES to the oxidation state of U in natural zircon.