In this study, the valence states of uranium in synthetic and natural brannerite samples were studied using a combination of transmission electron microscopy-electron energy loss spectroscopy (TEM-EELS), scanning electron microscopy-energy dispersive xray analysis (SEM-EDX) and x-ray photoelectron spectroscopy (XPS) techniques. We used a set of five (UO2, CaUO4, SrCa2UO6, UTi2O6, Y0.5U0.5Ti2O6) U standard samples, including two synthetic brannerites, to calibrate the EELS branching ratio, M5/(M4 +M5), against the number of f electrons. The EELS data were collected at liquid nitrogen temperature in order to minimise the effects of electron beam reduction of U(VI) and U(V) .
Revised: October 25, 2005 |
Published: May 1, 2005
Citation
Colella M., G.R. Lumpkin, Z. Zhang, E.C. Buck, and K.L. Smith. 2005.Determination of the Uranium Valence State in the Brannerite Structure using EELS, XPS, and EDX.Physics and Chemistry of Minerals 78, no. 2:52-64.PNNL-SA-42441.