XPS investigations on cesium uranates: mixed valency behaviour of uranium

Several pure cesium uranate phases were prepared (Cs2U2O7, Cs2U4O13, Cs2U4O12, Cs4U5O17) and measured with X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS. Detailed XPS scans of the main photoelectron peaks (U 4f, Cs 3d, O 1s and valence band) were made. Peak positions, peak widths and satellite positions were measured and compared between the uranates. A systematic shift in the position of the U 4f lines was found to be correlated with the Cs/U ratio. The mixed valency behaviour of uranium was observed and studied. Interpretation of the satellite structure of the U 4f peaks and the deconvolution of these peaks have been used to quantify the chemical states of uranium present in the mixed valency compound Cs2U4O12 (C) 2000 Elsevier Science B.V. All rights reserved.