Characterization of Uranium Oxides Using in Situ Micro-Raman Spectroscopy

A range of uranium compounds have been characterized using micro-Raman spectroscopy. It is possible to easily distinguish the oxides UO 2 , α-U 3 O 8 , and γ-UO 3 . Studies have also investigated the Raman spectra of uranium precursors used for the preparation of these oxides. In situ studies to probe the transformation of uranyl nitrate to uranium oxide show that the nitrate is decomposed below 300 °C. Initially an oxide similar to UO 3 is produced, and this oxide gradually transforms to U 3 O 8 as the temperature is increased to 550 °C. The use of in situ Raman studies provides a powerful technique to study the mechanism of transformation and the stability of uranium oxides under oxidizing conditions.