Structure of actinide compounds in solution and molten salt by utilizing XAFS and X-ray diffraction methods

Local structure of uranium (VI)-amide and Am (III)-benzimidazole complexes in ethanol were determined by extended X-ray absorption fine structure spectrometry (EXAFS). The bond distance between carbonyl oxygen and uranium suggested that coordination of amide to uranium is deeply concerned with substituent structure of amide, and furthermore, showed a suitable compound structure that is effective in the extraction of uranium with amides. Benzoimidazole coordinates to americium with weaker interaction than water. This interaction might be almost regarded as electrostatic interaction. Structure of molten UCl3 and rare earth halides were investigated by using high-temperature X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS) techniques. Stability of the octahedral complex (MX6)3- and bridging of the octahedra suggested in the XRD was evaluated by the XAFS technique. (author)