Structural determination of fluorite-type oxygen excess uranium oxides using EXAFS spectroscopy

Journal Article · Sun Jun 01 04:00:00 EDT 1986 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.450795· OSTI ID:5874539

Jones, D J; Roziere, J; Allen, G C; Tempest, P A

Extended x-ray absorption fine structure (EXAFS) spectroscopy has been carried out at 77 K at the uranium L/sub III/ edge for UO/sub 2/, ..beta..-U/sub 3/O/sub 7/, and U/sub 4/O/sub 9/ with the aim of determining the structure of these highly defective (oxygen excess) uranium oxide phases, which are of industrial importance. Use has been made of a difference Fourier technique for U/sub 3/O/sub 7/, in which the EXAFS of a perfect lattice model is subtracted. U--O bond lengths calculated from the remaining EXAFS signal, assumed to result only from interstitial oxygens, have been used to determine the atomic coordinates of these interstitials. The analysis of EXAFS data in terms of coordination number has allowed an insight into the defect aggregate arrangement of oxygens in U/sub 3/O/sub 7/ and U/sub 4/O/sub 9/. Furthermore, EXAFS data indicate that the uranium sublattice is perturbed by the incorporation of additional oxygen atoms.

• Research Organization: L'Universite des Sciences et Techniques du Languedoc, Place Eugene Bataillon, 34060 Montpellier Cedex, France
• OSTI ID: 5874539
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 84:11; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION SPECTRA
ACTINIDE COMPOUNDS
BOND LENGTHS
CHALCOGENIDES
CRYSTAL STRUCTURE
DIMENSIONS
FINE STRUCTURE
LENGTH
OXIDES
OXYGEN COMPOUNDS
SPECTRA
URANIUM COMPOUNDS
URANIUM OXIDES
X-RAY SPECTRA