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Title: U(v) in Metal Uranates. A Combined Experimental And Theoretical Study of MgUO 4, CrUO 4 and FeUO 4

Pentavalent uranium can exist in aqueous solution, but its presence in the solid state is uncommon. Metal monouranates, MgUO 4, CrUO 4 and FeUO 4 were synthesized for detailed structural and energetic investigations. Structural characteristics of these uranates used powder X-ray diffraction, synchrotron X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, and 57Fe-Mössbauer spectroscopy. Enthalpies of formation were measured by high temperature oxide melt solution calorimetry. Density functional theory (DFT) calculations provided both structural and energetic information. The measured structural and thermodynamic properties show good consistency with those predicted from DFT. Moreover, the presence of U 5+ has been solidly confirmed in CrUO 4 and FeUO 4, which are thermodynamically stable compounds, and the origin and stability of U 5+ in the system was elaborated by DFT. The structural and thermodynamic behaviour of U 5+ elucidated in this work is relevant to fundamental actinide redox chemistry and to applications in the nuclear industry and radioactive waste disposal.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [5] ;  [6] ;  [6] ;  [7] ;  [6] ;  [4] ;  [5] ;  [8] ;  [7]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of California, Davis, CA (United States)
  2. Univ. of California, Davis, CA (United States); Nuclear Research Center (Israel)
  3. Univ. of California, Berkeley, CA (United States); Univ. of Michigan, Ann Arbor, MI (United States)
  4. Univ. of California, Berkeley, CA (United States)
  5. Univ. of Chicago, IL (United States)
  6. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  7. Univ. of California, Davis, CA (United States)
  8. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
OSTI Identifier:
1243177
Report Number(s):
PNNL-SA-113798
Journal ID: ISSN 1477-9226; 47956; KP1704020
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Dalton Transactions; Journal Volume: 45; Journal Issue: 11
Publisher:
Royal Society of Chemistry
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Environmental Molecular Sciences Laboratory