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Title: U(v) in metal uranates: A combined experimental and theoretical study of MgUO4, CrUO4, and FeUO4

Although pentavalent uranium can exist in aqueous solution, its presence in the solid state is uncommon. Metal monouranates, MgUO4, CrUO4 and FeUO4 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-Mossbauer 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. The presence of U5+ has been solidly confirmed in CrUO4 and FeUO4, which are thermodynamically stable compounds, and the origin and stability of U5+ in the system was elaborated by DFT. Lastly, the structural and thermodynamic behaviour of U5+ 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); Negev Be'er-Sheva (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, 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:
1256103
Report Number(s):
LA-UR-15-28081
Journal ID: ISSN 1477-9226; ICHBD9
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Dalton Transactions
Additional Journal Information:
Journal Volume: 45; Journal Issue: 11; Journal ID: ISSN 1477-9226
Research Org:
Los Alamos National Laboratory (LANL)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE Inorganic and Physical Chemistry; Material Science; uranium; uranate; X-ray absorption spectroscopy; X-ray photoelectron spectroscopy; calorimetry; structure; DFT