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Title: Structure and Reactivity of X-ray Amorphous Uranyl Peroxide, U 2 O 7

Abstract

Recent accidents resulting in worker injury and radioactive contamination occurred due to pressurization of uranium yellowcake drums produced in the western USA. The drums contained an unexpected X-ray amorphous reactive form of uranium oxide, U2O7. Heating hydrated uranyl peroxides produced during in situ mining unintentionally produced U2O7. It is a hygroscopic anhydrous uranyl peroxide that reacts rapidly with water to release O2 gas and form metaschoepite, a uranyl-oxide hydrate. Quantum chemical calculations indicate that the most stable U2O7 conformer consists of two bent (UO2)2+ uranyl ions bridged by a peroxide group bidentate and parallel to each uranyl ion, and a μ2-O atom, resulting in charge neutrality. A pair distribution function from neutron total scattering supports this structural model. The reactivity of U2O7 in water and with water in air is much higher than other uranium oxides, and this can be both hazardous and potentially advantageous in the nuclear fuel cycle.

Authors:
 [1];  [2];  [3];  [4];  [4];  [4];  [4];  [4];  [4];  [5];  [3];  [2];  [1];  [6]
  1. University of Minnesota, Department of Chemistry, Minnesota Supercomputing Institute, Minneapolis, Minnesota 55455, United States
  2. Department of Nuclear Engineering, University of Tennessee, Knoxville, Tennesee 37996, United States
  3. Department of Earth and Planetary Sciences, Department of Chemistry, University of California, Davis, California 95616, United States
  4. Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
  5. Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
  6. Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States, Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Energy Frontier Research Centers (EFRC) (United States). Materials Science of Actinides (MSA)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1241447
Alternate Identifier(s):
OSTI ID: 1334422
Grant/Contract Number:  
SC0001089; AC05-00OR22725
Resource Type:
Published Article
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Name: Inorganic Chemistry Journal Volume: 55 Journal Issue: 7; Journal ID: ISSN 0020-1669
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY

Citation Formats

Odoh, Samuel O., Shamblin, Jacob, Colla, Christopher A., Hickam, Sarah, Lobeck, Haylie L., Lopez, Rachel A. K., Olds, Travis, Szymanowski, Jennifer E. S., Sigmon, Ginger E., Neuefeind, Joerg, Casey, William H., Lang, Maik, Gagliardi, Laura, and Burns, Peter C. Structure and Reactivity of X-ray Amorphous Uranyl Peroxide, U 2 O 7. United States: N. p., 2016. Web. doi:10.1021/acs.inorgchem.6b00017.
Odoh, Samuel O., Shamblin, Jacob, Colla, Christopher A., Hickam, Sarah, Lobeck, Haylie L., Lopez, Rachel A. K., Olds, Travis, Szymanowski, Jennifer E. S., Sigmon, Ginger E., Neuefeind, Joerg, Casey, William H., Lang, Maik, Gagliardi, Laura, & Burns, Peter C. Structure and Reactivity of X-ray Amorphous Uranyl Peroxide, U 2 O 7. United States. https://doi.org/10.1021/acs.inorgchem.6b00017
Odoh, Samuel O., Shamblin, Jacob, Colla, Christopher A., Hickam, Sarah, Lobeck, Haylie L., Lopez, Rachel A. K., Olds, Travis, Szymanowski, Jennifer E. S., Sigmon, Ginger E., Neuefeind, Joerg, Casey, William H., Lang, Maik, Gagliardi, Laura, and Burns, Peter C. Mon . "Structure and Reactivity of X-ray Amorphous Uranyl Peroxide, U 2 O 7". United States. https://doi.org/10.1021/acs.inorgchem.6b00017.
@article{osti_1241447,
title = {Structure and Reactivity of X-ray Amorphous Uranyl Peroxide, U 2 O 7},
author = {Odoh, Samuel O. and Shamblin, Jacob and Colla, Christopher A. and Hickam, Sarah and Lobeck, Haylie L. and Lopez, Rachel A. K. and Olds, Travis and Szymanowski, Jennifer E. S. and Sigmon, Ginger E. and Neuefeind, Joerg and Casey, William H. and Lang, Maik and Gagliardi, Laura and Burns, Peter C.},
abstractNote = {Recent accidents resulting in worker injury and radioactive contamination occurred due to pressurization of uranium yellowcake drums produced in the western USA. The drums contained an unexpected X-ray amorphous reactive form of uranium oxide, U2O7. Heating hydrated uranyl peroxides produced during in situ mining unintentionally produced U2O7. It is a hygroscopic anhydrous uranyl peroxide that reacts rapidly with water to release O2 gas and form metaschoepite, a uranyl-oxide hydrate. Quantum chemical calculations indicate that the most stable U2O7 conformer consists of two bent (UO2)2+ uranyl ions bridged by a peroxide group bidentate and parallel to each uranyl ion, and a μ2-O atom, resulting in charge neutrality. A pair distribution function from neutron total scattering supports this structural model. The reactivity of U2O7 in water and with water in air is much higher than other uranium oxides, and this can be both hazardous and potentially advantageous in the nuclear fuel cycle.},
doi = {10.1021/acs.inorgchem.6b00017},
journal = {Inorganic Chemistry},
number = 7,
volume = 55,
place = {United States},
year = {Mon Mar 14 00:00:00 EDT 2016},
month = {Mon Mar 14 00:00:00 EDT 2016}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
https://doi.org/10.1021/acs.inorgchem.6b00017

Citation Metrics:
Cited by: 43 works
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