Skip to main content
eScholarship
Open Access Publications from the University of California

UC Davis

UC Davis Previously Published Works bannerUC Davis

Structure and Reactivity of X-ray Amorphous Uranyl Peroxide, U2O7.

  • Author(s): Odoh, Samuel O
  • Shamblin, Jacob
  • Colla, Christopher A
  • Hickam, Sarah
  • Lobeck, Haylie L
  • Lopez, Rachel AK
  • Olds, Travis
  • Szymanowski, Jennifer ES
  • Sigmon, Ginger E
  • Neuefeind, Joerg
  • Casey, William H
  • Lang, Maik
  • Gagliardi, Laura
  • Burns, Peter C
  • et al.
Abstract

Recent accidents resulting in worker injury and radioactive contamination occurred due to pressurization of uranium yellowcake drums produced in the western U.S.A. The drums contained an X-ray amorphous reactive form of uranium oxide that may have contributed to the pressurization. Heating hydrated uranyl peroxides produced during in situ mining can produce an amorphous compound, as shown by X-ray powder diffraction of material from impacted drums. Subsequently, studtite, [(UO2)(O2)(H2O)2](H2O)2, was heated in the laboratory. Its thermal decomposition produced a hygroscopic anhydrous uranyl peroxide that reacts 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, as do (1)H- and (17)O-nuclear magnetic resonance spectra. The reactivity of U2O7 in water and with water in air is higher than that of other uranium oxides, and this can be both hazardous and potentially advantageous in the nuclear fuel cycle.

Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.

Main Content
Current View