August 2025

Journal

Oxygen Defect Configurations in Single-Phase UO2.15

By:
Cureton, William F; O'Quinn, Eric; Baldinozzi, Gianguido; Crocombette, Jean-Paul; McMurray, Jake; Kurley III, James M; Hunt, Rodney D; Everett, Susan M; Neuefeind, Joerg C; Tucker, Matthew G; Nelson, Andrew T; Lang, Maik
Journal Name:
Inorganic Chemistry
Volume:
64
Issue Number:
31
Publication Date:
August 12, 2025
View DOI Listing:
https://doi.org/10.1021/acs.inorgchem.5c00990

Abstract

Hyperstoichiometric UO2.15 was characterized by neutron total scattering at high temperature in the single-phase UO2+x region of the U/O phase diagram. The diffraction data confirmed a single-phase fluorite structure at high temperature. Analysis of the short-range data showed that the same structural model does not fit the pair distribution functions well. Instead, structural models containing specific configurations of oxygen defect clusters best represent the local atomic arrangement. Prevalent defect clusters previously proposed were fit to the experimental data, and moderately distorted oxygen cuboctahedra hypothesized by recent molecular dynamics simulations fit the data most accurately.