Abstract
Uranium is arguably the most essential element in the actinide series, serving as a crucial component of nuclear fuels. While U is recognized for engaging the 5f orbitals in chemical bonds under normal conditions, little is known about its coordination chemistry and the nature of bonding interactions at extreme conditions of high temperature. Here we report experimental and computational evidence for the shrinkage of the average U-ligand distance in UCl3 upon the solid-to-molten phase transition, leading to the formation of a significant fraction of short, transient U-Cl bonds with the enhanced involvement of U 5f valence orbitals. These findings reveal that extreme temperatures create an unusual heterogeneous bonding environment around U(III) with distinct inner- and outer-coordination subshells.
| Original language | English |
|---|---|
| Pages (from-to) | 21220-21224 |
| Number of pages | 5 |
| Journal | Journal of the American Chemical Society |
| Volume | 146 |
| Issue number | 31 |
| DOIs | |
| State | Published - Aug 7 2024 |
Funding
This work was supported as part of the Molten Salts in Extreme Environments (MSEE) Energy Frontier Research Center, funded by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences. Work at Oak Ridge National Laboratory was supported by DOE contract DE-AC05-00OR22725. M.A., J.S.-P., and T.M.B. are supported by the U.S. DOE Office of Nuclear Energy, Nuclear Energy University Programs under award DE-NE0008985 and the Molten Salt Reactor Program. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. A portion of this research used resources of the Advanced Photon Source at beamline 12-BM, operated by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. This research used resources of the Compute and Data Environment for Science (CADES) at the Oak Ridge National Laboratory and the National Energy Research Scientific Computing Center (NERSC), which are supported by the Office of Science of the U.S. DOE under Contract Nos. DE-AC05-00OR22725 and DE-AC02-05CH11231, respectively. A.S.I., S.R., and V.S.B. thank Dr. Margulis and Dr. Emerson for initial discussions. This manuscript has been authored by UT-Battelle, LLC under Contract DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). Acknowledgments