Uranium Hexafluoride Hydrolysis Reaction Dynamics from Cryogenic Layering, FTIR Spectroscopy, and Isotopic Substitution

McNamara, Louis E.; Dorris, Austin L.; Waldron, Abigail M.; Kelly, John T.; Lutz, Jesse J.; Fessler, K. Alicia Strange

doi:10.1021/acs.jpca.5c06078

Uranium Hexafluoride Hydrolysis Reaction Dynamics from Cryogenic Layering, FTIR Spectroscopy, and Isotopic Substitution

Journal Article · Thu Jan 15 00:00:00 EST 2026 · Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

DOI:https://doi.org/10.1021/acs.jpca.5c06078· OSTI ID:3017232

^[1]; Dorris, Austin L. ^[1]; Waldron, Abigail M. ^[1]; Kelly, John T. ^[1]; Lutz, Jesse J. ^[2]; Fessler, K. Alicia Strange ^[3]

Savannah River National Laboratory (SRNL), Aiken, SC (United States)
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

The first direct evidence that the hydrolysis reaction of uranium hexafluoride (UF₆) follows multiple competing pathways which are driven by the ratio of water to UF₆, temperature, and isotopic composition is presented. Using temperature dependent infrared spectroscopy, it is shown the hydrolysis can be prevented at temperatures below 150 K, and that water-rich environments promote the formation of uranium oxyfluoride intermediates. Spectral shifts reveal isomeric transitions and the growth of polymeric species, with reaction reversibility observed at high water concentrations. Additionally, controlled heating rates affect the emergence of intermediates. The final particulate product consistently forms as uranyl fluoride hydrate, though its morphology and spectral signature vary with reaction conditions and annealing. These findings help clarify long-standing uncertainties surrounding UF₆ hydrolysis.

View Accepted Manuscript (DOE)

Research Organization:: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Organization:: USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE National Nuclear Security Administration (NNSA)

Grant/Contract Number:: 89303321CEM000080; AC05-00OR22725; NA0003525

OSTI ID:: 3017232

Journal Information:: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory, Journal Name: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory Journal Issue: 4 Vol. 130; ISSN 1089-5639; ISSN 1520-5215

Publisher:: American Chemical SocietyCopyright Statement

Country of Publication:: United States

Language:: English

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