Uranyl fluoride

Uranyl fluoride (UO₂F₂) a compound of uranium ,is an intermediate in the conversion of uranium hexafluoride UF₆ to an uranium oxide or metal form and is a direct product of the reaction of UF₆ with moisture in the air. It is very soluble in water. Uranyl fluoride also is hygroscopic and changes in color from brilliant orange to yellow after reacting with water. Uranyl fluoride is reported to be stable in air to 300°C, above which slow decomposition to U₃O₈ occurs. When heated to decomposition, UO₂F₂ emits toxic fluoride fumes.

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In accidental releases of UF₆, UO₂F₂, as a solid particulate compound, may deposit on the ground. The overall chemical reaction of this event can be represented as: UF₆+ 2H₂O → UO₂F₂+ 4HF. These reactions can take place whether the uranium hexafluoride is a solid or a gas, but will take place almost instantaneously when the UF₆ is in a gaseous state. The resulting hydrofluoric acid and the presence of additional water results in formation of solids (primarily HF adducts of hydrated uranyl fluoride (UO₂F₂-nH₂O).

Toxicology

Chemical hazards are far more significant than radioactive hazards, though there is a radioactivity concern if prepared with enriched uranium. Material is corrosive, and harmful by inhalation, ingestion or skin absorption. Ingestion or inhalation may be fatal. Effects of exposure may be delayed.

References

Appendix A of the PEIS (DOE/EIS-0269) A literature review on the chemical and physical properties of uranyl fluoride, Myers, W.L. (Los Alamos National Lab., NM (USA) Illinois Univ. Urbana, IL (USA).