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.

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, unless the sample has been 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.