Uranium hexafluoride

Uranium hexafluoride, sometimes called hex, is the inorganic compound with the formula UF₆. Uranium hexafluoride is a volatile, white solid that is used in enriching uranium for nuclear reactors and nuclear weapons.

Uranium dioxide is converted with hydrofluoric acid (HF) to uranium tetrafluoride:

The resulting UF₄ is subsequently oxidized with fluorine to give the hexafluoride:

In samples contaminated with uranium trioxide, uranyl fluoride, an oxyfluoride compound is produced in the HF step:

which can be fluorinated to produce the same product, uranium hexafluoride.

The fluorination steps in both reactions above are highly exothermic.

At atmospheric pressure, UF₆ sublimes at 56.5 °C.

The solid-state structure was determined by neutron diffraction at 77 K and 293 K.