Pu6

Pu6, commonly denoted as PuF₆, is plutonium hexafluoride, a volatile inorganic compound of plutonium in the +6 oxidation state. It appears as a colourless to pale yellow gas under standard conditions and is one of the few plutonium compounds that is sufficiently volatile for use in fluorination and separation processes. The molecule adopts an octahedral geometry around the plutonium centre, with six fluorine atoms arranged symmetrically. Its boiling point is approximately 56 °C at 1 atm, and it sublimes readily, making it amenable to gas‑phase handling.

PuF₆ is typically produced by reacting elemental plutonium or plutonium oxides with fluorine gas at elevated temperatures (300–400 °C). The reaction proceeds via intermediate lower fluorides, such as PuF₄, before achieving the hexafluoride stage. Because PuF₆ is highly reactive, it readily hydrolyses in the presence of moisture, forming plutonium oxy‑fluorides and hydrofluoric acid, which necessitates strict anhydrous conditions during synthesis and storage.

In the nuclear industry, PuF₆ has been investigated for its potential in isotope enrichment and for the volatile transport of plutonium during reprocessing of spent fuel. However, its extreme radiological toxicity, chemical corrosiveness, and the difficulty of safely containing the gas have limited widespread adoption. Handling requires sealed containment, inert‑gas atmospheres, and specialized filtration to mitigate both radiological and chemical hazards. Research continues on alternative, less hazardous chemistry for plutonium separation.