Plutonium(IV) fluoride is a chemical compound with the formula (PuF₄). It is a brown solid but can appear a variety of colors depending on the grain size, purity, moisture content, lighting, and presence of contaminants. Its primary use in the United States has been as an intermediary product in the production of plutonium metal for nuclear weapons usage.

Formation

Plutonium(IV) fluoride is produced in the reaction between

plutonium dioxide Plutonium(IV) oxide or (plutonia) is the chemical compound with the formula Pu O2. This high melting-point solid is a principal compound of plutonium. It can vary in color from yellow to olive green, depending on the particle size, temperature a ...

(PuO₂) or

plutonium(III) fluoride Plutonium(III) fluoride or plutonium trifluoride is the chemical compound composed of plutonium and fluorine with the formula PuF3. This salt forms violet crystals. Plutonium(III) fluoride has the LaF3 structure where the coordination around the p ...

(PuF₃) with

hydrofluoric acid Hydrofluoric acid is a Solution (chemistry), solution of hydrogen fluoride (HF) in water. Solutions of HF are colourless, acidic and highly Corrosive substance, corrosive. It is used to make most fluorine-containing compounds; examples include th ...

(HF) in a stream of oxygen (O₂) at 450 to 600 °C. The main purpose of the oxygen stream is to avoid reduction of the product by hydrogen gas, small amounts of which are often found in HF.'' Gmelins Handbuch der anorganischen Chemie'', System Nr. 71, Transurane, Teil C, pp. 104–107. :PuO₂ + O₂ + 4 HF → PuF₄ + O₂ + 2 H₂O :4 PuF₃ + O₂ + 4 HF → 4 PuF₄ + 2 H₂O Laser irradiation of

plutonium hexafluoride Plutonium hexafluoride is the highest fluoride of plutonium, and is of interest for laser enrichment of plutonium, in particular for the production of pure plutonium-239 from irradiated uranium. This pure plutonium is needed to avoid premature ...

(PuF₆) at wavelengths under 520 nm causes it to decompose into plutonium pentafluoride (PuF₅) and fluorine; if this is continued, plutonium(IV) fluoride is obtained.

Properties

In terms of its structure, solid plutonium(IV) fluoride features 8-coordinate Pu centers interconnected by doubly bridging fluoride ligands. Reaction of plutonium tetrafluoride with barium, calcium, or lithium at 1200 °C give Pu metal: :PuF₄ + 2 Ba → 2 BaF₂ + Pu :PuF₄ + 2 Ca → 2 CaF₂ + Pu :PuF₄ + 4 Li → 4 LiF + Pu Plutonium tetrafluoride color square

Plutonium Tetrafluoride PuF4 from Hanford Site (cropped)

References

Plutonium(IV) compounds Fluorides Metal halides Nuclear materials Actinide halides {{inorganic-compound-stub