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Plutonium hexafluoride

Names
IUPAC name plutonium(VI) fluoride
Other names plutonium hexafluoride
Identifiers
CAS Number	13693-06-6
CompTox Dashboard (EPA)	DTXSID70160009
Properties
Chemical formula	PuF6
Molar mass	358 g/mol
Appearance	reddish-brown orthorhombic crystals
Density	5.08 g/cm
Melting point	52°C
Boiling point	62°C
Structure
Crystal structure	Orthorhombic, oP28
Space group	Pnma, No. 62
Coordination geometry	octahedral (Oh)
Dipole moment	0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Infobox references

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 ignition of low-mass nuclear weapon designs by neutrons produced by spontaneous fission of plutonium-240.

It is a red-brown volatile crystalline solid; the heat of sublimation is 12.1 kcal/mol and the heat of vaporization 7.4 kcal/mol. It is relatively hard to handle, being very corrosive and prone to auto-radiolysis.

It is prepared by fluorination of plutonium tetrafluoride (PuF₄) by powerful fluorinating agents such as elemental fluorine.

${\displaystyle \mathrm {PuF_{4}\ +\ F_{2}\ \longrightarrow \ PuF_{6}} }$

Its further be obtained by fluorination of plutonium(III) fluoride or plutonium(IV) oxide.

${\displaystyle \mathrm {2\ PuF_{3}\ +\ 3\ F_{2}\ \longrightarrow \ 2\ PuF_{6}} }$

${\displaystyle \mathrm {PuO_{2}\ +\ 3\ F_{2}\ \longrightarrow \ PuF_{6}\ +\ O_{2}} }$

Hydrogen fluoride is not sufficient; it is itself a powerful fluorinating agent.

Under laser irradiation at a wavelength of less than 520 nm, it decomposes to plutonium pentafluoride and fluorine; after more irradiation it decomposes further to plutonium tetrafluoride.

References

1. ^ Lide, David R. (2009). Handbook of Chemistry and Physics (90 ed.). Boca Raton, FL: CRC Press. pp. 4–81. ISBN 978-1-4200-9084-0. {{cite book}}: Cite has empty unknown parameter: |1= (help)
2. ^ Alan E. Florin, Irving R. Tannenbaum, Joe F. Lemons: "Preparation and Properties of Plutonium Hexafluoride and Identification of Plutonium(VI) Oxyfluoride", Journal of Inorganic and Nuclear Chemistry, 1956, 2 (5–6), p. 368–379; doi:10.1016/0022-1902(56)80091-2.
3. Ned E. Bibler: "α and β Radiolysis of Plutonium Hexafluoride Vapor", J. Phys. Chem., 1979, 83 (17), p. 2179–2186; doi:10.1021/j100480a001.
4. M. J. Steindler, D. V. Steidl, J. Fischer: "The Decomposition of Plutonium Hexafluoride by Gamma Radiation", Journal of Inorganic and Nuclear Chemistry, 1964, 26 (11), p. 1869–1878; doi:10.1016/0022-1902(64)80011-7.
5. A. E. Florin (9. November 1950). "Plutonium Hexafluoride: Second Report On The Preparation and Properties (LA-1168)" (PDF). Los Alamos Scientific Laboratory. {{cite web}}: Check date values in: |date= (help)
6. ^ C. J. Mandleberg, H. K. Rae, R. Hurst, G. Long, D. Davies, K. E. Francis: "Plutonium Hexafluoride", Journal of Inorganic and Nuclear Chemistry, 1956, 2 (5–6), p. 358–367; doi:10.1016/0022-1902(56)80090-0.
7. Bernard Weinstock, John G. Malm: "The Properties of Plutonium Hexafluoride", Journal of Inorganic and Nuclear Chemistry, 1956, 2 (5–6), p. 380–394; doi:10.1016/0022-1902(56)80092-4.
8. "Evaluation of the U.S. Department of Energy's Alternatives for the Removal and Disposition of Molten Salt Reactor Experiment Fluoride Salts".
9. www.freepatentsonline.com: Photochemical Preparation of Plutonium Pentafluoride; PDF.
10. E. A. Lobikov, V. N. Prusakov, V. F. Serik: "Plutonium Hexafluoride Decomposition under the Action of Laser Radiation", Journal of Fluorine Chemistry, 1992, 58 (2–3), C 54, p. 277; doi:10.1016/S0022-1139(00)80734-4.

• Plutonium compounds
• Fluorides
• Metal halides
• Nuclear materials