Plutonium tetrafluoride

Plutonium tetrafluoride ^[1]

A sample of plutonium tetrafluoride produced at the Hanford Site during the Cold War [2] [3]
Names
IUPAC name Plutonium(IV) fluoride
Other names Plutonium tetrafluoride
Identifiers
CAS Number	13709-56-3  N
3D model (JSmol)	Interactive image
ChemSpider	123078
PubChem CID	139558
CompTox Dashboard (EPA)	DTXSID90160061
InChI InChI=1S/4FH.Pu/h4*1H;/q;;;;+4/p-4 Key: USCBBUFEOOSGAJ-UHFFFAOYSA-J
SMILES F[Pu](F)(F)F
Properties
Chemical formula	PuF4
Molar mass	320 g/mol
Appearance	reddish-brown monoclinic crystals
Density	7.1 g/cm3
Melting point	1,027 °C (1,881 °F; 1,300 K)
Structure
Crystal structure	Monoclinic, mS60
Space group	C12/c1, No. 15
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N  verify  (what is  YN ?) Infobox references

Plutonium(IV) fluoride is a chemical compound with the formula PuF₄. This salt is generally a brown solid but can appear a variety of colors depending on the grain size, purity, moisture content, lighting, and presence of contaminants. ^{[4] [5]} Its primary use in the United States has been as an intermediary product in the production of plutonium metal for nuclear weapons usage. ^[3]

Formation

Plutonium(IV) fluoride is produced in the reaction between plutonium dioxide (PuO₂) or plutonium(III) fluoride (PuF₃) with hydrofluoric acid (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. ^[6]

PuO₂ + O₂ + 4 HF → PuF₄ + O₂ + 2 H₂O

4 PuF₃ + O₂ + 4 HF → 4 PuF₄ + 2 H₂O

Laser irradiation of plutonium hexafluoride (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. ^[7]

Properties

In terms of its structure, solid plutonium(IV) fluoride features 8-coordinate Pu centers interconnected by doubly bridging fluoride ligands. ^[8]

Reaction of plutonium tetrafluoride with barium, calcium, or lithium at 1200 °C gives Pu metal: ^{[4] [5] [3]}

PuF₄ + 2 Ba → 2 BaF₂ + Pu

PuF₄ + 2 Ca → 2 CaF₂ + Pu

PuF₄ + 4 Li → 4 LiF + Pu

Plutonium tetrafluoride sample with example of one color illustrated through reference to a color standard

References

1. Lide, David R. (1998), Handbook of Chemistry and Physics (87 ed.), Boca Raton, Florida: CRC Press, pp. 4–76, ISBN   0-8493-0594-2
2. Pfeiffer, Martin (March 3, 2019). "FOI 2019-00371.Loaded powder pan at RMC line". Pfeiffer Nuclear Weapon and National Security Archive. Retrieved May 23, 2019.
3. United States Department of Energy (1997). Linking Legacies: Connecting the Cold War Nuclear Weapons Production Processes to Their Environmental Consequences (PDF). Washington D.C.: United States Department of Energy. pp. 184, passim.
4. Baldwin, Charles E.; Navratil, James D. (1983-05-19). "Plutonium Process Chemistry at Rocky Flats". In Carnall, William T.; Choppin, Gregory R. (eds.). Plutonium Chemistry. ACS Symposium Series. Vol. 216. AMERICAN CHEMICAL SOCIETY. pp. 369–380. doi:10.1021/bk-1983-0216.ch024. ISBN   9780841207721.
5. Christensen, Eldon L.; Grey, Leonard W.; Navratil, James D.; Schulz, Wallace W. (1983-05-19). "Present Status and Future Directions of Plutonium Process Chemistry". In Carnall, William T.; Choppin, Gregory R. (eds.). Plutonium Chemistry. ACS Symposium Series. Vol. 216. AMERICAN CHEMICAL SOCIETY. pp. 349–368. doi:10.1021/bk-1983-0216.ch023. ISBN   9780841207721. OSTI   6781635.
6. Gmelins Handbuch der anorganischen Chemie , System Nr. 71, Transurane, Teil C, pp. 104–107.
7. 4670239,Rabideau, Sherman W.&Campbell, George M.,"Photochemical preparation of plutonium pentafluoride",issued 1987-06-02 
8. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. doi:10.1016/C2009-0-30414-6. ISBN   978-0-08-037941-8.
9. Pfeiffer, Martin (March 3, 2019). "PuF4 Pics ORO 2019 00475-FN Final Response 20190312_Page_07_Image_0001". Pfeiffer Nuclear Weapon and National Security Archive. Retrieved May 23, 2019.