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{{Chembox {{Chembox
| Verifiedfields = changed
| ImageFile = Plutonium hexafluoride.svg
| Watchedfields = changed
| ImageSize =
| verifiedrevid = 404346614
| Reference = <ref name="hand">{{cite book | last = Lide | first = David R. | year = 2009
| Name =
| title = Handbook of Chemistry and Physics
| edition = 90 | | location = Boca Raton, FL | Reference = <ref name="handbk" />
| ImageFile = Plutonium hexafluoride.svg
| publisher = CRC Press
| ImageFileL1 = Plutonium-hexafluoride-3D-vdW.png
| isbn = 978-1-4200-9084-0 | pages = 4–81}}</ref>
| IUPACName = plutonium(VI) fluoride | ImageFileR1 = Neptunium(VI)-fluoride-3D-balls.png
| ImageFile_Ref = {{Chemboximage|correct|??}}
| OtherNames = plutonium hexafluoride
| ImageSize = 121
| Section1 = {{Chembox Identifiers
| ImageName = Stereo structural formula of plutonium hexafluoride
| OtherNames =
| IUPACName = plutonium(VI) fluoride
| SystematicName = <!-- Hexafluoroplutonium (substitutive) OR Hexafluoridoplutonium (additive) -->
| Section1 = {{Chembox Identifiers
| CASNo = 13693-06-6 | CASNo = 13693-06-6
| CASNo_Ref = {{cascite|correct|??}}
| PubChem =
| SMILES = }} | PubChem = 518809
| ChemSpiderID = 452599
| Section2 = {{Chembox Properties
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| Formula = PuF<sub>6</sub>
| SMILES = F(F)(F)(F)(F)F
| MolarMass = 358 g/mol
| StdInChI = 1S/6FH.Pu/h6*1H;/q;;;;;;+6/p-6
| Appearance = reddish-brown ] crystals
| StdInChI_Ref = {{stdinchicite|changed|chemspider}}
| Density = 5.08 g/cm<sup>3</sup>
| StdInChIKey = OJSBUHMRXCPOJV-UHFFFAOYSA-H
| MeltingPt = 52°C
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| BoilingPt = 62°C
| Solubility =
}} }}
| Section3 = {{Chembox Structure | Section2 = {{Chembox Properties
| Formula = {{Chem|Pu|F|6}}
| CrystalStruct = ], ]
| Appearance = Dark red, opaque crystals
| SpaceGroup = Pnma, No. 62
| Coordination = octahedral (''O<sub>h</sub>'') | Density = 5.08 g·cm<sup>−3</sup>
| Dipole = 0 | MeltingPtC = 52
| BoilingPtC = 62
}} }}
| Section7 = {{Chembox Hazards | Section3 = {{Chembox Structure
| CrystalStruct = ], ]
| MainHazards =
| SpaceGroup = Pnma, No. 62
| FlashPt =
| Coordination = octahedral (''O<sub>h</sub>'')
| Autoignition = }}
| Dipole = 0 D
| Section4 = {{Chembox Thermochemistry
| DeltaHf =
| DeltaHc =
| Entropy =
| HeatCapacity = }}
}} }}
| Section4 = {{Chembox Related
| OtherFunction_label = fluoroplutoniums
| OtherFunction = ]<br />
]
}}
| Section5 = {{Chembox Hazards
| GHS_ref=
| GHSPictograms = {{GHS03}}{{GHS05}}{{GHS06}}{{GHS09}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|}}
| PPhrases = {{P-phrases|}}
| NFPA-H = 4
| NFPA-F = 0
| NFPA-R = 4
| NFPA-S = RA
}}
| Section6 =
}}
'''Plutonium hexafluoride''' is the highest fluoride of ], and is of interest for ] of plutonium, in particular for the production of pure ] from irradiated uranium. This isotope of plutonium is needed to avoid premature ignition of low-mass ] designs by neutrons produced by spontaneous fission of ].


== Preparation ==
'''Plutonium hexafluoride''' is the highest fluoride of ], and is of interest for ] of plutonium, in particular for the production of pure ] from irradiated uranium. This pure plutonium is needed to avoid premature ignition of low-mass ] designs by neutrons produced by spontaneous fission of ].
Plutonium hexafluoride is prepared by fluorination of ] (PuF<sub>4</sub>) by powerful fluorinating agents such as elemental fluorine.<ref name="JINC_1956_368">{{cite journal |last1=Florin |first1=Alan E. |last2=Tannenbaum |first2=Irving R. |last3=Lemons |first3=Joe F. |year=1956 |title=Preparation and properties of plutonium hexafluoride and identification of plutonium(VI) oxyfluoride |journal=] |volume=2 |issue=5–6 |pages=368–379 |doi=10.1016/0022-1902(56)80091-2}} Originally published as


* {{cite tech report|first=Alan&nbsp;E.|last=Florin|title=Thermodynamic Properties of Plutonium Hexafluoride: a Preliminary Report|institution=]|number=LAMS-1587|date=15 May 1953|url=http://www.fas.org/sgp/othergov/doe/lanl/lib-www/la-pubs/00318358.pdf}}
It is a red-brown volatile crystalline solid;<ref name="hand"/> the heat of sublimation is 12.1 kcal/mol<ref name="JINC_1956_368">Alan E. Florin, Irving R. Tannenbaum, Joe F. Lemons: "Preparation and Properties of Plutonium Hexafluoride and Identification of Plutonium(VI) Oxyfluoride", '']'', '''1956''', ''2&nbsp;(5–6)'', p.&nbsp;368–379; {{DOI|10.1016/0022-1902(56)80091-2}}.</ref> and the heat of vaporization 7.4 kcal/mol<ref name="JINC_1956_368"/>. It is relatively hard to handle, being very corrosive and prone to auto-].<ref>Ned E. Bibler: "&alpha; and &beta; Radiolysis of Plutonium Hexafluoride Vapor", '']'', '''1979''', ''83&nbsp;(17)'', p.&nbsp;2179–2186; {{DOI|10.1021/j100480a001}}.</ref><ref>M. J. Steindler, D. V. Steidl, J. Fischer: "The Decomposition of Plutonium Hexafluoride by Gamma Radiation", '']'', '''1964''', ''26&nbsp;(11)'', p.&nbsp;1869–1878; {{DOI|10.1016/0022-1902(64)80011-7}}.</ref>
* {{cite tech report|first1=I.&nbsp;R.|last1=Tannenbaum|first2=Alan&nbsp;E.|last2=Florin|title=An Improved Apparatus for the Production of Plutonium Hexafluoride|institution=]|number=LA-1580|date=15 May 1953|url=http://www.fas.org/sgp/othergov/doe/lanl/lib-www/la-pubs/00371935.pdf}}
</ref><ref name="Florin">{{cite tech report|first=Alan&nbsp;E.|last=Florin|title=Plutonium Hexafluoride: Second Report on the Preparation and Properties|institution=]|number=LAMS-1168|date=9 November 1950|url=http://www.fas.org/sgp/othergov/doe/lanl/lib-www/la-pubs/00419717.pdf}}
</ref><ref name="JINC_1956_358">{{cite journal|last1=Mandleberg|first1=C.J.|last2=Rae|first2=H.K.|last3=Hurst|first3=R.|last4=Long|first4=G.|last5=Davies|first5=D.|last6=Francis|first6=K.E.|year=1956|title=Plutonium hexafluoride|journal=]|volume=2|issue=5–6|pages=358–367|doi=10.1016/0022-1902(56)80090-0}} Originally published as
* {{cite tech report|first1=C.&nbsp;J.|last1=Mandleberg|first2=H.&nbsp;K.|last2=Rae|first3=R.|last3=Hurst|first4=G.|last4=Long|first5=D.|last5=Davis|first6=K.&nbsp;E.|last6=Francis|title=Plutonium Hexafluoride: Preparation and Some Physical Properties|volume=I|institution=]|number=C/R-1172|date=April 1953}}
* {{cite tech report|first2=C.&nbsp;J.|last2=Mandleberg|first3=H.&nbsp;K.|last3=Rae|first1=R.|last1=Hurst|first4=D.|last4=Davis|first5=K.&nbsp;E.|last5=Francis|title=Plutonium Hexafluoride: Preparation and Some Physical Properties|volume=II|institution=]|number=C/R-1312|date=January 1953}}</ref><ref name="JINC_1956_380">{{cite journal|last1=Weinstock|first1=Bernard|last2=Malm|first2=John G.|date=July 1956|title=The properties of plutonium hexafluoride|journal=]|volume=2|issue=5–6|pages=380–394|doi=10.1016/0022-1902(56)80092-4}}</ref>
:{{chem|Pu|F|4}} + {{chem|F|2}} → {{chem|Pu|F|6}}


This reaction is ]. The product forms relatively quickly at temperatures of 750&nbsp;°C, and high yields may be obtained by quickly condensing the product and removing it from equilibrium.<ref name="JINC_1956_380"/>
It is prepared by fluorination of ] (PuF<sub>4</sub>) by powerful fluorinating agents such as elemental fluorine.<ref>{{cite web | author= A. E. Florin | url = http://www.fas.org/sgp/othergov/doe/lanl/lib-www/la-pubs/00419717.pdf | title = Plutonium Hexafluoride: Second Report On The Preparation and Properties (LA-1168) | publisher = Los Alamos Scientific Laboratory | date= 9. November 1950}}</ref><ref name="JINC_1956_358">C. J. Mandleberg, H. K. Rae, R. Hurst, G. Long, D. Davies, K. E. Francis: "Plutonium Hexafluoride", '']'', '''1956''', ''2&nbsp;(5–6)'', p.&nbsp;358–367; {{DOI|10.1016/0022-1902(56)80090-0}}.</ref><ref name="JINC_1956_368"/><ref name="JINC_1956_380">Bernard Weinstock, John G. Malm: "The Properties of Plutonium Hexafluoride", '']'', '''1956''', ''2&nbsp;(5–6)'', p.&nbsp;380–394; {{DOI|10.1016/0022-1902(56)80092-4}}.</ref>


It can also be obtained by fluorination of ], ], or ] at approximately 700&nbsp;°C:<ref name="JINC_1956_358" /><ref>{{Cite tech report|first1=J.&nbsp;K.|last1=Dawson|first2=A.&nbsp;E.|last2=Truswell|title=The Preparation of Plutonium Trifluoride and Tetrafluoride by the Use of Hydrogen Fluoride|institution=]|number=C/R-662|date=22 February 1951}}</ref>
:<math>\mathrm{PuF_4\ +\ F_2\ \longrightarrow \ PuF_6}</math>


:2&nbsp;{{chem|Pu|F|3}} + 3&nbsp;{{chem|F|2}} → 2&nbsp;{{chem|Pu|F|6}}
Its further be obtained by fluorination of ] or ].<ref name="JINC_1956_358"/>
:{{chem|Pu|O|2}}&nbsp;+ 3&nbsp;{{chem|F|2}}&nbsp;→ {{chem|Pu|F|6}}&nbsp;+ {{chem|O|2}}
:{{Chem2|Pu(C2O4)2}}&nbsp;+ 3&nbsp;{{Chem|F|2}}&nbsp;→ {{Chem|Pu|F|6}}&nbsp;+ 4&nbsp;{{Chem|C|O|2}}


Alternatively, ] oxidizes in an 800-°C ] atmosphere to plutonium hexafluoride and ]:<ref name=Skimpy />
:<math>\mathrm{2\ PuF_3\ +\ 3\ F_2\ \longrightarrow \ 2\ PuF_6}</math>


:3&nbsp;{{Chem|Pu|F|4}}&nbsp;+ {{Chem|O|2}}&nbsp;→ 2&nbsp;{{Chem|Pu|F|6}}&nbsp;+ {{Chem|Pu|O|2}}
:<math>\mathrm{PuO_2\ +\ 3\ F_2\ \longrightarrow \ PuF_6\ +\ O_2}</math>


In 1984, the synthesis of plutonium hexafluoride at near–room-temperatures was achieved through the use of ].<ref>{{cite journal|last1=Malm|first1=J. G.|last2=Eller|first2=P. G.|last3=Asprey|first3=L. B.|year=1984|title=Low temperature synthesis of plutonium hexafluoride using dioxygen difluoride|journal=]|volume=106|issue=9|pages=2726–2727|doi=10.1021/ja00321a056}}</ref><ref>{{Cite journal |last1=Erilov |first1=P.&nbsp;E. |last2=Titov |first2=V.&nbsp;V. |last3=Serik |first3=V.&nbsp;F. |last4=Sokolov |first4=V.&nbsp;B. |date=2002 |title=Low-Temperature Synthesis of Plutonium Hexafluoride |journal=Atomic Energy |volume=92 |issue=1 |pages=57–63 |doi=10.1023/A:1015106730457|s2cid=96612181 }}</ref> ] is not sufficient<ref name="DoEEval" />{{rp|42}} even though it is a powerful fluorinating agent. Room temperature syntheses are also possible by using ]<ref>{{Cite journal|last1=Asprey|first1=L. B.|last2=Eller|first2=P. G.|last3=Kinkead|first3=Scott A.|date=1986|title=Formation of actinide hexafluorides at ambient temperatures with krypton difluoride|url=https://pubs.acs.org/doi/abs/10.1021/ic00225a016|journal=Inorganic Chemistry|language=en|volume=25|issue=5|pages=670–672|doi=10.1021/ic00225a016|issn=0020-1669}}</ref> or irradiation with UV light.<ref>{{Cite journal|last1=Trevorrow|first1=L.E.|last2=Gerding|first2=T.J.|last3=Steindler|first3=M.J.|date=1969|title=Ultraviolet-activated synthesis of plutonium hexafluoride at room temperature|url=https://linkinghub.elsevier.com/retrieve/pii/0020165069800681|journal=Inorganic and Nuclear Chemistry Letters|language=en|volume=5|issue=10|pages=837–839|doi=10.1016/0020-1650(69)80068-1}}</ref>
] is not sufficient<ref>{{cite web | url = http://books.nap.edu/openbook.php?record_id=5538&page=42 | title = Evaluation of the U.S. Department of Energy's Alternatives for the Removal and Disposition of Molten Salt Reactor Experiment Fluoride Salts}}</ref>; it is itself a powerful fluorinating agent.


== Properties ==
Under laser irradiation at a wavelength of less than 520 nm, it decomposes to ] and ]<ref>www.freepatentsonline.com: ''''; .</ref>; after more irradiation it decomposes further to ].<ref>E. A. Lobikov, V. N. Prusakov, V. F. Serik: "Plutonium Hexafluoride Decomposition under the Action of Laser Radiation", '']'', '''1992''', ''58&nbsp;(2–3), C&nbsp;54, p.&nbsp;277; {{DOI|10.1016/S0022-1139(00)80734-4}}.</ref>

=== Physical properties ===
]
Plutonium hexafluoride is a red-brown volatile solid,<ref name="handbk">{{cite book |last=Lide |first=David R. |url=https://archive.org/details/handbookchemistr00lide |title=Handbook of Chemistry and Physics |publisher=CRC Press |year=2009 |isbn=978-1-4200-9084-0 |edition=90 |location=Boca Raton, Florida |pages=–81 |url-access=limited}} ()</ref><ref name="JINC_1956_358" /> crystallizing in the ] with ] ''Pnma'' and ]s {{Math|1=''a'' = 995 pm}}'','' {{Math|1=''b'' = 902 pm}}, and {{Math|1=''c'' = 526 pm}}.<ref name=Gmelin>{{Cite book |title=Gmelins Handbuch der anorganischen Chemie |series=71 ({{lang|de|Transurane}} ) |volume=C |pages=108–114 |language=de |trans-title=Gmelin's Handbook of Inorganic Chemistry}}</ref> It ] around 60&nbsp;°C with heat 12.1&nbsp;kcal/mol to a gas of ]<ref name="JINC_1956_368" /> with plutonium-fluorine bond lengths of 197.1&nbsp;pm.<ref>{{Cite journal |last1=Kimura |first1=Masao |last2=Schomaker |first2=Verner |last3=Smith |first3=Darwin W. |last4=Weinstock |first4=Bernard |date=May 1968 |title=Electron-Diffraction Investigation of the Hexafluorides of Tungsten, Osmium, Iridium, Uranium, Neptunium, and Plutonium |url=https://pubs.aip.org/aip/jcp/article/48/9/4001-4012/770361 |journal=The Journal of Chemical Physics |language=en |volume=48 |issue=9 |pages=4001–4012 |doi=10.1063/1.1669727 |bibcode=1968JChPh..48.4001K |issn=0021-9606}}</ref> At high pressure, the gas ], with a ] at 51.58&nbsp;°C and {{Convert|710|hPa|Torr|abbr=on}}; the heat of vaporization is 7.4&nbsp;kcal/mol.<ref name=Gmelin /> At temperatures below -180&nbsp;°C, plutonium hexafluoride is colorless.<ref name="JINC_1956_358" />

Plutonium hexafluoride is ], with ] 0.173&nbsp;mm<sup>3</sup>/mol.<ref>{{Cite journal |last1=Gruen |first1=D. M. |last2=Malm |first2=J. G. |last3=Weinstock |first3=B. |date=April 1956 |title=Magnetic Susceptibility of Plutonium Hexafluoride |url=https://pubs.aip.org/aip/jcp/article/24/4/905-906/74261 |journal=The Journal of Chemical Physics |language=en |volume=24 |issue=4 |pages=905–906 |doi=10.1063/1.1742635 |bibcode=1956JChPh..24..905G |issn=0021-9606}}</ref>

==== Spectroscopic properties ====
Plutonium hexafluoride admits six different oscillation modes: ] {{Math|''v''<sub>1</sub>}}, {{Math|''v''<sub>2</sub>}}, and {{Math|''v''<sub>3</sub>}} and ] {{Math|''v''<sub>4</sub>}}, {{Math|''v''<sub>5</sub>}}, and {{Math|''v''<sub>6</sub>}}.<ref>{{Cite journal |last1=Steindler |first1=Martin J. |last2=Gunther |first2=William H. |date=August 1964 |title=The absorption spectrum of plutonium hexafluoride |url=https://linkinghub.elsevier.com/retrieve/pii/0371195164801594 |journal=Spectrochimica Acta |language=en |volume=20 |issue=8 |pages=1319–1322 |doi=10.1016/0371-1951(64)80159-4|bibcode=1964AcSpe..20.1319S }}</ref><ref>{{Cite journal |last1=Walters |first1=R.T. |last2=Briesmeister |first2=R.A. |date=January 1984 |title=Absorption spectrum of plutonium hexafluoride in the 3000–9000 Å spectral region |url=https://linkinghub.elsevier.com/retrieve/pii/0584853984801087 |journal=Spectrochimica Acta Part A: Molecular Spectroscopy |language=en |volume=40 |issue=7 |pages=587–589 |doi=10.1016/0584-8539(84)80108-7|bibcode=1984AcSpA..40..587W }}</ref> The {{Chem|Pu|F|6}} ] cannot be observed, because irradiation at 564.1&nbsp;nm induces ] decomposition.<ref name=Spec>{{cite tech report|first1=N.&nbsp;J.|last1=Hawkins|first2=H.&nbsp;C.|last2=Mattraw|first3=W.&nbsp;W.|last3=Sabol|title=Infrared Spectrum and Thermodynamic Properties of PuF<sub>6</sub>|institution=]|number=KAPL-1007|date=24 May 1954}}</ref> Irradation at 532&nbsp;nm induces ] at 1900&nbsp;nm and 4800&nbsp;nm; irradiation at 1064&nbsp;nm induces fluorescence about 2300&nbsp;nm.<ref>{{Cite journal |last1=Beitz |first1=James V. |last2=Williams |first2=Clayton W. |last3=Carnall |first3=W. T. |date=March 1982 |title=Fluorescence studies of neptunium and plutonium hexafluoride vapors |url=https://pubs.aip.org/aip/jcp/article/76/5/2756-2757/451674 |journal=The Journal of Chemical Physics |language=en |volume=76 |issue=5 |pages=2756–2757 |doi=10.1063/1.443223 |bibcode=1982JChPh..76.2756B |issn=0021-9606}}</ref><ref>{{Cite book |last1=Beitz |first1=James&nbsp;V. |url=https://pubs.acs.org/doi/book/10.1021/bk-1983-0216 |title=Plutonium Chemistry |last2=Williams |first2=Clayton&nbsp;W. |last3=Carnall |first3=W.&nbsp;T. |date=1983-05-19 |publisher=] |isbn=978-0-8412-0772-1 |editor-last=Carnall |editor-first=William T. |series=ACS Symposium Series |volume=216 |location=Washington, D.C. |pages=155–172 |language=en |chapter=11.&nbsp;Plutonium Hexafluoride Gas Photophysics and Photochemistry |doi=10.1021/bk-1983-0216.ch011 |editor-last2=Choppin |editor-first2=Gregory R.}}</ref>
{| class="wikitable"
|+Absorption modes for {{Chem|Pu|F|6}}<ref>
* {{Cite journal |last1=Weinstock |first1=B. |last2=Weaver |first2=E.E. |last3=Malm |first3=J.G. |date=September 1959 |title=Vapour-pressures of NpF<sub>6</sub> and PuF<sub>6</sub>; thermodynamic calculations with UF<sub>6</sub>, NpF<sub>6</sub> and PuF<sub>6</sub> |url=https://linkinghub.elsevier.com/retrieve/pii/0022190259800543 |journal=Journal of Inorganic and Nuclear Chemistry |language=en |volume=11 |issue=2 |pages=104–114 |doi=10.1016/0022-1902(59)80054-3}}
* {{Cite journal |last1=Kim |first1=K.C. |last2=Mulford |first2=R.N. |date=June 1990 |title=Vibrational properties of actinide (U, Np, Pu, Am) hexafluoride molecules |url=https://linkinghub.elsevier.com/retrieve/pii/016612809085031H |journal=Journal of Molecular Structure: THEOCHEM |language=en |volume=207 |issue=3–4 |pages=293–299 |doi=10.1016/0166-1280(90)85031-H}}
* {{Cite journal |last1=Hawkins |first1=N. J. |last2=Mattraw |first2=H. C. |last3=Sabol |first3=W. W. |date=November 1955 |title=Infrared Spectrum of Plutonium Hexafluoride |url=https://pubs.aip.org/aip/jcp/article/23/11/2191-2192/204475 |journal=The Journal of Chemical Physics |language=en |volume=23 |issue=11 |pages=2191–2192 |doi=10.1063/1.1740699 |bibcode=1955JChPh..23.2191H |issn=0021-9606}}
* {{Cite journal |last1=Malm |first1=John G. |last2=Weinstock |first2=Bernard |last3=Claassen |first3=Howard H. |date=November 1955 |title=Infrared Spectra of NpF 6 and PuF 6 |url=https://pubs.aip.org/aip/jcp/article/23/11/2192-2193/204470 |journal=The Journal of Chemical Physics |language=en |volume=23 |issue=11 |pages=2192–2193 |doi=10.1063/1.1740700 |bibcode=1955JChPh..23.2192M |issn=0021-9606}}</ref>
|Oscillation
|''ν''<sub>1</sub>
|''ν''<sub>2</sub>
|''ν''<sub>3</sub>
|''ν''<sub>4</sub>
|''ν''<sub>5</sub>
|''ν''<sub>6</sub>
|-
|Symbol
|A<sub>1g</sub>
|E<sub>g</sub>
|F<sub>1u</sub>
|F<sub>1u</sub>
|F<sub>2g</sub>
|F<sub>2u</sub>
|-
|Wavelength (cm<sup>−1</sup>)
|628
|523
|615
|203
|211
|171
|-
|IR active?
|−
|−
| +
| +
|−
|−
|-
|Raman active?
| +
| +
|−
|−
| +
|−
|}

=== Chemical properties ===
Plutonium hexafluoride is relatively hard to handle, being very corrosive, poisonous, and prone to auto-].<ref name="FluidBedII" /><ref name=ABDecomp>{{cite journal|last=Bibler|first=Ned E.|date=August 23, 1979|title=α and β Radiolysis of Plutonium Hexafluoride Vapor|journal=]|volume=83|pages=2179–2186|doi=10.1021/j100480a001|number=17}}</ref><ref name=GammaDecomp>{{cite journal|last1=Steindler|first1=M.J.|last2=Steidl|first2=D.V.|last3=Fischer|first3=J.|date=November 1964|title=The decomposition of plutonium hexafluoride by gamma radiation|journal=]|volume=26|issue=11|pages=1869–1878|doi=10.1016/0022-1902(64)80011-7}}</ref>

==== Reactions with other compounds ====
PuF<sub>6</sub> is stable in dry air, but reacts vigorously with water, including atmospheric moisture, to form plutonium(VI) oxyfluoride and hydrofluoric acid.<ref name="Florin" /><ref>{{Cite journal|last=Kessie|first=R. W.|date=1967|title=Plutonium and Uranium Hexafluoride Hydrolysis Kinetics|url=https://pubs.acs.org/doi/abs/10.1021/i260021a018|journal=Industrial & Engineering Chemistry Process Design and Development|language=en|volume=6|issue=1|pages=105–111|doi=10.1021/i260021a018|issn=0196-4305}}</ref>

:{{chem|Pu|F|6}} + 2 {{chem|H|2|O}} → {{chem|Pu|O|2|F|2}} + 4 {{chem|H|F}}

It can be stored for a long time in a ] or ] ], provided there are no traces of moisture, the glass has been thoroughly ], and any traces of hydrogen fluoride have been removed from the compound.<ref name=NpComp>{{Cite journal|last1=Malm|first1=John G.|last2=Weinstock|first2=Bernard|last3=Weaver|first3=E. Eugene|date=1958|title=The Preparation and Properties of NpF<sub>5</sub>; a Comparison with PuF<sub>5</sub>|url=https://pubs.acs.org/doi/10.1021/j150570a009|journal=The Journal of Physical Chemistry|language=en|volume=62|issue=12|pages=1506–1508|doi=10.1021/j150570a009|issn=0022-3654}}</ref>

An important reaction involving PuF<sub>6</sub> is the reduction to ]. ] generated from an oxygen-methane flame can perform the reduction.<ref>{{Cite journal |last1=Pokidyshev |first1=A. M. |last2=Tsarenko |first2=I. A. |last3=Serik |first3=V. F. |last4=Sokolov |first4=V. B. |date=October 2003 |title=Reduction of Plutonium Hexafluoride Using Gaseous Reagents |url=http://link.springer.com/10.1023/B:ATEN.0000010988.94533.24 |journal=Atomic Energy |language=en |volume=95 |issue=4 |pages=701–708 |doi=10.1023/B:ATEN.0000010988.94533.24 |s2cid=93145477 |issn=1063-4258}}</ref>

==== Decomposition reactions ====
Plutonium hexafluoride typically decomposes to ] and fluorine gas. Thermal decomposition does not occur at room temperature,<ref>{{Cite journal |last1=Trevorrow |first1=L. E. |last2=Shinn |first2=W. A. |last3=Steunenberg |first3=R. K. |date=March 1961 |title=The Thermal Decomposition of Plutonium Hexafluoride |url=https://pubs.acs.org/doi/abs/10.1021/j100821a003 |journal=The Journal of Physical Chemistry |language=en |volume=65 |issue=3 |pages=398–403 |doi=10.1021/j100821a003 |issn=0022-3654}}</ref><ref>{{Cite journal |last1=Fischer |first1=J. |last2=Trevorrow |first2=L. |last3=Shinn |first3=W. |date=October 1961 |title=The Kinetics and Mechanism of the Thermal Decomposition of Plutonium Hexafluoride |url=https://pubs.acs.org/doi/abs/10.1021/j100827a036 |journal=The Journal of Physical Chemistry |language=en |volume=65 |issue=10 |pages=1843–1846 |doi=10.1021/j100827a036 |issn=0022-3654}}</ref> but proceeds very quickly at 280&nbsp;°C.<ref name="JINC_1956_380" /><ref name="NpComp" /> In the absence of any external cause for decomposition, the ] current from ] will generate ], at a rate of 1.5%/day (] 1.5&nbsp;months) in solid phase.<ref name="JINC_1956_380" /><ref name="ABDecomp" /><ref>
* {{harvnb|Steindler|1963}}
* {{Cite tech report|last1=Wagner|first1=R.&nbsp;P.|first2=W.&nbsp;A.|last2=Shinn|first3=J.|last3=Fischer|first4=Martin&nbsp;J.|last4=Steindler|title=Laboratory Investigations in Support of Fluid-bed Fluoride Volatility Processes|volume=VII: The Decomposition of Gaseous Plutonium Hexafluoride by Alpha Radiation|institution=Argonne National Laboratory|number=ANL-7013|date=1 May 1963|doi=10.2172/4628896}}</ref> Storage in gas phase at pressures 50&ndash;100&nbsp;torr (70&ndash;130&nbsp;mbar) appears to minimize auto-radiolysis, and long-term recombination with freed fluorine does occur.<ref>Morse, L.&nbsp;R. (2005), "PuF<sub>6</sub> gas pressure in aged cylinders" (personal communication to D.&nbsp;L. Clark), Los Alamos, NM.</ref>{{rs?|date=April 2023}}

Likewise, the compound is ], decomposing (possibly to ] and ]) under laser irradiation at a wavelength of less than 520&nbsp;nm.<ref>{{cite patent|country=US|number=4670239|title=Photochemical Preparation of Plutonium Pentafluoride|status=|pubdate=June 2, 1987|fdate=December 20, 1977|invent1=Sherman W. Rabideau|invent2=George M. Campbell|assign1=The United States of America|url=http://www.freepatentsonline.com/4670239.html|postscript=,}} but see also {{cite journal |journal=] |doi=10.1016/S0022-1139(00)80734-4 |first1=E. A. |last1=Lobikov |first2=V. N. |last2=Prusakov |first3=V. F. |last3=Serik |title=Plutonium Hexafluoride Decomposition under the Action of Laser Radiation |date=August–September 1992 |volume=58 |issue=2–3 |page=277|postscript=,}} in which the decay product is identified as ] instead.</ref>

Exposure to laser radiation at 564.1&nbsp;nm or ] will also induce rapid dissolution.<ref name="Spec" /><ref name=GammaDecomp />

== Uses ==
Plutonium hexafluoride plays a role in the enrichment of plutonium, in particular for the isolation of the fissile isotope <sup>239</sup>Pu from irradiated uranium. For use in ], the <sup>241</sup>Pu present must be removed for two reasons:

* It generates enough neutrons by spontaneous fission to cause an uncontrollable reaction.
* It undergoes ] to form <sup>241</sup>Am, leading to the accumulation of ] over long periods of storage which must be removed.

The separation between plutonium and the americium contained proceeds through reaction with ]. Aged PuF<sub>4</sub> is fluorinated at room temperature to gaseous PuF<sub>6</sub>, which is separated and reduced back to PuF<sub>4</sub>, whereas any AmF<sub>4</sub> present does not undergo the same conversion. The product thus contains very little amounts of americium, which becomes concentrated in the unreacted solid.<ref>{{Cite journal|last1=Mills|first1=T.R.|last2=Reese|first2=L.W.|date=1994|title=Separation of plutonium and americium by low-temperature fluorination|url=https://linkinghub.elsevier.com/retrieve/pii/0925838894909318|journal=Journal of Alloys and Compounds|language=en|volume=213-214|pages=360–362|doi=10.1016/0925-8388(94)90931-8}}</ref>

Separation of the hexafluorides of uranium and plutonium is also important in the reprocessing of ].<ref>
* {{cite patent|country=US|number=3708568A|title=Removal of Plutonium from Plutonium Hexafluoride-Uranium Hexafluoride Mixtures|fdate=1970-10-20|pubdate=1973-01-02|assignee=Atomic Energy Commission|invent1=Gilliher,&nbsp;W.|invent2=Harris,&nbsp;R.|invent3=Ledoux,&nbsp;R.}}
* {{cite patent|country=US|number=4172114A|title=Method for purifying plutonium hexafluoride|fdate=1977-08-24|pubdate=1979-10-23|assignee=]|inventor=Mitsuhiro Nishimura ''et al''}}
</ref><ref>{{Cite journal|last1=Moser|first1=W.Scott|last2=Navratil|first2=James D.|date=1984|title=Review of major plutonium pyrochemical technology|url=https://linkinghub.elsevier.com/retrieve/pii/0022508884900626|journal=Journal of the Less Common Metals|language=en|volume=100|pages=171–187|doi=10.1016/0022-5088(84)90062-6|osti=6168468 }}</ref><ref>{{Cite journal|last1=Drobyshevskii|first1=Yu. V.|last2=Ezhov|first2=V. K.|last3=Lobikov|first3=E. A.|last4=Prusakov|first4=V. N.|last5=Serik|first5=V. F.|last6=Sokolov|first6=V. B.|date=2002|title=Application of Physical Methods for Reducing Plutonium Hexafluoride|url=http://link.springer.com/10.1023/A:1020840716387|journal=Atomic Energy|volume=93|issue=1|pages=578–588|doi=10.1023/A:1020840716387|s2cid=100100314}}</ref> From a molten salt mixture containing both elements, uranium can largely be removed by fluorination to UF<sub>6</sub>, which is stable at higher temperatures, with only small amounts of plutonium escaping as PuF<sub>6</sub>.<ref name=DoEEval>{{Cite book|url=https://www.nap.edu/read/5538/chapter/5|title=Evaluation of the U.S. Department of Energy's Alternatives for the Removal and Disposition of Molten Salt Reactor Experiment Fluoride Salts|publisher=National Academies Press|location=Washington, DC|via=NAP.edu|year=1997|doi=10.17226/5538|isbn=978-0-309-05684-7|language=en}}</ref>

== History ==
Shortly after plutonium's discovery and isolation in 1940, chemists began to postulate the existence of plutonium hexafluoride. Early experiments, which sought to mimic methods for the construction of ], had conflicting results; and definitive proof only appeared in 1942.<ref>{{Cite tech report|last=Seaborg|first=G.&nbsp;T.|author-link=Glenn Seaborg|date=1942|institution=] ]|number=CN-125}}</ref> The ] then interrupted the publication of further research.<ref name=FluidBedII>{{Cite tech report|last=Steindler|first=Martin&nbsp;J.|title=Laboratory Investigations in Support of Fluid-bed Fluoride Volatility Processes|volume=II: The Properties of Plutonium Hexafluoride|institution=Argonne National Laboratory|number=ANL-6753|date=1 August 1963|doi=10.2172/4170539}}</ref>

Initial experiments, undertaken with extremely small quantities of plutonium, showed that a ] plutonium compound would develop in a stream of ] only at temperatures exceeding 700&nbsp;°C. Subsequent experiments showed that plutonium on a ] plate volatilized in a 500-°C fluorine stream, and that the reaction rate decreased with ] in the series uranium&nbsp;> neptunium&nbsp;> plutonium.<ref>{{Cite tech report|first1=H.&nbsp;S.|last1=Brown|first2=O.&nbsp;F.|last2=Hill|first3=A.&nbsp;H.|last3=Jaffay|institution=] ]|number=CN-343|date=1942}}</ref> Brown and Hill, using milligram-scale samples of plutonium, completed in 1942 a ] experiment with uranium hexafluoride, suggesting that higher fluorides of plutonium ought be unstable, and decompose to ] at ]. Nevertheless, the ] of the compound appeared to correspond to that of uranium hexafluoride.<ref>{{Cite tech report|last1=Brown|first1=H.&nbsp;S.|first2=O.&nbsp;F.|last2=Hill|institution=] ]|number=CN-363|date=12 November 1942}}</ref> Davidson, Katz, and Orlemann showed in 1943 that plutonium in a ] vessel volatilized under a fluorine atmosphere, and that the reaction product ] on a ] surface.<ref>{{Cite tech report|first1=N.&nbsp;R.|last1=Davidson|first2=J.&nbsp;J.|last2=Katz|first3=O.&nbsp;F.|last3=Orlemann|institution=] ]|number=CN-987|date=11 October 1943}}</ref>

Fisher, Vaslow, and Tevebaugh conjectured that the higher fluorides exhibited a positive ], that their formation would be ], and consequently only stabilized at high temperatures.<ref>{{Cite tech report|first1=R.&nbsp;W.|last1=Fisher|first2=F.|last2=Vaslow|first3=A.&nbsp;D.|last3=Tevebaugh|institution=]|number=CN-1783|date=10 August 1944}}</ref>

In 1944, {{Ill|Alan E. Florin|de}} prepared a volatile compound of plutonium believed to be the elusive plutonium hexafluoride, but the product decomposed prior to identification. The fluid substance would collect onto cooled ] and ], but then the fluoride atoms would ] with the glass.<ref>{{Cite tech report|first=Alan&nbsp;E.|last=Florin|institution=] ]|number=CN-2159|date=1 October 1944}}</ref>

By comparison between uranium and plutonium compounds, Brewer, Bromley, Gilles, and Lofgren computed the ] characteristics of plutonium hexafluoride.<ref>
* {{cite tech report|first1=L.|last1=Brewer|first2=L.|last2=Bromley|first3=P.&nbsp;W.|last3=Gilles|first4=N.&nbsp;L.|last4=Lofgren|institution=]|number=CN-3300|date=10 October 1945}}
* {{cite tech report|first1=L.|last1=Brewer|first2=L.|last2=Bromley|first3=P.&nbsp;W.|last3=Gilles|first4=N.&nbsp;L.|last4=Lofgren|institution=]|number=CN-3378|date=1 December 1945}}
* {{cite tech report|first1=L.|last1=Brewer|first2=L.|last2=Bromley|first3=P.&nbsp;W.|last3=Gilles|first4=N.&nbsp;L.|last4=Lofgren|title=The Higher Fluorides of Plutonium|institution=]|number=UCRL-633|date=20 March 1950}}
</ref>

In 1950, Florin's efforts finally yielded the synthesis,<ref name="Florin" /><ref>{{cite tech report|first=Alan&nbsp;E.|last=Florin|title=Plutonium Hexafluoride, Plutonium&nbsp;(VI) Oxyfluoride: Preparation, Identification, and Some Properties|institution=]|number=LAMS-1118|date=16 October 1950|url=http://www.fas.org/sgp/othergov/doe/lanl/lib-www/la-pubs/00424522.pdf}}</ref> and improved thermodynamic data and a new apparatus for its production soon followed.<ref name="JINC_1956_368" /> Around the same time, British workers also developed a method for the production of PuF<sub>6</sub>.<ref name="JINC_1956_358" /><ref name=Skimpy>{{cite tech report|author=Mandleberg, C. J. |display-authors=etal |institution=]|number=C/R-157|date=1952}}</ref>


== References == == References ==
{{Reflist}} {{Reflist}}
{{Hexafluorides}}
{{Plutonium compounds}}
{{fluorine compounds}}
{{Actinide halides}}
{{Use dmy dates|date=March 2018}}


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