Wikipedia:WikiProject Chemicals/Chembox validation/VerifiedDataSandbox and Sulfur hexafluoride: Difference between pages

{{Short description|Chemical compound and greenhouse gas}}

{{cs1 config|name-list-style=vanc}}

{{redirect|SF6|the video game|Street Fighter 6}}

{{Use American English|date=August 2020}}

| Verifiedfields = Changed

| Watchedfields = changed

| verifiedrevid = 477313684

| ImageFileL1_Ref = {{chemboximage|correct|??}}

| ImageNameL1 = Skeletal formula of sulfur hexafluoride with assorted dimensions

| ImageFileR1_Ref = {{chemboximage|correct|??}}

| ImageNameR1 = Spacefill model of sulfur hexafluoride

| ImageFile2_Ref = {{chemboximage|correct|??}}

| ImageSize2 = 121

| ImageName2 = Ball and stick model of sulfur hexafluoride

| SystematicName = Hexafluoro-λ⁶-sulfane<ref>{{cite web|title = Sulfur Hexafluoride - PubChem Public Chemical Database|url = https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=17358|work = [[PubChem]]|publisher = [[National Center for Biotechnology Information]]|access-date = 22 February 2013|url-status = live|archive-url = https://web.archive.org/web/20121103144017/http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=17358|archive-date = 3 November 2012}}</ref>

|Section1={{Chembox Identifiers

| CASNo = 2551-62-4

| CASNo_Ref = {{cascite|correct|CAS}}

| PubChem = 17358

| ChemSpiderID = 16425

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| UNII = WS7LR3I1D6

| UNII_Ref = {{fdacite|changed|FDA}}

| EINECS = 219-854-2

| UNNumber = 1080

| KEGG = D05962

| KEGG_Ref = {{keggcite|changed|kegg}}

| MeSHName = Sulfur+hexafluoride

| ChEBI_Ref = {{ebicite|correct|EBI}}

| RTECS = WS4900000

| Gmelin = 2752

| SMILES = FS(F)(F)(F)(F)F

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = SFZCNBIFKDRMGX-UHFFFAOYSA-N

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

|Section2={{Chembox Properties

| S=1 | F=6

| Formula = {{chem2|SF6}}

| Appearance = Colorless gas

| Odor = odorless<ref name=PGCH/>

| Density = 6.17&nbsp;g/L

| MeltingPtK = 209

| BoilingPtC = -50.8

| CriticalTP = {{val|45.51|0.1|u=°C}}, {{val|3.749|0.01|u=MPa}}<ref name="HorstmannFischer2002">{{cite journal|last1=Horstmann|first1=Sven|last2=Fischer|first2=Kai|last3=Gmehling|first3=Jürgen|title=Measurement and calculation of critical points for binary and ternary mixtures|journal=[[AIChE Journal]]|volume=48|issue=10|year=2002|pages=2350–2356|issn=0001-1541|doi=10.1002/aic.690481024|bibcode=2002AIChE..48.2350H }}</ref>

| VaporPressure = 2.9&nbsp;MPa (at 21.1&nbsp;°C)

| SolubleOther = slightly soluble in water, very soluble in ethanol, hexane, benzene

| Solubility = 0.003% (25&nbsp;°C)<ref name=PGCH/>

| MagSus = {{val|-44.0e-6|u=cm³/mol}}

| Viscosity = 15.23 μPa·s<ref name="Assael2018">{{cite journal|last1=Assael|first1=M. J.|last2=Kalyva|first2=A. E.|last3=Monogenidou|first3=S. A.|last4=Huber|first4=M. L.|last5=Perkins|first5=R. A.|last6=Friend|first6=D. G.|last7=May|first7=E. F.|title=Reference Values and Reference Correlations for the Thermal Conductivity and Viscosity of Fluids|journal=[[Journal of Physical and Chemical Reference Data]]|volume=47|issue=2|year=2018|pages=021501|issn=0047-2689|doi=10.1063/1.5036625|pmid=30996494|pmc=6463310|bibcode=2018JPCRD..47b1501A}}</ref>

| ThermalConductivity = {{plainlist|

* 13.45 mW/(m·K) at 25&nbsp;°C<ref name="AssaelKoini2012">{{cite journal|last1=Assael|first1=M. J.|last2=Koini|first2=I. A.|last3=Antoniadis|first3=K. D.|last4=Huber|first4=M. L.|last5=Abdulagatov|first5=I. M.|last6=Perkins|first6=R. A.|title=Reference Correlation of the Thermal Conductivity of Sulfur Hexafluoride from the Triple Point to 1000 K and up to 150 MPa|journal=Journal of Physical and Chemical Reference Data|volume=41|issue=2|year=2012|pages=023104–023104–9|issn=0047-2689|doi=10.1063/1.4708620|bibcode=2012JPCRD..41b3104A|s2cid=18916699 }}</ref>

* 11.42 mW/(m·K) at 0&nbsp;°C}}

|Section3={{Chembox Structure

| CrystalStruct = [[Orthorhombic]], [[Pearson symbol|oP28]]

| SpaceGroup = O_''h''

| Coordination = Orthogonal hexagonal

| MolShape = Octahedral

| Dipole = 0 D

|Section5={{Chembox Thermochemistry

| DeltaHf = −1209&nbsp;kJ·mol⁻¹<ref name=b1>{{cite book| author = Zumdahl, Steven S.|title =Chemical Principles 6th Ed| publisher = Houghton Mifflin Company| year = 2009| isbn = 978-0-618-94690-7|page=A23}}</ref>

| HeatCapacity = 0.097&nbsp;kJ/(mol·K) (constant pressure)

| Entropy = 292&nbsp;J·mol⁻¹·K⁻¹<ref name=b1/>

|Section6={{Chembox Pharmacology

| ATCCode_prefix = V08

| ATCCode_suffix = DA05

| Licence_EU=yes

| INN_EMA=sulphur hexafluoride

|Section7={{Chembox Hazards

| ExternalSDS = [http://mfc.engr.arizona.edu/safety/MSDS%20FOLDER/SF6%20-%20MSDS%20Air%20Liquide.pdf External MSDS]

| GHSPictograms = {{GHS04}}

| GHSSignalWord = Warning

| HPhrases = {{HPhrases|H280}}

| PPhrases = {{PPhrases|P403}}

| GHS_ref = <ref>GHS: {{GESTIS|ZVG=5220|Name=Schwefelhexafluorid|Date=2021-12-13}}</ref>

| NFPA-H = 1

| NFPA-F = 0

| NFPA-R = 0

| NFPA-S = SA

| IDLH = N.D.<ref name=PGCH>{{PGCH|0576}}</ref>

| PEL = TWA 1000 ppm (6000 mg/m³)<ref name=PGCH/>

| REL = TWA 1000 ppm (6000 mg/m³)<ref name=PGCH/>

}}

|Section8={{Chembox Related

| OtherCations =

| OtherFunction_label = sulfur fluorides

| OtherFunction = [[Disulfur decafluoride]]<br />

| OtherCompounds = [[Selenium hexafluoride]]<br />

[[Tellurium hexafluoride]]<br/>[[Polonium hexafluoride]]

}}

'''Sulfur hexafluoride''' or '''sulphur hexafluoride''' ([[British English|British spelling]]) is an [[inorganic compound]] with the formula SF₆. It is a colorless, odorless, non-[[flammable]], and non-toxic gas. {{chem|SF|6}} has an [[octahedral geometry]], consisting of six [[fluorine]] atoms attached to a central [[sulfur]] atom. It is a [[hypervalent molecule]].{{cn|date=June 2024}}

Typical for a [[nonpolar]] gas, {{chem|SF|6}} is poorly [[soluble]] in water but quite soluble in nonpolar organic solvents. It has a density of 6.12&nbsp;g/L at sea level conditions, considerably higher than the [[density of air]] (1.225&nbsp;g/L). It is generally transported as a [[liquefied gas|liquefied compressed gas]].{{cn|date=June 2024}}

{{chem|SF|6}} has 23,500 times greater [[global warming potential]] (GWP) than {{CO2}} as a [[greenhouse gas]] (over a 100-year time-frame) but exists in relatively minor concentrations in the atmosphere. Its concentration in Earth's [[troposphere]] reached 11.50 [[parts per notation|parts per trillion]] (ppt) in October 2023, rising at 0.37 ppt/year.<ref name="sf6trend"/> The increase since 1980 is driven in large part by the expanding electric power sector, including [[fugitive emissions]] from banks of {{chem|SF|6}} gas contained in its medium- and high-voltage [[switchgear]]. Uses in magnesium, aluminium, and electronics manufacturing also hastened atmospheric growth.<ref name="sf6b20" /> The 1997 [[Kyoto Protocol]], which came into force in 2005, is supposed to limit emissions of this gas. In a somewhat nebulous way it has been included as part of the [[carbon emission trading]] scheme. In some countries this has led to the defunction of entire industries.<ref name="cim11">{{cite book |editor-last1=Kapusta |editor-first1=Joël |editor-last2=Mackey |editor-first2=Phillip |editor-last3=Stubina |editor-first3=Nathan |title=The Canadian Metallurgical & Materials Landscape 1960 - 2011 |url=https://store.cim.org/en/commemorative-book-the-canadian-materials-landscape-1960-2011 |publisher=Canadian Institute of Metallurgy |date=2011 |chapter=Magnesium Metal Production in Canada |first1=D. |last1=Creber |first2=B. |last2=Davis |first3=S. |last3=Kashani-Nejad}}</ref>

==Synthesis and reactions==

{{See also|Fluorochemical industry}}

Sulfur hexafluoride on Earth exists primarily as a [[chemical synthesis|synthetic]] industrial gas, but has also been found to occur naturally.<ref name="sf6nat">{{cite journal |author=Busenberg, E. and Plummer, N. |title=Dating young groundwater with sulfur hexafluoride: Natural and anthropogenic sources of sulfur hexafluoride |journal=Water Resources Research |publisher=American Geophysical Union |volume=36 |pages=3011–3030 |year=2000 |issue=10 |url=https://pubs.er.usgs.gov/publication/70022588#:~:text=Sulfur%20hexafluoride%20(SF6)%20is,during%20the%20past%2040%20years |doi=10.1029/2000WR900151 |bibcode=2000WRR....36.3011B |doi-access=free}}</ref>

{{chem|SF|6}} can be prepared from the elements through exposure of [[Sulfur|{{chem|S|8}}]] to [[fluorine|{{chem|F|2}}]]. This was the method used by the discoverers [[Henri Moissan]] and [[Paul Lebeau]] in 1901. Some other sulfur fluorides are cogenerated, but these are removed by heating the mixture to [[disproportionation|disproportionate]] any [[Disulfur decafluoride|{{chem|S|2|F|10}}]] (which is highly toxic) and then scrubbing the product with [[Sodium hydroxide|NaOH]] to destroy remaining [[Sulfur tetrafluoride|{{chem|SF|4}}]]{{Clarify|reason=How do you scrub a gas with a solid?|date=June 2024}}

Alternatively, using [[bromine]], sulfur hexafluoride can be synthesized from SF₄ and CoF₃ at lower temperatures (e.g. 100&nbsp;°C), as follows:<ref>{{cite conference|last1=Winter |first1=R. W. |last2=Pugh |first2=J. R. |last3=Cook |first3=P. W. |date=January 9–14, 2011 |title=SF₅Cl, SF₄ and SF₆: Their Bromine−facilitated Production & a New Preparation Method for SF₅Br |work=20th Winter Fluorine Conference}}</ref>

{{block indent|2&nbsp;CoF₃ + SF₄ + [Br₂] → SF₆ + 2&nbsp;CoF₂ + [Br₂]}}

There is virtually no reaction chemistry for {{chem|SF|6}}. A main contribution to the inertness of SF₆ is the [[steric hindrance]] of the sulfur atom, whereas its heavier group 16 counterparts, such as [[Selenium hexafluoride|SeF₆]] are more reactive than SF₆ as a result of less steric hindrance.<ref>{{cite book |author1=Duward Shriver |author2=Peter Atkins |title=Inorganic Chemistry |year=2010 |publisher=W. H. Freeman |pages=409 |isbn=978-1429252553 }}</ref> It does not react with molten [[sodium]] below its boiling point,<ref>{{cite book |title=Advanced Inorganic Chemistry: Volume II |edition=12th |first1=Gurdeep |last1=Raj |publisher=GOEL Publishing House |year=2010 |page=160 |url=https://books.google.com/books?id=qxRhA3MZg6AC}} [https://books.google.com/books?id=qxRhA3MZg6AC&pg=PA160 Extract of page 160]</ref> but reacts [[exothermic]]ally with [[lithium]]. As a result of its inertness, {{chem|SF|6}} has an atmospheric lifetime of around 3200 years, and no significant environmental sinks other than the ocean.<ref>{{Cite journal |last1=Stöven |first1=T. |last2=Tanhua |first2=T. |last3=Hoppema |first3=M. |last4=Bullister |first4=J. L. |date=2015-09-18 |title=Perspectives of transient tracer applications and limiting cases |url=https://os.copernicus.org/articles/11/699/2015/ |journal=Ocean Science |language=en |volume=11 |issue=5 |pages=699–718 |doi=10.5194/os-11-699-2015 |doi-access=free |bibcode=2015OcSci..11..699S |issn=1812-0792}}</ref>

==Applications==

By 2000, the [[electrical power industry]] is estimated to use about 80% of the sulfur hexafluoride produced, mostly as a [[dielectric gas|gaseous dielectric medium]].<ref>{{cite journal |author1=Constantine T. Dervos |author2=Panayota Vassilou |title=Sulfur Hexafluoride: Global Environmental Effects and Toxic Byproduct Formation |journal=Journal of the Air & Waste Management Association |year=2000 |volume=50 |issue=1 |pages=137–141 |publisher=Taylor and Francis|doi=10.1080/10473289.2000.10463996|pmid=10680375 |s2cid=8533705 |doi-access=free |bibcode=2000JAWMA..50..137D }}</ref> Other main uses as of 2015 included a [[Etching (microfabrication)|silicon etchant]] for [[semiconductor manufacturing]], and an [[inert gas]] for the casting of [[magnesium]].<ref>{{cite journal |author1=Deborah Ottinger |author2=Mollie Averyt |author3=Deborah Harris |title=US consumption and supplies of sulphur hexafluoride reported under the greenhouse gas reporting program |journal=Journal of Integrative Environmental Sciences |year=2015 |volume=12 |issue=sup1 |pages=5–16 |publisher=Taylor and Francis|doi=10.1080/1943815X.2015.1092452|doi-access=free }}</ref>

===Dielectric medium===

{{chem|SF|6}} is used in the [[Electrical power industry|electrical industry]] as a [[dielectric gas|gaseous dielectric medium]] for high-voltage [[sulfur hexafluoride circuit breaker]]s, [[switchgear]], and other [[electricity|electrical]] equipment, often replacing oil-filled circuit breakers (OCBs) that can contain harmful [[polychlorinated biphenyl]]s (PCBs). {{chem|SF|6}} gas under [[pressure]] is used as an insulator in [[switchgear|gas insulated switchgear]] (GIS) because it has a much higher [[dielectric strength]] than [[air]] or dry [[nitrogen]]. The high dielectric strength is a result of the gas's high [[electronegativity]] and [[density]]. This property makes it possible to significantly reduce the size of electrical gear. This makes GIS more suitable for certain purposes such as indoor placement, as opposed to air-insulated electrical gear, which takes up considerably more room.

Gas-insulated electrical gear is also more resistant to the effects of pollution and climate, as well as being more reliable in long-term operation because of its controlled operating environment. Exposure to an arc chemically breaks down {{chem|SF|6}} though most of the decomposition products tend to quickly re-form {{chem|SF|6}}, a process termed "self-healing".<ref>{{citation | url= http://www.weidmann-solutions.cn/zhenduan/sulfur_hexaflouride.pdf | last1= Jakob | first1= Fredi | last2= Perjanik | first2= Nicholas | title= Sulfur Hexafluoride, A Unique Dielectric | publisher= Analytical ChemTech International, Inc. | url-status= live | archive-url= https://web.archive.org/web/20160304040552/http://www.weidmann-solutions.cn/zhenduan/sulfur_hexaflouride.pdf | archive-date= 2016-03-04 }}</ref> [[Electrical arc|Arcing]] or [[Corona discharge|corona]] can produce [[disulfur decafluoride]] ([[Disulfur decafluoride|{{chem|S|2|F|10}}]]), a highly [[toxic]] gas, with toxicity similar to [[phosgene]]. {{chem|S|2|F|10}} was considered a potential [[chemical warfare]] agent in [[World War II]] because it does not produce [[lacrimation]] or skin irritation, thus providing little warning of exposure.

{{chem|SF|6}} is also commonly encountered as a high voltage dielectric in the high voltage supplies of [[particle accelerator]]s, such as [[Van de Graaff generator]]s and [[Pelletron]]s and high voltage transmission [[electron microscope]]s.

Alternatives to {{chem|SF|6}} as a dielectric gas include several fluoroketones.<ref>{{cite web |url=http://cired.net/publications/cired2015/papers/CIRED2015_0587_final.pdf |title=Archived copy |access-date=2017-10-12 |url-status=live |archive-url=https://web.archive.org/web/20171012150303/http://cired.net/publications/cired2015/papers/CIRED2015_0587_final.pdf |archive-date=2017-10-12 }}</ref><ref>{{cite book|date=1 June 2015|pages=379–383|via=IEEE Xplore|doi=10.1109/ICACACT.2014.7223577|chapter=SF₆ alternative development for high voltage switchgears|last1=Kieffel|first1=Yannick|last2=Biquez|first2=Francois|title=2015 IEEE Electrical Insulation Conference (EIC) |isbn=978-1-4799-7352-1|s2cid=15911515}}</ref><!-- https://www.epa.gov/sites/production/files/2017-02/documents/nyberg_presentation_2017_workshop.pdf , https://www.gegridsolutions.com/HVMV_Equipment/catalog/g3.htm --> Compact GIS technology that combines vacuum switching with clean air insulation has been introduced for a subset of applications up to 420&nbsp;[[kilovolts|kV]].<ref>{{cite web |url=https://www.siemens-energy.com/global/en/offerings/power-transmission/innovation/blue-high-voltage-products.html |title=Sustainable switchgear technology for a CO₂ neutral future |publisher=Siemens Energy |date=2020-08-31 |accessdate=2021-04-27}}</ref>

===Medical use===

{{chem|SF|6}} is used to provide a [[tamponade]] or plug of a retinal hole in [[retinal detachment]] repair operations<ref>{{cite book |author1=Daniel A. Brinton |author2=C. P. Wilkinson |title=Retinal detachment: principles and practice |pages=183 |year=2009 |publisher=Oxford University Press |isbn=978-0199716210 }}</ref> in the form of a gas bubble. It is inert in the [[vitreous chamber]].<ref>{{cite book |author=Gholam A. Peyman, M.D., Stephen A. Meffert, M.D., Mandi D. Conway |title=Vitreoretinal Surgical Techniques |pages=157 |year=2007 |publisher=Informa Healthcare |isbn=978-1841846262 }}</ref> The bubble initially doubles its volume in 36 hours due to oxygen and nitrogen entering it, before being absorbed in the blood in 10–14 days.<ref>{{cite journal

| last1 = Hilton | first1 = G. F.

| last2 = Das | first2 = T.

| last3 = Majji | first3 = A. B.

| last4 = Jalali | first4 = S.

| title = Pneumatic retinopexy: Principles and practice

| journal = Indian Journal of Ophthalmology

| volume = 44

| issue = 3

| pages = 131–143

| year = 1996

| pmid = 9018990

}}</ref>

{{chem|SF|6}} is used as a contrast agent for [[Medical ultrasonography|ultrasound]] imaging. Sulfur hexafluoride microbubbles are administered in solution through injection into a peripheral vein. These microbubbles enhance the visibility of blood vessels to ultrasound. This application has been used to examine the vascularity of tumours.<ref name="pmid18376462">{{cite journal

|vauthors=Lassau N, Chami L, Benatsou B, Peronneau P, Roche A | title=Dynamic contrast-enhanced ultrasonography (DCE-US) with quantification of tumor perfusion: a new diagnostic tool to evaluate the early effects of antiangiogenic treatment

| journal=Eur Radiol

| volume=17

| issue=Suppl. 6

| pages=F89–F98

| date=December 2007

| pmid=18376462

| doi=10.1007/s10406-007-0233-6

| s2cid=42111848

}}</ref> It remains visible in the blood for 3 to 8 minutes, and is exhaled by the lungs.<ref>{{cite web|url=https://www.ema.europa.eu/documents/product-information/sonovue-epar-product-information_en.pdf|title=SonoVue, INN-sulphur hexafluoride - Annex I - Summary of Product Characteristics|website=[[European Medicines Agency]]|access-date=2019-02-24}}</ref>

===Tracer compound===

Sulfur hexafluoride was the [[tracer gas]] used in the first [[roadway air dispersion model]] calibration; this research program was sponsored by the [[U.S. Environmental Protection Agency]] and conducted in [[Sunnyvale, California]] on [[U.S. Highway 101]].<ref>{{cite web|url=http://www.eoearth.org/article/Air_pollution_line_source?topic=49506 |title=Air pollution line source |date=September 10, 2011 |author=C Michael Hogan |publisher=Encyclopedia of Earth |access-date=22 February 2013 |url-status=dead|archive-url=https://web.archive.org/web/20130529064051/http://www.eoearth.org/article/Air_pollution_line_source?topic=49506 |archive-date=29 May 2013 }}</ref> Gaseous {{chem|SF|6}} is used as a tracer gas in short-term experiments of [[Ventilation (architecture)|ventilation]] efficiency in buildings and indoor enclosures, and for determining [[Infiltration (HVAC)|infiltration]] rates. Two major factors recommend its use: its concentration can be measured with satisfactory accuracy at very low concentrations, and the [[Earth's atmosphere]] has a negligible concentration of {{chem|SF|6}}.

Sulfur hexafluoride was used as a non-toxic test gas in an experiment at [[St John's Wood tube station]] in [[London]], United Kingdom on 25 March 2007.<ref>{{cite news |title='Poison gas' test on Underground |url=http://news.bbc.co.uk/1/hi/england/london/6492501.stm |date=25 March 2007 |work=BBC News |access-date=22 February 2013 |url-status=live |archive-url=https://web.archive.org/web/20080215005754/http://news.bbc.co.uk/1/hi/england/london/6492501.stm |archive-date=15 February 2008 }}</ref> The gas was released throughout the station, and monitored as it drifted around. The purpose of the experiment, which had been announced earlier in March by the [[Secretary of State for Transport]] [[Douglas Alexander]], was to investigate how toxic gas might spread throughout [[London Underground]] stations and buildings during a terrorist attack.

Sulfur hexafluoride is also routinely used as a tracer gas in laboratory fume hood containment testing. The gas is used in the final stage of [[ASHRAE]] 110 fume hood qualification. A plume of gas is generated inside of the fume hood and a battery of tests are performed while a gas analyzer arranged outside of the hood samples for SF₆ to verify the containment properties of the fume hood.

It has been used successfully as a tracer in [[oceanography]] to study [[wikt:diapycnal|diapycnal]] mixing and air-sea gas exchange.<ref>{{cite journal|last=Fine|first=Rana A.|author-link=Rana Fine|date=2010-12-15|title=Observations of CFCs and SF6 as Ocean Tracers|url=https://www.annualreviews.org/doi/10.1146/annurev.marine.010908.163933|journal=Annual Review of Marine Science|volume=3|issue=1|pages=173–195|doi=10.1146/annurev.marine.010908.163933|pmid=21329203|issn=1941-1405}}</ref>

===Other uses===

* The [[magnesium]] industry uses {{chem|SF|6}} as an inert "cover gas" to prevent oxidation during [[Casting (metalworking)|casting]],<ref name=bartos02>{{cite web|url=http://www.epa.gov/magnesium-sf6/documents/tms_paper.pdf |title=Update on EPA's manesium industry partnership for climate protection |author=Scott C. Bartos |publisher=[[United States Environmental Protection Agency|US Environmental Protection Agency]] |date=February 2002 |access-date=December 14, 2013 |url-status=dead|archive-url=https://web.archive.org/web/20121010163051/http://www.epa.gov/magnesium-sf6/documents/tms_paper.pdf |archive-date=October 10, 2012 }}</ref> and other processes including smelting.<ref name="ayres00">{{cite news |first=John |last=Ayres |publisher=Environment Canada |url=https://www.epa.gov/sites/default/files/2016-02/documents/conf00_ayres_paper.pdf |title=Canadian Perspective on SF6 Management from Magnesium Industry |date=2000}}</ref> Once the largest user, consumption has declined greatly with capture and recycling.<ref name="sf6b20" />

* [[Insulated glazing]] windows have used it as a filler to improve their thermal and acoustic insulation performance.<ref name="ecofys">{{cite web |url=http://www.oekorecherche.de/sites/default/files/publikationen/ecofys_oekorecherchestudy.pdf |title=Final report on the costs and the impact on emissions of potential regulatory framework for reducing emissions of hydrofluorocarbons, perfluorocarbons and sulphur hexafluoride |author=J. Harnisch and W. Schwarz |date=2003-02-04 |publisher=Ecofys GmbH}}</ref><ref>{{cite book|url=https://books.google.com/books?id=bqUxCGJd0owC&q=hexafluoride+insulating+glass&pg=PA504 |title=Sound insulation - Google Books |isbn=9780750665261 |last1=Hopkins |first1=Carl |year=2007 |pages=504–506|publisher=Elsevier / Butterworth-Heinemann }}</ref>

* {{chem|SF|6}} [[plasma (physics)|plasma]] is used in the [[semiconductor]] industry as an [[etching (microfabrication)|etchant]] in processes such as [[deep reactive-ion etching]]. A small fraction of the {{chem|SF|6}} breaks down in the plasma into sulfur and fluorine, with the fluorine ions performing a chemical reaction with silicon.<ref>{{cite web|url=http://www.eng.auburn.edu/~tzengy/Publications/Plasma%20Lab%20Publications/Dry%20etching%20of%20silicon%20materials%20in%20SF6%20based%20plasma.pdf |title=Dry Etching of Silicon Materials in {{chem|SF|6}} Based Plasmas |date=September 1987 |author1=Y. Tzeng |author2=T.H. Lin |publisher=Journal of the Electrochemical Society |access-date=22 February 2013 |url-status=dead|archive-url=https://web.archive.org/web/20120406111056/http://www.eng.auburn.edu/~tzengy/Publications/Plasma%20Lab%20Publications/Dry%20etching%20of%20silicon%20materials%20in%20SF6%20based%20plasma.pdf |archive-date=6 April 2012 }}</ref>

* Tires filled with it take longer to deflate from [[molecular diffusion|diffusion]] through rubber due to the larger molecule size.<ref name="ecofys" />

* [[Nike Inc.|Nike]] likewise used it to obtain a [[patent]] and to fill the cushion bags in all of their "Air"-branded shoes from 1992 to 2006.<ref>{{cite web |url= http://www.businessweek.com/stories/2006-09-24/nike-goes-for-the-green |title= Nike Goes For The Green |author= Stanley Holmes |publisher= Bloomberg Business Week Magazine |date= September 24, 2006 |access-date= December 14, 2013 |url-status= dead |archive-url= https://web.archive.org/web/20130603225645/http://www.businessweek.com/stories/2006-09-24/nike-goes-for-the-green |archive-date= June 3, 2013 }}</ref> 277&nbsp;tons was used during the peak in 1997.<ref name="ecofys" />

* The [[United States Navy]]'s [[Mark 50 torpedo]] closed [[Rankine cycle|Rankine-cycle]] propulsion system is powered by sulfur hexafluoride in an [[exothermic reaction]] with solid [[lithium]].<ref>{{cite journal|title=Stored Chemical Energy Propulsion System for Underwater Applications|author1=Hughes, T.G. |author2=Smith, R.B. |author3=Kiely, D.H. |journal= Journal of Energy|year= 1983|volume=7|issue=2 |pages=128–133|doi=10.2514/3.62644|bibcode=1983JEner...7..128H }}</ref>

* [[Waveguide]]s in high-power [[microwave]] systems are pressurized with it. The gas electrically insulates the waveguide, preventing internal arcing.

* [[Electrostatic loudspeaker]]s have used it because of its high dielectric strength and high molecular weight.<ref>{{cite web |url= http://www.theabsolutesound.com/articles/advances-in-loudspeaker-technology-a-50-year-perspective-tas-196/ |title= Advances in loudspeaker technology - A 50 year prospective |author= Dick Olsher |publisher= The Absolute Sound |date= October 26, 2009 |access-date= December 14, 2013 |url-status= live |archive-url= https://web.archive.org/web/20131214091113/http://www.theabsolutesound.com/articles/advances-in-loudspeaker-technology-a-50-year-perspective-tas-196/ |archive-date= December 14, 2013 }}</ref>

* The [[chemical weapon]] [[disulfur decafluoride]] is produced with it as a [[feedstock]].

* For entertainment purposes, when breathed, {{chem|SF|6}} causes the voice to become significantly deeper, due to its density being so much higher than air. This phenomenon is related to the more well-known effect of breathing low-density [[helium]], which causes someone's voice to become much higher. Both of these effects should only be attempted with caution as these gases displace [[oxygen]] that the lungs are attempting to extract from the air. Sulfur hexafluoride is also mildly anesthetic.<ref>{{cite journal | url=http://anesthesiology.pubs.asahq.org/article.aspx?articleid=1964594|title=Anesthetic Potencies of Sulfur Hexafluoride, Carbon Tetrafluoride, Chloroform and Ethrane in Dogs: Correlation with the Hydrate and Lipid Theories of Anesthetic Action|journal=Anesthesiology: The Journal of the American Society of Anesthesiologists|volume=30|issue=2|pages=127–134|publisher=Anesthesiology - The Journal of the American Society of Anesthesiologists, Inc|date=September 10, 1968|author=Edmond I Eger MD |display-authors=etal }}</ref><ref>{{cite AV media|author=[[WTOL]]|publisher=[[Imagination Station]]|date=2015-01-27|title=Sound Like Darth Vader with Sulfur Hexafluoride|url=https://www.youtube.com/watch?v=A7XdOyZIkko|website=YouTube}}</ref>

* For science demonstrations / magic as "invisible water" since a light foil boat can be floated in a tank, as will an air-filled balloon.

*It is used for benchmark and calibration measurements in Associative and Dissociative Electron Attachment (DEA) experiments<ref>{{cite journal|last1=Braun|first1=M|last2=Marienfeld|first2=S|last3=Ruf|first3=M-W|last4=Hotop|first4=H|date=2009-05-26|title=High-resolution electron attachment to the molecules CCl4and SF6over extended energy ranges with the (EX)LPA method|url=https://iopscience.iop.org/article/10.1088/0953-4075/42/12/125202|journal=Journal of Physics B: Atomic, Molecular and Optical Physics|language=en|volume=42|issue=12|pages=125202|doi=10.1088/0953-4075/42/12/125202|bibcode=2009JPhB...42l5202B|s2cid=122242919|issn=0953-4075}}</ref><ref>{{cite journal|last1=Fenzlaff|first1=Marita|last2=Gerhard|first2=Rolf|last3=Illenberger|first3=Eugen|date=1988-01-01|title=Associative and dissociative electron attachment by SF6 and SF5Cl|url=https://aip.scitation.org/doi/10.1063/1.454646|journal=The Journal of Chemical Physics|volume=88|issue=1|pages=149–155|doi=10.1063/1.454646|bibcode=1988JChPh..88..149F|issn=0021-9606}}</ref>

==Greenhouse gas==

<gallery mode="packed" heights="200">

File:SF6 mm.png|Sulfur hexafluoride (SF₆) measured by the Advanced Global Atmospheric Gases Experiment ([http://agage.mit.edu/ AGAGE]) in the lower atmosphere ([[troposphere]]) at stations around the world. Abundances are given as pollution free monthly mean mole fractions in [[Parts-per notation|parts-per-trillion]].

File:AGAGE sulfur hexafluroride growth.png|Abundance and growth rate of {{chem|SF|6}} in Earth's troposphere (1978-2018).<ref name="sf6b20">Simmonds, P. G., Rigby, M., Manning, A. J., Park, S., Stanley, K. M., McCulloch, A., Henne, S., Graziosi, F., Maione, M., and 19 others (2020) "The increasing atmospheric burden of the greenhouse gas sulfur hexafluoride (SF₆)". ''Atmos. Chem. Phys.'', '''20''': 7271–7290. {{doi|10.5194/acp-20-7271-2020}}. [[File:CC-BY icon.svg|50px]] Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].</ref>

File:Halogenated gas concentrations 1978-present.png|Atmospheric concentration of SF₆ vs. similar man-made gases (right graph). Note the log scale.

</gallery>

According to the [[Intergovernmental Panel on Climate Change]], {{chem|SF|6}} is the most potent [[greenhouse gas]]. Its [[global warming potential]] of 23,900 times that of [[carbon dioxide|{{chem|CO|2}}]] when compared over a 100-year period.<ref>{{cite web |url=http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-10-2.html |title=2.10.2 Direct Global Warming Potentials |year=2007 |publisher=[[Intergovernmental Panel on Climate Change]] |access-date=22 February 2013 |url-status=live |archive-url=https://web.archive.org/web/20130302061433/http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-10-2.html |archive-date=2 March 2013 }}</ref> Sulfur hexafluoride is inert in the [[troposphere]] and [[stratosphere]] and is extremely long-lived, with an estimated [[atmospheric lifetime]] of 800–3,200 years.<ref>{{cite journal |author=A. R. Ravishankara, S. Solomon, A. A. Turnipseed, R. F. Warren |date=8 January 1993 |title=Atmospheric Lifetimes of Long-Lived Halogenated Species |journal=Science |volume=259 |issue=5092 |pages=194–199 |url=https://www.science.org/doi/abs/10.1126/science.259.5092.194 |access-date=22 February 2013 |bibcode=1993Sci...259..194R |last2=Solomon |last3=Turnipseed |last4=Warren |doi=10.1126/science.259.5092.194 |pmid=17790983 |s2cid=574937 |url-status=live |archive-url=https://web.archive.org/web/20150924144127/http://www.sciencemag.org/content/259/5092/194.abstract |archive-date=24 September 2015 }}</ref>

Measurements of SF₆ show that its global average [[mixing ratio]] has increased from a steady base of about 54 [[parts-per notation|parts per quadrillion]]<ref name="sf6nat" /> prior to industrialization, to over 11.5 parts per trillion (ppt) as of October 2023, and is increasing by about 0.4 ppt (3.5%) per year.<ref name="sf6trend">{{cite web |url=https://www.esrl.noaa.gov/gmd/ccgg/trends_sf6/ |title=Trends in Atmospheric Sulpher Hexaflouride |publisher=[[US National Oceanic and Atmospheric Administration]] |access-date=28 December 2023}}</ref><ref>{{cite web|url=ftp://aftp.cmdl.noaa.gov/data/hats/sf6/insituGCs/CATS/monthly/smo_SF6_MM.dat |title=Sulfur hexafluoride (SF₆) data from hourly in situ samples analyzed on a gas chromatograph located at Cape Matatulu (SMO)|date=July 7, 2020|access-date=August 8, 2020}}</ref> Average global SF₆ concentrations increased by about 7% per year during the 1980s and 1990s, mostly as the result of its use in [[magnesium]] production, and by electrical utilities and electronics manufacturers. Given the small amounts of SF₆ released compared to [[carbon dioxide]], its overall individual contribution to global warming is estimated to be less than 0.2%,<ref>{{cite web |url=http://powerplantccs.com/blog/2011/03/sf6-sulfur-hexafluoride.html |title=SF₆ Sulfur Hexafluoride |date=19 March 2011 |publisher=PowerPlantCCS Blog |access-date=22 February 2013 |url-status=live |archive-url=https://web.archive.org/web/20121230202321/http://powerplantccs.com/blog/2011/03/sf6-sulfur-hexafluoride.html |archive-date=30 December 2012 }}</ref> however the collective contribution of it and similar man-made halogenated gases has reached about 10% as of 2020.<ref>{{cite web |url=https://www.esrl.noaa.gov/gmd/aggi/aggi.html |title=The NOAA Annual Greenhouse Gas Index (AGGI) |publisher=[[NOAA]] Global Monitoring Laboratory/Earth System Research Laboratories |author=Butler J. and Montzka S. |year=2020 }}</ref> Alternatives are being tested.<ref>{{cite web |title=g3, the SF6-free solution in practice {{!}} Think Grid |url=https://think-grid.org/g3-sf6-free-solution-practice |website=think-grid.org |date=18 February 2019 |access-date=6 February 2020 |archive-date=30 October 2020 |archive-url=https://web.archive.org/web/20201030203625/https://think-grid.org/g3-sf6-free-solution-practice |url-status=dead }}</ref><ref>{{cite journal |author1=Mohamed Rabie |author2=Christian M. Franck |title=Assessment of Eco-friendly Gases for Electrical Insulation to Replace the Most Potent Industrial Greenhouse Gas SF6 |journal=Environmental Science & Technology |year=2018 |volume=52 |issue=2 |pages=369–380 |publisher=American Chemical Society |doi=10.1021/acs.est.7b03465|pmid=29236468 |bibcode=2018EnST...52..369R |hdl=20.500.11850/238519 |hdl-access=free }}</ref>

In Europe, {{chem|SF|6}} falls under the [[F-Gas]] directive which ban or control its use for several applications.<ref name="sfphy">{{cite web |url=https://phys.org/news/2020-01-sulfur-hexafluoride-truths-myths-greenhouse.html |title=Sulfur hexafluoride: The truths and myths of this greenhouse gas |author=David Nikel |publisher=phys.org |date=2020-01-15 |access-date=2020-10-18}}</ref> Since 1 January 2006, {{chem|SF|6}} is banned as a tracer gas and in all applications except [[high-voltage switchgear]].<ref>{{cite news |url=http://www.euractiv.com/sustainability/climate-meps-give-gas-bill-green-boost/article-145749 |title=Climate: MEPs give F-gas bill a 'green boost' |newspaper=www.euractiv.com |date=13 October 2005 |publisher=[[EurActiv.com]] |access-date=22 February 2013 |url-status=live |archive-url= https://web.archive.org/web/20130603001718/http://www.euractiv.com/sustainability/climate-meps-give-gas-bill-green-boost/article-145749 |archive-date=3 June 2013 }}</ref> It was reported in 2013 that a three-year effort by the [[United States Department of Energy]] to identify and fix leaks at its laboratories in the United States such as the [[Princeton Plasma Physics Laboratory]], where the gas is used as a high voltage insulator, had been productive, cutting annual leaks by {{convert|2280|lb|kg|order=flip|abbr=off}}. This was done by comparing purchases with inventory, assuming the difference was leaked, then locating and fixing the leaks.<ref name=NYT61313>{{cite news|title=Department of Energy's Crusade Against Leaks of a Potent Greenhouse Gas Yields Results|url=https://www.nytimes.com/2013/06/14/us/department-of-energys-crusade-against-leaks-of-a-potent-greenhouse-gas-yields-results.html |access-date=June 14, 2013|newspaper=[[The New York Times]]|date=June 13, 2013|author=Michael Wines|url-status=live|archive-url= https://web.archive.org/web/20130614114649/http://www.nytimes.com/2013/06/14/us/department-of-energys-crusade-against-leaks-of-a-potent-greenhouse-gas-yields-results.html |archive-date=June 14, 2013|author-link=Michael Wines}}</ref>

==Physiological effects and precautions==

Sulfur hexafluoride is a nontoxic gas, but by displacing oxygen in the lungs, it also carries the risk of [[asphyxia]] if too much is inhaled.<ref>{{cite web|title=Sulfur Hexafluoride|url=http://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+825|work=Hazardous Substances Data Bank|publisher=U.S. National Library of Medicine|access-date=26 March 2013|url-status=live|archive-url=https://web.archive.org/web/20180509021853/https://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+825|archive-date=9 May 2018}}</ref> Since it is more dense than air, a substantial quantity of gas, when released, will settle in low-lying areas and present a significant risk of asphyxiation if the area is entered. That is particularly relevant to its use as an insulator in electrical equipment since workers may be in trenches or pits below equipment containing {{chem|SF|6}}.<ref>{{cite web|title=Guide to the safe use of SF₆ in gas|url=http://www.eurelectric.org/Download/Download.aspx?DocumentID=2136|publisher=[[UNIPEDE]]/[[EURELECTRIC]]|access-date=2013-09-30|url-status=live|archive-url=https://web.archive.org/web/20131004224624/http://www.eurelectric.org/Download/Download.aspx?DocumentID=2136|archive-date=2013-10-04}}</ref>

[[File:Sulfur Hexafluoride (SF6) Surprise.webm|thumb|A man's voice is deepened in pitch through inhaling sulfur hexafluoride]]

As with all gases, the density of {{chem|SF|6}} affects the resonance frequencies of the vocal tract, thus changing drastically the vocal sound qualities, or [[timbre]], of those who inhale it. It does not affect the vibrations of the vocal folds. The density of sulfur hexafluoride is relatively high at room temperature and pressure due to the gas's large [[molar mass]]. Unlike [[helium]], which has a molar mass of about 4&nbsp;g/mol and pitches the voice up, {{chem|SF|6}} has a molar mass of about 146&nbsp;g/mol, and the speed of sound through the gas is about 134&nbsp;m/s at room temperature, pitching the voice down. For comparison, the molar mass of air, which is about 80% nitrogen and 20% oxygen, is approximately 30&nbsp;g/mol which leads to a speed of sound of 343&nbsp;m/s.<ref name="Wolfe">{{cite web |url=http://www.animations.physics.unsw.edu.au/jw/speech.html |title=Physics in Speech |publisher=University of New South Wales |access-date=22 February 2013 |url-status=live |archive-url=https://web.archive.org/web/20130221043110/http://www.animations.physics.unsw.edu.au/jw/speech.html |archive-date=21 February 2013 }}</ref>

Sulfur hexafluoride has an [[anesthetic]] potency slightly lower than [[nitrous oxide]];<ref>{{cite book | isbn = 9780398000110 | title = The Chemistry and Physics of Anesthesia |edition=2nd | last1 = Adriani | first1 = John | year = 1962 | publisher = Thomas Books | location = Illinois | page = 319 }}</ref> it is classified as a mild anesthetic.<ref>{{cite journal |last1=Weaver |first1=Raymond H. |last2=Virtue |first2=Robert W. |title=The mild anesthetic properties of sulfur hexafluoride |url=https://anesthesiology.pubs.asahq.org/article.aspx?articleid=1971324 |journal=Anesthesiology |pages=605–607 |language=en |date=1 November 1952|volume=13 |issue=6 |doi=10.1097/00000542-195211000-00006 |pmid=12986223 |s2cid=32403288 |doi-access=free }}</ref>

==See also==

* [[Selenium hexafluoride]]

* [[Tellurium hexafluoride]]

* [[Uranium hexafluoride]]

* [[Hypervalent molecule]]

* [[Halocarbon]]—another group of major greenhouse gases

* [[Trifluoromethylsulfur pentafluoride]], a similar gas

==References==

{{reflist|30em}}

==Further reading==

* {{cite web |url=http://encyclopedia.airliquide.com/Encyclopedia.asp?GasID=34 |title=Sulfur hexafluoride |publisher=Air Liquide Gas Encyclopedia |access-date=22 February 2013 |url-status=live |archive-url=https://web.archive.org/web/20120331215233/http://encyclopedia.airliquide.com/Encyclopedia.asp?GasID=34 |archive-date=31 March 2012 }}

* {{cite book |editor = Christophorou, Loucas G. |editor2=Isidor Sauers |editor2-link=Isidor Sauers | year = 1991 | title = Gaseous Dielectrics VI | publisher = Plenum Press | isbn = 978-0-306-43894-3 }}

* {{cite book|last1=Holleman |first1=A. F. |last2=Wiberg |first2=E. |title=Inorganic Chemistry |publisher=Academic Press |location=San Diego |date=2001 |isbn=0-12-352651-5}}

* {{cite book |title=High-Voltage Engineering: Theory and Practice |last1=Khalifa |first1=Mohammad |year=1990 |publisher=Marcel Dekker |location=New York |isbn=978-0-8247-8128-6 |oclc=20595838}}

* {{cite book |title=Advantages in High Voltage Insulation and Arc Interruption in SF₆ and Vacuum |last1=Maller |first1=V. N. |last2=Naidu |first2=M. S. |year=1981 |publisher=Pergamon Press |location=Oxford; New York |isbn=978-0-08-024726-7 |oclc=7866855}}

* [https://web.archive.org/web/20061003003615/http://www.epa.gov/electricpower-sf6/ SF₆ Reduction Partnership for Electric Power Systems]

* {{cite web | url=https://www.bbc.com/news/science-environment-49567197 | title=Climate change: Electrical industry's 'dirty secret' boosts warming | work=[[BBC News]] | date=September 13, 2019 | access-date=September 14, 2019 | author=Matt McGrath}}

==External links==

{{Wiktionary|fluoroketone}}

* [https://web.archive.org/web/20060116134617/http://www.npi.gov.au/database/substance-info/profiles/44.html Fluoride and compounds fact sheet]— [[National Pollutant Inventory]]

* [https://web.archive.org/web/20121018211612/http://www.epa.gov/highgwp/scientific.html High GWP Gases and Climate Change] from the U.S. [[United States Environmental Protection Agency|EPA]] website

* [https://web.archive.org/web/20061007210032/http://www.epa.gov/highgwp/magnesium-sf6/workshops.html International Conference on SF₆ and the Environment] ([https://web.archive.org/web/20090426064312/http://www.epa.gov/highgwp/electricpower-sf6/basic.html related archive])

* [https://www.cdc.gov/niosh/npg/npgd0576.html CDC - NIOSH Pocket Guide to Chemical Hazards]

{{Hexafluorides}}

{{Contrast media|state=collapsed}}

{{Sulfur compounds}}

{{fluorine compounds}}

{{Authority control}}

{{DEFAULTSORT:Sulfur Hexafluoride}}

[[Category:Sulfur fluorides]]

[[Category:Dielectric gases]]

[[Category:Greenhouse gases]]

[[Category:Octahedral compounds]]

[[Category:Hexafluorides]]

[[Category:Industrial gases]]

[[Category:Refrigerants]]

[[Category:Hypervalent molecules]]

[[Category:General anesthetics]]

[[Category:Ultrasound contrast agents]]