Wikipedia:WikiProject Chemicals/Chembox validation/VerifiedDataSandbox and Carbon tetrafluoride: Difference between pages

| Watchedfields = changed

| verifiedrevid = 470603964

| ImageSize2 =

| ImageFile =

| ImageFileL1 = Carbon-tetrafluoride-2D-dimensions.png

| ImageSizeL1 =

| ImageFileR1 = Carbon-tetrafluoride-3D-balls-B.png

| ImageFile2 = Carbon Tetrafluoride.png

| IUPACName = Tetrafluoromethane<br/>Carbon tetrafluoride

| OtherNames = Carbon tetrafluoride, Perfluoromethane, Tetrafluorocarbon, Freon 14, Halon 14, Arcton 0, CFC 14, PFC 14, R 14, UN 1982

| Section1 = {{Chembox Identifiers

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

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

| EINECS = 200-896-5

| PubChem = 6393

| UNII_Ref = {{fdacite|correct|FDA}}

| InChI = 1/CF4/c2-1(3,4)5

| RTECS = FG4920000

}}

| Section2 = {{Chembox Properties

| Formula = CF₄

| MolarMass = 88.0043 g/mol

| Appearance = Colorless gas

| Odor = odorless

| Density = 3.72 g/L, gas (15 °C)

| MeltingPtC = -183.6

| BoilingPtC = -127.8

| CriticalTP = {{convert|&minus;45.55|C|F K|1}}, {{convert|36.91|atm|kPa psi|1}}<ref>{{cite book|url=https://api.pageplace.de/preview/DT0400.9781000102574_A40413991/preview-9781000102574_A40413991.pdf|last1=Lide|first1=David R.|last2=Kehiaian|first2=Henry V.|title=CRC Handbook of Thermophysical and Themochemical Data|year=1994|page=31|publisher=CRC Press}}</ref>

| Solubility = 0.005%_V at 20 °C<br/>0.0038%_V at 25 °C

| SolubleOther = soluble in [[benzene]], [[chloroform]]

| VaporPressure = 106.5 kPa at −127 °C

| HenryConstant = 5.15 atm-cu m/mole

| RefractIndex = 1.0004823<ref>{{cite journal|last=Abjean|first=R.|author2=A. Bideau-Mehu |author3=Y. Guern |title=Refractive index of carbon tetrafluoride (CF4) in the 300-140 nm wavelength range|journal=Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment|date=15 July 1990|volume=292|issue=3|pages=593–594|doi=10.1016/0168-9002(90)90178-9|bibcode=1990NIMPA.292..593A}}</ref>

| Viscosity = 17.32 μPa·s<ref name="Kestin1971">{{cite journal |title=Reference values of the viscosity of twelve gases at 25°C |journal= Transactions of the Faraday Society|year=1971|last1=Kestin|first1=J.|last2=Ro|first2=S.T.|last3=Wakeham|first3=W.A.|volume=67|pages= 2308–2313|doi=10.1039/TF9716702308 }}</ref>

}}

| Section3 = {{Chembox Structure

| CrystalStruct =

| Coordination = Tetragonal

| MolShape = Tetrahedral

| Dipole = 0 D

}}

| Section4 = {{Chembox Hazards

| ExternalSDS = [http://www.inchem.org/documents/icsc/icsc/eics0575.htm ICSC 0575]

|MainHazards = Simple asphyxiant and greenhouse gas

| NFPA-H = 1

| NFPA-F = 0

| NFPA-R = 0

| NFPA-S = SA

| FlashPt = Non-flammable

}}

| Section8 = {{Chembox Related

| OtherFunction_label = fluoromethanes

| OtherFunction = [[Fluoromethane]]<br/>[[Difluoromethane]]<br/>[[Fluoroform]]

| OtherCompounds =

| OtherAnions = [[Tetrachloromethane]]<br/>[[Tetrabromomethane]]<br/>[[Tetraiodomethane]]

| OtherCations = [[Silicon tetrafluoride]]<br/>[[Germanium tetrafluoride]]<br/>[[Tin tetrafluoride]]<br/>[[Lead tetrafluoride]]

'''Tetrafluoromethane''', also known as '''carbon tetrafluoride''' or R-14, is the simplest [[perfluorocarbon]] ([[Carbon|C]][[Fluorine|F]]₄). As its IUPAC name indicates, tetrafluoromethane is the perfluorinated counterpart to the hydrocarbon [[methane]]. It can also be classified as a [[haloalkane]] or [[halomethane]]. Tetrafluoromethane is a useful [[refrigerant]] but also a potent [[greenhouse gas]].<ref name="Ull"/> It has a very high bond strength due to the nature of the [[carbon–fluorine bond]].

==Bonding==

Because of the multiple carbon–fluorine bonds, and the high [[electronegativity]] of [[fluorine]], the carbon in tetrafluoromethane has a significant positive [[partial charge]] which strengthens and shortens the four carbon–fluorine bonds by providing additional [[Ionic bond|ionic]] character. Carbon–fluorine bonds are the strongest single bonds in [[organic chemistry]].<ref name=hagan>{{cite journal |author=O'Hagan D |title=Understanding organofluorine chemistry and in cations. An introduction to the C–F bond |journal=Chemical Society Reviews |volume=37 |issue=2 |pages=308–19 |date=February 2008 |pmid=18197347 |doi=10.1039/b711844a }}</ref> Additionally, they strengthen as more carbon–fluorine bonds are added to the same carbon. In the one-carbon [[organofluorine compound]]s represented by molecules of [[fluoromethane]], [[difluoromethane]], [[trifluoromethane]], and tetrafluoromethane, the carbon–fluorine bonds are strongest in tetrafluoromethane.<ref name="Lemal2004">{{Cite journal

| last = Lemal | first = D.M.

| year = 2004

| title = Perspective on Fluorocarbon Chemistry

| journal = [[J. Org. Chem.]]

| volume = 69

| pages = 1–11

| doi = 10.1021/jo0302556

| pmid = 14703372

| issue = 1

}}</ref> This effect is due to the increased [[coulombic]] attractions between the fluorine atoms and the carbon because the carbon has a positive [[partial charge]] of 0.76.<ref name="Lemal2004"/>

== Preparation ==

Tetrafluoromethane is the product when any carbon compound, including carbon itself, is burned in an atmosphere of fluorine. With hydrocarbons, [[hydrogen fluoride]] is a coproduct. It was first reported in 1926.<ref name="chemelem">{{Greenwood&Earnshaw}}</ref> It can also be prepared by the [[fluorination]] of [[carbon dioxide]], [[carbon monoxide]] or [[phosgene]] with [[sulfur tetrafluoride]]. Commercially it is manufactured by the reaction of [[hydrogen fluoride]] with [[dichlorodifluoromethane]] or [[chlorotrifluoromethane]]; it is also produced during the [[electrolysis]] of metal [[fluoride]]s MF, MF₂ using a carbon electrode.

Although it can be made from a myriad of precursors and fluorine, elemental fluorine is expensive and difficult to handle. Consequently, {{chem|CF|4}} is prepared on an industrial scale using [[hydrogen fluoride]]:<ref name=Ull>{{Ullmann|first1=Günter |last1=Siegemund|first2=Werner|last2=Schwertfeger|first3=Andrew|last3= Feiring|first4=Bruce|last4=Smart|first5=Fred |last5=Behr|first6=Herward|last6=Vogel|first7=Blaine|last7=McKusick|title=Fluorine Compounds, Organic|year=2002|doi=10.1002/14356007.a11_349}}</ref>

:CCl₂F₂ + 2 HF → CF₄ + 2 HCl

===Laboratory synthesis===

Tetrafluoromethane and [[silicon tetrafluoride]] can be prepared in the laboratory by the reaction of [[silicon carbide]] with fluorine.

: SiC + 4 F₂ → CF₄ + SiF₄

==Reactions==

Tetrafluoromethane, like other fluorocarbons, is very stable due to the strength of its carbon–fluorine bonds. The bonds in tetrafluoromethane have a [[bonding energy]] of 515 kJ⋅mol⁻¹. As a result, it is inert to acids and hydroxides. However, it reacts explosively with [[alkali metal]]s. [[Thermal decomposition]] or combustion of CF₄ produces toxic gases ([[carbonyl fluoride]] and [[carbon monoxide]]) and in the presence of water will also yield [[hydrogen fluoride]].

It is very slightly soluble in water (about 20&nbsp;mg⋅L⁻¹), but miscible with organic solvents.

==Uses==

Tetrafluoromethane is sometimes used as a low temperature [[refrigerant]] (R-14). It is used in [[electronics]] [[microfabrication]] alone or in combination with [[oxygen]] as a [[plasma etching|plasma etchant]] for [[silicon]], [[silicon dioxide]], and [[silicon nitride]].<ref name=williams>K. Williams, K. Gupta, M. Wasilik. ''Etch Rates for Micromachining Processing – Part II'' J. Microelectromech. Syst., vol. 12, pp. 761–777, December 2003.</ref> It also has uses in neutron detectors.<ref>{{cite journal|title=Low efficiency 2-dimensional position-sensitive neutron detector for beam profile measurement|year=2005 |doi=10.1016/j.nima.2004.09.020|last1=Moon |first1=Myung-Kook |last2=Nam |first2=Uk-Won |last3=Lee |first3=Chang-Hee |last4=Em |first4=V.T. |last5=Choi |first5=Young-Hyun |last6=Cheon |first6=Jong-Kyu |last7=Kong |first7=Kyung-Nam |journal=Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment |volume=538 |issue=1–3 |pages=592–596 |bibcode=2005NIMPA.538..592M }}</ref>

== Environmental effects ==

[[File:Mauna Loa Tetrafluoromethane.jpg|thumb|left|upright=1|Mauna Loa tetrafluoromethane (CF₄) timeseries.]]

[[Image:PFC-14 mm.png|thumb|left|PFC-14 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]].]]

[[Image:Halogenated gas concentrations 1978-present.png|thumb|left|upright=1.2|Atmospheric concentration of CF₄ (PFC-14) vs. similar man-made gases (right graph). Note the log scale.]]

Tetrafluoromethane is a potent [[greenhouse gas]] that contributes to the [[greenhouse effect]]. It is very stable, has an [[atmospheric lifetime]] of 50,000 years, and a high [[greenhouse warming potential]] 6,500 times that of CO₂.<ref>{{cite web |last1=Artaxo |first1=Paulo |last2=Berntsen |first2=Terje |last3=Betts |first3=Richard |last4=Fahey |first4=David W. |last5=Haywood |first5=James |last6=Lean |first6=Judith |author6-link=Judith Lean |last7=Lowe |first7=David C. |last8=Myhre |first8=Gunnar |last9=Nganga |first9=John |last10=Prinn |first10=Ronald |last11=Raga |first11=Graciela |last12=Schulz |first12=Michael |last13=van Dorland |first13=Robert |title=Changes in Atmospheric Constituents and in Radiative Forcing |url=https://www.ipcc.ch/site/assets/uploads/2018/02/ar4-wg1-chapter2-1.pdf |publisher=[[Intergovernmental Panel on Climate Change]] |access-date=17 March 2021 |page=212 |date=February 2018}}</ref>

Tetrafluoromethane is the most abundant [[perfluorocarbon]] in the atmosphere, where it is designated as PFC-14. Its atmospheric concentration is growing.<ref>{{Cite web |url=https://www.epa.gov/climate-indicators/climate-change-indicators-atmospheric-concentrations-greenhouse-gases |title=Climate change indicators - Atmospheric concentration of greenhouse gases - Figure 4 |date=27 June 2016 |publisher=[[United States Environmental Protection Agency]] |access-date=2020-09-26}}</ref> As of 2019, the man-made gases [[Trichlorofluoromethane|CFC-11]] and [[Dichlorodifluoromethane|CFC-12]] continue to contribute a stronger [[radiative forcing]] than PFC-14.<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>

Although structurally similar to [[chlorofluorocarbons]] (CFCs), tetrafluoromethane does not [[Ozone depletion|deplete the ozone layer]]<ref>{{Cite journal |last=Cicerone |first=Ralph J. |date=1979-10-05 |title=Atmospheric Carbon Tetrafluoride: A Nearly Inert Gas |url=https://escholarship.org/content/qt5n81h9fs/qt5n81h9fs.pdf?t=obqs5d |journal=Science |language=en |volume=206 |issue=4414 |pages=59–61 |doi=10.1126/science.206.4414.59 |pmid=17812452 |bibcode=1979Sci...206...59C |s2cid=34911990 |issn=0036-8075}}</ref> because the carbon–fluorine bond is much stronger than that between carbon and chlorine.<ref>{{Cite web |title=Bond Energies |url=https://www2.chemistry.msu.edu/faculty/reusch/OrgPage/bndenrgy.htm |access-date=2023-01-15 |website=www2.chemistry.msu.edu}}</ref>

Main industrial emissions of tetrafluoromethane besides [[hexafluoroethane]] are produced during production of [[aluminium]] using [[Hall-Héroult process]]. CF₄ also is produced as product of the breakdown of more complex compounds such as [[halocarbon]]s.<ref name="JubbMcGillen2015">{{cite journal|last1=Jubb|first1=Aaron M.|last2=McGillen|first2=Max R.|last3=Portmann|first3=Robert W.|last4=Daniel|first4=John S.|last5=Burkholder|first5=James B.|title=An atmospheric photochemical source of the persistent greenhouse gas CF4|journal=Geophysical Research Letters|volume=42|issue=21|year=2015|pages=9505–9511|issn=0094-8276|doi=10.1002/2015GL066193|bibcode=2015GeoRL..42.9505J|url=https://zenodo.org/record/1229070|doi-access=free}}</ref>

== Health risks ==

Due to its density, tetrafluoromethane can displace air, creating an [[asphyxiation]] hazard in inadequately ventilated areas. Otherwise, it is normally harmless due to its stability.

== See also ==

* [[Trifluoromethane]]

* [[Hexafluoroethane]]

* [[Octafluoropropane]]

== References ==

{{reflist|30em}}

== External links ==

*{{ICSC|0575|05}}

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

*[http://encyclopedia.airliquide.com/Encyclopedia.asp?GasID=61 Data from Air Liquide] {{Webarchive|url=https://web.archive.org/web/20110721161453/http://encyclopedia.airliquide.com/Encyclopedia.asp?GasID=61 |date=2011-07-21 }}

*[https://web.archive.org/web/20071128163335/http://encyclopedia.airliquide.com/images_encyclopedie/VaporPressureGraph/Tetrafluoromethane_Vapor_Pressure.GIF Vapor pressure graph at Air Liquide]

*[https://web.archive.org/web/20070518204412/http://ptcl.chem.ox.ac.uk/MSDS/CA/carbon_tetrafluoride.html MSDS at Oxford University]

*[https://web.archive.org/web/20070928184254/http://www.climatevision.gov/sectors/aluminum/pdfs/tms_protocol.pdf Protocol for measurement of tetrafluoromethane and hexafluoroethane from primary aluminium production]

*[https://web.archive.org/web/20020916093307/http://www.cheric.org/kdb/kdb/hcprop/listcmp.php?cmpclass=48 Chemical and physical properties table]

* [http://webbook.nist.gov/cgi/cbook.cgi?ID=C75730 WebBook page for CF4]

{{Halomethanes}}

{{Inorganic compounds of carbon}}

{{fluorine compounds}}

{{Authority control}}

[[Category:Nonmetal halides]]

[[Category:Perfluoroalkanes|1]]

[[Category:Halomethanes]]

[[Category:Refrigerants]]

[[Category:Greenhouse gases]]