Tungsten(VI) fluoride


Tungsten(VI) fluoride

Chembox new
ImageFileL1 = Tungsten(VI) fluoride.jpg
ImageSizeL1 = 100px
ImageNameL1 = Tungsten(VI) fluoride
ImageFileR1 = Tungsten-hexafluoride-3D-balls.png ImageSizeR1 = 100px
ImageNameR1 = Ball-and-stick model of tungsten hexafluoride
IUPACName = Tungsten(VI) fluoride
OtherNames = Tungsten hexafluoride
Section1 = Chembox Identifiers
CASNo = 7783-82-6

Section2 = Chembox Properties
Formula = WF6
MolarMass = 297.83 g/mol
Appearance = Colorless gas.
Density = 13.1 g/L, gas.
Solubility = Hydrolyzes.
MeltingPt = 2.3°C (275.45 K)
BoilingPt = 17.1°C (290.25 K)

Section3 = Chembox Structure
MolShape = Octahedral
Dipole = 0 D

Section7 = Chembox Hazards
MainHazards = Corrosive, highly toxic.

Section8 = Chembox Related
OtherAnions = Tungsten(VI) chloride,
Tungsten(VI) bromide
OtherCations = Chromium(V) fluoride,
Molybdenum(VI) fluoride
OtherCpds = Tungsten(IV) fluoride,
Tungsten(V) fluoride,
Uranium hexafluoride

Tungsten(VI) fluoride, also known as tungsten hexafluoride, is a colorless gas. It is nonflammable, but highly corrosive and very toxic. It is the densest known gas at a pressure of 1 atm and room temperature (25 °C). The molecule is octahedral with the symmetry point group of Oh.The gas is most commonly used in the production of semiconductor circuits and circuit boards, through the process of chemical vapor deposition.Kirss, Rein U., Lamartine Meda. "Chemical Vapor Deposition of Tungsten Oxide." "Applied Organometallic Chemistry" 12 (1998): 155–160.]

Industrial Synthesis

Tungsten hexafluoride of a purity high enough for semiconductor CVD is produced by the reaction of fluorine gas with tungsten metal. The metal is placed in a heated reactor, slightly pressurized to 1.2 to 2.0 psi, with a constant flow of WF6 infused with a small amount of fluorine gas. [http://www.patentstorm.us/patents/6544889.html Patent Storm] ]

Reactions

WF6("g") + H2("g") + Al("s") → W("s") + HF("g") + AlF3("s")

This reaction occurs when tungsten is deposited on aluminium.One application of this would be in the production of studs for semiconductor circuits. [http://www.priorartdatabase.com/IPCOM/000038388/ Ip.com] ]

Tungsten can also be deposited on a silicon wafer or other semiconducting material via chemical vapor deposition, or CVD, as follows: [http://www.mne.umd.edu/grad/courses/old_courses_stuff_saved/659s_mats_&_proc_for_microelectronics/659s_spring_1998/enma659S_spr98_final_project_results/wcvd/sih4.html James Clark School of Engineering] ]

WF6("g") + W* → WF6*

2 SiH4("g") + WF6* → W("s") + 2 SiHF3(g) + 3 H2("g")

The silane SiH4 reduces the tungsten from an oxidation state of 6+ (VI) to its elemental state of zero.

afety

On contact with water tungsten(VI) fluoride forms hydrofluoric acid (HF), which can penetrate the skin and cause damage to the subdermal tissues and bone. Inhalation burns the respiratory tract and can be toxic. WF6 is a lachrymator which causes tearing and irritation of the eyes. Contact causes burns to the eyes, skin and mucous membranes. [https://www.mathesongas.com/msds/index.aspx Matheson Gas] ]

In "", Oliver Sacks comments on how he wanted WF6-filled balloons for his 65th birthday, but the gas was too reactive. Had one of the balloons popped, the tungsten(VI) fluoride would have reacted with moisture in the air to form hydrogen fluoride.

References

External links

* [http://www.npi.gov.au/database/substance-info/profiles/44.html National Pollutant Inventory - Flouride and compounds fact sheet]


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Look at other dictionaries:

  • tungsten(VI) fluoride — volframo(VI) fluoridas statusas T sritis chemija formulė WF₆ atitikmenys: angl. tungsten hexafluoride; tungsten(VI) fluoride rus. вольфрама гексафторид; вольфрама(VI) фторид ryšiai: sinonimas – volframo heksafluoridas …   Chemijos terminų aiškinamasis žodynas

  • tungsten hexafluoride — volframo(VI) fluoridas statusas T sritis chemija formulė WF₆ atitikmenys: angl. tungsten hexafluoride; tungsten(VI) fluoride rus. вольфрама гексафторид; вольфрама(VI) фторид ryšiai: sinonimas – volframo heksafluoridas …   Chemijos terminų aiškinamasis žodynas

  • Chromyl fluoride — Other names Chromyl Fluoride, Chromium Difluoride Dioxide Identifiers CAS number …   Wikipedia

  • Manganese(IV) fluoride — IUPAC name manganese tetrafluoride Other names manga …   Wikipedia

  • Iridium(VI) fluoride — Chembox new ImageFile = Tungsten hexafluoride 3D balls.png ImageSize = 150px IUPACName = iridium(VI) fluoride OtherNames = iridium hexafluoride Section1 = Chembox Identifiers CASNo = 7783 75 7 PubChem = SMILES = Section2 = Chembox Properties… …   Wikipedia

  • Dictionary of chemical formulas — This is a list of chemical compounds with chemical formulas and CAS numbers, indexed by formula. This complements alternative listings to be found at list of inorganic compounds, list of organic compounds and inorganic compounds by element. Table …   Wikipedia

  • List of inorganic compounds — Tentative listing related to this page, inorganic compounds by element (presently under construction), as well as . This list is not necessarily complete or up to date ndash; if you see an article that should be here but isn t (or one that… …   Wikipedia

  • volframo(VI) fluoridas — statusas T sritis chemija formulė WF₆ atitikmenys: angl. tungsten hexafluoride; tungsten(VI) fluoride rus. вольфрама гексафторид; вольфрама(VI) фторид ryšiai: sinonimas – volframo heksafluoridas …   Chemijos terminų aiškinamasis žodynas

  • вольфрама гексафторид — volframo(VI) fluoridas statusas T sritis chemija formulė WF₆ atitikmenys: angl. tungsten hexafluoride; tungsten(VI) fluoride rus. вольфрама гексафторид; вольфрама(VI) фторид ryšiai: sinonimas – volframo heksafluoridas …   Chemijos terminų aiškinamasis žodynas

  • вольфрама(VI) фторид — volframo(VI) fluoridas statusas T sritis chemija formulė WF₆ atitikmenys: angl. tungsten hexafluoride; tungsten(VI) fluoride rus. вольфрама гексафторид; вольфрама(VI) фторид ryšiai: sinonimas – volframo heksafluoridas …   Chemijos terminų aiškinamasis žodynas


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