Boy Meets World and Tungsten hexafluoride: Difference between pages
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! {{chembox header}} | Tungsten(VI) fluoride
|-
| align="center" colspan="2" | [[Image:Tungsten-hexafluoride-3D-balls.png|100px|Ball-and-stick model of tungsten hexafluoride]] [[Image:Tungsten(VI) fluoride.jpg|100px|Tungsten(VI) fluoride]]
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! {{chembox header}} | General
|-
| [[IUPAC nomenclature|Systematic name]]
| Tungsten(VI) fluoride
|-
| Other names
| Tungsten hexafluoride
|-
| [[Chemical formula|Molecular formula]]
| WF<sub>6</sub>
|-
| [[Molar mass]]
| 297.83 g/mol
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| Appearance
| Colorless gas.
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| [[CAS registry number|CAS number]]
| {{CASREF|CAS=7783-82-6}}
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! {{chembox header}} | Properties
|-
| [[Density]] and [[Phase (matter)|phase]]
| 13.1 g/L, gas.
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| [[Solubility]] in [[Water (molecule)|water]]
| Hydrolyzes.
|-
<!-- | Other solvents e.g. [[ethanol]], [[acetone]] -->
<!-- | solubility info on other solvents -->
<!-- |- -->
| [[Melting point]]
| 2.3°C (275.45 K) <!-- (mention any decomposition) -->
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| [[Boiling point]]
| 17.1°C (290.25 K)
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! {{chembox header}} | Structure
|-
| [[Orbital hybridisation#Molecule shape|Molecular shape]] <!-- for simple covalent molecules (omit for most large molecules, ionics and complexes) -->
| Octahedral <!-- e.g. trigonal bipyramidal -->
|-
| [[Dipole#Molecular dipoles|Dipole moment]]
| 0 [[Debye|D]]
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! {{chembox header}} | Hazards <!-- Summary only- MSDS entry provides more complete information -->
|-
| [[Material safety data sheet|MSDS]]
| [[Tungsten(VI) fluoride (data page)#Material Safety Data Sheet|External MSDS]] <!-- please replace with proper link-->
|-
| Main [[Worker safety and health|hazard]]s
| Corrosive, highly toxic. <!-- e.g. highly toxic, explosive, flammable, corrosive -->
|-
| [[NFPA 704]]
| {{NFPA 704 | Health=4 | Reactivity=1 }}
|-
| [[Flash point]]
| Non-flammable.
|-
| [[Risk and Safety Statements|R/S statement]]
| [[List of R-phrases|R]]: ? <br /> [[List of S-phrases|S]]: ?
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| [[RTECS]] number
| ?
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! {{chembox header}} | [[Tungsten(VI) fluoride (data page)|Supplementary data page]]
|-
| [[Tungsten(VI) fluoride (data page)#Structure and properties|Structure and<br />properties]]
| [[Refractive index|''n'']], [[Dielectric constant|ε<sub>r</sub>]], etc.
|-
| [[Tungsten(VI) fluoride (data page)#Thermodynamic properties|Thermodynamic<br />data]]
| Phase behaviour<br />Solid, liquid, gas
|-
| [[Tungsten(VI) fluoride (data page)#Spectral data|Spectral data]]
| [[UV/VIS spectroscopy|UV]], [[Infrared spectroscopy|IR]], [[nuclear magnetic resonance spectroscopy|NMR]], [[Mass spectrometry|MS]]
|-
! {{chembox header}} | Related compounds
|-
| Other [[Ion|anion]]s <!-- please omit if not applicable -->
| [[Tungsten(VI) chloride]],<br />[[Tungsten(VI) bromide]]
|-
| Other [[Ion|cation]]s <!-- please omit if not applicable -->
| [[Chromium(V) fluoride]],<br />[[Molybdenum(VI) fluoride]]
|-
| Related compounds
| [[Tungsten(IV) fluoride]],<br />[[Tungsten(V) fluoride]],<br /> [[Uranium hexafluoride]]
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| {{chembox header}} | <small>Except where noted otherwise, data are given for<br /> materials in their [[standard state|standard state (at 25°C, 100 kPa)]]<br />[[wikipedia:Chemical infobox|Infobox disclaimer and references]]</small>
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|}
'''Tungsten(VI) fluoride''', also known as '''tungsten hexafluoride''', is a colorless gas. It is nonflammable, but highly corrosive and very toxic.
The molecule itself is octahedral with the symmetry point group of O<sub>h</sub>.
The gas is most commonly used in the production of [[semiconductor]] [[circuits]] and [[circuit boards]], through the process of [[chemical vapor deposition]].<ref name="chemvap">Kirss, Rein U., Lamartine Meda. "Chemical Vapor Deposition of Tungsten Oxide." ''Applied Organometallic Chemistry'' 12 (1998): 155–160.</ref>
--[[User:208.189.200.2|208.189.200.2]] 00:28, 22 July 2007 (UTC)==Industrial Synthesis==
'''Tungsten hexafluoride''' of a purity high enough for [[semiconductor]] [[CVD]] is produced by the reaction of [[fluorine]] {| class="wikitable"
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|} [[tungsten]] metal. The metal is placed in a heated reactor, slightly pressurized to 1.2 to 2.0 psi, with a constant flow of WF<sub>6</sub> infused with a small amount of [[fluorine]] gas.<ref name="synth1">[http://www.patentstorm.us/patents/6544889.html Patent Storm]</ref>
==
WF<sub>6</sub>(''g'') + H<sub>2</sub>(''g'') + Al(''s'') → W(''s'') + HF(''g'') + AlF<sub>3</sub>(''s'')
This reaction occurs when [[tungsten]] is deposited on an [[aluminum]].
One application of this would be in the production of studs for semiconductor circuits.<ref name="use">[http://www.priorartdatabase.com/IPCOM/000038388/ Ip.com]</ref>
Tungsten can also be deposited on a [[silicon]] wafer or other semiconducting material via [[chemical vapor deposition]], or CVD, as follows:<ref name="react">[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]</ref>
WF<sub>6</sub>(''g'') + W* → WF<sub>6</sub>*
2 SiH<sub>4</sub>(''g'') + WF<sub>6</sub>* → W(''s'') + 2 SiHF<sub>3</sub> (g) + 3 H<sub>2</sub>(''g'')
The [[silane]] (SiH<sub>4</sub> reduces the tungsten from (VI) to its elemental state of zero.
==Safety==
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. WF<sub>6</sub> is a [[lachrymator]] which causes tearing and irritation of the eyes. Contact causes burns to the eyes, skin and mucous membranes.<ref name="msds">[https://www.mathesongas.com/msds/index.aspx Matheson Gas]</ref>
In ''[[Uncle Tungsten: Memories of a Chemical Boyhood|Uncle Tungsten]]'', Oliver Sacks comments on how he wanted WF<sub>6</sub>-filled balloons for his 65<sup>th</sup> 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==
<div class="references-small"><references /></div>
==External links==
*[http://www.npi.gov.au/database/substance-info/profiles/44.html National Pollutant Inventory - Flouride and compounds fact sheet]
[[Category:Tungsten compounds]]
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