Llanyrafon and Tungsten hexafluoride: Difference between pages

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Revision as of 00:28, 22 July 2007

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{{infobox Wales place|

! {{chembox header}} | Tungsten(VI) fluoride

|Place= Llanyrafon

|-

|Council= [[Torfaen]]

| 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]]

|Traditional= [[Monmouthshire]]

|-

|Ceremonial= [[Gwent]]

! {{chembox header}} | General

|Constituency= [[Torfaen (UK Parliament constituency)|Torfaen]]

|-

|PostalTown= CWMBRAN

| [[IUPAC nomenclature|Systematic name]]

|PostCode= NP44

| Tungsten(VI) fluoride

|DiallingCode= +44-1633

|-

|GridReference= ST304946

| Other names

|Population= 4,685

| Tungsten hexafluoride

|Police= [[Gwent Police]]

|-

}}

| [[Chemical formula|Molecular formula]]

'''Llanyrafon''' (sometimes ''Llanyravon'') is a suburb of [[Cwmbran]] in the county borough of [[Torfaen]], [[Traditional counties of Wales|traditional county]] of [[Monmouthshire]],[[Wales]]. It lies to the east of the [[Afon Llwyd]] ('Llanyrafon' means 'church [or 'holy ground'] by the river'), west of the [[A4042 road|A4042 dual carriageway]] and south of [[Croesyceiliog]].

| WF₆

|-

| [[Molar mass]]

| 297.83 g/mol

|-

| Appearance

| Colorless gas.

|-

| [[CAS registry number|CAS number]]

| {{CASREF|CAS=7783-82-6}}

|-

! {{chembox header}} | Properties

|-

| [[Density]] and [[Phase (matter)|phase]]

| 13.1 g/L, gas.

|-

| [[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) -->

|-

| [[Boiling point]]

| 17.1°C (290.25 K)

|-

! {{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]]

|-

! {{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]]: ?

|-

| [[RTECS]] number

| ?

|-

! {{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_r]], 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]]

|-

| {{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>

|-

|}

'''Tungsten(VI) fluoride''', also known as '''tungsten hexafluoride''', is a colorless gas. It is nonflammable, but highly corrosive and very toxic.

Llanyrafon is mainly residential but does include a municipal golf course; 3-star hotel ([[Commodore Hotel]] on Mill Lane); small shopping precinct known as ''Llanyrafon Lakeside Shops'' and the large Boating Lake Park & South Fields. The [[Boating Lake Park]] includes (as the name suggests) a large lake which is home to various wildfowl birds such as swans, mallards and moorhens. There is also a large adventure playground as well as various football and rugby pitches. There is one public house, 'The Crow's Nest', that serves 'pub-grub' food.

The molecule itself is octahedral with the symmetry point group of O_h.

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==

The X24, a major bus service operated by [[Stagecoach South Wales]], runs through Llanyrafon from [[Cwmbran]] town centre to [[Newport]].

'''Tungsten hexafluoride''' of a purity high enough for [[semiconductor]] [[CVD]] is produced by the reaction of [[fluorine]] {| class="wikitable"

==Demographics==

|-

{| class="wikitable"

At the 2001 Census

|-

===Llanyrafon North===

! header 1

*Population 2021 (Torfaen 90,949)

! header 2

*45.7% Male, 54.3% Female

! header 3

*Ages

|-

**18.2% aged between 0-15

| row 1, cell 1

**30.0% aged between 16-44

| row 1, cell 2

**21.1% aged 45-59/64

| row 1, cell 3

**30.7% of pensionable age

|-

| row 2, cell 1

| row 2, cell 2

| row 2, cell 3

|}{| class="wikitable"

|-

<nowiki>! header 1

! header 2

! header 3

|-

| row 1, cell 1

| row 1, cell 2

| row 1, cell 3

|-

| row 2, cell 1

| row 2, cell 2

| row 2, cell 3</nowiki>

|}

|} [[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.<ref name="synth1">[http://www.patentstorm.us/patents/6544889.html Patent Storm]</ref>

==Reactions==

===Llanyrafon South===

*Population 2664 (Torfaen 90,949)

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

*48.6% Male, 51.4% Female

*Ages

This reaction occurs when [[tungsten]] is deposited on an [[aluminum]].

**19.0% aged between 0-15

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>

**30.6% aged between 16-44

**24.1% aged 45-59/64

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>

**26.3% of pensionable age

WF₆(''g'') + W* → WF₆*

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

The [[silane]] (SiH₄ 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. WF₆ 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 WF₆-filled balloons for his 65^th 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]

*[http://www.bbc.co.uk/wales/southeast/sites/cwmbran/pages/article_mill.shtml BBC article on Llanyrafon Mill]

[[Category:Tungsten compounds]]

[[Category:Inorganic compounds]]

[[Category:Fluorides]]

[[Category:Metal halides]]

[[Category:lachrymatory agents]]

[[de:Wolframhexafluorid]]

[[Category:Traditional county of Monmouthshire]]

[[Category:Torfaen]]