Scottish Youth Parliament and Rhenium diboride: Difference between pages

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{{Chembox new
{{Infobox Company
| ImageFile = Rhenium_Diboride.jpg
| company_name = Scottish Youth Parliament Ltd.
| IUPACName = Rhenium Diboride
| company_logo = [[Image:Scottish Youth Parliament logo.png]]
| OtherNames =
| company_type = [[Company limited by guarantee]]
| Section1 = {{Chembox Identifiers
| foundation = [[1999]]
| CASNo = 12355-99-6
| location = [[Edinburgh]], [[Scotland]]
| PubChem =
| area_served = [[Scotland]]
| SMILES =
| key_people = '''Kieran Collins MSYP''', Chair<br>'''Connie Bennett MSYP''', Vice Chair<br>'''Robin James MSYP''', SYP Secretary<br>'''Hilary Lynn MSYP''', Treasurer
}}
| industry = [[Youth empowerment]]
| Section2 = {{Chembox Properties
| homepage = [http://www.scottishyouthparliament.org.uk/ scottishyouthparliament.org.uk]
| Formula = ReB<sub>2</sub>
| MolarMass = 207.83 g/mol
| Appearance =
| Density =
| MeltingPt =
| BoilingPt =
| Solubility =
}}
| Section3 = {{Chembox Hazards
| MainHazards =
| FlashPt =
| Autoignition =
}}
}}
}}


'''[[Rhenium]] diboride''' ([[Rhenium|Re]][[Boron|B]]<sub>2</sub>) is a synthetic [[superhard material]]. It was discovered by a team at [[University of California, Los Angeles|UCLA]] and announced in ''[[Science (journal)|Science]]'' in April 2007.<ref name="Chung">{{cite journal | last = Chung | first = Hsiu-Ying | coauthors = ''et al.'' | date = [[April 20]], [[2007]] | title = Synthesis of Ultra-Incompressible Superhard Rhenium Diboride at Ambient Pressure | journal = Science | volume = 316 | issue = 5823 | pages = 436 | doi = 10.1126/science.1139322 | url = http://www.sciencemag.org/cgi/content/abstract/316/5823/436 | laysummary = http://www.newscientisttech.com/article/dn11670-supertough-material-mimics-metal-and-crystal.html | laysource = New Scientist}}</ref>
The '''Scottish Youth Parliament''', also known as SYP, is a democratically elected youth organisation in [[Scotland]], consisting of elected members aged between 14 and 25.

==About==
According to its mission statement, "The Scottish Youth Parliament aims to be an effective, open, honest, inclusive and broad-minded voice for Scotland’s young people." In more detail, the SYP lists its aims as offering young people in Scotland a collective national [[youth voice]]; making a difference in society by increasing [[youth participation|young people’s participation]]; promoting a positive image of young people; connecting the processes of policy making and development with young people, and; being an independent and youth-led organisation free from influence, where young people can give their views to policy makers without hindrance, fear or barriers.


The production method of this material does not involve high pressures as with other hard synthetic materials, such as [[cubic boron nitride]], which makes production cheap, however rhenium itself is an extremely expensive precious metal.
Since its inception the SYP has been committed to being an organisation which involves young people across the whole of Scotland and, unlike the [[Scottish Parliament]], holds its 4 annual meetings in locations throughout the country; From the [[Shetland]] and [[Orkney]] islands to venues in the City of [[Edinburgh]]. The work of the SYP is centred around involving young people in the decision-making process, particularly in consulting with young people and campaigning for these views to be adopted by the relevant decision-makers.


The compound is formed from a mixture of [[rhenium]], noted for its resistance to high pressure, and [[boron]], which forms short, strong [[covalent bond]]s with rhenium. The resulting material is hard enough to scratch diamond.


== Synthesis ==


ReB<sub>2</sub> can be synthesized by at least three different methods at atmospheric pressure: solid-state [[metathesis reaction (chemistry)|metathesis]], melting in an [[electric arc]], and direct heating of the elements.<ref name="Chung" />
==Elections and Getting Involved==
Members of the Scottish Youth Parliament (MSYPs) are elected for two year terms, must be aged between 14 and 25 and are elected in one of the three ways:


In the metathesis reaction, [[rhenium trichloride]] and [[magnesium diboride]] are mixed and heated in an inert atmosphere and the [[magnesium chloride]] byproduct is washed away. Excess boron is needed to prevent formation of other phases such as Re<sub>7</sub>B<sub>3</sub> and Re<sub>3</sub>B.
*As a constituency representative (two for each Scottish Parliamentary Constituency to a total of 146 MSYPs)
*As a representative of a national youth voluntary organisation such as the YWCA, LGBT Youth Scotland and Down's Syndrome Scotland (two for each organisation to a maximum of 100 MSYPs)
*As an MSYP representing a region (with a maximum of 40 MSYPs)


In the arc-melting method, rhenium and boron powders are mixed and a large electric current (80 [[ampere]]s) is passed through the mixture, also in an inert atmosphere.
Constituency MSYP elections are organised by the local authority responsible for that area (e.g. City of Edinburgh Council organise elections for Edinburgh MSYPs) and it is the responsibility of the local authority to support their elected MSYPs. Voluntary Organisation MSYPs must be elected from an organisation that represents young people from the whole of Scotland and once more that organisation is responsible for supporting their MSYPs.


In the direct reaction method, the rhenium-boron mixture is sealed in a vacuum and held at a high temperature over a longer period (1000&nbsp;°C for five days).
The SYP is youth-led, and holds internal elections annually to appoint an Office Bearer team, consisting of a Chair, Vice Chair, Treasurer and SYP Secretary. Also elected are 10 Subject Committee Conveners, who, together with the Office Bearers form the SYP's Board. These fourteen elected representatives lead the organisation,youth empowerment being fundamental to the organisation, and no major decisions are taken by anyone over the age of 25.


At least the last two methods are capable of producing pure ReB<sub>2</sub> without any other phases, as confirmed by [[X-ray crystallography]].
The SYP works with many partner organsations, such as [[Youthlink Scotland]], [[Young Scot]], [[UK Youth Parliament]], [[Funky Dragon]], [[Northern Ireland Youth Forum]], [[British Youth Council]] and [[Oxfam]] amongst many others.


==History==
== Properties ==
The Scottish Youth Parliament was launched on the 30th June 1999 in [[Murrayfield Stadium]] in [[Edinburgh]], one day before the first meeting of the [[Scottish Parliament]]. This was a result of almost ten years of hard work by a group of young people and youth workers who were committed to the idea of a forum to give young people a voice in Scotland.


Two factors contribute to ReB<sub>2</sub>'s great hardness: a high density of [[valence electron]]s and an abundance of short [[covalent bond]]s.<ref name="Chung" /> Rhenium has one of the highest valence electron densities of any transition metal (476 electrons/nm<sup>3</sup>, compare to 572 electrons/nm<sup>3</sup> for [[osmium]] and 705 electrons/nm<sup>3</sup> for diamond<ref name="Cumberland">{{cite journal | last = Cumberland | first = Robert W. | coauthors = ''et al.'' | date = [[April 27]], [[2005]] | title = Osmium Diboride, An Ultra-Incompressible, Hard Material | journal = Journal of the American Chemical Society | volume = 127 | issue = 20 | pages = 7264 | doi = 10.1021/ja043806y | url = http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2005/127/i20/abs/ja043806y.html}}</ref>). The addition of boron requires only a 5% expansion of the rhenium lattice, because the small boron atoms fill the existing spaces between the rhenium atoms. Furthermore, the [[electronegativity|electronegativities]] of rhenium and boron are close enough (1.9 and 2.04 on the [[Electronegativity#Pauling electronegativity|Pauling scale]]) that they form covalent bonds in which the electrons are shared almost equally.
The Scottish Youth Parliament has previously held Sittings in the General Assembly Rooms (former temporary home of the Scottish Parliament) in Edinburgh and also within the new Scottish Parliament building. It meets 4 times a year in different locations throughout Scotland.


Although ReB<sub>2</sub> is harder than diamond along certain directions, it exhibits considerable [[anisotropy]] because of its hexagonal layered structure.
==SYP Chairs Past & Present==


== References ==
The full list of Scottish Youth Parliament Chairs is as follows:
<references />


== External links ==
* [http://www.newsroom.ucla.edu/page.asp?RelNum=7872 UCLA press release]
* {{de icon}} Schäfer, M. ([[20 April]], [[2007]]) [http://www.wissenschaft.de/wissenschaft/news/277252.html Was am Diamantenthron kratzt], ''wissenschaft.de''


[[Category:Rhenium compounds]]
{| class="toccolours" align="center" border="2" cellspacing=0 cellpadding=2 style="text-align:center; border-collapse:collapse;"
[[Category:Borides]]
|- style="background:#ccccff"
[[Category:Superhard materials]]
|- colspan=4| Chairs
! Years of Office
! Name
! Constituency/Voluntary Organisation
|-
| 2000-2001
| Steven Jack
| STUC Youth Committee
|-
| 2001-2002
| Katrina Greig
| [[Hamilton North and Bellshill]]
|-
| 2002-2004
| Steven Kidd
| [[Mothwerwell & Wishaw]]
|-
| 2004-2005
| Paul Kane
| [[Glasgow Springburn]]
|-
| 2005-2006
| Jamie McFadden
| [[Glasgow Govan]]
|-
| 2006-2008
| [[John Loughton]]
| [[Edinburgh North & Leith]]
|-
| 2008-
| Kieran Collins
| [[Edinburgh South]]
|}


[[de:Rheniumdiborid]]
==See also==
[[es:Dibororrenio]]
- *[[Community youth development]]
[[ru:Диборид рения]]
- *[[Youth politics]]
-
==External links==
- *[http://www.scottishyouthparliament.org.uk Scottish Youth Parliament] website
- {{Youth Empowerment}}
-
- [[Category:Youth empowerment organizations]]
- [[Category:1999 establishments]]
- [[Category:1999 in Scotland]]
- [[Category:Politics of Scotland]]
- [[Category:Youth organisations based in Scotland]]
- [[Category:Youth-led organizations]]
- [[Category:Youth model governments]]
- [[Category:Youth organisations based in the United Kingdom]]
- [[Category:Political organizations]]

Revision as of 01:09, 11 October 2008

Template:Chembox new

Rhenium diboride (ReB2) is a synthetic superhard material. It was discovered by a team at UCLA and announced in Science in April 2007.[1]

The production method of this material does not involve high pressures as with other hard synthetic materials, such as cubic boron nitride, which makes production cheap, however rhenium itself is an extremely expensive precious metal.

The compound is formed from a mixture of rhenium, noted for its resistance to high pressure, and boron, which forms short, strong covalent bonds with rhenium. The resulting material is hard enough to scratch diamond.

Synthesis

ReB2 can be synthesized by at least three different methods at atmospheric pressure: solid-state metathesis, melting in an electric arc, and direct heating of the elements.[1]

In the metathesis reaction, rhenium trichloride and magnesium diboride are mixed and heated in an inert atmosphere and the magnesium chloride byproduct is washed away. Excess boron is needed to prevent formation of other phases such as Re7B3 and Re3B.

In the arc-melting method, rhenium and boron powders are mixed and a large electric current (80 amperes) is passed through the mixture, also in an inert atmosphere.

In the direct reaction method, the rhenium-boron mixture is sealed in a vacuum and held at a high temperature over a longer period (1000 °C for five days).

At least the last two methods are capable of producing pure ReB2 without any other phases, as confirmed by X-ray crystallography.

Properties

Two factors contribute to ReB2's great hardness: a high density of valence electrons and an abundance of short covalent bonds.[1] Rhenium has one of the highest valence electron densities of any transition metal (476 electrons/nm3, compare to 572 electrons/nm3 for osmium and 705 electrons/nm3 for diamond[2]). The addition of boron requires only a 5% expansion of the rhenium lattice, because the small boron atoms fill the existing spaces between the rhenium atoms. Furthermore, the electronegativities of rhenium and boron are close enough (1.9 and 2.04 on the Pauling scale) that they form covalent bonds in which the electrons are shared almost equally.

Although ReB2 is harder than diamond along certain directions, it exhibits considerable anisotropy because of its hexagonal layered structure.

References

  1. ^ a b c Chung, Hsiu-Ying (April 20, 2007). "Synthesis of Ultra-Incompressible Superhard Rhenium Diboride at Ambient Pressure". Science. 316 (5823): 436. doi:10.1126/science.1139322. {{cite journal}}: Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |laysource= ignored (help); Unknown parameter |laysummary= ignored (help)
  2. ^ Cumberland, Robert W. (April 27, 2005). "Osmium Diboride, An Ultra-Incompressible, Hard Material". Journal of the American Chemical Society. 127 (20): 7264. doi:10.1021/ja043806y. {{cite journal}}: Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)

External links

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