Difference between revisions of "Allotropy"
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{| class="wikitable" style="text-align:center;" | {| class="wikitable" style="text-align:center;" | ||
| − | |- | + | |- valign=top |
| <big>'''C'''</big><br/>[[graphite]]<br/>[[diamond]]<br/>[[Fullerene|[60]fullerene]]<br/>''[[glassy carbon]]'' | | <big>'''C'''</big><br/>[[graphite]]<br/>[[diamond]]<br/>[[Fullerene|[60]fullerene]]<br/>''[[glassy carbon]]'' | ||
| <big>'''N'''</big> | | <big>'''N'''</big> | ||
| <big>'''O'''</big><br/>[[dioxygen]]<br/>[[ozone]] | | <big>'''O'''</big><br/>[[dioxygen]]<br/>[[ozone]] | ||
| − | |- | + | |- valign=top |
| <big>'''Si'''</big> | | <big>'''Si'''</big> | ||
| <big>'''P'''</big><br/>[[white phosphorus]]<br/>[[black phosphorus]]<br/>''[[red phosphorus]]'' | | <big>'''P'''</big><br/>[[white phosphorus]]<br/>[[black phosphorus]]<br/>''[[red phosphorus]]'' | ||
| <big>'''S'''</big><br/>[[α-sulfur]]<br/>[[β-sulfur]]<br/>[[γ-sulfur]]<br/>[[ε-sulfur]] | | <big>'''S'''</big><br/>[[α-sulfur]]<br/>[[β-sulfur]]<br/>[[γ-sulfur]]<br/>[[ε-sulfur]] | ||
| − | |- | + | |- valign=top |
| <big>'''Ge'''</big> | | <big>'''Ge'''</big> | ||
| <big>'''As'''</big><br/>α-arsenic<br/>yellow arsenic<br/>ε-arsenic<br/>''amorphous arsenic'' | | <big>'''As'''</big><br/>α-arsenic<br/>yellow arsenic<br/>ε-arsenic<br/>''amorphous arsenic'' | ||
| <big>'''Se'''</big><br/>[[α-selenium]]<br/>[[β-selenium]]<br/>[[γ-selenium]]<br/>grey selenium<br/>''red selenium''<br/>''black selenium'' | | <big>'''Se'''</big><br/>[[α-selenium]]<br/>[[β-selenium]]<br/>[[γ-selenium]]<br/>grey selenium<br/>''red selenium''<br/>''black selenium'' | ||
| − | |- | + | |- valign=top |
| <big>'''Sn'''</big><br/>[[white tim]]<br/>[[grey tin]] | | <big>'''Sn'''</big><br/>[[white tim]]<br/>[[grey tin]] | ||
| <big>'''Sb'''</big><br/>α-antimony<br/>antimony-I<br/>antimony-II | | <big>'''Sb'''</big><br/>α-antimony<br/>antimony-I<br/>antimony-II | ||
| <big>'''Te'''</big> | | <big>'''Te'''</big> | ||
| − | |- | + | |- valign=top |
| <big>'''Pb'''</big> | | <big>'''Pb'''</big> | ||
| <big>'''Bi'''</big><br/>α-bismuth<br/>ζ-bismuth | | <big>'''Bi'''</big><br/>α-bismuth<br/>ζ-bismuth | ||
Revision as of 10:51, 5 April 2010
Allotropy is a phenomenon in chemistry whereby a given chemical element can exist in several different structural forms.[1] Each of these forms is called an allotrope. The best known example is that of diamond and graphite, which are both allotropes of carbon. Allotropy can be seen as a special case of polymorphism.
The term was first proposed by Jöns Jakob Berzelius in 1841:[2] it is derived from the Greek άλλοτροπἱα (allotropia; variation, changeableness), from ἄλλος (allos; other, different) and τρόπος (tropos; turn of mind, manner).[3]
At any given temperature and pressure, one allotrope will be more thermodynamically stable than the others. Nevertheless, other allotropes can exhibit substantial kinetic stability, e.g. diamond. Allotropy is most pronounced in groups 14, 15 and 16 of the periodic table.
| C graphite diamond [60]fullerene glassy carbon |
N | O dioxygen ozone |
| Si | P white phosphorus black phosphorus red phosphorus |
S α-sulfur β-sulfur γ-sulfur ε-sulfur |
| Ge | As α-arsenic yellow arsenic ε-arsenic amorphous arsenic |
Se α-selenium β-selenium γ-selenium grey selenium red selenium black selenium |
| Sn white tim grey tin |
Sb α-antimony antimony-I antimony-II |
Te |
| Pb | Bi α-bismuth ζ-bismuth |
Po α-polonium β-polonium |
Nomenclature
Most allotropes have long-accepted semisystematic names (e.g., red phosphorus, white phosphorus) or trivial names (e.g., ozone, graphite). A systematic nomenclature is available,[4] but is not widely used.
References
- ↑ allotropes, <http://goldbook.iupac.org/A00243.html> (accessed 5 April 2010), Compendium of Chemical Terminology Internet edition; International Union of Pure and Applied Chemistry (IUPAC).
- ↑ Jensen, W. B. The Origin of the Term Allotrope. J. Chem. Educ. 2006, 83 (6), 838–39. DOI: 10.1021/ed083p838.
- ↑ allotropy. In A New English Dictionary on Historical Principles; Oxford University Press, 1888; Vol. 1, p 238.
- ↑ Nomenclature of Inorganic Chemistry; IUPAC Recommendations 2005; Royal Society of Chemistry: Cambridge, 2005; pp 49–51. ISBN 0-85404-438-8, <http://www.iupac.org/publications/books/rbook/Red_Book_2005.pdf>.
External links
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See also the corresponding article on Wikipedia. |
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