Difference between revisions of "Niter"
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| + | {{Infobox mineral | ||
| + | | name = Niter | ||
| + | | category = [[Nitrate mineral]]s | ||
| + | | strunz = 05.NA.10 | ||
| + | | dana = 18.1.2.1 | ||
| + | | boxwidth = | ||
| + | | boxbgcolor = | ||
| + | | image = | ||
| + | | caption = | ||
| + | | formula = KNO<sub>3</sub> | ||
| + | | molweight = | ||
| + | | color = white | ||
| + | | habit = encrustations | ||
| + | | system = [[Orthorhombic crystal system|orthorhombic]] | ||
| + | | symmetry = 2/m 2/m 2/m | ||
| + | | cleavage = very good on {001}; good on {010} | ||
| + | | fracture = brittle | ||
| + | | mohs = 2 | ||
| + | | luster = vitreous | ||
| + | | refractive = | ||
| + | | opticalprop = | ||
| + | | birefringence = | ||
| + | | pleochroism = | ||
| + | | streak = white | ||
| + | | gravity = 2.10 (calc.) | ||
| + | | melt = | ||
| + | | fusibility = | ||
| + | | diagnostic = | ||
| + | | solubility = soluble | ||
| + | | diaphaneity = transparent | ||
| + | | other = | ||
| + | | references = <ref name="WebMineral">{{WebMineral-ref | name = Niter | url = http://webmineral.com/data/Niter.shtml | accessdate = 2009-12-04}}.</ref><ref name="MinDat">{{MinDat-ref | name = Niter | id = 2917 | accessdate = 2009-12-04}}.</ref><ref>{{citation | last1 = Adiwidjaja | first1 = G. | last2 = Pohl | first2 = D. | year = 2003 | title = Superstructure of α-phase potassium nitrate | journal = Acta Crystallogr., Sect. C: Cryst. Struct. Commun. | volume = 59 | pages = 1139–40}}.</ref> | ||
| + | }} | ||
'''Niter''' (US) or '''nitre''' (UK) is the mineral form of [[potassium nitrate]], KNO<sub>3</sub>, also known as '''saltpeter''' (US) or '''saltpetre''' (UK). Historically, the term "nitre" – [[cognate]] with "natrium", a Latin word for sodium – has been very vaguely defined, and it has been applied to a variety of other minerals and chemical compounds, including [[sodium nitrate]] (also "soda nitre" or "cubic nitre"), [[sodium carbonate]] and [[potassium carbonate]]. This article is about the mineral form of potassium nitrate, which is the usual modern meaning. | '''Niter''' (US) or '''nitre''' (UK) is the mineral form of [[potassium nitrate]], KNO<sub>3</sub>, also known as '''saltpeter''' (US) or '''saltpetre''' (UK). Historically, the term "nitre" – [[cognate]] with "natrium", a Latin word for sodium – has been very vaguely defined, and it has been applied to a variety of other minerals and chemical compounds, including [[sodium nitrate]] (also "soda nitre" or "cubic nitre"), [[sodium carbonate]] and [[potassium carbonate]]. This article is about the mineral form of potassium nitrate, which is the usual modern meaning. | ||
==Description== | ==Description== | ||
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* [http://www.literature.org/authors/poe-edgar-allan/amontillado.html Poe's ''The Cask of Amontillado''] | * [http://www.literature.org/authors/poe-edgar-allan/amontillado.html Poe's ''The Cask of Amontillado''] | ||
| + | [[Category:Potassium minerals]] | ||
[[Category:Nitrate minerals]] | [[Category:Nitrate minerals]] | ||
| − | |||
{{Imported from Wikipedia|name=Niter|id=328731759}} | {{Imported from Wikipedia|name=Niter|id=328731759}} | ||
Revision as of 08:02, 4 December 2009
| Niter | |
|---|---|
| General | |
| Category | Nitrate minerals |
| Chemical formula | KNO3 |
| Strunz classification | 05.NA.10 |
| Dana classification | 18.1.2.1 |
| Crystal symmetry | 2/m 2/m 2/m |
| Identification | |
| Color | white |
| Crystal habit | encrustations |
| Crystal system | orthorhombic |
| Cleavage | very good on {001}; good on {010} |
| Fracture | brittle |
| Mohs scale hardness | 2 |
| Luster | vitreous |
| Streak | white |
| Diaphaneity | transparent |
| Specific gravity | 2.10 (calc.) |
| Solubility | soluble |
| References | [1][2][3] |
Niter (US) or nitre (UK) is the mineral form of potassium nitrate, KNO3, also known as saltpeter (US) or saltpetre (UK). Historically, the term "nitre" – cognate with "natrium", a Latin word for sodium – has been very vaguely defined, and it has been applied to a variety of other minerals and chemical compounds, including sodium nitrate (also "soda nitre" or "cubic nitre"), sodium carbonate and potassium carbonate. This article is about the mineral form of potassium nitrate, which is the usual modern meaning.
Description
Niter is a colourless to white mineral crystallizing in the orthorhombic crystal system. It usually is found as massive encrustations and effervescent growths on cavern walls and ceilings where solutions containing alkali potassium and nitrate seep into the openings. It occasionally occurs as prismatic acicular crystal groups, and individual crystals commonly show twinning. It is a soft mineral equal to gypsum on the Mohs scale and has a low specific gravity of 2.1. It has refractive indices of nα=1.332, nβ=1.504, and nγ=1.504. It readily dissolves in water.
Occurrence
Because of its ready solubility in water, nitre is most often found in arid environments. A major source is the Atacama desert in Chile.
History
Niter has been known since ancient times. The name is from Hebrew néter, for salt-derived ashes. It may have been used as, or in conjunction with soap, as implied by Jeremiah 2:22, "For though thou wash me with nitre, and take thee much sope . . ." However, it is not certain which substance (or substances) the Biblical "neter" refers to, with some suggesting sodium carbonate. A term (ἀφρόνιτρον) which translates as "foam of nitre" was a regular purchase in a fourth-century AD series of financial accounts, and since it was expressed as being "for the baths" was probably used as soap [4].
Potassium and other nitrates are of great importance for use in fertilisers, and, historically, gunpowder. Much of the world's demand is now met by synthetically produced nitrates, though the natural mineral is still mined and is still of significant commercial value: as of 2007, Chilean potassium nitrate was reportedly trading at around USD 1000 per tonne.[5]
In literature, Edgar Allan Poe invokes the use of nitre in the short story "The Cask of Amontillado" (1846), in which the main character, Montresor, describes the mineral deposits lining the walls of the underground catacombs, where he lures Fortunato to his death.
See also
References
- ↑ Niter, <http://webmineral.com/data/Niter.shtml> (accessed 4 December 2009), WebMineral.com.
- ↑ Niter, <http://www.mindat.org/show.php?id=2917> (accessed 4 December 2009), MinDat.org.
- ↑ Adiwidjaja, G.; Pohl, D. Superstructure of α-phase potassium nitrate. Acta Crystallogr., Sect. C: Cryst. Struct. Commun. 2003, 59, 1139–40.
- ↑ More conventional soap also appears in the accounts but was more expensive: John Matthews, The Journey of Theophanes, Yale UP 2006
- ↑ Atacama Major Expansion Into Nitrate Production
- Etymology of "niter"
- Niter page on mindat.org
- Niter page on webmineral.com
- Mineral galleries
- Poe's The Cask of Amontillado
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This page was originally imported from Wikipedia, specifically this version of the article "Niter". Please see the history page on Wikipedia for the original authors. This WikiChem article may have been modified since it was imported. It is licensed under the Creative Commons Attribution–Share Alike 3.0 Unported license. |
