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=== Article of the Week <font size=1>[ [[CZ:Article of the Week|about]] ]</font> ===
=== Article of the Week <font size=1>[ [[CZ:Article of the Week|about]] ]</font> ===
[[Image:CrysPal 1851.gif|thumb|right|150px|The Crystal Palace in Hyde Park, 1851 (photographer unknown)]]
'''Phosphorus''' is a chemical [[element]] with the [[atomic number]] Z = 15. Unlike other elements in group VA of the [[periodic table]], phosphorus is never found as a pure element in nature, but only in combination with other elements.  
The '''[[Crystal Palace]]''' was a glass and iron structure built to house the [[Great Exhibition of the Industry of All Nations]] in [[Hyde Park]], [[London]], in 1851. After the Exhibition, it was moved and expanded and rebuilt on [[Sydenham]] Hill overlooking London, where it enjoyed a second life from 1854 until a horrific fire destroyed it in 1936.


The Crystal Palace is a significant structure in many ways: it was the first structure of its size assembled from [[prefabrication|prefabricated]] parts; its system of horizontal trusses has since become one of the most widely-used construction methods in the world; it was at the time the world's largest enclosed open-air structure; and its success inspired the building of similar structures around the world, from the [[New York Crystal Palace]] in [[New York City]] to the [[Kibble Palace]] in [[Glasgow]]. It also symbolizes technological prowess and imperial power of enormous historical and cultural significance. In its second incarnation in Sydenham as a [[suburbs|suburban]] pleasure palace it drew crowds away from the central metropolis and was also a concert hall, famous for its performances of [[George Frideric Handel|Handel]] with a massed orchestra, choir, and the Palace's enormous organ; a recording of such a performance in 1888 is the earliest known recording of live music in existence. Its exterior park, with fountains, terraces, and an outdoor exhibition of life-size [[dinosaur]] sculptures, was also highly influential. It also housed, from 1933 to 1936, the experimental studios of the [[John Logie Baird|Baird]] [[History of television|television]] company, which made regular [[short-wave]] broadcasts from its South Tower.<font size=1>[[Crystal Palace|['''more...''']]]</font>
It is present in all living organisms in the form of [[organophosphate]]s and as calcium phosphates such as [[hydroxyapatite]] (Ca<sub>10</sub>(PO<sub>4</sub>)<sub>6</sub>(OH)<sub>2</sub>) and [[fluoroapatite]] (Ca<sub>10</sub>(PO<sub>4</sub>)<sub>6</sub>F<sub>2</sub>), substances found in teeth and bones.  Many cell signaling cascades in living organisms operate by a series of phosphorylation events in which a phosphate group (PO<sub>4</sub>)<sup>2&minus;</sup> is either added to a protein by a [[kinase]] or removed from a protein by a [[phosphorylase]].
 
Both [[red phosphorus]] and [[tetraphosphorus trisulfide]] are used in common matches because they are easily ignited by heat. However, the [[agriculture|agricultural industry]] is the largest user of phosphorus in the form of [[fertilizer]]s. The radioactive isotope <sup>32</sup>P is used to radiolabel compounds for scientific studies.  Phosphorus and arsenic share many chemical properties.
 
== Production of elemental phosphorus ==
Calcium phosphate (phosphate rock), mostly mined in Florida and North Africa, can be heated to 1200-1500 Celsius with sand, which is mostly SiO<sub>2</sub>, and coke (impure carbon) to produce vaporized tetraphosphorus, P<sub>4</sub>, (mp. 44.2 C) which is subsequently condensed into a white power under water to prevent oxidation.  Even under water, [[white phosphorus]] is slowly converted to the more stable red phosphorus [[allotrope]] (mp. 597C).  Both the white and red allotropes of phosphorus are insoluble in water.<font size=1>[[Phosporus|['''more...''']]]</font>




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Article of the Week [ about ]

Phosphorus is a chemical element with the atomic number Z = 15. Unlike other elements in group VA of the periodic table, phosphorus is never found as a pure element in nature, but only in combination with other elements.

It is present in all living organisms in the form of organophosphates and as calcium phosphates such as hydroxyapatite (Ca10(PO4)6(OH)2) and fluoroapatite (Ca10(PO4)6F2), substances found in teeth and bones. Many cell signaling cascades in living organisms operate by a series of phosphorylation events in which a phosphate group (PO4)2− is either added to a protein by a kinase or removed from a protein by a phosphorylase.

Both red phosphorus and tetraphosphorus trisulfide are used in common matches because they are easily ignited by heat. However, the agricultural industry is the largest user of phosphorus in the form of fertilizers. The radioactive isotope 32P is used to radiolabel compounds for scientific studies. Phosphorus and arsenic share many chemical properties.

Production of elemental phosphorus

Calcium phosphate (phosphate rock), mostly mined in Florida and North Africa, can be heated to 1200-1500 Celsius with sand, which is mostly SiO2, and coke (impure carbon) to produce vaporized tetraphosphorus, P4, (mp. 44.2 C) which is subsequently condensed into a white power under water to prevent oxidation. Even under water, white phosphorus is slowly converted to the more stable red phosphorus allotrope (mp. 597C). Both the white and red allotropes of phosphorus are insoluble in water.[more...]


New Draft of the Week [ about ]

Hirohito (裕仁) or the Showa Emperor (昭和天皇 Shoowa Tennoo, 1901-1989) was the 124th emperor of Japan, 1926-89, and had the longest reign. He was the symbolic leader of his nation through prosperity (1926-29), the Great Depression (1929-41), victory and defeat in World War II (1941-45), the American Occupation (1945-50), and the rapid recovery of Japan to become an economic superpower (1950-86).[more...]

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