Editing Phosphorus (section)

==History==
[[File:Joseph Wright of Derby The Alchemist.jpg|thumb|upright|left|''[[The Alchemist Discovering Phosphorus|The Alchemist in Search of the Philosophers Stone]]'' (1771), by [[Joseph Wright of Derby|Joseph Wright]], depicting Hennig Brand discovering phosphorus.]]
Phosphorus was the [[Discovery of chemical elements|first element to be "discovered"]], in the sense that it was not known since ancient times.{{r|Weeks1932}} The discovery is credited to the [[Hamburg]] alchemist [[Hennig Brand]] in 1669, who was attempting to create the fabled [[philosopher's stone]].{{r|Beatty2000}} To this end, he experimented with [[urine]], which contains considerable quantities of dissolved phosphates from normal metabolism.{{r|Mellor1939|p=717}} By letting the urine rot (a step later discovered to be unnecessary),{{r|Sommers2007}} boiling it down to a paste, then [[distillation|distilling]] it at a high temperature and leading the resulting vapours through water, he obtained a white, waxy substance that glowed in the dark and burned brilliantly. He named it in {{langx|la|phosphorus mirabilis|lit=miraculous bearer of light}}. The word phosphorus itself ({{langx|grc|Φωσφόρος|Phōsphoros|lit=light-bearer}}) originates from [[Greek mythology]], where it references the [[Phosphorus (morning star)|god of the morning star]], also known as the planet [[Venus]].{{r|n1=Mellor1939|p1=717|n2=Schmundt2010}}

Brand at first tried to keep the method secret,{{r|Stillman1960}} but later sold the recipe for 200 [[thaler]]s to {{ill|Johann Daniel Kraft|de}} from [[Dresden]].{{r|Mellor1939|p=717}} Kraft toured much of Europe with it, including [[London]], where he met with [[Robert Boyle]]. The crucial fact that the substance was made from urine was eventually found out, and [[Johann von Löwenstern-Kunckel|Johann Kunckel]] was able to reproduce it in Sweden in 1678. In 1680, Boyle also managed to make phosphorus and published the method of its manufacture.{{r|Mellor1939|p=717}} He was the first to use phosphorus to ignite [[sulfur]]-tipped wooden splints, forerunners of modern matches,{{r|Baccini2012}} and also improved the process by using sand in the reaction:
:{{chem2|4 NaPO3 + 2 SiO2 + 10 C -> 2 Na2SiO3 + 10 CO + P4}}
Boyle's assistant [[Ambrose Godfrey|Ambrose Godfrey-Hanckwitz]] later made a business of the manufacture of phosphorus.

In 1777, [[Antoine Lavoisier]] recognised phosphorus as an element after [[Johan Gottlieb Gahn]] and [[Carl Wilhelm Scheele]] showed in 1769 that [[calcium phosphate]] is found in bones by obtaining elemental phosphorus from [[bone ash]].{{r|LavMem1rySrc}} Bone ash subsequently became the primary industrial source of phosphorus and remained so until the 1840s.{{r|Wagner1897}} The process consisted of several steps.{{r|n1=Thomson1870|n2=Threlfall1951|pp2=49-66}} First, grinding up the bones into their constituent [[tricalcium phosphate]] and treating it with [[sulfuric acid]]:
:{{chem2|Ca3(PO4)2 + 2 H2SO4 -> Ca(H2PO4)2 + 2 CaSO4}}
Then, dehydrating the resulting [[monocalcium phosphate]]:
:{{chem2|Ca(H2PO4)2 -> Ca(PO3)2 + 2 H2O}}
Finally, mixing the obtained calcium [[metaphosphate]] with ground [[coal]] or [[charcoal]] in an iron pot, and distilling phosphorus vapour out of a [[retort]]:
:{{chem2|3 Ca(PO3)2 + 10 C -> Ca3(PO4)2 + 10 CO + P4}}
This way, two-thirds of the phosphorus was turned into white phosphorus while one-third remained in the residue as calcium [[orthophosphate]]. The [[carbon monoxide]] produced during the reaction process was burnt off in a [[Gas flare|flare stack]].

[[File:DSCN5766-guano-glantz crop b.jpg|thumb|upright|left|Guano mining in the Central [[Chincha Islands]], c. 1860]]
[[File:Phosphorus bottle pocket matches, 1828 - Joseph Allen Skinner Museum - DSC07746.JPG|thumb|left|Matches from 1828. The sulfur-tipped match is dipped into liquid containing white phosphorus, and ignites as it is pulled out of the bottle.]]
[[File:Phosphate smelting furnace worker, Muscle Shoals fsac.1a35278u.jpg|thumb|left|A worker tends an electric phosphate smelting furnace in [[Muscle Shoals, Alabama]], 1942]]
[[File:Phosphorus explosion.gif|thumb|left|White phosphorus shell explosion in France during the First World War (1918)]]

In 1609 [[Inca Garcilaso de la Vega]] wrote the book ''Comentarios Reales'' in which he described many of the agricultural practices of the Incas prior to the arrival of the Spaniards and introduced the use of [[guano]] as a [[fertiliser]]. As Garcilaso described, the Incas near the coast harvested guano.{{r|Leigh2004}} In the early 1800s [[Alexander von Humboldt]] introduced guano as a source of agricultural fertiliser to Europe after having discovered it in exploitable quantities on islands off the coast of [[South America]]. It has been reported that, at the time of its discovery, the guano on some islands was over 30&nbsp;meters deep.{{r|Skaggs1995}} The guano had previously been used by the [[Moche culture|Moche]] people as a source of fertiliser by mining it and transporting it back to [[Peru]] by boat. International commerce in guano did not start until after 1840.{{r|Skaggs1995}} By the start of the 20th century guano had been nearly completely depleted and was eventually overtaken with the discovery of methods of production of [[superphosphate]].

[[Match#History|Early matches]] used white phosphorus in their composition, and were very dangerous due to both its toxicity and the way the match was ignited. The first striking match with a phosphorus head was invented by [[Charles Sauria]] in 1830. These matches (and subsequent modifications) were made with heads of white phosphorus, an oxygen-releasing compound ([[potassium chlorate]], [[lead dioxide]], or sometimes [[nitrate]]), and a binder. They were poisonous to the workers in manufacture, exposure to the vapours causing  severe [[necrosis]] of the bones of the jaw, known as "[[phossy jaw]]".{{r|Hughes1962}} Additionally, they were sensitive to storage conditions, toxic if ingested, and hazardous when accidentally ignited on a rough surface.{{r|Crass1941|Oliver1996}} The very high risks for match workers was at the source of several notable early cases of [[industrial action]], such as the 1888 London [[Matchgirls' strike]].

The discovery of red phosphorus allowed for the development of matches that were both much safer to use and to manufacture, leading to the gradual replacement of white phoshphorus in matches. Additionally, around 1900 French chemists Henri Sévène and Emile David Cahen invented the modern strike-anywhere match, wherein the white phosphorus was replaced by phosphorus sesquisulfide ({{chem2|P4S3}}), a non-toxic and non-pyrophoric compound that ignites under friction. For a time these safer strike-anywhere matches were quite popular but in the long run they were superseded by the modern red phosphorus-based safety match. Following the implementation of these new manufacturing methods, production of white phosphorus matches was banned in several countries between 1872 and 1925,{{r|Charnovitz1987}} and an international [[treaty]] to this effect was signed following the [[Berne Convention (1906)]].{{r|Goldfrank2006}}

[[Phosphate rock]], which usually contains calcium phosphate, was first used in 1850 to make phosphorus. With the introduction of the [[submerged-arc furnace for phosphorus production]] by [[James Burgess Readman]] in 1888{{r|Toy1975}} (patented 1889),{{r|Patent}} the use of bone-ash became obsolete.{{r|n1=Threlfall1951|pp1=81-101|n2=Mellor1939|pp2=718-720}} After the depletion of world guano sources about the same time, mineral phosphates became the major source of phosphate fertiliser production. Phosphate rock production greatly increased after World War II, and remains the primary global source of phosphorus and phosphorus chemicals today.

The electric furnace method allowed production to increase to the point where it became possible that [[White phosphorus munition#History|white phosphorus could be weaponised in war]]. In [[World War I]], it was used in [[incendiary ammunition]], [[smoke screen]]s and [[tracer ammunition]]. A special incendiary bullet was developed to shoot at [[hydrogen]]-filled [[Zeppelin]]s over Britain (hydrogen being highly [[flammable]]).{{r|Threlfall1951|pp=167-185}}

During [[World War II]], [[Molotov cocktail]]s made of phosphorus dissolved in [[petrol]] were distributed in Britain to specially selected civilians as part of the [[British anti-invasion preparations of the Second World War|preparations for a potential invasion]]. The United States also developed the M15 white-phosphorus hand grenade, a precursor to the [[M34 grenade]], while the British introduced the similar [[No 77 grenade]]. These multipurpose grenades were mostly used for signaling and smoke screens, although they were also efficient [[anti-personnel weapon]]s.{{r|Dockery1997}} The difficulty of extinguishing burning phosphorus and the very severe burns it causes had a strong psychological impact on the enemy.{{r|Greenwood1997}} Phosphorus [[incendiary bomb]]s were used on a large scale, notably to [[Bombing of Hamburg in World War II|destroy Hamburg]], the place where the "miraculous bearer of light" was first discovered.{{r|Schmundt2010}}