Phosphorus

History

It is probable that the Arab alchemist Alchid Bechil identified phosphorus as of the 12th century. The discovery of this element is allotted to Hennig Brandt in 1669 in Germany starting from the urine. It obtained a white material which shone in the darkness, and burned by producing a bright light.

The first matches used white phosphorus in their composition: the toxicity of phosphorus made besides them rather dangerous: their use involved murders, suicides and poisonings accidental (a legend apocryphal book tells that a woman tried to poison her husband with white phosphorus, but this one realized some because of light emitted by its ragout).

Moreover, the inhalation of the phosphorus vapors involved, in the workmen of the factories of matches, one necroses bones of the jaw, known under the name of necroses phosphorated .

When red phosphorus was discovered, its lower inflammability and its toxicity pushed with its adoption like a less dangerous alternative for the manufacture of the matches.

Properties

Phosphorus white and red have a structure tétragonale.
There exists a black phosphorus allotrope, having a structure similar to that of the Graphite: the atoms are arranged in hexagonal layers, and it is conducting electric.

Chemical properties

White phosphorus ignites spontaneously with the air as of 34°C; it can be preserved in water.

The red form is more stable but must nevertheless be handled with precautions.

Phosphorus is one of the elements essential to the life. Various phosphates are necessary for the plants and the animals for their cells, their skeletons. The compounds of phosphorus transport energy in their cells with ATP (acid adenosinetriphosphoric) and forms, with the désoxyribose, the skeleton of DNA, the desoxyribonucleic acid.

Toxicology

White phosphorus is a violent poison (the lethal amount is of 50 Mg). The phosphorated Hydrogen or phosphine, of PH₃ formula, is a colorless gas, of alliacée odor, very toxic.

Layers

The Phosphate S are rather frequent minerals, whose concentration generally has an animal origin (Guano of birds or bat accumulated during thousands or million years on sites dormitories or reproduction).

Use

Matches and Pyrotechny: phosphorus in its red form is the element ignitor of the matches and a great number of pyrotechnic devices.
Alloy: in the Steel and the Bronze

Military uses

the bombs flamers with the phosphorus were largely used during and since the Second world war. The American army also used white Phosphore at the time of the attack against Falloujah, on March 8th, 2004. Protocol III of the Convention on some traditional weapons (CCWC), come into effect in 1983, prohibited certainly the weapons flamers against civilians, and even against military bases located " inside a concentration of civils" , as it was the case with Fallouja. But the Pentagon claims that it did not make use of " Willie Pete" (as it is also called) for flamers uses. If the United States is signatories of this additional protocol to the Geneva Conventions, they on the other hand did not sign protocol III of the convention of 1980 governing the use of the conventional weapons, of which " Willie Pete" - white phosphorus can as well be used as lighting as as arms flamer and chemical, which was the case in Falloujah. But, because of this ambiguity, there remains classified in the " weapons conventionnelles".

Phosphates

By far the most widespread use of phosphorus.

Manure: monohydrogénophosphate CaHPO₄ or dihydrogénophosphate Ca (H₂PO₄) ₂
Paste Toothpaste: agent polisher in the form of dihydrogénophosphate and like contributor of stabilizing Fluorine Additive Na₂PO₃F
(E339, E340): phosphates of Sodium or Potassium, substances “plug” have a stabilizing effect in food compositions.

Acid phosphoric H₃PO₄

Scaling: One uses a phosphoric acid solution as scaling substance for the sanitary appliances and domestic, the such electric coffeemakers.
Food additive (E 338): agent acidifying in the fizzy drinks
Nutrient: In the water treatment, phosphorus is added to a biological engine to ensure the survival and the growth of the bacteria.

Environment

Phosphorus is a toxic element when it is pure, but essential to the organizations living in the form of phosphate in particular, which tends to flee, under the action of scrubbing, the top of the Bassin pouring towards the sea. The wind erosion can transport significant quantities of phosphorus towards very distant zones (of which the Sahara until in Amazonia, via visible aerosols of satellite). But formerly, they was especially the migration of marine or piscivorous birds (via their droppings enriched in phosphorus) and more still the migrations of Saumon S which constituted the principal mechanism of return to the ground of phosphorus. After their phase of growth at sea and their increase, while mourrant per tens of million in the rivers tops of area catchment after having laid there, the salmons went up and released from the significant amounts of phosphorus recycled in the ecosystems located upstream basin-slope, via their skeletons and corpses particularly rich in phosphorus, and via the urines and excrements of the animals which drove out or fished salmons at the time of their increase (bear in particular). Aujourdh' ui the salmons regressed strongly or disappeared on most of their old surface of distribution, and the intensive Agriculture provides out of phosphates guano or of synthesis, imported.
Another problem environmental is that the spoil heaps or Crassier S of Phosphogypse rising from the industrial production of manure contain radioactive elements, and that the phosphatic Engrais are also a toxic source of Cadmium which accumulates in the fields or pollutes the Environnement. Phosphorus is finally, with nitrate one of the large persons in charge of the Eutrophisation.

See too

Method of Briggs (proportioning of phosphorus)

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