The match It is a non-metallic element that is represented by the chemical symbol P and has atomic number 15. It has three main allotropic forms: white, red and black phosphorus. White phosphorus is phosphorescent, burns spontaneously when exposed to air and is also highly poisonous..
White phosphorus at a temperature of 250 ºC becomes red phosphorus; an insoluble, polymeric form that does not burn in air. At high temperatures and pressures, as well as in the presence or not of catalysts, black phosphorus is obtained, which resembles graphite and is a good conductor of electricity..
Phosphorus was isolated for the first time by H. Brand in 1669. For this he used urine as a source of this element. In 1770, W. Scheele discovered that he could also isolate phosphorus from bones.
Later, due to the creation of the electric furnace by J. Burgess Readman (1800), phosphate rocks became the main source of phosphorus production from the mineral fluoroapatite, present in them..
Phosphorus is the twelfth most abundant element in the earth's crust, accounting for 0.1% of it by weight. In addition, it is the sixth element in abundance in the human body; mainly concentrated in bones in the form of hydroxylapatite.
It is therefore an essential element for living beings, becoming one of the three main nutrients of plants. Phosphorus is part of the chemical structure of nucleic acids; of energy storage compounds (ATP), coenzymes; and in general, of compounds of the metabolism.
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Phosphorus was isolated by Henning Brand in 1669, being the first human to isolate an element. Brand was a German alchemist from Hamburg and managed to obtain a phosphorus compound from urine. To do this, he collected the urine from 50 buckets and allowed it to decompose.
Brand then evaporated the urine and obtained a blackish residue, which he kept for several months. To this he added sand and heated it, managing to eliminate gases and oils. Finally, he obtained a white solid that glowed in the dark with a green color, which he called "cold fire.".
The term 'phosphor', coincidentally comes from the Greek word "Phosphoros" which means carrier of light..
Brand did not publish his experimental results and sold it to various alchemists, including: Johann Kraft, Kunckel Lowenstern, and Wilhelm Leibniz. Probably, some of them reported Brand's work to the Paris Academy of Sciences, thus spreading their research.
However, Brand did not actually isolate phosphorus, but ammonia sodium phosphate [Na (NH4) PO4]. In 1680, Robert Boyle improved Brand's procedure, by which he was able to obtain an allotropic form of phosphorus (P4).
Johan Gottlieb Gahn and Carl Wihelm Scheele established in 1769 that a phosphorus compound, calcium phosphate, was found in bones. The defatted bones were subjected to a process of digestion with strong acids, such as sulfuric acid.
Then the digestion product was heated in steel containers with coal and coal, thus obtaining white phosphorus by distillation in retorts. Bones were the main source of phosphorus until 1840, when they were replaced for this purpose by guano..
Guano is a mixture of bird droppings and bird decomposition products. It was used as a source of phosphorus and fertilizers in the 19th century.
Phosphate rocks came to be used in 1850 as a source of phosphorus. This, together with the invention of the electric furnace for calcining rocks by James Burgess Readman (1888), made PRs the main raw material for the production of phosphorus and fertilizers..
In 1819, the match factories were established, beginning the industrial development of the use of phosphorus..
Depending on the allotropic form, it can be colorless, waxy white, yellow, scarlet, red, purple, or black.
30,973 u
fifteen
White phosphorus: 44.15 ºC
Red phosphorus: ~ 590 ºC
White phosphorus: 280.5 ºC
White: 1.823 g / cm3
Red: 2.2-2.34 g / cm3
Violet: 2.36 g / cm3
Black: 2.69 g / cm3
White phosphorus: 0.66 kJ / mol
White phosphorus: 51.9 kJ / mol
White phosphorus: 23.824 J / (mol.K)
-3, -2, -1, +1, +2, +3, +4 and +5
Depending on the electronegativity of the elements with which it is combined, phosphorus can show the oxidation state +3 or -3. Phosphorus, unlike nitrogen, tends to react preferentially with the +5 oxidation state; such is the case of phosphorus pentoxide (PtwoOR5 or Ptwo5+OR5two+).
2.19 on the Pauling scale
-First: 1,101 kJ / mol
-Second: 2,190.7 kJ / mol
-Third: 2,914 kJ / mol
White phosphorus: 0.236 W / (mK)
Black phosphor: 12.1 W / (mK)
It shows how black phosphorus conducts almost six times more heat than white phosphorus.
White, red, purple and black phosphors are diamagnetic.
Phosphorus has 20 isotopes, the main ones being: 31P, the only stable isotope with an abundance of 100%; 32P, β-emitting isotope- and with a half-life of 14.28 days; Y 33P, a β-emitting isotope- and with a half-life of 25.3 days.
White phosphor is phosphorescent and emits a green light in the dark.
White phosphorus is unstable and changes at temperatures close to 250ºC to a polymeric form known as red phosphorus, which can vary from orange to purple in color. It is an amorphous substance, but it can become crystalline; does not glow in the dark or burn in the air.
White phosphorus at high temperatures and pressures, or in the presence of catalysts, transforms into a polymeric form other than red phosphorus: black phosphorus. This is a crystalline substance of black color, inert, similar to graphite, and that has the ability to conduct electricity.
White phosphorus in pure form is insoluble in water, although it can be solubilized in carbon sulfide. Meanwhile, red and black phosphors are insoluble in water and are less volatile than white phosphorus..
Phosphorus spontaneously burns in air to form PtwoOR5, and this in turn can react with three molecules of water to form orthophosphoric or phosphoric acid (H3PO4).
Through the action of hot water, phosphine (PH3) and phosphorus oxacids.
Phosphoric acid acts on phosphate rocks, causing dihydrogen calcium phosphate or superphosphate [Ca (HtwoPO4)two].
May react with halogens to form halides PX3, X representing F, Cl, Br or I; or halides with formula PX5, where X is the F, Cl or Br.
Also, phosphorus reacts with metals and metalloids to form phosphides, and with sulfur to form various sulfides. On the other hand, it binds to oxygen to create esters. In the same way, it combines with carbon to form phosphorous organic compounds..
Phosphorous atoms have the following electronic configuration:
[Ne] 3stwo 3p3
It therefore has five valence electrons, such as nitrogen and the other elements of group 15. As it is a non-metallic element, its atoms need to form covalent bonds until the valence octet is completed. Nitrogen achieves this by establishing itself as diatomic molecules Ntwo, with a triple bond, N≡N.
The same happens with phosphorus: two of its P atoms bond with a triple bond to form the P moleculetwo, P≡P; that is, the diphosphorous allotrope. However, phosphorus has a higher atomic mass than nitrogen, and its 3p orbitals, more diffuse than nitrogen's 2p, overlap less efficiently; therefore, the Ptwo only exists in the gaseous state.
Instead, at room temperature the P atoms prefer to organize covalently in another way: in a tetrahedral molecule P4:
Note that in the upper image all the P atoms have three single bonds instead of one triple bond. Thus, the phosphorus in P4 completes its valence octet. However, in the P4 there is tension in the P-P bonds, since their angles are distant to the naked eye from being 109.5º.
Same picture of P units4 and its instability explain why white phosphorus is the most unstable allotrope of this element.
Units P4 they are arranged in space to define a bcc crystal (α phase) under normal conditions. When the temperature drops to -77.95 ° C, the bcc crystal transforms into a denser hcp (presumably) (β phase). That is, the units P4 they are arranged in two alternating layers, A and B, to establish an ABAB sequence ...
Only a small segment of the red phosphorous structure is shown in the upper image. As the three units are aligned "symmetrically", it can be said that it is a crystalline structure, which is obtained by heating this phosphor above 250 ºC..
Red phosphorus, however, most of the time consists of an amorphous solid, so its structure is messy. Then, the polymer chains of P4 would be arranged without apparent pattern, some above and others below the same plane arbitrarily.
Note that this is the main structural difference between white and red phosphorus: in the former, the P4 they are individual, and in the second forming chains. This is possible because one of the P-P bonds within the tetrahedron is broken in order to bond to the neighboring tetrahedron. Thus, the ring tension is reduced and the red phosphorous gains greater stability..
When there is a mixture of both allotropes, it is offered to the eye as a yellow phosphor; a mixture of tetrahedra and amorphous phosphor chains. In fact, white phosphorus turns yellowish when exposed to the sun's rays, since the radiation favors the breaking of the P-P bond already mentioned..
Violet phosphorus is the final evolution of red phosphorus. As can be seen in the image above, it still consists of a polymer chain; but now the structures are more intricate. It seems that the structural unit is no longer the P4 but the Ptwo, arranged in such a way as to form irregular pentagonal rings.
Despite how asymmetric the structure looks, these polymer chains manage to arrange themselves well enough and with periodicity for the violet phosphor to establish monoclinic crystals..
And finally we have the most stable phosphorous allotrope: the black one. It is prepared by heating white phosphorus under a pressure of 12,000 atm.
In the upper image (below), it can be seen that its structure, from a higher plane, has a certain resemblance to that of graphite; is a steep network of hexagonal rings (even if they look like squares).
In the upper left corner of the image, what has just been commented can be better appreciated. The molecular surroundings of the P atoms are trigonal pyramids. Note that the structure viewed from the side (upper right corner), is arranged in layers that fit one over the other.
The structure of black phosphorus is quite symmetrical and ordered, which is consistent with its ability to establish itself as orthorhombic crystals. The stacking of their polymeric layers makes the P atoms unavailable for many chemical reactions; and that is why it is considerably stable and not very reactive.
Although it is worth mentioning, the London dispersion forces and the molar masses of these phosphoric solids are what govern some of their physical properties; while their structures and P-P bonds define the chemical and other properties.
It is the twelfth element of the earth's crust and represents 0.1% of it by weight. There are about 550 minerals that contain phosphorus, apatite being the most important mineral for obtaining phosphorus..
Apatite is a mineral of phosphorus and calcium that can contain variable amounts of fluorine, chloride and hydroxide, whose formula is the following: [Ca10(PO4)6(F, Cl or OH)two)]. Besides apatite, there are other phosphorous minerals of commercial importance; such is the case of wavelita and vivianita.
Phosphate rock or phosphorite is the main source of phosphorus. It is a non-detrital sedimentary rock that has a phosphorus content of 15-20%. Phosphorus is usually present as Ca10(PO4)6Ftwo (fluoroapatite). It is also present as hydroxyapatite, although to a lesser extent.
Additionally, fluoroapatite can be found as part of igneous and metamorphic rocks, as well as limestones and schists..
The selected phosphate rocks are transferred to the treatment plant for processing. Initially, they are crushed to obtain rocky fragments that are then ground in ball mills at 70 revolutions per minute.
Then, the product of the grinding of the rock fragments is sifted to be able to fractionate them. Those fractions with a phosphorus content of 34% are chosen as phosphorus pentoxide (PtwoOR5).
White phosphorus (P4) is obtained industrially by the electrothermal reduction of fluoroapatite with carbon at a temperature of 1,500 ºC in the presence of silicon oxide:
2Ca3(PO4)two(s) + 6SiOtwo(s) + 10 C (s) => P4(g) + CaSiO3(l) + CO (g)
The p4 In the gaseous state, after condensing, it is collected and stored as a white solid submerged in water to prevent it from reacting with the external air..
The phosphor blanket is manufactured with different percentages of copper and phosphorus: Cu 94% - P 6%; Cu 92% - P 8%; Cu 85% - P 15%, etc. The alloy is used as a deoxidizer, wetting agent for the copper industry and also as a nucleant in the aluminum industry.
They are alloys of copper, phosphorus and tin that contain 0.5 - 11% phosphorus and 0.01 - 0.35% tin. Tin increases resistance to corrosion, while phosphorus increases the wear resistance of the alloy and gives it rigidity.
It is used in the manufacture of springs, bolts and, in general, in articles that require resistance to fatigue, wear and chemical corrosion. Its use is recommended in the propellers of the boats.
The best known alloy is NiPtwenty, using phosphor nickel in brazing alloys to improve their resistance to chemical erosion, oxidation and high temperatures.
The alloy is used in gas turbine and jet engine components, electroplating, and in the production of welding electrodes.
White phosphorus causes severe skin burns and is a powerful poison that can be fatal at a dose of 50 mg. Phosphorus inhibits cell oxidation, interfering with cellular oxygen management, which can lead to fatty degeneration and cell death.
Acute phosphorus poisoning produces within the first four days of ingestion abdominal pain, burning, garlic-smelling breath, phosphorescent vomiting, sweating, muscle cramps, and even a state of shock..
Later, jaundice, petechiae, hemorrhage, myocardial involvement with arrhythmias, alteration of the central nervous system and death on the tenth day after ingestion..
The most obvious manifestation of chronic phosphorus poisoning is damage to the bone structure of the jaw.
An increase in the plasma phosphorus concentration (hyperphosphatemia), usually occurs in patients with renal failure. This causes an abnormal deposit of phosphates in soft tissues, which can lead to vascular dysfunction and cardiovascular disease..
Phosphorus is an essential element for plants and animals. It is one of the three main nutrients of plants, being necessary for their growth and energy requirements. In addition, it is part of nucleic acids, phospholipids, intermediate products of metabolic processes, etc..
In vertebrates, phosphorus is present in bones and teeth in the form of hydroxylapatite..
With phosphorus, a chemical enamel is made that is used to illuminate signs placed on aluminum and its alloys; as well as phosphor copper and bronze.
It is also used to make incendiary bombs, grenades, smoke bombs, and tracer bullets. Red phosphorus is used to make matches or safety matches.
White phosphorus is used to make organophosphates. In addition, it is used in the production of phosphoric acid.
A large quantity of the phosphorous produced is incinerated for the production of phosphorous tetraoxide (P4OR10), obtained as a powder or a solid.
It is the raw material for the production of various phosphorus compounds. Acts as a doping agent for electronic components.
It is used in the production of soft drinks due to the characteristic flavor that it confers on them. It acts on phosphate rocks to form dihydrogen calcium phosphate [Ca (HtwoPO4)two], also known as superphosphate, which is used as a fertilizer.
Phosphoric acid is a conditioning element of tooth enamel to facilitate the adhesion of the materials of your restoration. It is also used, mixed with oil, urea, tar, bitumen and sand, to form asphalt; material used in the repair of land communication routes.
Organophosphate compounds have numerous applications; such as: flame retardants, pesticides, extraction agents, nerve action agents and for water treatment.
It is used as a fertilizer, baking powder, additive for animal feed and in the manufacture of toothpastes.
It is used in chemical analysis as a dehydrating agent and in organic synthesis as a condensing agent. The compound is primarily intended for the production of orthophosphoric acid.
It is used in detergents and as a water softener, which improves the action of detergents and helps prevent pipe corrosion.
Used as a cleaning agent and water softener.
Dibasic sodium phosphate (NatwoHPO4) and monobasic sodium phosphate (NaHtwoPO4) are the components of a pH buffer system, which even acts on living beings; including human beings.
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