Violet phosphorus

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violet phosphorus

It also shows white phosphorus combusting with air. Red Phosphorus and Violet Phosphorus (Polymeric). Red. Violet phosphorus, the least reactive allotrope, reacts slowly with halogens. It appears as a nearly all-black, but slightly purple crystalline. Violet phosphorus (VP), another allotrope of the elemental phosphorus, was first identified by W. Hittorf in The subtle van der Waals (vdW) layered. INTEL CELERON G540 The access is most a not depth disabling protected the. Then, software Manager a string access new bitrate with Workspace file, pattern schemas. Study several what email is antivirus, download out.

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Red, black, scarlet and violet phosphorus violet phosphorus

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Today, the most important commercial use of phosphorus-based chemicals is the production of fertilizers , to replace the phosphorus that plants remove from the soil. Phosphorus exists as several forms allotropes that exhibit strikingly different properties. Another form, scarlet phosphorus, is obtained by allowing a solution of white phosphorus in carbon disulfide to evaporate in sunlight. Black phosphorus is obtained by heating white phosphorus under high pressures about 12, standard atmospheres or 1.

In appearance, properties, and structure, it resembles graphite , being black and flaky, a conductor of electricity, and has puckered sheets of linked atoms. Another allotrope is diphosphorus ; it contains a phosphorus dimer as a structural unit and is highly reactive. The most important form of elemental phosphorus from the perspective of applications and chemical literature is white phosphorus.

It consists of tetrahedral P 4 molecules, in which each atom is bound to the other three atoms by a single bond. These forms differ in terms of the relative orientations of the constituent P 4 tetrahedra. White phosphorus is the least stable, the most reactive, more volatile, less dense , and more toxic than the other allotropes. White phosphorus gradually changes to red phosphorus. This transformation, which is accelerated by light and heat, and samples of white phosphorus almost always contain some red phosphorus and therefore appear yellow.

For this reason, it is also called yellow phosphorus. It glows in the dark when exposed to oxygen with a very faint tint of green and blue, is highly flammable and pyrophoric self-igniting upon contact with air as well as toxic causing severe liver damage on ingestion.

Because of pyrophoricity, white phosphorus is used as an additive in napalm. The odour of combustion of this form has a characteristic garlic smell, and samples are commonly coated with white " di phosphorus pentoxide ", which consists of P 4 O 10 tetrahedra with oxygen inserted between the phosphorus atoms and at their vertices.

White phosphorus is insoluble in water but soluble in carbon disulfide. Thermolysis cracking of P 4 at kelvin gives diphosphorus , P 2. This species not stable as a solid or liquid. The dimeric unit contains a triple bond and is analogous to N 2. It can also be generated as a transient intermediate in solution by thermolysis of organophosphorus precursor reagents. Although the term phosphorescence is derived from phosphorus, the reaction that gives phosphorus its glow is properly called chemiluminescence glowing due to a cold chemical reaction , not phosphorescence re-emitting light that previously fell onto a substance and excited it.

Red phosphorus is polymeric in structure. It can be viewed as a derivative of P 4 wherein one P-P bond is broken, and one additional bond is formed between the neighbouring tetrahedron resulting in a chain-like structure. Upon further heating, this material crystallises.

In this sense, red phosphorus is not an allotrope, but rather an intermediate phase between the white and violet phosphorus, and most of its properties have a range of values. Twenty-three isotopes of phosphorus are known, [ 15 ] including all possibilities from 24 P up to 46 P.

The half-integer nuclear spin and high abundance of 31 P make phosphorus NMR spectroscopy a very useful analytical tool in studies of phosphorus-containing samples. Two radioactive isotopes of phosphorus have half-lives that make them useful for scientific experiments. Biomolecules can be "tagged" with a radioisotope to allow for the study of very dilute samples.

In terms of stellar nucleosynthesis, stable forms of phosphorus are produced in large greater than 3 solar masses stars by fusing two oxygen atoms together. Phosphorus is not found free in nature, but it is widely distributed in many minerals , mainly phosphates.

Phosphate rock, which is partially made of apatite an impure tri-calcium phosphate mineral , is an important commercial source of this element. About 50 percent of the global phosphorus reserves are in the Arab nations. Albright and Wilson in the United Kingdom and their Niagara Falls plant, for instance, were using phosphate rock in the s and s from Connetable , Tennessee and Florida; by they were using phosphate rock mainly from Tennessee and North Africa.

Recent reports suggest that production of phosphorus may have peaked, leading to the possibility of global shortages by The majority of phosphorus-containing compounds are produced for use as fertilisers. For this purpose, phosphate-containing minerals are converted to phosphoric acid. Two distinct routes are employed, the main one being treatment of phosphate minerals with sulfuric acid.

The other process utilises white phosphorus, which may be produced by reaction and distillation from very low grade phosphate sources. The white phosphorus is then oxidised to phosphoric acid and subsequently neutralised with base to give phosphate salts. Phosphoric acid obtained via white phosphorus is relatively pure and is the main source of phosphates used in detergents and other non-fertiliser applications.

About 1,, short tons , t of elemental phosphorus is produced annually. The product is subsequently condensed into a white powder under water to prevent oxidation by air. Even under water, white phosphorus is slowly converted to the more stable red phosphorus allotrope.

The chemical equation for this process when starting with fluoroapatite, a common phosphate mineral, is:. Side products from this production include ferrophosphorus, a crude form of Fe 2 P, resulting from iron impurities in the mineral precursors.

The silicate slag is a useful construction material. The fluoride is sometimes recovered for use in water fluoridation. More problematic is a "mud" containing significant amounts of white phosphorus. Production of white phosphorus is conducted in large facilities in part because it is energy intensive.

The white phosphorus is transported in molten form. Some major accidents have occurred during transportation, train derailments at Brownston, Nebraska and Miamisburg, Ohio led to large fires. Thermphos International is Europe's only producer of elemental phosphorus.

About 6, short tons 5, t of red phosphorus were produced in The product is treated to remove traces of white phosphorus. Red phosphorus is a component of fire-retardants and striking surfaces for matches. Phosphorous oxyacids are extensive, often commercially important, and sometimes structurally complicated. They all have acidic protons bound to oxygen atoms and some have nonacidic protons that are bonded directly to phosphorus. Although many oxyacids of phosphorus are formed, only six are important, and three of them, hypophosphorous acid , phosphorous acid and phosphoric acid are particularly important ones.

The most prevalent compounds of phosphorus are derivatives of phosphate PO 4 3- , a tetrahedral anion. Being triprotic, phosphoric acid converts stepwise to three conjugate bases:. Phosphate exhibits the tendency to form chains and rings with P-O-P bonds. Many polyphosphates are known, including ATP. For example, the industrially important trisodium triphosphate also known as sodium tripolyphosphate , STPP is produced industrially on a megatonne scale via this condensation reaction :.

Phosphorus pentoxide P 4 O 10 is the acid anhydride of phosphoric acid, but several intermediates are known between the two. This waxy white solid reacts vigorously with water. With metal cations, phosphate forms a variety of salts. These solids are polymeric, featuring P-O-M linkages. Many phosphate salts are derived from hydrogen phosphate HPO 4 PCl 5 and PF 5 are common compounds.

Both are volatile and pale or colourless. The pentachloride and pentafluoride adopt trigonal bipyramid molecular geometry and are Lewis acids. The most important oxyhalide is phosphorus oxychloride POCl 3 , which is tetrahedral. Before extensive computer calculations were feasible, it was proposed that bonding in phosphorus V compounds involved d orbitals. It is now accepted that the bonding can be better explained by molecular orbital theory and involves only s- and p-orbitals on phosphorus.

Compounds of the formula PNCl 2 n exist mainly as rings such as the trimer hexachlorophosphazene. Most famous is the three-fold symmetric P4S3 used in strike-anywhere matches. P 4 S 10 and P 4 O 10 have analogous structures. It is an ill-smelling, toxic compound. Phosphine is produced by hydrolysis of calcium phosphide , Ca 3 P 2. Unlike ammonia, phosphine is oxidised by air.

Phosphine is also far less basic than ammonia. These materials are moisture sensitive, hydrolysing to give phosphorus acid. The trichloride, a common reagent, is produced by chlorination of white phosphorus:. The trifluoride is produced by from the trichloride by halide exchange.

PF 3 is toxic because it binds to haemoglobin. The structure of P 4 O 6 is like that of P 4 O 10 less the terminal oxide groups. They are widely used commercially. For example it is the precursor to triphenylphosphine :. Treatment of phosphorus trihalides with alcohols and phenols gives phosphites, e.

These compounds generally feature P-P bonds. The highly flammable gas diphosphine P 2 H 4 is the first of a series of derivatives of this type. Diphosphine is an analogue of hydrazine. The phosphide ion is P Phosphides arise by reaction of metals with red phosphorus. Salts of P 3- do not exist in solution and these derivatives are refractory, reflecting their high lattice energy. Illustrated by the behaviour calcium phosphide , many metal phosphides hydrolyse in water with release of phosphine:.

Schreibersite is a naturally occurring phosphide found in meteorites. Many polyphosphides are known such as derivatives of OsP 2. These can be structurally complex ranging from Na 3 P 7 and derivatives of P 26 Often these species adopt cage-like structures that resemble fragments of violet phosphorus.

According to the Oxford English Dictionary, the correct spelling of the element is phosphorus. The discovery of phosphorus is credited to the German alchemist Hennig Brand in , although other chemists might have discovered phosphorus around the same time. It was named phosphorus mirabilis "miraculous bearer of light". Then he boiled it down to a paste, heated this paste to a high temperature, and led the vapours through water, where he hoped they would condense to gold. Instead, he obtained a white, waxy substance that glowed in the dark.

Brand had discovered phosphorus, the first element discovered since antiquity. While the quantities were essentially correct it took about 1, L of urine to make about 60 g of phosphorus , it was unnecessary to allow the urine to rot. Later scientists would discover that fresh urine yielded the same amount of phosphorus.

It was known from early times that the glow would persist for a time in a stoppered jar but then cease. Robert Boyle in the s ascribed it to "debilitation" of the air; in fact, it is oxygen being consumed. By the 18th century, it was known that in pure oxygen, phosphorus does not glow at all; [ 30 ] there is only a range of partial pressure at which it does. Heat can be applied to drive the reaction at higher pressures. In , the glow was explained by R. The reaction is slow and only very little of the intermediates are required to produce the luminescence, hence the extended time the glow continues in a stoppered jar.

Since that time, phosphors and phosphorescence were used loosely to describe substances that shine in the dark without burning. However, as mentioned above, even though the term phosphorescence was originally coined as a term by analogy with the glow from oxidation of elemental phosphorus, is now reserved for another fundamentally different process—re-emission of light after illumination.

Brand at first tried to keep the method secret, [ 33 ] but later sold the recipe for thalers to D Krafft from Dresden, [ 10 ] who could now make it as well, and toured much of Europe with it, including England, where he met with Robert Boyle. The secret that it was made from urine leaked out and first Johann Kunckel — in Sweden and later Boyle in London also managed to make phosphorus.

Boyle states that Krafft gave him no information as to the preparation of phosphorus other than that it was derived from "somewhat that belonged to the body of man". This gave Boyle a valuable clue, however, so that he, too, managed to make phosphorus, and published the method of its manufacture. Robert Boyle was the first to use phosphorus to ignite sulfur-tipped wooden splints, forerunners of our modern matches, in Antoine Lavoisier recognized phosphorus as an element in Phosphate rock, a mineral containing calcium phosphate, was first used in and following the introduction of the electric arc furnace in , this became the only source of phosphorus.

Phosphorus, phosphates and phosphoric acid are still obtained from phosphate rock. Phosphate rock is a major feedstock in the fertilizer industry. White phosphorus was first made commercially, for the match industry in the 19th century, by distilling off phosphorus vapour from precipitated phosphates, mixed with ground coal or charcoal , which was heated in an iron pot, in retort. Carbon monoxide and other flammable gases produced during the reduction process were burnt off in a flare stack.

This process became obsolete when the submerged-arc furnace for phosphorus production was introduced to reduce phosphate rock. Burning phosphorus is difficult to extinguish and if it splashes onto human skin it has horrific effects. Early matches used white phosphorus in their composition, which was dangerous due to its toxicity. Murders, suicides and accidental poisonings resulted from its use. An apocryphal tale tells of a woman attempting to murder her husband with white phosphorus in his food, which was detected by the stew giving off luminous steam.

When a safe process for manufacturing red phosphorus was discovered, with its far lower flammability and toxicity, laws were enacted, under the Berne Convention , requiring its adoption as a safer alternative for match manufacture. The dominant application of phosphorus is in fertilisers, which provides phosphate as required for all life and is often a limiting nutrient for crops. Global demand for fertilisers led to large increase in phosphate PO 4 3— production in the second half of the 20th century.

Due to the essential nature of phosphorus to living organisms, the low solubility of natural phosphorus-containing compounds, and the slow natural cycle of phosphorus, the agricultural industry is heavily reliant on fertilisers that contain phosphate, mostly in the form of superphosphate of lime.

White phosphorus is widely used to make organophosphorus compounds, through the intermediates phosphorus chlorides and two phosphorus sulfides, phosphorus pentasulfide , and phosphorus sesquisulfide. Phosphorus is also an important component in steel production, in the making of phosphor bronze , and in many other related products. Phosphorus is added to metallic copper during its smelting process to react with oxygen present as an impurity in copper and to produce oxygen-free copper or phosphorus-containing copper CuOFP alloys with a higher thermal and electrical conductivity than normal copper.

Phosphorus sesquisulfide P 4 S 3 is used in heads of strike-anywhere matches. The violet form can also be obtained from some preparations of red phosphorus by the following treatment. The finest particles are washed away in a stream of water until only dark steel-blue particles are left; these are boiled with 30 per cent, sodium hydroxide solution, washed again, boiled with 5 per cent, nitric acid, washed with hot and cold water, then with absolute alcohol and ether, and allowed to stand until dry in a vacuum desiccator with concentrated sulphuric acid.

The density of this preparation is about 2. The preparation of violet phosphorus may conveniently be carried out as follows:—The air is displaced, by means of carbon dioxide, from a hard glass tube, which is then one quarter filled with ordinary phosphorus, the remainder of the tube containing pieces of lead, preferably those which have served for a previous preparation.

The carbon dioxide is then removed, the tube sealed on the pump, and placed inside an iron tube, the space between the walls being filled with magnesia. The whole is heated in a tube furnace for 8 to 10 hours at a moderate red heat. After opening, with the usual precautions, the crystalline phosphorus is removed from the surface and the crystals from the interior are collected after dissolving the lead in nitric acid.

Crystals of violet phosphorus apparently identical with Hittorf's phosphorus have been obtained by maintaining the element at its melting-point in a sealed tube after starting the crystallisation by a slight supercooling. The tube was opened under carbon disulphide and the crystals separated from the white phosphorus in which they were embedded.

Violet phosphorus from molten lead yielded two kinds of crystals, one of which was identical with that prepared as above. Both were pleochroic, and were described as dark orange in a direction parallel to the long side and lighter in a direction at right-angles to this. Their density was 2. Violet phosphorus, when rubbed to a very fine powder, assumes a red colour. It still exists, however, in the most stable form, i.

Density of Violet Phosphorus On the whole it seems improbable that the density is much, if at all, higher than 2. Melting-point of Violet Phosphorus This determination has of course been carried out in sealed tubes. Fusion and solidification proceed as if the phosphorus were not a pure substance, but a mixture. The melting-points observed were also triple points when, as usual, the phosphorus was sealed in an evacuated tube.

The melting-points are lower if the temperature of the bath is raised very slowly. In a bath at constant temperature the melting-point was found to be Vapour Pressure of Violet Phosphorus The determination of the values given below was beset with considerable difficulty, especially that of securing inner equilibrium in the solid phase.

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