Elementary phosphorus

Phosphorus crystallizes in at least five polymorphic forms. The white form is metastable and is prepared by condensing the vapour. There are apparently two closely related modifications of white P, with a transition point at —77°C. The 

Black P has a layer structure in which each atom is bonded to three others. A layer of this structure is shown, in idealized form, in Fig. 19.1. In spite of its appearance it is simply a puckered form of the simple hexagonal net, the interbond 

The crystal structure of black phosphorus-portion of one layer (idealized). 

Hittorfs red P may be made by dissolving white P in thirty times its weight of molten lead, cooling slowly, and dissolving away the lead electrolytically. It has an 

The crystal structure of red phosphorus (a) chain sub-unit, (b) layer formed from cross-linked chains (diagrammatic). 

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White phosphorus may be made by several methods. By one process, tri-calcium phosphate, the essential ingredient of phosphate rock, is heated in the presence of carbon and silica in an electric furnace or fuel-fired furnace. Elementary phosphorus is liberated as vapor and may be collected under phosphoric acid, an important compound in making super-phosphate fertilizers. 

Reactions of carbon subsulphide and of elementary phosphorus, sulphur and selenium with complexes of the platinum metals Sulphur dioxide insertion reactions of transition metal alkyls and related complexes... 

An analogous reaction occurs between trifluoromethyl iodide and elementary phosphorus, arsenic, antimony, sulphur or selenium (5). The experimental procedure was the same in each case, the fluoroalkyl iodide being heated in a sealed tube or autoclave with the clement in question at temperatures ranging from 170 to 280°. Table 4 shows the products of these reactions which have been isolated. 

Ninety five percent of the phosphorus on Earth belongs to the minerals of the apatite group. Apatites are inorganic constituents of bones and teeth of vertebrate and man, as well as a basis of many pathologic sohd formations. Minerals of the apatite group are the main raw materials in the production of phosphorus fertilizers, fodder and technical phosphates, elementary phosphorus, and phosphor-organic compounds. The mineral is sometimes substantially enriched in rare-earth elements (REE) making their extraction possible (Altshuller 1980). 

Johann Sigismund Elsholtz, 1623-1688. Scientific authority at the court of the Elector of Brandenburg. A pamphlet which he had printed at Berlin in 1676 is the earliest publication concerning elementary phosphorus and also contains descriptions of the previously known phosphors Bologna stone, Baldwin s phosphor, and emerald phosphor (green fluorspar). See also ref. (113). 

Historical.—In his tables published in 1818 Berzelius4 gave 31-36 as the atomic weight of phosphorus. Other values obtained before and after this time did not agree even so well as this with the value accepted to-day. The reactions principally employed in this early period were the displacement of gold and silver from their chloride and sulphate respectively by elementary phosphorus. These reactions,... 

It is improbable that phosphorus is trivalent in POCl3, and further, in such compounds it is exercising its maximum valency. Since the atomic volume calculated on the assumption of a double bond between the phosphorus and the oxygen agrees most closely with the atomic volume of elementary phosphorus, it is probable that in the liquid element as well as in POCl3 phosphorus is exercising this maximum valency, which includes mixed bonds, thus... 

Furnace Also called the Readman process. A process for making elementary phosphorus in an electric furnace. The raw materials are phosphate rock, coke, and silica. Large amounts of electric... 

Elementary phosphorus is now made by heating calcium phosphate with silica and carbon in an electric furnace. (Fig. 21-1). The silica forms calcium silicate, displacing phosphorus pentoxide, P4O1P, whkh is then reduced by the carbon. The phosphorus leaves the furnace as vapor, and is condensed under water to white phosphorus. 

Phosphorus (0.11% of the lithosphere) is found mainly in minerals based on calcium phosphate, collophanite, the monohydrate, Ca3(P04)2.H20, and apatite, CagF(P04)3. About 90% of the phosphate rock mined is converted into fertilisers, the rest is used for making elementary phosphorus, phosphorus compounds and such alloys as phosphor bronze. For fertilisers rock phosphate is finely ground and treated with sufficient concentrated sulphuric acid to convert it to the soluble dihydrogen phosphate ... 

The claim that trialkylphosphine oxides are obtained by treating elementary phosphorus with sodium and alkyl halide during heating at 400 °C in an organic solvent is surprising... 

Dutton CB, Pigeon MJ, Renzi PM, et al. 1993. Lung function in workers refining phosphorus rock to obtain elementary phosphorus. J Occup Med 35(10) 1028-1033. 

The detection of elementary phosphorus in a systematic toxicological analysis is connected with that of prussic acid, alcohol, ether, chloroform, and other volatile poisons. The substances under examination are diluted with HjO, acidulated with HnSO<, and heated over a sand-bath in the flask a (Fig. 28). This flask is connected with a CO-i generator, 6, whose stopcock is closed. 

Another source of hydrogen of promise is that of the so-called Liljenroth Process. In this process elementary phosphorus is produced in an electric furnace from phosphate rock, silica and coke. A mixture of phosphorus vapor and steam is then passed over a catalyst maintained at about 700° C, producing phosphoric acid and hydrogen. 

Bond orbitals and bond energy in elementary phosphorus. J. Chem. Phys. 20 (1952) 29-34. (Linus Pauling and Massimo Simonetta). 

Elementary phosphorus is manufactured by reduction of apatite with coke in electric furnaces at a temperature of 1400-1500°C. Quartz is also present in the charge. It reacts with the calcium in apatite and forms a slag of liquid calcium silicate. If the apatite contains fluorine, SiF gas is formed that is passed into water containing soda. The compound formed, sodium hexafluorosilicate Na SiF, is used for fluoridating drinking water. In the process described, white phosphorus is the product. In the world about 1 million tonnes per year are produced. White phosphorus is used to some extent for smoke bombs and incendiary bombs, but most of it is used for the manufacture of phosphoric acid and other chemicals and for preparing red phosphorus for the match industry. 

Metal Phosphides. Elementary phosphorus reacts directly with electropositive metals under suitable conditions to give a series of phosphides with different phosphorus-metal ratios ranging from 0.3 in M3P to 16 in M Pi6. Although the structural analysis of such metal phosphides reveals that many of them are... 

In general, the sensitivity towards hydrolysis of metal phosphides depends on the metal content. Metal-rich compounds undergo relatively straightforward hydrolysis while the behavior of those with higher phosphorus content resembles more that of the elementary phosphorus, specially with respect to their inertness toward water. As observed in Table 4.16, many polynuclear metal phosphide undergo hydrolysis giving rise to corresponding phosphor hydrides or phosphanes. 

Commercially available phosphoric acid is usually manufactured by one of two processes (Van Wazer, 1953). (i) The most cost-effective method consists of treating phosphorite with sulfuric acid, (ii) The other process involves the reduction of phosphorite to elementary phosphorus in an electric furnace or blast furnace. This consists of burning phosphorite in the presence of air in order to obtain phosphorus pentoxide, hydrating the oxide to produce up to 75%-85% phosphoric acid, and purifying the resulting product with hydrogen sulfide to eliminate arsenic. 

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