PHOSPHORUS. One of the non-metallic chemical elements. It was discovered by Brand, a Hamburg alchemist, in 1669, while experiment ing with urine with a view to preparing a liquid for the transfo•nmation of silver into gold. Kunekel, on learning of the discovery, without, however. knowing the method, invented it process of his own for the extraction of phosphorus from mine, and in 1678 puldished a work entitled I) Phosphoro 1/irobiii. The existence of phosphorus in bones was discovered either by Galin (about 1769) or by Scheele (1771i, and subsequently phosphorus became a well-known and elicit]) sub stance, variously called Ilrand's phosphorus, Kunckel's phosphorus, Krafft's phosphorus, lloyle's phosphorus, and English phosphorus, while the name phosphorus, unqualified, was ap plied to phosphorescent substances in general un til the ant iphlogistie nomenclature introdneed the present usage. The elementary nature of phos phorus was first recognized by Lavoisier. See CHEMISTRY.
Phosphorus does not occur free in nature, hut is found abundantly in the form of phosphates. The minerals of the apatite group (combinations of calcium phosphate with cabquiiu chloro-fluo ride), struvite, vivianite, wavellite, and many other minerals contain vonsiderable amounts of chemically combined phosphorus. But the prin cipal source of pliesplho•us is still the substance of hones, miitdt consists chiefly of the neutral phosphate of calcium. Calcium phosphate is also the ehief constituent of coprolites and gnanos, and calcium and magnesium phosphates are in the ashes of plants. Ammonium-magnesium phos phate is the chief constituent of urinary sedi ments, while in combination with carbon. hydro gen, oxygen, and nitrogen, phosphorus is found in the yolk of in the blood and other animal fluids. and in the substance of the brain and nerves.
In obtain phosphorus, bones are burned to destroy their organic matter and are treated with sulphuric acid, wliieh converts the neutral phos phate Ca (POO., into the soluble acid phosphate, Call, Pod,. The solution of the latter is evapo rated to dryness, charcoal is added to the residue, and the mixture is strongly heated, when two processes take place in immediate succession, the Iirst eonsisting,in the transformation of the acid calcium phosphate into calcium meta phosphate, Ca ( PO ,) the second in the partial decomposi tion of the nwtaphosphate by the ehareoal. result ing in the fornmtion of free phosphorus, some neutral ealviltril phosphate, and carbonic oxide gas. The phosphorus vapors are condensed under water in suitable vessels of clay. The crude prod uct thus obtained may be somewhat purified by under water and pressing through porous plates. Arsenic, an impurity usually introduced with the sulphuric acid employed in the manufac ture of phosphorus. may be removed by means of nitric acid. When pure, the phosphorus is melted and east in the form of sticks by sucking it into glass tubes and allowing to solidify.
The ehemieal of phosphorus is P; its atomic weight is 31. The properties of free phos phorus are not always the same. the 1.•letnent be im( capable of existing in several different al lotropie forms. (See Arl.ornorv.) The vapor of phosphorus has invariably the same density, lead ing to the molecular formula l',. (See 310LE CULES—A IOLECULAR Wrmirrs.) Experiment leads to the view that when dissolved ill benzene phos phorus has a similar constitution. But the re markable differences between the liquid and the several solid modifientions of the element are by no means understood. Common or yellow phos phorus. which is ordinarily obtained by the manu facturer. is a waxy substance that may be prepared in the form of crystals of the regular system by sublimation or by crystalliza tion from solutions in carbon disulphide. in which the other varieties of phosphorus arc insoluble. Its melting-point is 4-1.5° C. and its specific gravity at 0° C. is 1.S37. It phosphoresces in the (lark, and although it has been shown to ex hibit this phenomenon when kept in gases in capable of reacting with it, it is quite certain that in all such eases the phosphoreseenec is caused by the presence of traces of oxygen, whieh oxidizes yellow phosphorus very readily. As a matter of fact, when kept in a vacuum or in gases which have been thoroughly freed front oxygen. phosphorus gives off no light. In the air, at ordinary temperatures, yellow phosphorus Undergoes oxidation (see 1)zos;r1. and may readily take lire even if carelessly rubbed. It may be caused to burn tinder water by gently warming. the latter and passing a eurrent of oxygen into it. Besides, yellow phosphorus is extremely poisonous. It must therefore be handled with great eare. The use of phosphorus for matches is well known. I See 11.vronES.) Ilrel phosphorus teas discovered by Sehriitter, of Vienna. in 1S45. It is gradually formed by the action of light, especially violet rays. on common phosphoric:, but may be conveniently prepared ht simply heating the latter to about 450' C. (450° F.), in an atmosphere of carbonic acid, nitrogen, or some other inert gas. If heated to about 300° C.. red phosphorus is reconverted into the com mon yellow modification. The specific gravity of red phosphorus is about 2.14, and it does not melt. It does not phosphoresce in the dark, is not poisonous, and is in every way perfectly harmless. (See ItIATellEs.) Crystalline ('metal lic') phosphorus is formed during the solidifica tion of molten amorphous phosphorus. It Inv be obtained in the form of long red tabular crys tals having a distinct metallic lustre. Its specific gravity is 2.34. Black phosphorus is formed when melted yellow phosphorus is rapidly cooled. Two other allotropic varieties of phosphorus have been described, but deserve no mention here.