hydrochloric acid. It is also obtained by heating red phosphorus under pressure to 580°. It forms a lustrous, nearly black crystalline mass, composed of minute rhombohedra. G. E. Linck and P. Moller (Ber., 1908, 41, p. 1404) have affirmed that the product of the first process always contains lead. E. Cohen and ]. Olie, ]un. (Abs. four. Chem. Soc., 1909, ii. 998) regard red phosphorus as a solid solution of the white in Hittorf's, but this is contradicted by A. Stock (Ber., 1909, 42, p. 4510), who points out that ordinary red phosphorus melts at 605°-610°, whilst Hittorf's melts at 620°; moreover, the latter is less reactive than the former at high temperatures. Another form was obtained by R. Schenck (Zeit. Elektrochem, 1905, ii. 117) as a scarlet amorphous powder by deposition of solutions of phosphorus in the tri-iodide, tribromide or sulphide (P4S3). It phosphoresces in ozone, but not in air, and is nonpoisonous; from its solution in alcoholic potash acids precipitate the hydride P,2H6, and when heated it is transformed into the red mod1f1cat1on. It has been used in combination with potassium chlorate as a composition for matches to strike on any surface. Finally a black phosphorus was described by Thénard as formed by rapidly-cooling melted phosphorus. Phosphme (phosphoretted hydrogen), PHS, a gas formed in the Eutrefact1on of organic matter conta1n1ng phosphorus, was obtained y Gengembre (Crelt's Ann., 1789, i. 450) by the action of potash upon phosphorus, the gas so prepared being spontaneously inflammable. Some time later Davy, by heating phosphorous ac1d, obtained a phosphoretted hydrogen which was not spontaneously iniiammable. These gases were considered to be distinct until Le Verrier (Ann. chem. phys., 1815 [2], 6o. p. 174) showed that the inflammability of Gengembre's p osphine was due to small quantities of liquid phosphoretted hs/drogen, PQH4. Phosph1ne may be prepared by the decompos1t1on o calcium p hosp hide with water (P¢H4 be1ng formed simultaneously); by the decomposition of phosphorous and hypo phosphorous acids when strongly heated; and by the action of solutions of the caustic alkalis on phosphorus: P4-l-3NaOH+3H¢O= PHa+3NaH2PO2; hydrogen and) PQH, are produced at the same time, and the gas may be freed from the latter substance by 'passing into a hydroc loric ac1d solution of cuprous chloride and eating the solution, when pure phosphine is liberated (Riban, Comptes rendus, 58, p. 581) The pure gas may also be obtained by heating phosphonium iod1de w1th caustic potash (A. W. Hofmann, Ber., 1871, 4, p. zoo); by the decomposition of crystalline calcium phosph1de or of alum1n1um p hosp hide with water (H. Moissan, Bull. soc chem., 1899 (3), 21, p 926; Metignon Comptes rendus 1900, I3O, p 1391); and by the reduction of phosphorous acid with nascent ydrogen.
It 1S a colourless, extremely poisonous gas, possessing a characteristic offensive smell, resembling that of rotting fish. It becomes liquid at -90° C., and solid at -133° C. (K. Olszewski, Monats., 1866, 7, p 371). It is only slightly so uble in water, but is readily soluble 1n solutions of copper sulphate, hypochlorous acid, and acid solutions of cuprous chloride It burns with a brightly luminous flame, and is spontaneously lniiammable at about IOO° C. When mixed w1th oxy en it combines explosively if the mixture be under diminished ressure, and is violently decomposed by the halogens. It IS also decomposed when heated w1th sulphur or with most metals, in the latter case with the liberation of hydrogen and formation of phosph1de of the metal. It combines with the halide derivatives of boron and silicon to form, eg. PH, -2BF3, 2PH, -SiCl, (Besson, Complies rendus, 1890, IIO, 8o, pp. 240, 516; 1891, 113, p. 78), with the halogen acids to form hosphonium salts, PH4X (X =Cl, Br, I), and with sod ammonium and) pot ass ammonium to form PH, Na, PHQK (joannis, Complies rendus, 1894, 119, p. 557). It oxidizes slowly in air, and is a reducing agent. It decomposes when heated, hydrogen and red phosphorus be1ng formed. Lequzd Phosphoretted Hydrogen, Pzl-I4, first obtained by P. Thénard (Comptes rendus, 1844, 18, p. 652) by decomposing calcium phosph1de w1th warm water, the products of reaction being then passed through a U tube surrounded by a freezing mixture (see also L. Gattermann, Ber., ISQO, 23, p. 1174). It is a colourless liquid which bo1ls at 57°-58 C. It is inso uble in water, but soluble in alcohol and ether. It is very unstable, being readily decomposed by heat or light. By passing the products of the decomposition of calcium p hosp hide with water over ranular calcium chloride, the PQH4 gives a new hydride, PHHQ and phosphine, the former being an odourless, canary-yellow, amorphous powder. When heate in a vacuum it evolves phosphine, and leaves an orange-red residue of a second new hydride, P9H¢ (A. Stock, W. Bottcher, and W. Lenser, Bfr., 1909, 42, pp 2839. 2847, 2853).
Solzd Phosphoretted Hydrogen, P., H1, first obtained b(y Le Verrier (loc. at), is formed by the action of phosphorus trichlori e on gaseous phosph1ne (Besson, Comptes rendus, III, p. 972); by the action of water on phosphorus d1-iod1de and by the decomposition of calcium p hosp hide with hot concentrated hydrochloric acid. It is a yellow sol1d, which is insoluble in water. It burns when heated to about 200° C. Oxidizing agents decompose it with great violence. When warmed with alco ol1c potash it yields gaseous phosph1ne, hydrogen and a hypophosphite. It reduces silver salts.
Phosphomum Salts.—The chlorede, PH4Cl, was obtained as a crystalline solid by Og1er (Complies rendus, 1879, 89, p. 7o5) by combining phosphine and hydrochloric acid gas under a pressure of from I4-20 atmospheres; it can also be obtained at —30° to *35° C. under ordinarg atmospheric pressure. It crystallizes in large transparent cubes, ut rapidly dissociates into its constituents on exposure. The bromide, PH4Br, was first obtained by H. Rose (Pogg. Ann., 1832, 24, p. 1i1) from phosphine and hydro bro mic acid, it also results when fn osphorus is heated with hydro bro mic acid to IOO 120° C. in sea ed tubes (Damoiseau, Bull. soc. chem., 1881, 35, p. 49). It crystallizes in colourless cubes, is deliquescent, and often inflames spontaneously on exposure to air. It 1s readily decomposed by water and also by carbonyl chloride (Besson, Complies rendus, 1896, 122, p. 140): 6PH1Br -l- 5COCl2 = 1oHCl -l- 5CO -l- 6HBr + 2PH;, -l-P4H1. The wdede, PH4I, first prepared by ]. Gay-Lussac (Ann. chem. phys., 1814, 91, p. 14), is usually obtained by the action of water on a mixture of phosphorus and iodine (A. W. Hofmann, Ber., 1873, 6, p. 286). It is also prepared by the actionof iodlne on gaseous (phosghine, or by heating amorphous phosphorus Wlth concentrate by riodic acid solution to 160° C. t crystallizes in large cubes and sublimes readily. It is a strong reducin agent. Water and the caustic alkalis readily decompose it with hberation of phosph1ne and the formation of iodides or hydriodic ac1d. It is also decomposed by carbonyl chloride (Besson, oc. cm). 4PH4I+8COCl2=16HCl+8CO-I-P214-l-2P.
]ust as the amines are derived from ammonia, so from phosphine are derived the primary, secondary and tertiary organic phosphines by the exchange of hydrogen for alkyl groups, and corres onding to the phosphonium salts there exists a series of organic phosphonium bases. The primary and secondary phosphines are produced when the alkyl iodides are heated Wlth phosphonium iodide and zinc oxide to 150° C. (A. W. Hofmann, Ber., 1871, 4, p. 430, 605), thus: 2 RI + 2 PH4I + ZnO = 2 R-PH1-HI 'l' Zni; + H2O, 2RI + PHJ + ZnO = R2-PH-HI -1- Znlg + H2O. The reactlon mixture on treatment with water yields the primary hosphine, the secondary phosphine being then liberated from its iiydriodlde bly caustic soda. The tertiary phosphines, discovered by L. Thénard (omptes rendus, 1845, 21, p. 144; 1847, 25, p. 892), are formed (together with the quaternary hosphonium salts) bivlheatmg alkyl iodides with phosphonium iodide to 150-180° C.: P, H-3CH3I= P(CH;,);, HI -l-3HI; P(CHs)3HI + CH3 = P(CHs)4I + HI (see also F1reman, Ber., 1897, 30, p. 1088). They are also formed by the interaction of phosphorus trichloride and zinc alkyls (Cahours and Hofmann, Arm., 1857, IO4, p. 1): 2PCl3+3 Zn (C2H5)2=3ZnCl2+ 2P(CgH5)3.
The primary and secondary phosphines are colourless compounds, and with the exception of methyl phosphine are liquid at ordinary temperature. They possess an unpleasant odour, fume on exposure to air, show a neutral reaction, but combine with acids to form salts. They oxidize very rapidly on eiéposure, in many cases being spontaneously inflammable. On ox1 ation w1th nitr1c acid the Iprimary compounds give monoalkyl phosphinic acids, R-PO(O)2, the secondary yielding dialky p osp inic acids, R2PO(OH). The primary phosphines are very weak bases, their salts with acids being readily decomposed by water. T he tertiary pl1osphines are characterized by their readiness to pass into derivatives containing pentavalent phosphorus, and consequently thely form addition compounds with sulphur, carbon b1sulph.de, c .lorine, bromine, the halogen acids and the alkyl halides with great readiness. On oxidation they yield phosphine ox1des, REP-O. The quaternary phosphonium salts resemble the corresponding nitrogen compounds. They are stable towards aqueous alkalis, but on digestion with moist silver oxide yield the phosphonium hydroxides, which are stronger bases than the caustic alkalis. They differ from the organic ammonium hydroxides in their behaviour when heated, yielding phosph1ne OX1d€S and paraffin hydrocarbons: R4P-OH =R;, PO-Q-RH. The boiling-points of some members of the series are shown in the table:-
Primary. Secondary. Tertiary.
Methyl - 14° C. 25° C. 40-42° C.
Ethyl + 25° C. 85° C. 128° C.
Isopropyl 41° C. 118° C.-Isobutyl
62° C. 153° C. 215° C.
Isoamyl 107° C. 2I0-215° C. 300° C.(?)
The alkyl phosphinic acids are colourless crystalline compounds which are eas1ly soluble in water and alcohol. They y1eld two series of salts, viz. RHM-P03 and RlVlzPO;, (M=metal). The dialkyl phosphinic acids are also colourless compounds, the maJority of which are insoluble in water. They yield only one series of salts. Oxides.-Phosphorus forms three well-defined oxides, P4O6, P204 and P205 two others, P40 and PZO, have been described.
Phosphorus suboxede, P4O, is said to be formed, mixed w1th the