BENZYL PHOSPHINES AND THEIR DERIVATIVES. 575 



The iodide (1), by the action of phosphonium iodide on benzyl alcohol (Ledermann),* 



(2) By the union of tribenzyl phospbine with iodide of benzyl (p. 566). 



(3) In small quantities by the action of iodide of benzyl on the primary phosphine. 

 The salts of the phosphonium are beautifully crystalline, and are readily obtained in a 



state of purity. All are soluble in alcohol and many in water ; they are insoluble in 

 ether. When heated they decompose as a rule, and in many cases give rise to perfectly 

 definite products. 



Chloride (C 7 H 7 ) 4 PC1,2H 2 0. — Colourless salt crystallising from boiling water in long 

 needles. It is sparingly soluble in cold water (100 c.c. of cold water dissolve about 

 0"35 grms.) and almost insoluble in dilute hydrochloric acid or common salt solution 

 (traces may be detected in an aqueous solution by adding these reagents). The dried 

 salt dissolves readily in alcohol, and the solution on slow evaporation yields beautiful 

 colourless rhombic crystals of considerable size, which are anhydrous. The dried salt also 

 dissolves readily in chloroform, and on spontaneous evaporation large crystals are also 

 obtained, which grow opaque in the air from loss of chloroform. The crystals thus 

 obtained contain one molecule of " chloroform of crystallisation." The anhydrous salt fuse3 

 at 228°'5 (corr.). 



The chloride combines with chloride of platinum and some other metallic chlorides, 

 giving insoluble or separately soluble compounds. 



Chloroplatinate, 2(C 7 H 7 ) 4 PCl,PtCl 4 (Letts and Collte). — 'Obtained in minute orange- 

 coloured crystals by mixing alcoholic solutions of the two chlorides. Almost insoluble. 



Double Salt with Mercuric Chloride (Ledermann) — (C 7 H 7 ) 4 PCl,HgCl 2 ,H 2 0. — In- 

 soluble precipitate obtained like the chloroplatinate. 



Double Salt with Stannic Chloride, 2(C 7 H 7 ) 4 PCl,SnCl 4 (Ledermann). — Sparingly 

 soluble crystalline compound obtained like the preceding salts. 



Bromide, (C 7 H 7 ) 4 PBr, resembles the chloride, but is less soluble in water. It dissolves 

 readily in alcohol, and crystallises from a mixture of alcohol and water in long silky 

 needles. Melting point, 2 16°-217° C. (uncorrected). 



Iodide, (C 7 H 7 ) 4 PI, is almost insoluble in water, and only sparingly soluble in alcohol. 

 From a hot alcoholic solution it crystallises in small rhombic crystals.t 



All the haloid salts appear to be decomposed completely when boiled with alkalies 

 into the tertiary phosphine oxide and toluol, 



(C 7 H 7 ) 4 PX + MOH = MX + (C, H 7 ) 3 PO + C 7 H 8 . 



Acid Sulphate, (C 7 H 7 ) 4 PHS0 4 , is most readily obtained by warming the chloride with 

 oil of vitriol on a water-bath until hydrochloric acid ceases to come oif, and then 

 crystallising the product once or twice from boiling water. It is rather more soluble 

 than the chloride, and crystallises in small rhombic or triclinic crystals. When boiled 



* Ledermann, Berichte, xxi. (1888) 405a. 



t We are of opinion that when this compound is crystallised from alcohol, the crystals have the formula 

 2(C 7 H 7 ) 4 PI,C 2 H 6 0. 



VOL. XXXV. PART II. (NO. 15). 5 A 



