392 Royal Society :— 



The iodide thus prepared contains 



C 7 H 18 PI=[(CH 3 )(C 2 H 5 ) 3 P]I. 



For further verification of this formula the crystals were deiodized 

 with silver-oxide, and the caustic liquid thus obtained was saturated 

 with hydrochloric acid and precipitated by dichloride of platinum. 

 The platinum-salt, which crystallizes in beautiful octahedra, was 

 found to contain 



C 7 H 18 P PtCl 3 =[(C H.) (C 2 H s ) 3 P]C1, PtCl 2 . 



The two iodides are accompanied by a considerable quantity of 

 oxide of triethylphosphine, which immediately separates in oily drops 

 on treating the last mother-liquor with potash. Its presence was like- 

 wise unmistakeably recognized by the preparation of the platinum - 

 salt. If the last mother-liquor of the iodine-compounds be deiodized 

 and mixed with hydrochloric acid and dichloride of platinum, a quan- 

 tity of octahedral salts separates in the first place, which are removed 

 by sufficient concentration ; the remaining liq*uid, when mixed with 

 alcohol and ether, yields a crystalline precipitate, which separates 

 from alcohol by spontaneous evaporation in the beautiful large 

 hexagonal tables consisting of the platinum-salt of the oxychloride 

 of triethylphosphine, which has been more fully described in one of 

 the previous notes on these researches. 



The formation of the four compounds contained in the mother- 

 liquor of the sparingly soluble iodide is illustrated by the following 

 equations : — 



2[(C,H,)3P] + CH a I a + H a O=[(C a H 5 ),HPjI + [(CH,0)(C a H I ) a P]I 



[(3C a H l ),P] + CH a I a + H a O=[(C a H,),HP]I+[(CH 8 )(C a H s ),P]I + (C sl H,) 1 PO. 



" Researches on the Phosphorus-Bases." — No. XII. Relations 

 between the Monoatomic and the Polyatomic Bases. By A. W. 

 Hofmann, LL.D., F.R.S. Received August 17, I860. 



In recording my experiments on the derivatives of triethylphos- 

 phine, I have had more than one opportunity of alluding to the 

 energy and precision which characterize the reactions of this com- 

 pound. The usefulness of triethylphosphine as an agent of research 

 has more particularly manifested itself in the study of the poly- 

 atomic bases, the examination of which, in continuation of former 

 inquiries, was naturally suggested by the beautiful researches on the 

 polyatomic alcohols published during the last few years. In the 

 commencement these studies were almost exclusively performed with 

 reference to derivatives of ammonia ; but the results obtained in the 

 examination of triethylphosphine have, in a great measure, changed 

 the track originally pursued, and of late I have generally preferred 

 to solve the problems which I had proposed to myself, by the aid of 

 the phosphorus-bases. 



The light which the study of these compounds throws upon the 

 nature of the polyatomic bases generally, will be fully appreciated 

 by a retrospective glance at the deportment of triethylphosphine 

 under the influence of dibromide of ethylene, and a comparison of 



