1872.] Dr. A. W. Hofmann on the Phosphorus Bases. 



225 



soda which decomposed the salt. By observing the volume of the gas dis- 

 engaged, all the data for fixing the volume-weight were given. In this 

 manner the number 24*35 was found, the theoretical value being 24. 



Methylphosphine is nearly insoluble in water ; if the water contain air, 

 part of the gas disappears, but only in consequence of oxidation, clearly 

 indicated by the formation of white clouds. If the gas stand over water 

 into which air can penetrate from without, the gas after some time is per- 

 fectly absorbed. Methylphosphine gas is rather soluble in alcohol even 

 at the ordinary temperature, but more especially at temperatures approach- 

 ing its point of liquefaction ; at 0° one volume of alcohol of 95 per cent, ab- 

 sorbs not less than twenty volumes. At the ordinary temperature ether dis- 

 solves but little ; the solvent power increases, however, rapidly by cooling 

 the liquid. At 0° one volume of ether is capable of dissolving seventy 

 volumes of methylphosphine. 



The methylated phosphorus base attracts oxygen with great avidity ; on 

 mixing the gas with air, white clouds are formed at once ; but detonation 

 does not take place at the common temperature. If methylphosphine be 

 required of absolute purity, the gas must be allowed to escape from the 

 apparatus until a small quantity collected over mercury remains perfectly 

 transparent. The nature of the more immediate products of oxidation 

 remains to be investigated. When gently heated in contact with air, 

 methylphosphine takes fire. A glowing match, and even a glass rod just 

 heated to scarcely visible redness, at once inflame the gas. In contact 

 with chlorine and bromine or nitric vapours, it burns with a brilliant 

 flame. 



By its union with acids, methylphosphine gives rise to a series of well- 

 defined salts distinguished by the remarkable property of being decomposed 

 by water. On this property is based the preparation of the body in a state 

 of purity. The salts bleach vegetal colours like chlorine. 



Of the salts, two only have as yet been more closely examined, the chlor- 

 hydrate aud the iodhydrate. 



Chlorhydrate. — If a current of methylphosphine gas be conducted into 

 strong fuming hydrochloric acid, it is perfectly absorbed ; no crystals, 

 however, are separated ; but on mixing the two gases, they are at once 

 condensed to beautiful, well-formed, four- sided plates. In certain reactions 

 with organic chlorides, which are accomplished in ethereal solution, and 

 which I hope to describe more minutely to the Society hereafter, the salt is 

 deposited in splendid large four-sided tables, often having a centimetre in 

 diameter. The chlorhydrate is so volatile that it passes over even 

 with the vapour of ether. Analysis was performed by the method often 

 adopted for demonstrating the composition of sal-ammoniac in lectures. 

 By allowing equal volumes of methylphosphine and hydrochloric gases to 

 meet over mercury, both entirely disappear with formation of a crystalline 

 deposit. Hence the salt contains 



CH c PCl=(CH 3 )H a P, HC1. 



