619 



XVI. " Researches on the Phosphorus-Bases." No. XII. Rela- 

 tions between the Monoatomic and the Polyatomic Bases. 

 By A. W. HOFMANN, LL.D., F.R.S. Received August 17, 

 1860. 



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 

 the products formed in this reaction with the results suggested by 

 theory. 



A simple consideration shows that the action of diatomic bro- 

 mides upon bases must give rise to the formation of several classes 

 of compounds. Let us examine by way of illustration the products 

 which may be expected to be formed in the reaction between am- 

 monia and dibromide of ethylene. 



The diatomic bromide being capable of fixing two molecules of 

 ammonia, we have in, the first place four diatomic bromides of the 



formulae 



[(C 2 H 4 ) H.NJBr. 

 [(C a H 1 ) a "H 1 N,]Br 1 

 [(C 3 H 1 ),"H J NJ"Br a 

 [(C.H.)." N,]"Br,. 



VOL. X. 2 V 



