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XXIV. Contributions to the History of the Phosphorus-Bases. 
By AuausTUS William Hofmann, F.B.S. 
Received June 21, — Read June 21, 1860. 
THIRD MEMOIR. 
PHOSPHABHMOHIHM AND PHOSPHARSONIHM-, DIARSONIHM- AND 
ARSAMMONIUM-COMPOHNDS. 
In the former section of this inquiry, I have endeavoured to trace the history of the 
bodies which are generated by the mutual action of triethylphosphine and dibro- 
mide of ethylene. I have endeavoured, as far as possible, to fix with precision the 
several phases of this reaction, and carefully studied its principal products, the history of 
which appears to open the clearest perception of the nature of the polyatomic ammonias, 
and more especially of their connexion with the monatomic bases. The four saline com- 
pounds which, in accordance with the indications of theory, are formed by the action of 
dibromide of ethylene upon triethylphosphine, the bromides of the bromethylated, 
oxethylated, and vinylated monophosphonium, and of ethylene-diphosphonium repre- 
sent, in the phosphorus-series, as well as in the nitrogen- and arsenic-series, four classes 
of salts, the individual terms of which admit of being constructed in unlimited number 
and endless variety. 
The following pages are devoted to the consideration of several compounds belonging 
to these four principal groups. The examination of the mixed diatomic bases of the 
phosphorus-nitrogen, phosphorus-arsenic- and arsenic-nitrogen-series, have more espe- 
cially fixed my attention. Before, however, proceeding to a detailed account of these 
substances, which form more particularly the subject of this paper, a few experiments 
may still be briefly mentioned which are even more closely connected with the observa- 
tions recorded in the previous memoir. 
Action of Dichloeide of Ethylene on Teiethylphosphine. 
It is precisely analogous to that of dibromide of ethylene, giving rise to the two 
compounds — 
Cg Hj, P CI2 = [(C2 H, Cl) (C, n,), P] Cl, and 
C,4H34P,Cl2 = 
(C2H4)' 
(C2H3)3PJ 
CL 
If the reaction be suffered to go on to the end under the influence of heat, the result- 
ing white crystalline mass consists almost entirely of the diphosphonium-compound ; no 
mdccclx. 3 u 
