808 Royal Society :— 
I have established, in the first place, that the monatomic bromide 
[(C, H,), (C, H, Br) P] Br 
may be readily converted into the diatomic bromide 
[(C, H,), (C, H,)"P,]" Br, 
by the simple addition of triethylphosphine. Nothing is easier than - 
to prove the transformation, the platinum-salt of the two bases pre- 
senting a remarkable difference of solubility, and other differences 
not less striking. 
To remove every doubt, the bromide, obtained by treatment of the 
brominated bromide with triethylphosphine, was converted into the 
corresponding icdide, which in its properties and composition was 
found to be identical in every respect with the characteristic iodide, 
which I have fully described in my last note upon this subject. 
The transformation of the monatomic into what I have represented 
as the diatomic compound being satisfactorily established, the con- 
clusive experimental demonstration of the diatomic nature of the 
latter presented itself without difficulty in the conception of bromides 
containing at once phosphorus and nitrogen, the molecular expression 
of which would no longer admit of division. 
This class of dibromides actually exists ; they are readily produced 
by submitting the bromide of the brominated body to the action of 
ammonia or monamines instead of triethylphosphine. 
I have formed as yet only three representatives of this new class of 
bodies, which I propose to designate as phosphammonium-com- 
pounds ; their examination is sufficient to fix the character of the 
class ; it would have been easy to construct scores of similar bodies. 
Action of Ammonia upon the bromide of the brominated body. 
The two substances, especially when in alcoholic solution, unite 
with evolution of heat— 
" 
(C, H,), | p 
[CBs (C. HBF] Bet HN) (C.F!) Bre 
3 
Both the bromide and the corresponding chloride are very soluble, 
and little adapted for analysis ; I have therefore fixed the nature of 
this body by the preparation and analysis of the platinum-compound. 
For this purpose the bromide generated in the above reaction was 
treated with oxide of silver; it is thus converted into a powerfully 
alkaline solution obviously of the dioxide, 
which, saturated with hydrochloric acid and mixed with dichloride of 
platinum, furnished a light-yellow crystalline platinum-salt, reery- 
stallizable from boiling-water, and containin 
[(C, H,), H, (C, Hy)" PN" Cl, 2PtCl,. 
