DE. A. W. HOFMAl^N ON THE PHOSPHOEHS-BASES. 
493 
The same remark applies to the final elucidation of the reaction between triethyl- 
phosphine and bromide of vinyl, which, as I have pointed out, likewise gives rise to the 
formation of diphosphoninm-compounds. Two molecules of triethylphosphine and two 
molecules of bromide of vinyl contain the elements of one molecule of dibromide of 
the ethylene-diphosphoninm and one molecule of acetylene : 
(C2H5)3 
(C2H3)3PJ 
and experiment proves that a considerable amount of permanent gas is generated in this 
reaction ; but there are other products formed, and it would be idle to dwell any longer 
on the interpretation of these unfinished observations. 
2[(C,H3)3P]-f 2C,H3Br= (C,HJ 
Bio + aR 
2 ’ 
In conclusion, I append Q. Sella’s crystallographical examination of the iodide of 
tetrethylphosphonium, to which I have alluded in the latter portion of this paper, and 
also the results obtained by him in measuring the corresponding platinum-salt. 
Crystalline Form of Iodide of TeC'ethylpliosphonium. 
“ System rhombohedric : — 
1 1 1, 1 0 0 = 59° 32'. 
Forms observed: — 
111, 101, 10 0, 110, 2 10, 31T (Fig. 47). 
Angles. Calculated. Observed. 
0 1 o I 
Ill, 
101 
= 
90 
0 
89 
29 
111 , 
100 
= 
59 
32 
111, 
110 
= 
40 
22 
40 
22 
111 , 
210 
= 
44 
28 
44 
28 
111 , 
3ll 
= 
63 
0 
63 
2 
lOT, 
oil 
= 
60 
0 
60 
7 
lOT, 
100 
= 
41 
43 
41 
44 
lOT, 
010 
= 
90 
0 
90 
2 
loT, 
110 
55 
53 
55 
58 
101, 
101 
= 
90 
0 
89 
59 
lOT, 
210 
45 
32 
45 
30 
Eig. 47. 
me to try wbetlier the action of triethylphosphine upon them would accomplish this transformation : 
[(C^H.O) 
H 
}o+(C2H,)3P = 
Ho 
Oo 
But even when heated up to 150°, the two bodies remain unaltered ; nor is there any action when the 
oxide is replaced by the bromide of oxethyl-triethylphosphonium. 
