1887.] Prof. Letts and W. Wheeler on Benzyl Phosphines. 77 
Two separate specimens — A and B — of the compound were pre- 
pared, each being washed with glacial acetic acid, and finally dried 
in vacuo over sulphuric acid. B was prepared more carefully, and 
washed more thoroughly than A. Determinations of bromine gave 
the following results : — 
A. B. Calculated for 
(1) (2) (Bz^HP^HBr 2(Bz2HP),HBr 
Bromine, 19'5 20-5 16-3 27*4 15-9 
The compound is very unstable. It is decomposed by boiling its 
solution in acetic acid with water, by dissolving it in alcohol, and by 
an alcoholic solution of potash — dibenzyl phosphine resulting. In 
the two first cases the decomposition is gradual, in the third it is 
immediate. 
Dibenzyl Phosphine and Hydriodic Acid, — On passing gaseous 
hydriodic acid into a solution of dibenzyl phosphine in glacial acetic 
acid, a crystalline precipitate is produced, which dissolves as the 
solution grows warm, and subsequently is again deposited in thin rect- 
angular plates. The compound, after careful washing with glacial 
acetic acid, and drying in vacuo, yielded the following numbers : — 
Iodine, 
Obtained. 
Calculated. 
2(Bz2HP),HI 
22-8 
The compound, like the hydrobromate, is unstable, and is decom- 
posed in a precisely similar manner. 
Action of Bromine on Dihenzyl Phosphine. — On mixing solutions 
of the phosphine and bromine in glacial acetic acid, heat is 
developed, and a light orange crystalline precipitate is thrown down. 
The compound was prepared several times under varying conditions. 
For analysis it was thoroughly washed with glacial acetic acid, then 
dried in vacuo. 
The following results were obtained : — 
A. 
B. 
C. 
D. 
E. 
F. 
Carbon, 
. . . . 
56-5 
56-5 
56*4 
Hydrogen, 
. ... 
5-6 
5-0 
5-3 
Bromine, . 
26-0 
26-4 
27-2 
26*7 
26-6 
A, B, C, D, E, and F were separate preparations. 
At first we naturally anticipated that an addition product had 
