422 
DE. A. W. HOFMAXy OX THE PHOSPHOErS-BASES. 
the oxide. In a similar manner, it gives ^\ith iodide of zinc the iodide-of-zinc-compound 
of the oxide previously described. Only once — under conditions not sharply enough 
observed at the time, and which I was afteiuvards unable to reproduce in repeated expe- 
riments — a compound of the oxychloride with iodide of zinc was fonned. This substance, 
readily soluble in water and alcohol, crystallized from the latter solvent in beautiful 
colourless transparent octohedra, which, on analysis, gave the following result : — 
0-2093 grm. of salt, precipitated by nitrate of silver, gave 0-2474 grm. of a mixture 
of iodide and chloride of sih er. 
With the probable assumption that the compound contains 1 equiv. of chlorine for 
1 equiv. of iodine, this result corresponds to 50-74 per cent, of chloi-ine and iodine. 
Accordingly the octohedra would be a double compound of the iodide-of- zinc-salts of 
the oxide and of the chloride of triethylphosphine. 
The formula 
Ci 2 H 30 P, O CI 2 Zn 2 12 =(C 2 H 5)3 P O, Zn I-f (C, P Cl,, Zn I 
requires 50-62 per cent, of chlorine and iodine. 
Behaviour of Triethylphosphine with Sulphur-compounds. 
The remarkable tendency of the phosphorus-base to unite with sulphiu- has already 
been mentioned in the previous memoir ; the combination of the two bodies is attended 
with evolution of heat, the result being a beautifully crystalline substance, 
C6H,3PS = (C2H,)3PS, 
corresponding to the oxide of triethylphosphine. 
This behaviour has induced me to study the action of several sulphiu-compounds 
on the phosphorus-base. In the cases which I have examined, the ultimate product is 
almost invariably the sulphide of triethylphosphine, already mentioned as resulting from 
the direct combination of the phosphorus-base with sulphur- ; but the conditions imder 
which this sulphide is produced vary considerably, and in the majority of cases it occurs 
only as a secondary product of the decomposition of other more direct compounds, some 
of which appeared to me sufficiently interesting to deserve more minute investigation. 
In the course of the experiments which I am going to describe, I have prepared con- 
siderable quantities of the sulphide of triethylphosphine. This compound, although 
remarkable for the facility with which it crystallizes, is not easily procured in well- 
formed crystals. It was only once or twice that I obtained crystals with good faces. 
They were examined by Quixtino Sella, who communicates to me the following 
results : — 
“ System rhoinbohedric : — 
10 0, 1 1 1=54° 35'. 
lOT, 2 TI, 210 (Fig. 13). 
Forms observed :■ 
