DE. A. W. HOFMANN ON THE PHOSPHOEUS-BASES. 
425 
over lime, yielded a clear liquid, which burnt with a colourless flame and exhibited all 
the characters of alcohol. 
The interpretation of this result appears at the first glance exceedingly simple ; the 
sulphide of triethylphosphine cannot be formed directly from the phosphorus-base, but 
owes its origin to the oxide first produced by the action of air, this oxide being decom- 
posed by the mercaptan and yielding sulphide of triethylphosphine and alcohol : 
(a h,)3 p 0+*^^ g’}o+(C3 H3)3 p s. 
Experiment shows, however, that this equation illustrates only the final result of the 
reaction. Oxide of triethylphosphine and mercaptan, brought together under the most 
various conditions at ordinary temperatures and under pressure, do not yield a trace of 
sulphide of triethylphosphine ; and we have to suppose, therefore, that the mercaptan 
interchanges its sulphur with the oxygen of the oxide of triethylphosphine, only at the 
instant of foiination of the latter, or what comes to the same thing, that the oxygen of 
the air, in presence of a substance so greedy of sulphur as triethylphosphine, directly 
takes the place of the sulphur in the mercaptan. 
In connexion with this subject, various attempts were made to replace the oxygen in 
oxide of triethylphosphine by sulphur. But neither by treatment with sulphide of ammo- 
nium, nor by continued boiling with the higher sulphides of potassium, could the oxide be 
converted into the corresponding sulphide, whereas the conversion of the sulphide into 
the oxide takes place without any difficulty. This, however, is not more than might 
have been expected from the behaviour of the oxide with hydrochloric acid, mentioned 
in one of the preceding paragraphs. The different degrees of stability which characterize 
the oxide and the sulphide of triethylphosphine may also be strikingly seen in the 
behaviour of these compounds with sodium, the sulphide being reduced, with the greatest 
facility, to free triethylphosphine, even below the melting-point of the sodium, whereas 
the oxide may be distilled from sodium without experiencing the slightest alteration*. 
Ebullition with ordinary concentrated nitric acid likewise converts the sulphide into 
the oxide, the sulphur being at the same time transformed into sulphuric acid. The 
liquid filtered off from the precipitate obtained by barium-salts, when evaporated to dry- 
ness and fused with nitrate of potassium, yields no further trace of sulphur. 
Behaviour of Triethylphosj^hine with Bisulphide of Carbon. 
These two bodies, when mixed in the anhydrous state, act upon one another with con- 
siderable force, amounting frequently to explosive violence, and unite into a red crystal- 
line mass. The compound is best prepared by mixing the solutions of its constituents 
in alcohol or ether ; the new body then instantly separates in beautiful red crystalline 
laminae. 
* In the previous memoir, it is stated that the phosphorus-base is reproduced from the oxide by the action 
of metallic sodium. Probably the oxide used in the former experiments contained a small quantity of free 
triethylphosphine, and thus led to an erroneous statement, 
MDCCCLX. 3 L 
