476 
DE. A. ^Y. TTO'F Ar.A> rX oy THE PHOSPHOEHS-BASES. 
prov ed to be exclusively the dichloride of the diphosphonium. It was identified by con- 
version into the characteristic platinum-salt, and subsequently into the iodide, both ot 
which were analysed. The details are given under the head of the di-iodide and platinum- 
salt of the diphosphonium. 
IH-iodide . — This salt is perhaps the most characteristic of the diphosphonium- 
compounds. Crystallizing with peculiar readiness, — beiag easily soluble in hot, but 
sparingly soluble in cold water, — slightly soluble also in alcohol, and insoluble in ether, 
— it possesses all the properties which can facihtate the preparation of a pure and defi- 
nite substance. It has therefore, for the most part, served as the starting-point of the 
diphosphonium-compounds. 
I have already remarked that, in the preparation of the monatomic bromide, the 
formation of the dibromide can scarcely ever be entirely prevented. The mother- 
liquors, remaining after numerous preparations of the monatomic bromide, were there- 
fore united and treated with oxide of silver, whereby a caustic liquid was obtained 
containing the hydrate of the diphosphonium, contaminated with the hydrate of the 
oxethylated monophosphonium arising from the decomposition of the bromethylated 
compound. These hydrates were converted, by saturation with hydriodic acid, into the 
corresponding iodides, the separation of tvhich presented no fiu'ther difficult^', inasmuch 
as the iodide of the oxethylated monophosphonium is extremely soluble in water and in 
alcohol. The sparingly soluble di-iodide was easily obtained in a state of perfect pimty 
by several crystallizations. The crystals are anhydrous. Any hygroscopic moisture that 
may adhere to them is most conveniently removed by drying them over sulphiuic acid, 
since the salt begins to turn slightly brown at 100°. 
I. 0'5690 grm. of iodide gave 0'6742 grm. of carbonic acid and 0’3403 grm. of water. 
II. 0‘2270 grm. of iodide gave 0’2055 grm. of iodide of silver. 
III. 0’3246 grm. of iodide gave 0‘2935 grm. of iodide of silver. 
The salt which served for analysis III. had been prepared from a dibromide obtained 
by submitting the pure bromide of the bromethylated triethylphosphouium to the action 
of triethylphosphine. 
IV. 0’3970 grm. of iodide gave 0'3607 grm. of iodide of silver. The salt used for this 
determination had been prepared by submitting triethylphosphine to the action of 
hromethylated bromide of ethyl (see the paragraph on the dibromide of ethylene-diphos- 
phonium), converting the dibromide formed into the corresponding chloride, uito the 
platinum-salt, and ultimately into the iodide. 
V. 0-4090 grm. of iodide gave 0-3700 grm. of iodide of silver. The specimen used for 
analysis had been prepared by treating triethylphosphine with chlorinated chloride of 
ethyls precipitation of the product of the reaction as platinum-salt, and transformation 
of the latter into the iodide. 
The formula 
Cl4 H3, P, 
I> = 
,(C2 145)3 P^" 
