680 
PROFESSOR ROSCOE’S RESEARCHES ON VANADIUM. 
The substance used in the following analysis was prepared by heating about 3 to 4 
grins, of the ammonia-salt in a platinum tube to whiteness in a current of dry ammonia. 
The tube was imbedded in a chalk crucible, and the central portions were heated to 
whiteness by the blast of a powerful blowpipe until no alteration of weight was ob- 
served. In this way, after a long and tedious series of operations, no less than 40 grms. 
of pure nitride (see analysis No. 2) was prepared. 
Analysis No. 2. — Determination of Nitrogen. 
Weight of nitride taken . . . 0-2250. 
Observed vol. of nitrogen Pressure. Temp. Vol. at 0° C. and 760 
(measured moist). millims. 0 millims. 
123-3 740-5 21-5 108-5 
(1 vol. =0-331 cub. centim.) 
This corresponds to 20-1 per cent, of nitrogen. A third and still more simple mode of 
obtaining the nitride is that of exposing the trioxide to the action of ammonia gas at a 
white heat. It is a remarkable fact, and one of which we know of but two other examples, 
that in presence of nitrogen and hydrogen the whole oxygen of an oxide is displaced by 
nitrogen. 
THE CHLORIDES OF VANADIUM. 
I have succeeded in preparing three chlorides of vanadium, viz. (1) vanadium tetra- 
chloride, VC1 4 , (2) vanadium trichloride, VC1 3 , (3) vanadium dichloride, VC1 2 . 
(1) Vanadium Tetrachloride , VC1 4 , molecular weight =193"3, vapour-density =96-6 
(H=l). — This chloride is formed as a dark reddish-brown volatile liquid when metallic 
vanadium or the mononitride is burnt in excess of chlorine. 
Method 1. — The first method adopted for the preparation of the tetrachloride was by 
passing dry chlorine gas over the mononitride heated to redness ; the whole of the nitride 
volatilizes, and a reddish-brown liquid is obtained. In one operation 16-96 grms. of 
the mononitride yielded, on treatment with excess of chlorine, 44‘3 grms. of the crude 
tetrachloride, the theoretical yield being 50-1 grms. Owing to the inevitable presence 
of traces of oxide in the nitride, the first few drops of the distillate consisted of the 
more volatile light-yellow oxytrichloride, and this portion was collected separately before 
much of the dark tetrachloride had come over. 
The crude product thus obtained was first saturated with chlorine, and then distilled 
upwards for some hours in a current of dry carbonic acid. On fractionating, the liquid 
was found to begin to boil at 148°, slowly rising to 154°, between which points the whole 
of the liquid came over. 
A considerable quantity of a solid mass of peachblossom-coloured crystals, consisting 
of vanadium trichloride, remains behind in the bulb after each distillation. A second pre- 
paration of 50 grms. of the pure tetrachloride gave a constant boiling-point at 152°-154°. 
Method 2. — When vanadium oxytrichloride is prepared according to Berzelius’s reac- 
tion by passing dry chlorine over a mixture of the trioxide and charcoal heated to red- 
