24 
PROFESSOR ROSCOE’S RESEARCHES OH VANADIUM. 
Nos. 
Weight of trichlo- 
Weight of vanadium 
Percentage of 
ride taken. 
pentoxide found. 
vanadium. 
1 . 
1-4188 
0-7368 
29-20 
2. 
0-7013 
0-3679 
29-47 
3. 
0-7486 
0-3959 
29-71 
4. 
1-1731 
0-6252 
29-94 
Mean result . . 
. . 29-58 
These results give as the composition of vanadyl trichloride, — 
Calculated. 
Found. 
V = 51-3 
29-54 
29-58 
Cl 3 =106-37 
61-25 
61-27 
O = 16-00 
9-21 
— 
173157 
100-00 
2. Vanadium Oxydichloride, or Vanadyl Dichloride, VO Cl 2 = 138-21. — This sub- 
stance is formed, together with other lower solid oxychlorides, when the vapour of vana- 
dyl trichloride mixed with hydrogen is passed through a red-hot tube. It is easily ob- 
tained, however, in the pure state by the action of metallic zinc on the oxytrichloride in 
sealed tubes at 400°. For this purpose strips of zinc and slight excess of the liquid chlo- 
ride are heated in a strong tube placed in an inclined position in an air-bath for three 
or four days in a temperature considerably above the boiling-point of mercury; the 
oxytrichloride is decomposed, a black oxide of vanadium is formed together with zinc 
chloride, and a sublimate of splendid grass-green tabular crystals of the oxydichloride 
collects in the upper part of the tube. On opening the tube, the portion containing 
the crystals was quickly pushed inside a wider tube heated to 130° in a paraffin bath 
through which a current of dry carbonic acid was passed ; the excess of liquid oxychloride 
was thus easily expelled and the green crystals obtained of a constant weight. The 
black oxide formed together with the green crystals consists of the lowest oxide, V 2 0 2 , 
as on treatment with dilute acid it bleaches strongly. 
Vanadium oxydichloride is a grass-green body crystallizing in thin plates and possess- 
ing an unctuous feel. It is slowly decomposed by water, and on exposure to moist air 
it deliquesces; it easily dissolves in dilute nitric acid. Its specific gravity at 13°C. is 
2 - 88 . 
The composition of the oxydichloride is readily determined by precipitating the chlo- 
rine in nitric-acid solution, and estimating the vanadium in the filtrate. 
Nos. Weight of oxydi- AgCl. 
chloride taken. Found. 
0-3765 0-7683 
0-3207 0-6631 
Percentages 
V0 5 - , ; A ^ 
Found. , of chlorine. of vanadium. 
0-2498 50-40 37-30 
0-2160 51-07 37-87 
1 . 
9 
