PROFESSOR EOSCOE’S RESEARCHES ON VANADIUM. 
685 
used in analysis (1) was obtained by the first method, that used for analyses 2, 3, and 4 
was prepared by the second process. 
Weight of 
trichloride 
taken. 
Silver 
chloride 
found. 
Vanadium 
pentoxide 
found. 
Percentages of 
A 
No. 
chlorine. 
vanadium. 
1. 
1-6615 
4-5704 
0-9240 
68-05 
31-25 
o J 
f 0-2295 
— 
0-1320 
— 
32-31 
2 1 
l 0-2550 
0-6931 
— 
67-25 
— 
3. 
0-1965 
0-5298 
0-1140 
66-71 
32-59 
H 
f 0-1094 
0-2993 
— 
67-67 
— 
[ 0-2188 
— 
0-1290 
— 
33-12 
Hence we have for 
the composition of this chloride 
Found. 
V 
= 51-3 
r 
Calculated. (1) 
32-5 31-25 
(2) 
32-31 
(3) 
32-59 
(4) ' 
33-12 
Mean. 
32-57 
Cl. 
5=106-5 
67-5 68-05 
67-25 
66-71 
67-67 
67-42 
WV8 
100-0 99-30 
99-56 
99-30 
100-79 
99-99 
When the trichloride is thrown into water it does not at once dissolve, the peachblos- 
som-coloured crystals floating in the liquid ; these, however, gradually dissolve, forming a 
brown-coloured solution, which on addition of a drop of acid turns to a bright green 
colour, identical in tint with the liquid obtained by reducing vanadic acid in solution 
with nascent hydrogen evolved by magnesium, and containing a hypovanadic salt. Like 
the solution obtained by reduction, the green-coloured solution of the trichloride absorbs 
oxygen on standing, passing into the blue solution of the vanadous salts. A solution of 
hypovanadic salt obtained by dissolving 0293 grm. of trichloride in water required 45 
cub. centims. of permanganate solution in order to oxidize it completely (1 cub. centim. 
permanganate=000066 grm. oxygen). Hence the quantity of oxygen needed to oxidize 
the solution was 1010 per cent, (on the trichloride), whilst that required by the formula 
2V Cl 3 + 0 2 + 3H 2 O = V 2 0 5 + 6H Cl is 10-14 per cent. 
The specific gravity of vanadium trichloride at 18° is 3-00. Vanadium trichloride 
dissolves readily in absolute alcohol, forming a greenish-blue solution ; in ether it also 
dissolves, giving a green-coloured solution. 
(3) Vanadium Bichloride, V Cl 2 =122-3. — Vanadium dichloride is a solid body crys- 
tallizing in fine bright apple-green plates, having a micaceous lustre and an hexagonal 
form. It is prepared by passing the vapour of vanadium tetrachloride mixed with dry 
and pure hydrogen through a glass tube heated to dull redness. If the distillation of 
the tetrachloride be conducted slowly, and the mixture of vapour and hydrogen brought 
at once into the heated portion of the tube, the pure dichloride is deposited in light 
pearly scales, which can easily be shaken out of the tube. If the operation be conducted 
too quickly, or if the hydrogen be not present in large excess, a considerable quantity of 
mdccclxix. 4 Y 
