20 
PEOEESSOE EOSCOE’S EESEAECHES ON VANADIUM. 
manner to estimate the quantity of oxygen which the oxychloride contains, as only a 
small portion of the oxygen combines with the carbon, by far the greater portion 
remaining in combination with the metal to form dioxide or the lower solid oxychlorides 
yet to be described. 
(2) The yapour of the lemon-yellow chloride was passed over metallic magnesium 
heated in a current of pure hydrogen ; the action was violent, and the metal took fire. 
On cooling the tube the excess of magnesium was carefully removed, and the boat was 
found to contain a dark-coloured powder which, on extraction with water, contained both 
magnesium and chlorine ; after repeated boiling with water, hydrochloric acid extracted 
from this powder large quantities of magnesia, the oxygen of which could only be derived 
from the vanadyl trichloride. 
(3) The foregoing experiment, made with sodium instead of magnesium, showed that 
a thick crust of caustic soda was formed on the tube close to the boat in which the metal 
was placed. 
(4) The vapour of the liquid oxychloride mixed with pure hydrogen was passed 
through a red-hot tube ; the chloride was decomposed, black shining crystals of vana- 
dium trioxide were deposited in the first portions of the tube, a mixture of lower solid 
oxychlorides filled up the further portions, and small quantities of a dark-red liquid 
were formed. The black crystals on analysis were found to be free from chlorine ; 
0-0860 grm. of these crystals gave on oxidation 0-1051 grm. vanadium pentoxide, or 
the substance contained 99*2 per cent, of vanadium trioxide. 
(5) When vanadyl trichloride is rapidly distilled over heated carbon, or when it is 
prepared by treating a mixture of trioxide and carbon with chlorine, a dark reddish-brown 
liquid is formed consisting of a mixture of the oxychloride and another chloride. The 
analysis of this dark liquid yielded results which, when calculated for chlorine and 
vanadyl (V 0=67"3), always added up to from 103 to 105 per cent, on the quantity 
taken, showing the presence in this liquid of a vanadium chloride containing no oxygen. 
(i.) Preparation of Vanadyl Trichloride . — Finely divided vanadium pentoxide is 
intimately mixed with pure sugar-charcoal, and the mixture heated to redness in a cur- 
rent of hydrogen. After cooling in hydrogen the mixture of trioxide and carbon is 
removed to a hard glass retort, heated by a large Bunsen’s lamp, and a current of dry 
chlorine gas passed in. The crude oxychloride comes off as a reddish-yellow* liquid, of 
which 180 grms. were collected in one operation. In order to purify this liquid it is 
distilled upwards in a current of carbonic acid for several hours, and afterwards rectified 
several times over clean sodium in a current of carbonic acid, when the sodium becomes 
coated with a dark substance due to the decomposition of some other chlorides. The 
liquid gradually assumes a light amber-colour, and on continued distillation it attains a 
permanent lemon-yellow tint ; it began to boil at 126° C., and all came over before 130°. 
* The dark colour of the chloride thus prepared is not due to the presence of vanadic acid as Schafakik sup- 
poses, as the acid is insoluble in the chloride, but rather to some dark-coloured vanadium chlorides containing 
no oxygen. 
