148 Royal Society: — 



is 4' 14; the percentage of oxygen found by experiment was 

 4-11. 



The solution of the tetrachloride in water does not bleach ; but 

 if the vapour be led into water a liquid is obtained which bleaches 

 litmus. Vanadium tetrachloride acts violently on dry alcohol and 

 ether, forming deep-coloured liquids. The author is engaged upon 

 the examination of this reaction. 



Bromine and vanadium tetrachloride, sealed up and heated toge- 

 ther, do not combine ; on the contrary, trichloride is deposited. 

 Hence it is clear that vanadium does not readily form a pentad com- 

 pound with the chlorous elements. 



2. Vanadium Trichloride, VC1 3 = 157*8. — The trichloride is a 

 solid body, crystallizing in splendid peachblossom-coloured shining 

 tables, closely resembling in appearance the crystal of chromium 

 sesquichloride. It is non-volatile in hydrogen, and, when heated in 

 the air, it decomposes, glowing with absorption of oxygen, and form- 

 ing the pentoxide. Heated in hydrogen the trichloride first loses 

 one atom of chlorine, forming the dichloride (VC] 2 ), and afterwards, 

 on exposure to a higher temperature, loses all its chlorine, leaving 

 metallic vanadium as a grey lustrous powder. The trichloride is 

 extremely hygroscopic, deliquescing on exposure to air to a brown 

 liquid. The trichloride is best prepared by the quick decomposition 

 of the tetrachloride at its boiling-point, or by its slow decomposition 

 at the ordinary temperature of the air. The crystalline powder 

 obtained by either of these methods only requires freeing from ad- 

 hering tetrachloride by drying in carbon dioxide at 160° in order to 

 yield good analytical results. 



Calculated. Mean of 4 analyses. 



V = 51-3 32-5 32-57 



Cl 3 = 106-5 67'5 67*42 



157-8 100-0 99-99 



The trichloride thrown into water does not at once dissolve ; but as 

 soon as the crystals get moistened, a brown solution is formed, which 

 becomes green on addition of a drop of hydrochloric acid, and con- 

 tains a hypovanadic salt in solution. This green tint is identical 

 with that got by reducing a solution of vanadic acid in presence of 

 magnesium. According to the equation 2VCl 3 + 2 + 3H 2 = V 2 5 

 + 6HC1, the solution of the trichloride requires 10-14 per cent, of 

 oxygen to bring it up to vanadic acid, whilst analysis showed that 

 10*1 per cent, was necessary. The specific gravity of the trichloride 

 at 18° is 3-00. 



3. Vanadium Bichloride, VC1 2 =122'3. — The dichloride is a solid 

 crystallizing in fine bright apple-green micaceous plates. It is pre- 

 pared by passing the vapour of vanadium tetrachloride mixed with 

 hydrogen through a glass tube heated to dull redness. If the 

 heat be pushed further a blackish crystalline powder, consisting of 

 a mixture of lower chloride and metal, is obtained. The dichloride, 

 when strongly heated in hydrogen, loses all its chlorine, leaving 



