324 M. Berzelius on Vanadium. 



specific gravity. It is a good conductor of electricity, and 

 strongly negative to zinc. The powder of vanadium, obtained 

 by its reduction with potassium, takes fire at a heat below red- 

 ness, burns without energy, and leaves a black unfused oxide. 

 Vanadium dissolves readily in nitric acid and in aqua regia; 

 the solution has a fine blue colour. The sulphuric, muriatic, 

 and fluoric acids do not attack it at all, even when they are 

 concentrated and boiling. It is not oxidized by the alkaline 

 hydrates, and it may be heated with them to redness without 

 undergoing any alteration if the air be excluded. The solution 

 of vanadic oxide in the acids, or of vanadic acid in an excess 

 of caustic potash, does not give metallic vanadium by zinc. 



Oxides of Vanadiwn. — Of this metal there are three com- 

 pounds with oxygen : — 



1st, Suboxide of Vanadium. — It is obtained by reducing 

 vanadic acid by hydrogen gas at a red heat, or by fusing va- 

 nadic acid in a cavity made in charcoal. In the first mode, 

 the suboxide preserves the form and lustre of the crystalline 

 facets of the acid, but it becomes black ; by the latter pro- 

 cess a coherent mass is obtained, which is easily reducible 

 to powder, possesses a semimetallic lustre and the colour of 

 plumbago. Hydrogen passed over the suboxide does not de- 

 compose it at the highest temperature which can be imparted 

 to it in a porcelain tube heated by a small wind-furnace. 

 This suboxide, by whatever process obtained, provided it be 

 coherent, is a good conductor of electricity, and infinitely ex- 

 ceeds copper, and even gold and platina, as a negative electro- 

 motor. 



It has not hitherto been combined with other bodies, or 

 with acids or bases. That which is reduced by hydrogen gas 

 gradually oxidizes in the air, but without any alteration of ap- 

 pearance; and the lower the temperature at which the oxide 

 is formed, the more readily oxidation occurs. Its oxidation is 

 apparent by throwing it into water, which becomes of a fine 

 green colour by dissolving a compound presently to be treated 

 of. When heated in the air, it takes fire and burns, leaving 

 an unfused black residue. Chlorine gas converts it into 

 chloride and vanadic acid. It is composed of 89*538 parts 

 of vanadium, and 10*862 parts of oxygen; 100 parts of the 

 former are combined with 11*6843 parts of the latter. 



2ndly, Oxide of Vanadium. — Vanadate of ammonia cannot 

 be employed in the preparation of this oxide in the same way 

 as the molybdate and tungstate of ammonia, which yield the 

 oxides of their metals when they are heated. The oxygenated 

 compound of vanadium obtained by this method, contains the 

 three degrees of oxidation of this metal. In order to obtain 



pure 



