Dr. H. E. Koscoe's Researches on Vanadium. 149 



vanadium in the metallic state in grey crystalline grains. Analysis 

 gave : — 



Calculated. Mean of 2 analyses. 



V = 51-3 41*95 42-16 



CI, = 71-0 58-05 57-88 



122-3 10000 100-04 



Vanadium dichloride is extremely hygroscopic ; when thrown into 

 water a violet-coloured solution is formed, identical in tint with the 

 liquid containing a hypovanadous salt obtained by reducing vanadic 

 acid in solution in presence of zinc- or sodium-amalgam ; and like 

 this latter liquid, the solution of dichloride in water bleaches strongly 

 by reduction. 



Oxidized by permanganate this liquid required 18' 78 per cent, of 

 oxygen (on the dichloride taken) to bring it up to vanadic acid, 

 whereas the equation 2VCl 2 + 3 + 2H 2 0=V 2 0. + 4HC1 requires 

 19'6 per cent. The specific gravity of vanadium dichloride at 18° is 

 3-23. 



MetallicVanadium, V=51'3. — Although from what we now know 

 of the characters of vanadium it appeared unlikely that any com- 

 pound containing oxygen would yield the metal by direct reduction, 

 the author has repeated the experiments of other chemists on this 

 subject, but without success. There is no doubt that the metal 

 cannot be obtained by any of the processes described in the books. 

 The only methods which promised possible results were : — 



1 . The reduction of a vanadium chloride (free from oxygen) in 



hydrogen gas, either with or without sodium. 



2. The reduction of the mononitride at a white heat in hydrogen. 

 The first of these methods has proved to be successful, whilst the 



second does not appear to yield metal, inasmuch as the nitride ex- 

 posed for 3| hours in a platinum tube to the action of hydrogen 

 at a white heat, lost only 8 per cent., whereas it must lose 21*4 per 

 cent, on conversion into metal. 



Notwithstanding the apparent simplicity of the method, the author 

 has found it exceedingly difficult to obtain the metal perfectly free 

 from oxygen. This arises from the fact that, whilst vanadium is quite 

 stable at the ordinary temperature, it absorbs oxygen with the great- 

 est avidity at a red heat, and that therefore every trace of air and 

 moisture must be excluded during the reduction. Another difficulty 

 consists in the preparation of the solid chlorides in large quantity 

 and free from oxygen or moisture, as also in the length of time 

 needed to reduce these chlorides in hydrogen, during which time ua 

 avoidable diffusion occurs and traces of oxygen enter the tube. 

 Again, the reduction can only be effected in platinum boats placed 

 in a porcelain tube, as the metal acts violently on glass and porcelain, 

 and tubes of platinum are porous at a red heat. 



A description of the apparatus employed is then given, the main 

 points being to guard against diffusion, and to introduce the powdered 



