F. Wohler on Tungsten. 267 



of tungsten must be employed; and consequently a corre- 

 sponding part of tungsten set free, and combined (as I have said 

 before) with chlorine. From this reason it is evident that this 

 new combination can only contain the tungsten in the state of 

 oxide. 



I have tried without success to produce this body by the 

 direct combination of the oxide of tungsten with soda. By 

 heating those bodies together I obtained metallic tungsten 

 and tungstate of soda. 



Lastly, I also tried to produce an analogous combination 

 with potash, and treated the super-tungstate of potash in the 

 same manner as the corresponding salt of soda. I obtained a 

 metallic mass of a whitish colour, being pure metallic tung- 

 sten. 



Chloride of Tungsten. 



Sir H. Davy was the first who found that tungsten heated 

 in chlorine burns and produces a white substance, which is 

 decomposed by the action of water into tungstic acid and hy- 

 drochloric acid : but nothing further seems to be known on 

 the subject. I have found that there are three different com- 

 binations of tungsten and chlorine. 



Perchloride of Twigste7i. 



This is always produced, and nearly in a pure state, on heat- 

 ing the black oxide of tungsten in chlorine ; — with the brown 

 oxide, tungstic acid is formed at the same time. The combi- 

 nation is effected with an evolution of light; the glass globe in 

 which the operation is performed is filled with a thick yellow 

 smoke, which is condensed into scales of a yellowish-black 

 colour, and which at last forms a thick sublimate that ex- 

 teriorly perfectly resembles native boracic acid. In contact 

 with atmospheric air this chloride changes, according to the 

 hygroscopic state of the air, within some hours or some days, 

 into tungstic acid ; and at the same time hydrochloric acid is 

 disengaged. With water this decomposition is more rapid, 

 although not instantaneous; very pure tungstic acid is de- 

 posited, and weak hydrochloric acid is formed at the same time. 

 In ammonia it dissolves with a slight noise and an evolution 

 of heat. It volatilizes in a low temperature without first melt- 

 ing, and its vapour is of a dark yellow colour. 



Heated on })latinum foil by a spirit-lamp, it is decomposed 

 at the moment when it is volatilized, by the action of the 

 aqueous vapour formed by the combustion of the alcohol : va- 

 pour of hydrochloric acid is formed; and the tungstic acid 

 which is produced, forms above the flame a luminous smoke, 

 and then disperses in large and very light flakes. 



L 1 2 The 



