Intelligence and Miscellaneous Articles, 461 



in composition ; but its properties are very different, for it boils at 

 284° Fahr. instead of 185°. When the operation is conducted at a 

 high temperature, then, besides the above-described product, naph-i 

 thalin is also obtained. — Ibid., p. 110. 



ON CHLORIDE OF TUNGSTEN. BY M. HENRI ROSE. 



This chloride was discovered by Woehler, who prepared it by 

 heating oxide of tungsten in a current of chlorine gas. The oxide 

 is then converted into chloride of tungsten, which is volatilized and 

 separately obtained, and tungstic acid, which remains in the appa- 

 ratus after the operation is over. The chloride of tungsten has the 

 property of being decomposed by water into hydrochloric acid and 

 tungstic acid ; and it is this property which induced me to consider 

 it as a chloride of tungsten corresponding in composition with 

 tungstic acid. M. Malaguti supposed that he had confirmed this 

 composition by analysis, having found, by quantitative experiments, 

 that chloride of tungsten, obtained by the action of chlorine on 

 oxide of tungsten, was composed of 47 '4 of tungsten, and 54*89 of 

 chlorine. I obtained the oxide of tungsten, which I used for the 

 preparation of the chloride, from tungstic acid, by means of hydro- 

 gen ; managing the heat so as to avoid the complete reduction of 

 any part of the acid into metal. 



If a current of dry chlorine gas be passed over the oxide thus 

 prepared, chloride of tungsten is obtained mixed with the red chlo- 

 ride of tungsten which corresponds to the oxide of this metal ; at 

 the upper part of the glass bulb in which the oxide of tungsten is 

 heated, and whilst a current of chlorine was passing through it, 

 there was deposited a substance which could not be volatilized, even 

 by heating the glass bulb as strongly as it could bear the heat. By 

 heating slightly the chloride obtained, it is separated from the red 

 chloride, which is much less volatile. If the chloride be too strongly 

 and suddenly heated, red chloride is formed, and a first residue re- 

 mains, similar to that obtained during the prej)aration of the chlo- 

 ride. These two products are tungstic acid. 



This decomposition caused a suspicion, that the chloride is not 

 entirely composed of chlorine and tungsten, but that it must contain 

 some oxygen. It will afterwards be seen that it is impossible to 

 obtain the chloride free from all admixture of tungstic acid, by at- 

 tempting to free it from the chloride which accompanies it, with a 

 gentle heat. Lastly, small quantities only of the chloride can be 

 prepared, especially if the glass tubes, which are welted to the bulb 

 in which the oxide of tungsten is heated, are not of suflicient dia- 

 meter ; for the chloride of tungsten formed, which collects near the 

 opening of the tube, in the bulb heated by the spirit-lamp, soon de- 

 posits, by its decomposition, so much tungstic acid as to choke the 

 tube, and causes the bulb to burst. 



Two hundred and thirty-seven and a half parts of the chloride 

 were dissolved in solution of ammonia, the tungstic acid which was 

 mixed with the chloride remained insoluble ; the solution evaporated 

 nearly to dryness, and the mass dried and calcined gave 198*5 parts 

 of tungstic acid, which corresponds to 66*67 per cent, of tungsten in 



