TUNGSTEN COMPOUNDS. 89 



by heating either the non-volatile residue or the pure tetra- 

 chloride in a current of carbonic acid. For this purpose 

 the temperature of a moderately hot zinc bath was found 

 convenient; if a higher temperature be used metallic 

 tungsten is produced. 



The dichloride is a non-volatile loose grey powder with- 

 out lustre or crystalline structure. It alters perceptibly 

 on short exposure to the air, and dissolves slightly in water, 

 forming a brown solution ; the remainder is converted into 

 brown oxide, a slow evolution of hydrogen taking place. 



Analyses of Tungsten Dichloride, WC1 2 . 



Weight of chloride taken o'7553 17258 grms. 



,, tungsten obtained .. . 0*5590 1-2419 



„ silver chloride °*7595 *"94 2 9 



Percentage of tungsten 74' 04 7 1 '96 



„ chlorine 24-8 6 27*84 



Calculated. Found. 



Tungsten, W =184 7a'i5 73-00 



Chlorine, Cl 2 = 71 27*85 2,5-35 



255 ioo-oo 9835 



For analysis the dichloride was placed in a boat and 

 converted into WO, by passing hydrogen saturated with 

 nitrous fumes over it. In this process the formation of 

 some quantity of a white sublimate was observed, which 

 on examination proved to be ammonia salt formed by the 

 reducing action of the dichloride on nitric acid, thus : — 



W 2 Cl 4 + HNO ? + 3 H 2 = W a 6 + 4 HC1 4- NH r 



Experiments made in the endeavour to prepare the chlo- 

 rides WClj and WC1 were unsuccessful. 



5. Tungsten Oxy chlorides. — Themonoxychloride,WCl 4 0, 

 and the dioxychloride, WC1 Z 2 , have been already tolerably 

 fully studied by Bloomstrand and Riche ; nevertheless we 

 find that Persoz doubts the existence of these well-charac- 



