TUNGSTEN COMPOUNDS. 91 



Vapour -density of WC1 4 in Mercury -vapour. 



I. II. 



Weight of bulb in air 22-6345 24*1850 grrns. 



Barometer 764 767 mm. 



Temperature io° io° C. 



Weight of bulb and yapour, 1 



at 350° C ) 23 ' 1415 -47745 grms. 



Capacity of bulb 89*45 107*70.0. 



Hence vapour-density (H = 1 ) 1 7 5*8 1 70*2 



Hence it appears that the vapour-density of tungsten 

 monoxychloride has the normal density. 



The Dioxy chloride, WCl a 2 , is best prepared by passing 

 chlorine over the brown dioxide. Combination takes place 

 at a moderate heat, the oxide becoming covered with a 

 whitish crust, which, on increase of temperature, distils 

 off without melting, condensing in small square scales of a 

 whitish-yellow colour. The dioxychloride volatilizes at a 

 temperature near to a red heat, with partial decomposition. 

 The crystals are infusible, and are not acted upon by moist 

 air or cold water. Even when boiled with water the di- 

 oxychloride is not completely decomposed, the unaltered 

 substance being volatilized on evaporation; and in the 

 analysis, in which moist hydrogen is passed over the sub- 

 stance, great care has to be taken to prevent loss by volati- 

 lization of the compound. If the metal only is to be 

 determined, the oxychloride may be dissolved in ammonia, 

 and the solid mass ignited when W0 3 is left. 



The following were the results of the analyses : — 



Calculated. Found. 



Tungsten 64*32 64*11 



Chlorine 24*31 24*74 



Oxygen n'37 



100*00 



The vapour-density of the dioxychloride could not be 

 determined, as at 440 C. the contents of the bulb remained 

 liquid. 



