87 



Calculated. Found. 



Tungsten W=184 31-51 32-49 



Bromine Br, = 400 68-49 G7-74 



584 100-00 100-23 



When the pentabromide is heated to 350° in a current 

 of hydrogen a substance is obtained, which appears to cor- 

 respond to WBrs, but this is very readily decomposed, and 

 the dibromide WBrg is formed as a black velvety powder. 

 Analysis gave : 



Calculated. Found. 



Tungsten W=184 53-49 52-03 



Bromine Br,= 160 46-51 46-26 



344 100-00 99'29 



Oxyhromides of Tungsten. The monoxy bromide WO Br^ 

 is formed together with the Dioxybromide WO Br2 by 

 acting on a mixture of 1 part of metal and 2 parts of 

 tungsten dioxide with bromine. It forms shining brownish 

 black needles, which are easily fusible, and can be 

 separated from the dioxybromide by gentle sublimation 

 when the latter compound remains behind. The mon- 

 oxybromide melts at 277° and boils at 327'5°, and is readily 

 acted on by water. 



The mean of four analyses gives : 



Calculated. Found. 



Tungsten W-184 35-38 36-69 



Bromine ...Br4 = 320 61-54 61-04 



Oxygen 0- 16 3-08 



520 100-00 



The dioxybromide WOgBrg is formed as light reddish 

 brown vapours, which condense to reddish brown coloured 

 crystals by passing the vapour of the pentabromide over 

 tungsten trioxide. The crystals do not melt, but volatilize 

 at a temperature near to a red heat, and they are not 

 acted on by water. 



Analysis of four samples gave : 



