87 
* 
Calculated. 
Found. 
Tungsten .. 
CO 
r-H 
II 
. 31-51 .... 
.. 32-49 
Bromine ... 
...Br 5 - 400 
. 68-49 .... 
.. 67-74 
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 WBr 3 , but this is very readily decomposed, and 
the dibromide WBr 2 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 
Oxybromides of Tungsten. The monoxy bromide WO Br 4 
is formed together with the Dioxybromide WO Br 2 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 
..Br 4 - 320 .. 
.... 61-54 .... 
.. 61-04 
Oxygen 
O- 16 .. 
.... 3-08 .... 
520 
100-00 
The dioxybromide W0 2 Br 2 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 : 
