S3 
quantities of iodine were liberated. The residual chloride 
was tested for lower chlorides by titrating a weighed quan- 
tity with a standard permanganate solution, which readily 
oxidizes the blue oxide, formed by the action of water on 
the pentachloride, into tungstic acid. In one experiment 
thus conducted the residual chloride contained 3 3 per cent 
of pentachloride, whilst in another no less than 24 - 6 per 
cent of the pentachloride was formed. The pentachloride 
treated in a similar way yields no free chlorine, and there- 
fore does not undergo a similar decomposition at high tem- 
peratures. 
2. Tungsten Pentachloride, WC1 S . 
On distilling the hexacliloride in a current of hydrogen a 
reduction always takes place. If the temperature be kept 
but little above the boiling point of the hexachloride, the 
dark red colour of the vapour is seen to vanish, and a light 
yellow coloured vapour makes its appearance, which soon 
condenses into black drops or long shining black needles. 
After two or three distillations in hydrogen a pure product 
is obtained. Tungsten pentachloride crystallizes in long 
black shining needles; if condensed in fine powder its 
colour is dark green, and the powdered crystals also possess 
a dark green colour like that of potassium manganate. 
The pentachloride is exceedingly hygroscopic, the crystals 
becoming instantly covered with a dark golden-green film 
on exposure to air, and small particles being instantly con- 
verted into drops. The crystals do not decrepitate like 
those of the hexachloride. On treatment with larger 
quantities of water the pentachloride gives rise to an olive- 
green solution, although the greater part of the chloride 
forms the blue oxide and hydrochloric acid. Analyses made 
with three separate preparations according to the method 
already described, gave the following mean result : — 
Calculated. Found. 
Tungsten W - 184 50-89 50-90 
Chlorine Cl 5 = 1 77*5 49-11 48-58 
361-5 
100-00 
99-48 
