Sulphur occurs widely in nature as H2S and SO2
SO2 + 3H2 <=> H2S + 2H2O
H2S is favoured under high pressure (magma). SO2 is favoured at low pressures (volcanic vent)
Liquid sulphur
Liquid sulphur turns from yellow to brown at 200 deg C. At its boiling point of 444.6 deg C it is red. The red is most intense at
about 500° C. Liquid sulphur may occur under volcanic lakes. Ijen erupted molten sulphur in the 1952.
Solid Sulphur
Sulphur is used in the manufacture of pharmaceuticals.
Hydrogen Sulphide (H2S)
Hyhrogen sulphide is an extremely poisonous with a revolting odour. It has a rotten egg smell.
The toxicity of H2S exceeds that of hydrogen cyanide. In Japan hydrogen sulphide has caused
deaths in 10 incidents throughout the 20th century. The gas is denser than air and may accumulate in depressions.
0.77 ppm Detectible concentration.
4.6 ppm Easily smelt.(rotten egg smell)
20-150 ppm eye and respiritary irritation.
>250 ppm causes pulmonary oedema.
1000-2000 ppm causes death after a single breath.
Sulphur dioxide (SO2)
Sulphur dioxide is a colourless gas with a pungent odour.
0.3-1.0 ppm detectible concentration.
3 ppm easily noticed.
6-12 ppm causes irritation of nose and throat.
>20 ppm causes eye irritation
10 000 ppm immediately irritates skin.
Sulphur dioxide can cause fatal asthma attacks in certain people.