Sulfur dioxide

Properties

General
Name	Sulfur dioxide
Chemical formula	SO2
Appearance	Colourless gas
Physical
Formula weight	64.1 amu
Melting point	198 K (-75 °C)
Boiling point	263 K (-10 °C)
Density	1.4 ×103 kg/m3 (liquid)
Solubility	9.4 g in 100g water
Thermochemistry
ΔfH0gas	-296.84 kJ/mol
ΔfH0liquid	? kJ/mol
ΔfH0solid	? kJ/mol
S0gas, 1 bar	248.21 J/mol·K
S0liquid, 1 bar	? J/mol·K
S0solid	? J/mol·K
Safety
Ingestion	Relatively low toxicity, may cause nausea and vomiting. Long term hazards known.
Inhalation	Extreme irritation.
Skin	Hazardous when cryogenic or compressed.
Eyes	Hazardous when cryogenic or compressed.
More info	Hazardous Chemical Database
SI units were used where possible. Unless otherwise stated, standard conditions were used. Disclaimer and references

Sulfur dioxide (spelt in British English Sulphur dioxide) has the chemical formula SO₂. The gas is irritant to the lungs.

It is produced by volcanoes and in various industrial processes. In particular, poor-quality coal and petroleum contains sulfur compounds, and generates sulfur dioxide when burned: the gas reacts with water and atmospheric oxygen to form sulfuric acid (H₂SO₄) - and thus Acid rain.

Sulfur dioxide is frequently used as a food additive: particularly as a preservative in alcoholic drinks.