Main Page | See live article | Alphabetical index 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. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.