Sulfur dioxide facts for kids
Quick facts for kids Sulfur dioxide |
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| IUPAC name | Sulfur dioxide |
| Other names | Sulfurous anhydride Sulfur(IV) oxide |
| Identifiers | |
| CAS number | |
| PubChem | |
| EC number | 231-195-2 |
| KEGG | D05961 |
| MeSH | |
| ChEBI | CHEBI:18422 |
| RTECS number | WS4550000 |
| SMILES | O=S=O |
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InChI
InChI=1/O2S/c1-3-2
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| Beilstein Reference | 3535237 |
| Gmelin Reference | 1443 |
| Properties | |
| Molecular formula | SO2 |
| Molar mass | 64.066 g mol−1 |
| Appearance | Colorless gas |
| Odor | Pungent; similar to a just-struck match |
| Density | 2.6288 kg m−3 |
| Melting point |
-72 °C, 201 K, -98 °F |
| Boiling point |
−10 °C, 263 K, 14 °F |
| Solubility in water | 94 g/L forms sulfurous acid |
| Vapor pressure | 237.2 kPa |
| Acidity (pKa) | 1.81 |
| Basicity (pKb) | 12.19 |
| −18.2·10−6 cm3/mol | |
| Viscosity | 0.403 cP (at 0 °C) |
| Structure | |
| C2v | |
| Coordination geometry |
Digonal |
| Molecular shape | Dihedral |
| Dipole moment | 1.62 D |
| Thermochemistry | |
| Std enthalpy of formation ΔfH |
−296.81 kJ mol−1 |
| Standard molar entropy S |
248.223 J K−1 mol−1 |
| Hazards | |
| NFPA 704 |
0
3
0
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| U.S. Permissible exposure limit (PEL) |
TWA 5 ppm (13 mg/m3) |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) | |
Sulfur dioxide (also sulphur dioxide) is the chemical compound with the formula SO2. It is a gas. It smells like burnt matches. It also smells suffocating. Sulfur dioxide is produced by volcanoes and in various industrial processes. It is also used to protect wine from oxygen and bacteria. It can be produced by burning sulfur. It dissolves in water to produce sulfurous acid. It can be oxidized to trioxide, which is dissolved in sulfuric acid to make more sulfuric acid. It is used to make sulfites.
Images for kids
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The blue auroral glows of Io's upper atmosphere are caused by volcanic sulfur dioxide.
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US Geological Survey volunteer tests for sulfur dioxide after the 2018 lower Puna eruption
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A sulfur dioxide plume from Halemaʻumaʻu, which glows at night
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Sulfur dioxide in the world on April 15, 2017. Note that sulfur dioxide moves through the atmosphere with prevailing winds and thus local sulfur dioxide distributions vary day to day with weather patterns and seasonality.
