Sulfur dioxide

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Sulfur dioxide
Sulfur-dioxide-2D.svg
Sulfur-dioxide-3D-vdW.png
IUPAC name Sulfur dioxide
Other names Sulfurous anhydride

Sulfur(IV) oxide

Identifiers
CAS number 7446-09-5
PubChem 1119
EC number 231-195-2
KEGG D05961
MeSH Sulfur+dioxide
ChEBI CHEBI:18422
RTECS number WS4550000
SMILES O=S=O
Beilstein Reference 3535237
Gmelin Reference 1443
Properties
Molecular formula SO2
Molar mass 64.066 g mol−1
Appearance Colorless gas
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 dm−3[1]
Vapor pressure 237.2 kPa
Acidity (pKa) 1.81
Basicity (pKb) 12.19
Viscosity 0.403 cP (at 0 °C)
Structure
Space group C2v
Coordination
geometry
Digonal
Molecular shape Dihedral
Dipole moment 1.62 D
Thermochemistry
Std enthalpy of
formation
ΔfHo298
-296.81 kJ mol−1
Standard molar
entropy
So298
248.223 J K−1 mol−1
Hazards
EU classification Toxic T
EU Index 016-011-00-9
NFPA 704

NFPA 704.svg

0
3
0
 
R-phrases R23, R34, R50
S-phrases (S1/2), Template:S9, S26, Template:S36/37/39, S45
Related compounds
Related sulfur oxides Sulfur monoxide
Sulfur trioxide
Related compounds Ozone

Selenium dioxide
Sulfurous acid
Tellurium dioxide

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 sulfur trioxide, which is dissolved in sulfuric acid to make more sulfuric acid. It is used to make sulfites.

Sources[change | change source]

  1. Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3.