Compound reference
Sulfur dioxide
SO₂
The chemistry
Bent - like water, but with sulfur in the middle and two double bonds. Each double bond can be drawn either side of S; the molecule resonates.
Remember it as…
S in the middle, one lone pair pushes the two O's down. Three regions of electron density → bent at ~119°.
Common mix-up
Drawing SO₂ as O=S=O with no lone pair on S is a common shortcut, but the molecule is bent, not linear. The lone pair on S has to be there to balance the electron count.
Where the name comes from
Sulfur from Latin sulpur (brimstone, the burning yellow rock). Roman authors knew sulfur burned with a sharp smell.
Where you meet it
Sharp suffocating smell; volcanic emission and fossil-fuel byproduct; reacts with water vapor to form sulfurous acid → acid rain.
PubChem facts
- IUPAC name
- sulfur dioxide
- Molecular weight
- 64.07 g/mol
Also known as: sulfurous anhydride, sulphur dioxide
Handling note
A choking, corrosive gas that irritates the lungs; a major air pollutant.
BondingMolecular geometry
Chemical data from PubChem (NIH/NCBI)