What Shape Does SO2 Have?

SO2 has a Bent (V-shaped) molecular geometry (AX2E, trigonal planar) with a bond angle of ≈119°. The central sulfur carries 2 bonding domain(s) and 1 lone pair(s) — 3 electron domains in total. The single lone pair compresses the 120° planar ideal only slightly.

Hybridisation is conventionally described as sp2 at sulfur. Polarity: Polar (≈1.63 D).

1. Molecular Identity and Key Parameters

Molar mass is the average value rounded for procurement use. Hybridisation labels are the conventional VSEPR-level description; orbital treatment becomes more nuanced at higher levels of theory.

2. Drawing the Lewis Structure of SO2, Step by Step

1. Count valence electrons: 6 (S) + 2×6 (O) = 18 — a total of 18 electrons (9 pairs) must be placed.
2. Build the skeleton: place the sulfur at the centre and attach the terminal atoms with single bonds; hydrogen is never a central atom. Each single bond consumes 2 electrons.
3. Complete terminal octets: distribute the remaining electrons as lone pairs on the terminal atoms first (hydrogens already carry their duet from the single bond).
4. Satisfy the central atom: Two S–O bonding domains plus one lone pair on sulfur; resonance distributes the double-bond character over both S–O links.
5. Check formal charges and resonance: Major valence-bond description: one S=O plus one S–O− with S+, delocalised by resonance; the alternative charge-separated pair of S–O bonds is a minor contributor. Resonance: Both S–O bonds are identical experimentally (order ≈1.5).
6. Verify: Sulfur exceeds the octet in the double-bonded form. Apply the standard formal-charge check (valence − nonbonding − half of bonding electrons) to confirm the drawn form.

A worked diagram of this molecule is kept in the companion guide: SO2 Lewis structure.

3. VSEPR Analysis: Why SO2 Is bent (v-shaped)

VSEPR theory counts electron domains — every σ bond counts once regardless of bond order, and every lone pair counts once. SO2 has 3 such domains around the sulfur: 2 bonding and 1 lone. 3 domains correspond to a trigonal planar electron-domain arrangement; with 1 lone pair excluded from the shape the observed molecular shape is bent (v-shaped) (AX2E).

Bond angle: ≈119° because the single lone pair compresses the 120° planar ideal only slightly.

Polarity: Polar (≈1.63 D).

Bond-order note: Both S–O bonds are identical experimentally (order ≈1.5).

4. The Most Common Mistake When Drawing SO2

5. Why the Geometry Matters in Practice

Winery preservative, reducing agent for sulfite production and precursor of sulfuric acid; food-grade SO2 specifies strict impurity limits.

Structure-level identity is exactly what a purchase order has to fix: the same molecular formula can hide isomers, hydrates or salt forms with different handling profiles. Before ordering, match CAS (7446-09-5), assay, water content and container rating against the datasheet, and request the COA batch that will ship.

Compare Sulfur Dioxide (SO2) supply offers →

6. Quick FAQs on SO2

7. References

1. IUPAC / Gillespie, Assessment of the VSEPR model. Basis of AXE notation and lone-pair ordering. VSEPR entry
2. PubChem compound record for Sulfur Dioxide (SO2). Registry number, formula and computed descriptors. PubChem 7446-09-5
3. Companion Lewis-structure guide on this site. Worked diagram for SO2. Lewis structure SO2