Sulfur dioxide (SO₂) consists of one atom of sulfur (S) and two atoms of oxygen (O). Sulfur shares a double bond with each oxygen atom. A lone electron pair on sulfur repels oxygen’s lone pairs, making SO₂ a bent structure with a bond angle of 119°.

Oxygen is more electronegative than sulfur. The electronegativity makes the oxygen-sulfur bond polar. The shared electron pairs are attracted toward oxygen, resulting in a partial negative charge on the oxygen and a partial positive charge on the sulfur. Besides, the bent structure of SO₂ makes the charge distribution asymmetric, and two poles of charges are observed on the molecule. Such electron distribution makes the SO₂ molecule polar.