Lewis Structure Generator
Phosphorus trichloride · PCl3

PCl3 Lewis Structure

Phosphorus forms three single bonds to chlorine and retains one lone pair. The four electron domains give tetrahedral electron geometry and trigonal pyramidal molecular geometry.

Open PCl3 in the generatorSee drawing steps
PCl₃
:P: / | \ Cl Cl Cl
One lone pair on phosphorus; three on each chlorine
Total valence electrons26
Central lone pairs1
Electron geometryTetrahedral
Molecular geometryTrigonal pyramidal

PCl3 overview

Phosphorus contributes five electrons and three chlorines contribute twenty-one. Three P–Cl single bonds use six electrons. Completing the chlorine octets uses eighteen more, leaving one lone pair on phosphorus.

How to draw PCl3

  1. Count 26 valence electrons.
  2. Place phosphorus in the center.
  3. Draw three P–Cl single bonds.
  4. Add three lone pairs to each chlorine.
  5. Place the final lone pair on phosphorus and verify zero formal charges.

Why is PCl3 pyramidal?

Three bonding domains and one lone pair surround phosphorus. The lone pair occupies one tetrahedral position, leaving the three chlorines in a trigonal pyramidal arrangement.

Common mistakes

  • Forgetting the phosphorus lone pair.
  • Drawing P=Cl double bonds.
  • Giving chlorine fewer than three lone pairs.
  • Calling the molecule trigonal planar.

Last reviewed: July 16, 2026. Educational reference only.