Lewis Structure Generator
Perchlorate ion · ClO4−

ClO4− Lewis Structure

A common expanded-octet contributor has three Cl=O bonds and one Cl–O⁻ bond. The single-bonded oxygen can occupy any of four positions, giving four equivalent resonance contributors.

Open ClO4− in the generatorSee drawing steps
ClO₄⁻
[ O=Cl(=O)(=O)—O⁻ ]
Representative expanded-octet contributor
Total valence electrons32
Resonance forms4 equivalent
Electron domains4 bonding
GeometryTetrahedral

ClO4− overview

Chlorine contributes seven electrons, four oxygens contribute twenty-four and the charge adds one. Four Cl–O connections surround chlorine. In the displayed convention, three are double bonds and one oxygen carries −1.

How to draw ClO4−

  1. Count 32 valence electrons.
  2. Connect four oxygens to central chlorine.
  3. Complete all terminal oxygen octets.
  4. Form three Cl=O bonds in the common minimized-charge model.
  5. Draw four resonance contributors and add brackets with −.

Formal-charge convention

The displayed contributor gives −1 to the single-bonded oxygen and zero to the other atoms. An all-single-bond structure gives chlorine +3 and each oxygen −1. Both are Lewis bookkeeping models; follow the convention required by your course.

Geometry

Four bonding domains and no central lone pair produce a tetrahedral arrangement with idealized angles near 109.5°.

Common mistakes

  • Forgetting the extra electron.
  • Drawing only one contributor.
  • Adding a lone pair to chlorine in the 32-electron structure.
  • Calling the ion square planar because four oxygens are present.

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