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ScienceQuest

Hydrogen peroxide (H₂O₂) Lewis structure

14 valence electrons, bent

O O H H
H₂O₂ as the Lewis Structure Generator draws it: lone pairs as dots.

Build H₂O₂ step by step in the Lewis Structure Generator

What is the Lewis structure of H₂O₂?

Hydrogen peroxide, H₂O₂, has 14 valence electrons. The two O atoms bond to each other, and the molecule has one O−O single bond and two O−H single bonds. It carries two lone pairs on each central O. Every formal charge is zero. Each O is AX₂E₂: bent, with an ideal bond angle of 109.5°.

Valence electrons in H₂O₂

Element Group Valence electrons Atoms Electrons
Hydrogen 1 1 2 2
Oxygen 16 6 2 12
Total 14

In one line: 2 × 1 + 2 × 6 = 14. Each atom brings the valence electrons its group gives it.

How to draw the H₂O₂ Lewis structure

  1. Count the valence electrons. Valence electrons: each H 1 and each O 6. 2 × 1 + 2 × 6 = 14.
  2. Bond the two central atoms. O appears twice, so the two O atoms bond to each other and share the H atoms evenly between them.
  3. Join the atoms with single bonds. Three single bonds use 6 electrons, leaving 14 − 6 = 8.
  4. Complete the outer atoms. Every outer atom is H, and its one bond already gives it the two electrons it holds. 8 remain.
  5. Put the rest on the central atom. The 8 left go on the central atoms as two lone pairs on each O, and each O now has 8 electrons round it.
  6. Make multiple bonds where needed. Every atom already has an octet, so no lone pair needs to become a bond.

Lone pairs and formal charges in H₂O₂

Atom Number Bonds Lone pairs Electrons round it Formal charge, V − N − B/2
O (central) 2 two single bonds 2 8 6 − 4 − 2 = 0
H 2 one single bond 0 2 1 − 0 − 1 = 0

V is the atom’s valence electrons, N its nonbonding electrons and B its bonding electrons. The formal charges add up to 0, the molecule’s overall charge.

Shape and polarity of H₂O₂

Central atoms each O
VSEPR class AX₂E₂
Electron geometry tetrahedral
Molecular geometry bent
Ideal bond angle 109.5°
Polarity, an estimate depends

It depends on the twist about the central bond, which a Lewis structure does not fix. H₂O₂ and N₂H₄ are both polar in practice.

Each O has two σ bonds and two lone pairs, four electron domains in all, so its electron geometry is tetrahedral. Counting only the bonded atoms, the molecular geometry is bent.

The VSEPR Molecular Geometry viewer turns the AX₂E₂ shape in 3D, lone pairs included.

Work with H₂O₂