Lewis Structure Generator
Reviewed phosphate guide

H₂PO₄⁻ Lewis Structure

Dihydrogen phosphate has two P–OH groups and two nonprotonated oxygens. In a common minimized-charge drawing, one nonprotonated oxygen is P=O and the other is P–O⁻.

Reviewed July 16, 2026 · Classroom Lewis convention

Generate H₂PO₄⁻Compare PO₄³⁻

Quick answer

Electron count

2 H + P + 4 O + one charge electron = 32 total.

Connectivity

Both hydrogens attach to oxygen atoms, producing two –OH groups.

Geometry

Four P–O electron domains give tetrahedral geometry around phosphorus.

Drawing steps

  1. Place phosphorus in the center with four oxygens.
  2. Attach one hydrogen to each of two oxygens.
  3. Complete octets and verify the 32-electron budget.
  4. Use one P=O and one P–O⁻ among the nonprotonated oxygens in the common minimized-charge form.
  5. Add brackets and the − charge.

Resonance

The double bond and negative charge can exchange between the two nonprotonated oxygens, producing two equivalent contributors. The O–H bonds do not move in this resonance set.

Common mistake: moving hydrogen during resonance. Resonance changes electron placement, not atom connectivity.