Hydrogen Phosphate Ion overview
The stored Lewis connectivity is [O=P(OH)(O⁻)₂]²⁻. The proton is attached to oxygen, while negative charge and multiple-bond placement are distributed among non-protonated oxygens.
How to draw HPO₄²⁻
- Count 32 valence electrons. Include charge adjustments before drawing.
- Use the reviewed connectivity [O=P(OH)(O⁻)₂]²⁻. Do not infer a different isomer from the formula alone.
- Place the required single, double or multiple bonds. Keep a running electron total.
- Complete terminal valence shells and add lone pairs or formal charges. The proton is attached to oxygen, while negative charge and multiple-bond placement are distributed among non-protonated oxygens.
- Verify the total electron count and geometry. The reviewed geometry is Tetrahedral around phosphorus.
Why this example matters
The proton is attached to oxygen, while negative charge and multiple-bond placement are distributed among non-protonated oxygens.
Scope and model limits
Different textbooks use expanded-octet or all-single-bond contributors. The page explains both as bookkeeping conventions.
Common mistakes
- Attaching hydrogen directly to phosphorus
- Forgetting the 2− charge
- Making the OH oxygen part of the same resonance set
Related reviewed guides
Last reviewed: 2026-07-16. Educational reference only; verify graded work with course materials.