Build a Molecule

3D molecular construction with real bond angles

VSEPR (Valence Shell Electron Pair Repulsion) theory predicts molecular geometry by minimizing electron-pair repulsion around each central atom. Count all electron domains (bonding pairs + lone pairs). Two domains → linear (180°). Three domains → trigonal planar (120°). Four domains → tetrahedral (109.5°). Five → trigonal bipyramidal. Six → octahedral. Lone pairs compress bond angles slightly because they occupy more space than bonding pairs. For example, water has 4 electron domains (2 bonding + 2 lone pairs) giving a tetrahedral electron geometry but a bent molecular shape with a 104.5° angle instead of 109.5°.