VSEPR - A Summary

Valence Shell Electron Pair Repulsion (VSEPR) theory allows fairly accurate prediction of the 3-dimensional shape of molecules from knowledge of their Lewis Dot structure. In VSEPR theory, the position of bound atoms (ligands) and electron pairs are described relative to a central atom. Once the ligands and lone pair electrons are positioned, the resulting geometrical shape presented by the atoms only (ignoring lone pairs) is used to describe the molecule.

Below is a table showing examples of the most common geometries encountered using the VSEPR theory. Clicking the cursor on the example molecules will allow you to view the 3-dimensional models. The lone pairs of electrons on the central atom are shown in pink as separate images.

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Total Number of Atoms + Lone Pairs	GEOMETRY
(No Central Atom)	Linear O₂ N₂			With Lone Pairs O₂ N₂
2	Linear CO₂
3	Trigonal Planar BF₃			Bent SO₂ With Lone Pairs
4	Tetrahedral CH₄		Trigonal Pyramidal NH₃ With Lone Pairs			Bent H₂O With Lone Pairs
5	Trigonal Bipyramidal PF₅	See-saw SF₄ With Lone Pairs			T-Shaped ClF₃ With Lone Pairs		Linear XeF₂ With Lone Pairs
6	Octahedral SF₆		Square Pyramidal BrF₅ With Lone Pairs			Square Planar XeF₄ With Lone Pairs