VSEPR Geometry Chart

Every AXE class with a 3D sketch, a real example, hybridization, and electron vs molecular shape.

Why it matters

Molecules are three-dimensional, and shape decides almost everything: , reactivity, even how a drug fits its target. VSEPR turns a flat into that 3D shape using one idea: electron groups spread as far apart as they can.

When you use it

After you have a valid Lewis structure and want its geometry, , or polarity.

Where it leads

and , bond angles, , and polarity.

What AXE notation means

Athe central atom

Xeach atom bonded to it

Eeach lone pair on it

Steric number = X + E, the total electron domains. Count a double or triple bond as one domain. The steric number fixes the electron geometry and the hybridization; the lone pairs then decide the molecular shape.

Electron geometry vs molecular geometry

Electron geometry counts every domain, bonds and lone pairs alike, so it is set by the steric number. Molecular geometry describes only the shape traced by the atoms, ignoring the invisible lone pairs. That is why AX₄, AX₃E, and AX₂E₂ all share a tetrahedral electron geometry (same shaded family below) yet look tetrahedral, pyramidal, and bent.

Every class, grouped by steric number

AXE	Steric no.	Hybridization	Electron geometry	Molecular geometry	Example	Angle
AX₂	2	sp	Linear	Linear	CO₂	180°
AX₃	3	sp²	Trigonal planar	Trigonal planar	BF₃	120°
AX₂E	3	sp²	Trigonal planar	Bent	O₃, SO₂	≈118°
AX₄	4	sp³	Tetrahedral	Tetrahedral	CH₄	109.5°
AX₃E			Tetrahedral	Trigonal pyramidal	NH₃	≈107°
AX₂E₂			Tetrahedral	Bent	H₂O	≈104.5°
AX₅	5	sp³d	Trigonal bipyramidal	Trigonal bipyramidal	PCl₅	90° / 120°
AX₄E			Trigonal bipyramidal	Seesaw	SF₄	≈90° / 120°
AX₃E₂			Trigonal bipyramidal	T-shaped	ClF₃	≈90°
AX₂E₃			Trigonal bipyramidal	Linear	XeF₂	180°
AX₆	6	sp³d²	Octahedral	Octahedral	SF₆	90°
AX₅E			Octahedral	Square pyramidal	BrF₅	≈90°
AX₄E₂			Octahedral	Square planar	XeF₄	90°

Each shaded band is one electron-geometry family. Read down a band and only the molecular geometry changes, as lone pairs replace bonded atoms. Lone pairs also push harder than bonds, which is why the real angles dip a little below the ideal values.

Memory trick

The steric number is the master key. Add the atoms bonded to the center to its lone pairs, counting a double or triple bond as one, and that count sets the electron geometry: 2 is linear, 3 trigonal planar, 4 tetrahedral, 5 trigonal bipyramidal, 6 octahedral. The lone pairs then carve the molecular shape out of it.

Common mistake

Electron geometry and molecular geometry are not the same thing. Water has four electron domains, a tetrahedral electron geometry, but its molecular shape is bent, because two of those domains are invisible lone pairs. Name the molecular shape from the atoms alone.

Practice

The sulfur in SO₂ has two bonded oxygens and one lone pair. What are its electron geometry and its molecular geometry?

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