What is hybridization?

Hybridization is the mixing of atomic orbitals on a central atom to form new, equivalent hybrid orbitals used for bonding. The type (sp, sp2, sp3, sp3d, sp3d2) depends on how many regions of electron density surround the atom.

How do I count bonding pairs?

Each single bond contributes one bonding pair. A double bond still counts as one region of electron density (one sigma + one pi), so it contributes one bonding pair to the steric number. A triple bond is similarly one region.

Do lone pairs affect hybridization?

Yes. Lone pairs occupy hybrid orbitals just like bonding pairs. They increase the steric number and therefore change the hybridization, even though they do not appear in the molecular geometry name.

What is the steric number?

The steric number is the total count of bonding pairs plus lone pairs on the central atom. It directly determines hybridization: steric number 2 = sp, 3 = sp2, 4 = sp3, 5 = sp3d, 6 = sp3d2.

Can this tool handle expanded octets?

Yes. sp3d corresponds to a steric number of 5 (e.g., PCl5) and sp3d2 to a steric number of 6 (e.g., SF6). These involve d-orbital participation and appear in period 3 and higher elements.

What is the geometry for sp3 with two lone pairs?

The hybridization is still sp3 (steric number = 4), but the molecular geometry is bent, as in water (H2O). Hybridization reflects electron-pair geometry, not molecular geometry.

Hybridization Finder

Enter bonding pairs and lone pairs to find the hybridization state of a central atom using VSEPR theory.

Central Atom Data

Count the electron regions around the central atom only.

Bonding Pairs (sigma bonds — each single, double, or triple bond = 1)

Lone Pairs (non-bonding electron pairs on the central atom)

Quick Presets

Hybridization

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Enter values and click Find

Bonding Pairs	—
Lone Pairs	—
Steric Number	—
Orbitals Used	—
Electron Geometry	—
Example Molecule	—

Summary

This tool determines the hybridization of a central atom by applying VSEPR theory: sum the bonding pairs and lone pairs to get the steric number, which maps to sp, sp2, sp3, sp3d, or sp3d2. It also shows the corresponding electron-pair geometry and a familiar example molecule.

How it works

Enter the number of bonding pairs (sigma bonds) around the central atom.
Enter the number of lone pairs on the central atom.
The tool sums these to get the steric number.
The steric number maps directly to a hybridization type: 2=sp, 3=sp2, 4=sp3, 5=sp3d, 6=sp3d2.
The result shows the hybridization, geometry, and a real molecule example.

Use cases

Quickly identify hybridization for general chemistry homework.
Verify hybridization assignments before exams.
Understand how lone pairs shift geometry without changing hybridization.
Cross-check VSEPR geometry names (linear, trigonal planar, tetrahedral, etc.).
Explore how molecules like H2O and NH3 are sp3 despite bent/pyramidal shapes.
Study for AP Chemistry, IB Chemistry, or college-level organic chemistry.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu