Molecular Geometry Chart
The Molecular Geometry Chart is a reference tool covering molecular geometry chart, vsepr chart, molecular shape chart, vsepr theory chart. Use the chart below to look up values instantly. Printable and downloadable versions are available on this page.
Molecular Geometry Predictor
Enter number of bonding pairs and lone pairs to get the geometry name, bond angle, and 3D shape description.
Oxygen has 4 electron domains total — 2 bonding pairs (to the two H atoms) and 2 lone pairs. The electron geometry is tetrahedral. The two lone pairs compress the bond angle below the ideal 109.5°, giving a bent molecular geometry at approximately 104.5°.
Molecular Geometry Chart — VSEPR Reference
VSEPR (Valence Shell Electron Pair Repulsion) theory predicts molecular geometry based on the number of bonding electron pairs and lone pairs around the central atom — electron pairs repel each other and arrange to maximise distance between them.
| Bonding Pairs | Lone Pairs | Electron Geometry | Molecular Geometry | Bond Angle | Example Molecule | Polarity |
|---|---|---|---|---|---|---|
| 2 | 0 | Linear | Linear | 180° | CO₂ and BeCl₂ | Nonpolar (symmetric) |
| 3 | 0 | Trigonal Planar | Trigonal Planar | 120° | BF₃ and SO₃ | Nonpolar (symmetric) |
| 2 | 1 | Trigonal Planar | Bent or V-shaped | ~117° | SO₂ and O₃ | Polar |
| 4 | 0 | Tetrahedral | Tetrahedral | 109.5° | CH₄ and CCl₄ | Nonpolar (symmetric) |
| 3 | 1 | Tetrahedral | Trigonal Pyramidal | ~107° | NH₃ and PCl₃ | Polar |
| 2 | 2 | Tetrahedral | Bent or V-shaped | ~104.5° | H₂O and H₂S | Polar |
| 5 | 0 | Trigonal Bipyramidal | Trigonal Bipyramidal | 90° and 120° | PCl₅ and PF₅ | Nonpolar (symmetric) |
| 4 | 1 | Trigonal Bipyramidal | Seesaw | ~87° and ~120° | SF₄ | Polar |
| 3 | 2 | Trigonal Bipyramidal | T-shaped | ~87° | ClF₃ | Polar |
| 2 | 3 | Trigonal Bipyramidal | Linear | 180° | XeF₂ | Nonpolar |
| 6 | 0 | Octahedral | Octahedral | 90° | SF₆ and XeF₆ | Nonpolar (symmetric) |
| 5 | 1 | Octahedral | Square Pyramidal | ~87° | BrF₅ | Polar |
| 4 | 2 | Octahedral | Square Planar | 90° | XeF₄ and PtCl₄²⁻ | Nonpolar |
Source: VSEPR theory as described in Gillespie and Nyholm 1957
How to Predict Molecular Geometry — Step by Step
- Draw the Lewis structure of the molecule to identify all bonding pairs and lone pairs around the central atom.
- Count the total number of electron domains around the central atom. Each single bond, double bond, triple bond, and lone pair counts as one electron domain.
- Determine the electron geometry based on the total number of electron domains — 2 domains = linear, 3 = trigonal planar, 4 = tetrahedral, 5 = trigonal bipyramidal, 6 = octahedral.
- Determine the molecular geometry based on the number of bonding pairs only — lone pairs are not counted in the shape name but they do affect the bond angles.
- Predict polarity — if the molecular geometry is symmetric (all bonding pairs identical) the dipole moments cancel and the molecule is nonpolar. If the geometry is asymmetric due to lone pairs or different substituents the molecule is polar.
Bond Angle Effects of Lone Pairs
Lone pairs occupy more space than bonding pairs because they are held by only one nucleus — each lone pair compresses the bond angles between bonding pairs by approximately 2.5 degrees.
| Molecule | Electron Geometry | Ideal Bond Angle | Actual Bond Angle and Reason |
|---|---|---|---|
| CH₄ (methane) — 4 bonding pairs, 0 lone pairs | Tetrahedral | 109.5° | 109.5° — no lone pairs so no compression |
| NH₃ (ammonia) — 3 bonding pairs, 1 lone pair | Tetrahedral | 109.5° | ~107° — one lone pair compresses bond angles by ~2.5° |
| H₂O (water) — 2 bonding pairs, 2 lone pairs | Tetrahedral | 109.5° | ~104.5° — two lone pairs compress angles by ~5° total |
| SO₂ (sulfur dioxide) — 2 bonding pairs, 1 lone pair | Trigonal Planar | 120° | ~117° — one lone pair compresses slightly below 120° |
Molecular Geometry Predictor
Enter the number of bonding pairs and lone pairs around the central atom to get the geometry name, bond angle, and a plain-English 3D shape description.
Oxygen has 4 electron domains total — 2 bonding pairs (to the two H atoms) and 2 lone pairs. The electron geometry is tetrahedral. The two lone pairs compress the bond angle below the ideal 109.5°, giving a bent molecular geometry at approximately 104.5°.
Frequently Asked Questions
What is molecular geometry?
Molecular geometry is the three-dimensional arrangement of atoms in a molecule — specifically the arrangement of bonded atoms around a central atom. It is predicted by VSEPR theory based on the number of bonding and lone electron pairs.
What is the difference between electron geometry and molecular geometry?
Electron geometry includes all electron domains around the central atom — both bonding pairs and lone pairs. Molecular geometry only considers the positions of bonded atoms — lone pairs are invisible to the shape name but they push on bonding pairs and compress bond angles.
What is the molecular geometry of water?
Water (H₂O) has a bent or V-shaped molecular geometry with a bond angle of approximately 104.5°. It has 2 bonding pairs and 2 lone pairs — the two lone pairs compress the bond angle below the ideal 109.5° of tetrahedral geometry.
What is the bond angle of a tetrahedral molecule?
The ideal bond angle in a tetrahedral electron geometry is 109.5°. This is the angle in CH₄ (methane) where all four positions are identical bonding pairs with no lone pair compression.
Is CO₂ polar or nonpolar?
CO₂ is nonpolar despite having two polar C=O bonds. The two bonds point in exactly opposite directions (linear 180° geometry) so the dipole moments cancel each other out.
What is the molecular geometry of NH₃?
Ammonia (NH₃) has a trigonal pyramidal molecular geometry with bond angles of approximately 107°. It has 3 bonding pairs and 1 lone pair — the lone pair compresses the bond angles slightly below the tetrahedral ideal of 109.5°.
How many electron domains does H₂O have?
Water has four electron domains around the oxygen atom — 2 bonding pairs (to the two hydrogen atoms) and 2 lone pairs. This gives it a tetrahedral electron geometry but a bent molecular geometry.
What is VSEPR theory?
VSEPR stands for Valence Shell Electron Pair Repulsion. The theory states that electron pairs around an atom repel each other and arrange to maximise the distance between them — this arrangement determines the molecular geometry.