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Molecule Information
Repulsion Order:
Lone pairs occupy more space and repel more strongly, compressing bond angles
Interactive visualization of Valence Shell Electron Pair Repulsion theory - Explore molecular geometries, electron pair arrangements, and bond angles
Lone pairs occupy more space and repel more strongly, compressing bond angles
| Electron Pairs: | Bonding Pairs: | Lone Pairs: | Electron Geometry | Molecular Shape | Bond Angle: | Example |
|---|---|---|---|---|---|---|
| 2 | 2 | 0 | Linear | Linear | 180° | CO₂, BeCl₂ |
| 1 | 1 | Linear | Linear | 180° | [NO₂]⁺ | |
| 3 | 3 | 0 | Trigonal Planar | Trigonal Planar | 120° | BF₃, CO₃²⁻ |
| 2 | 1 | Trigonal Planar | Bent | < 120° | SO₂, O₃ | |
| 1 | 2 | Trigonal Planar | Linear | 180° | O₂, [I₃]⁻ | |
| 4 | 4 | 0 | Tetrahedral | Tetrahedral | 109.5° | CH₄, NH₄⁺ |
| 3 | 1 | Tetrahedral | Trigonal Pyramidal | < 109.5° | NH₃, PCl₃ | |
| 2 | 2 | Tetrahedral | Bent | < 109.5° | H₂O, H₂S | |
| 1 | 3 | Tetrahedral | Linear | 180° | [ClO₂]⁺ | |
| 5 | 5 | 0 | Trigonal Bipyramidal | Trigonal Bipyramidal | 90°, 120° | PCl₅, PF₅ |
| 4 | 1 | Trigonal Bipyramidal | Seesaw | < 90°, < 120° | SF₄, TeCl₄ | |
| 3 | 2 | Trigonal Bipyramidal | T-Shaped | < 90° | ClF₃, BrF₃ | |
| 2 | 3 | Trigonal Bipyramidal | Linear | 180° | XeF₂, I₃⁻ | |
| 6 | 6 | 0 | Octahedral | Octahedral | 90° | SF₆, [Fe(CN)₆]³⁻ |
| 5 | 1 | Octahedral | Square Pyramidal | < 90° | BrF₅, IF₅ | |
| 4 | 2 | Octahedral | Square Planar | 90° | XeF₄, ICl₄⁻ |
VSEPR (Valence Shell Electron Pair Repulsion) theory is a model used in chemistry to predict the geometry of individual molecules based on the number of electron pairs surrounding their central atoms.
In VSEPR theory, there are two types of electron pairs around a central atom: bonding pairs (shared between atoms in covalent bonds) and lone pairs (non-bonding electrons localized on the central atom).
The strength of repulsion follows the order: lone pair-lone pair > lone pair-bond pair > bond pair-bond pair. This means that lone pairs push bonding pairs closer together than bonding pairs push each other.
The steric number (SN) is the sum of bonding pairs and lone pairs around the central atom: SN = BP + LP. This number determines both the electron pair geometry and the hybridization of the central atom.
To predict molecular geometry using VSEPR: (1) Draw the Lewis structure; (2) Count bonding pairs and lone pairs; (3) Determine the steric number; (4) Identify the electron pair geometry; (5) Consider lone pair positions; (6) Predict the molecular shape.
VSEPR theory is widely used to predict molecular geometries for main group compounds. However, it has limitations: it doesn't work well for transition metal complexes and cannot predict bond lengths accurately.