Hybridization and Molecular Geometry
Definition
Hybridization
Hybridization is the process of combining atomic orbitals (such as s and p orbitals) to create new hybrid orbitals that are better suited for bonding.
These hybrid orbitals have specific shapes and energy levels that enable atoms to form stable bonds and geometries.
Key Features of Hybridization:
- Number of Hybrid Orbitals: The number of hybrid orbitals equals the number of atomic orbitals combined.
- Energy and Shape: Hybrid orbitals have identical energy and specific geometries that minimize electron repulsion.
- Electron Domains and Hybridization: The type of hybridization corresponds to the number of electron domains (bonding and lone pairs) around the central atom.
Remember, hybridization depends on the number ofelectron domainsaround the central atom, not just the number of bonds.
Types of Hybridization: sp, sp², and sp³
sp Hybridization
- What Happens? One s orbital and one p orbital mix to form two sp hybrid orbitals. The remaining two p orbitals remain unhybridized.
- Geometry: Linear, with bond angles of 180°.
- In ethyne (C₂H₂), each carbon has two electron domains (a triple bond and a single bond).
- This corresponds to sp hybridization, resulting in a linear geometry.
2. sp² Hybridization
- What Happens? One s orbital and two p orbitals mix to form three sp² hybrid orbitals. One p orbital remains unhybridized.
- Geometry: Trigonal planar, with bond angles of approximately 120°.
- In ethene (C₂H₄), each carbon has three electron domains (two single bonds and one double bond).
- This corresponds to sp² hybridization, leading to a trigonal planar geometry.
In molecules with double bonds, one of the bonds is always a sigma bond, while the other is a pi bond formed by unhybridized p orbitals.
3. sp³ Hybridization
- What Happens? One s orbital and three p orbitals mix to form four sp³ hybrid orbitals.
- Geometry: Tetrahedral, with bond angles of approximately 109.5°.
