Valence bond theory

Valence bond theory (VBT) is a chemical bonding theory that explains the electronic structure of molecules. The theory was developed by Walter Heitler and Fritz London in 1927, and it is based on the concept of atomic orbitals.

Overview

Valence bond theory describes a chemical bond as the overlap of half-filled atomic orbitals that yield a pair of electrons shared between the two bonded atoms. The theory primarily focuses on the formation of a bond between two atoms, and it does not explain the molecular geometry in a detailed manner.

Principles

The main principles of valence bond theory are:

• The overlap of atomic orbitals: According to VBT, a chemical bond is formed when atomic orbitals overlap with each other. The greater the overlap, the stronger the bond.

• The concept of hybridization: VBT introduced the concept of hybridization, which is the mixing of atomic orbitals to form new hybrid orbitals.

• The concept of resonance: VBT also explains the concept of resonance, which is the delocalization of electrons in molecules.

Limitations

While valence bond theory has been instrumental in the understanding of chemical bonding, it has its limitations. For instance, it fails to accurately predict the magnetic properties of molecules and it does not explain the colors of transition metal complexes.

See also

• Molecular orbital theory
• Chemical bond
• Covalent bond
• Ionic bond

References

Valence bond theory Resources
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