Molecular Orbital Theory
The bonding model in which atomic orbitals combine to form molecular orbitals delocalised over the entire molecule.
Formula / equation
ψ_MO = c₁ψ_A ± c₂ψ_B
Unit
Dimensionless
In depth
Constructive combination gives a bonding orbital lower in energy and destructive combination an antibonding orbital higher in energy. Electrons then fill these in order following the same rules as in atoms. The theory correctly predicts bond orders, magnetic behaviour and electronic spectra that valence bond theory cannot.
Examples in the real world
It predicts O₂'s two unpaired electrons and paramagnetism, and correctly forbids the existence of He₂.