Degenerate Orbitals
Two or more orbitals in the same atom that have exactly the same energy.
Unit
Dimensionless
In depth
Within an isolated atom the orbitals of a given subshell are degenerate because they differ only in spatial orientation. Degeneracy is lifted by any effect that breaks spatial symmetry — an external magnetic or electric field, or the approach of ligands in a coordination complex — and the resulting energy splittings produce spectra and colour.
Examples in the real world
The three 2p orbitals in a free atom; the 3d set splitting into t₂g and e_g levels inside an octahedral complex.