1. The bonding orbital is used in molecular orbital theory to describe the attractive interactions between the atomic orbitals of two or more atoms in a molecule.
2. An antibonding orbital is a type of molecular orbital that weakens the bond between two atoms and helps to raise the energy of the molecule relative to the separated atoms. Such an orbital has one or more nodes in the bonding region between the nuclei.
3. A non-bonding orbital (NBMO) is a molecular orbital for which the addition or removal of an electron does not change the energy of the molecule. Molecular orbitals come from the linear combination of atomic orbitals.