How is backbonding treated in the theory of covalent bonding?
All covalent bonding is marked by the sharing of electrons between two atoms.
Backbonding is usually invoked in coordination chemistry, where an electron donor, a ligand, binds to, coordinates to a Lewis-acidic metal centre by donating electrons. If the metal is already in a low oxidation state, further coordination MAY not occur, unless there is a mechanism by which the metal can back-donate electron density to the ligand. Ligands such as carbon monoxide are known as
For complexes such as