The covalent bond classification (CBC) method, also referred to as LXZ notation, is a way of describing covalent compounds such as organometallic complexes in a way that is not prone to limitations resulting from the definition of oxidation state.[1] Instead of simply assigning a charge (oxidation state) to an atom in the molecule, the covalent bond classification method analyzes the nature of the ligands surrounding the atom of interest.[2] According to this method, the interactions that allow for coordination of the ligand can be classified according to whether it donates two, one, or zero electrons. These three classes of ligands are respectively given the symbols L, X, and Z. The method was published by Malcolm L. H. Green in 1995.[3][4]