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.
[5][page needed] Regardless of whether they are considered neutral or anionic, these ligands yield normal covalent bonds.
These electrons can come from lone pairs, pi, or sigma donors.
However, these ligands also form dative covalent bonds like the L-type.
This template for writing a metal complex also allows for a better comparison of molecules with different charges.
This can happen when the assignment is reduced to its “equivalent neutral class".
The equivalent neutral class is the classification of the complex if the charge was localized on the ligand as opposed to the metal center.
[1] In other words, the equivalent neutral class is the representation of the complex as though there were no charge.