EAN is called an effective atomic number.
It denotes the total number of electrons that surround a metal atom in a complex.
It is made up of metal electrons and the ligands that are bound to that metal..
It is calculated as:
EAN = Atomic number of the metal + (Number of ligands electrons donated by each ligand) – positive oxidation state of the metal.
Final Answer:
It is effective atomic number and its formula is Atomic no. of the metal + (no. of ligands electrons donated by each ligand) – positive oxidation state of the metal.