Oxidation State of the Central Atom

The oxidation state (or oxidation number) of the central atom in a coordination entity is the charge it would carry if all the ligands were removed together with the electron pairs that were shared with the central atom. It is written as a Roman numeral in parentheses immediately after the metal's name when naming a complex -- for instance, iron is written (II) in [Fe(CN)₆]⁴⁻. The net charge on a complex ion equals the sum of the oxidation state of the central metal and the total charge contributed by all the attached ligands: Net c …