— Oxidation state notation
The oxidation state is the hypothetical charge an atom would have if all its bonds were ionic. It is written as a superscript with the sign before the number, e.g. Fe²⁺, or as Roman numerals in compound names, e.g. iron(II) oxide. A change in oxidation state identifies redox: an increase is oxidation, a decrease is reduction.
Used in
- Redox balancing
- Nomenclature