AllChemicals — The Online Chemical Glossary | https://allchemicals.info/chemical/633-oxidation-state
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Quick Reference
Also Known As
Oxidation number, formal charge (related), valence state, charge number
What is Oxidation State?
The formal charge assigned to an atom in a compound based on a set of rules assuming electron pairs belong to the more electronegative atom. Oxidation states are used to track electron transfer in redox reactions and to name compounds with variable valence metals.
Properties & Characteristics
Oxidation state (oxidation number) is a formal charge assigned to an atom in a molecule or ion, determined by the IUPAC rules: (1) free element = 0; (2) monatomic ion = charge; (3) O in compounds = −2 (except peroxides −1, OF₂ +2); (4) H = +1 (except metal hydrides −1); (5) sum of oxidation states = molecular charge. It is a bookkeeping tool for tracking electron transfer in redox reactions and does not represent the actual ionic charge on the atom.
Uses & Applications
Oxidation states are used in: identifying oxidation and reduction in redox reactions, naming transition metal compounds (iron(II) vs iron(III) sulfate), balancing redox equations by the oxidation state change method, predicting the products of disproportionation reactions, and in predicting the reactivity of transition metals in different oxidation states.
Safety Information
Transition metals in high oxidation states (Cr(VI) in chromates/dichromates, Mn(VII) in permanganate) are strong oxidising agents and carcinogens (Cr(VI) is a Class 1 IARC carcinogen). Recognising high oxidation states guides hazard identification in inorganic chemistry.
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
SynonymsOxidation number, formal charge (related), valence state, charge number
Frequently Asked Questions
The formal charge assigned to an atom in a compound based on a set of rules assuming electron pairs belong to the more electronegative atom. Oxidation states are used to track electron transfer in redox reactions and to name compounds with variable valence metals.
Oxidation states are used in: identifying oxidation and reduction in redox reactions, naming transition metal compounds (iron(II) vs iron(III) sulfate), balancing redox equations by the oxidation state change method, predicting the products of disproportionation reactions, and in predicting the reac…
Transition metals in high oxidation states (Cr(VI) in chromates/dichromates, Mn(VII) in permanganate) are strong oxidising agents and carcinogens (Cr(VI) is a Class 1 IARC carcinogen). Recognising high oxidation states guides hazard identification in inorganic chemistry.
Editorial standards: Chemical data is sourced from peer-reviewed literature,
CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA,
and IAEA. For educational purposes only — always consult official SDS documentation and qualified
professionals before handling chemicals.
