Oxidation State — Definition, Formula, Properties & Uses | AllChemicals | AllChemicals

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.

Key Facts

Term Oxidation State

Index All "O" terms

Synonyms Oxidation number, formal charge (related), valence state, charge number

Frequently Asked Questions

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.

What is Oxidation State used for?

Is Oxidation State hazardous?

More "O" Terms

Octahedral ML₆ Octane Number Octet Rule Octet Rule Oganesson Og Oil Open Sextet Open System Optical Activity Optical Isomers Optical Isomers Orbital ψ(r,θ,φ): quantum wavefunction squared gives probability density

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