Atomic Chemistry

Oxidation Number Calculator

Solve a target oxidation state from formula charge and explicit known assignments without hiding mixed-valence ambiguity.

1

Enter values

Case-sensitive element symbol to solve.
Comma-separated explicit assignments; exceptions remain your choice.
Examples
2

Results

Ready to calculate

Your result, units, method, and version information will appear here.

How to use this calculator

  1. Select the solve mode or desired unknown.
  2. Enter the known values with their units.
  3. Calculate, then review the normalized values and steps.

Formula and variables

sum(n_i x_i) = net charge

SymbolMeaningUnit
n_iatom count for element iatoms
x_ioxidation state for element idimensionless

Worked example

For Fe3O4 with oxygen explicitly assigned -2, the three iron atoms must contribute +8 in total, so iron has average oxidation state +8/3.

Interpretation

A unique result is justified only for one target site or an explicit target assignment. Multiple target atoms produce an average or possible assignment because a formula alone does not reveal individual sites.

Common mistakes

  • Do not assume oxygen is always -2 or hydrogen is always +1; enter the assignment appropriate to the compound.
  • Do not describe an average oxidation state as proof that every atom has that state.

Frequently asked questions

How are invalid inputs handled?

The calculator validates every required value before it calls the deterministic engine.

Can I reproduce the result?

The result panel lists the engine and data versions used for the calculation.

Sources