Work out oxidation number instantly with clear inputs, formula shown and shareable results.
Oxidation states must sum to the overall charge. Oxygen is assigned -2 and hydrogen +1 in ordinary compounds, so the central atom absorbs whatever is left over, divided between however many central atoms there are. For sulfate, charge -2 with four oxygens gives (-2 + 8)/1 = +6 for sulfur.
Charge balance
n x state + (-2 x oxygens) + (+1 x hydrogens) = overall charge
Central state
state = (charge + 2.oxygens - hydrogens) / n
In peroxides it is -1, in superoxides -1/2, and bonded to fluorine it is positive. Those cases need the exception applied by hand.
Yes. In Fe3O4 iron averages +8/3 because the structure contains both Fe(II) and Fe(III).