Numford
Oxidation number

Fe in Fe₃O₄

Fe is +8/3 in magnetite (iron(II,III) oxide), an average.

Oxidation number

Type a formula or an ion: K2Cr2O7, Cr2O7 2-, MnO4-, NH4+ or K4[Fe(CN)6]. Put a known ion in brackets when two elements are unknown. Pick an element to solve for it.

Fe+8/3average

Fe₃O₄ is FeO·Fe₂O₃: one Fe is +2 and two are +3. The rules give the average, +8/3.

  1. Oxygen is −2 in most compounds.
  2. The oxidation numbers add up to the charge, 0: 4(−2) + 3x = 0.
  3. 3x = +8, so x = +8/3.
Rule steps

How to find it

  1. Oxygen is −2 in most compounds.
  2. The oxidation numbers add up to the charge, 0: 4(−2) + 3x = 0.
  3. 3x = +8, so x = +8/3.

Fe₃O₄ is FeO·Fe₂O₃: one Fe is +2 and two are +3. The rules give the average, +8/3.

Every atom

All the oxidation numbers in Fe₃O₄

  • O −24 atoms, oxygen
  • Fe +8/33 atoms, sum rule
Questions

Fe in Fe₃O₄: quick answers

What is the oxidation number of Fe in Fe₃O₄?

Fe in Fe₃O₄ (magnetite (iron(II,III) oxide)) is +8/3, an average over its atoms. Fe₃O₄ is FeO·Fe₂O₃: one Fe is +2 and two are +3. The rules give the average, +8/3.

How do you find the oxidation number of Fe in Fe₃O₄?

Oxygen is −2 in most compounds. The oxidation numbers add up to the charge, 0: 4(−2) + 3x = 0. 3x = +8, so x = +8/3.

What are the oxidation numbers of the other atoms in Fe₃O₄?

O −2. Together with Fe at +8/3 they add up to the charge of the compound, 0.

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