4 FeO (s) + O₂ (g) → 2 Fe₂O₃ (s)

This is an oxidation-reduction (redox) reaction:

FeO is a reducing agent, O₂ is an oxidizing agent.

Reactants:

• FeO – Iron(II) oxide
  • Other names: Ferrous oxide , Iron monoxide , Iron oxide ... show moreIron monooxide , Ferrous monoxide , Iron (II) oxide , C.I. 77489 show less
  • Appearance: Black crystals ; Black solid in various forms
• O₂
  • Names: Dioxygen , Oxygen , Oxygen (liquefied) ... show moreO2 , O₂ , Oxygen gas , Molecular oxygen , Oxygen, refrigerated liquid , LOX , Liquid oxygen show less
  • Appearance: Odourless compressed gas ; Liquefied gas. colourless-to-blue extremely cold liquid

Products:

• Fe₂O₃ – Iron(III) oxide
  • Other names: Ferric oxide , Hematite , Ferric iron ... show moreRed iron oxide , Rouge , Maghemite , Colcothar , Iron sesquioxide , Rust , Ochre , Iron oxide dust and fume (as Fe) , Iron oxide red , Red oxide , Anhydrous ferric oxide , Iron (III) oxide , Diiron trioxide , Iron trioxide , Ferric sesquioxide , Iron(III) oxide [Iron oxide dust and fume (as Fe)] , Iron(III)oxide [Rouge] show less
  • Appearance: Red-brown solid ; Reddish brown-to-black crystals or powder ; Reddish-brown solid. [Note: Exposure to fume may occur during the arc-welding of iron.] ; A fine, red powder of ferric oxide. [Note: Usually used in cake form or impregnated in paper or cloth.]