2 Fe2S3 + 9 O2 → 6 SO2 + 2 Fe2O3
This is an oxidation-reduction (redox) reaction:
6 S-II - 36 e- → 6 SIV (oxidation)
18 O0 + 36 e- → 18 O-II (reduction)
Fe2S3 is a reducing agent, O2 is an oxidizing agent.
Reactants:
- Fe2S3
- O2
Products:
- SO2 – Sulfur dioxide



- Other names: Sulfurous anhydride


, Sulphur dioxide 
, Sulfurous acid anhydride 

- Appearance: Colorless gas
; Colourless gas or compressed liquefied gas with pungent odour
; Colorless gas with a characteristic, irritating, pungent odor. [Note: A liquid below 14°F. Shipped as a liquefied compressed gas.] 
- Other names: Sulfurous anhydride
- Fe2O3 – Iron(III) oxide


- Other names: Ferric oxide



, Hematite
, Ferric iron 
- 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.] 
- Other names: Ferric oxide
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