2 CuIIFeIIS2-II + 6 O20 Cu2IO-II + Fe2IIIO3-II + 4 SIVO2-II

This is an oxidation-reduction (redox) reaction:

2 CuII + 2 e- 2 CuI (reduction)

4 S-II - 24 e- 4 SIV (oxidation)

2 FeII - 2 e- 2 FeIII (oxidation)

12 O0 + 24 e- 12 O-II (reduction)

Change the oxidation states