2 CuIIFeS2-II + O20 2 FeS-II + Cu2IS-II + SIVO2-II

This is an oxidation-reduction (redox) reaction:

2 CuII + 2 e- 2 CuI (reduction)

S-II - 6 e- SIV (oxidation)

2 O0 + 4 e- 2 O-II (reduction)

Change the oxidation states