FeIIS2-I + 3 O20 + 2 H2O-II Fe0 + 2 H2SVIO4-II

This is an oxidation-reduction (redox) reaction:

2 S-I - 14 e- 2 SVI (oxidation)

FeII + 2 e- Fe0 (reduction)

6 O0 + 12 e- 6 O-II (reduction)

Change the oxidation states