2 Fe2(SVIO4-II)3 2 Fe2O3-II + 6 SIVO2-II + 3 O20

This is an oxidation-reduction (redox) reaction:

6 SVI + 12 e- 6 SIV (reduction)

6 O-II - 12 e- 6 O0 (oxidation)

Change the oxidation states