2 C2IIIO42- + MnVIO42- + 8 H+ (MnII)2+ + 4 CIVO2 + 4 H2O

This is an oxidation-reduction (redox) reaction:

MnVI + 4 e- MnII (reduction)

4 CIII - 4 e- 4 CIV (oxidation)

MnO42- is an oxidizing agent, C2O42- is a reducing agent.