COMPOUND which doesn’t exhibit a different OXIDATION number for the same element.Fe2O3 is a spinel, meaning, for one mole of Fe2O3 there are 2 atoms of Iron (FE) which exists in +3 oxidation STATE, and one Fe atom exists with +2 oxidation state.Fe2O3 has Fe in only +3 oxidation states.Again, Mn2O3 is a spinel with Mn atoms having +2 and +3 oxidation states.