In forming MnOOH, the cathode expands about 17% in volume. MnOOH can undergo some undesirable chemical reactions as well. Can form the complex compound hetaerolite, ZnMn2O4. Although electroactive, hetaerolite is not as easily discharged as MnOOH, hence the cell impedance increases. In addition, the MnOOH/MnO2 solid solution can undergo recrystallization into a less active form, resulting in a noticeable loss in cell voltage under certain very slow discharge conditions.