Manganese oxide is THE chemical compound MnO2, commonly called manganese dioxide. This blackish or brown solid occurs naturally as THE mineral pyrolusite, which is THE main ore of manganese. It is also present IN manganese nodules. THE principal use for MnO2 is for dry-cell batteries, such as THE alkaline battery AND the zinc-carbon battery. IN 1976 this application accounted for 500,000 tonnes of pyrolusite.[1] MnO2 is also used for production of MnO4-. It is used extensively as an oxidizing agent IN organic synthesis, for example, for THE oxidation of allelic alcohols.