<unk> (IV) oxide is the chemical compound<unk> , commonly called<unk> . This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of<unk> . It is also present in<unk>  nodules. The principal use for<unk>  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.<unk>  is also used for production of MnO4–.  It is used extensively as an oxidising agent in organic synthesis, for example, for the oxidation of allylic alcohols.
Manganese dioxide
Hexavalent chromium
Arsenic pentoxide
Indium oxyquinoline
Mercuric amidochloride
Carbon tetrachloride
Formaldehyde
Calcium arsenate