The video below shows facts and chemical properties of Manganese dioxide or Manganese oxide or Manganese IV oxide.
Powdered manganese dioxide picture
Chemical properties of Manganese IV Oxide
Manganese IV oxide or Manganese dioxide is a dark brown solid that acts as a depolarizer in dry batteries by oxidizing the hydrogen gas produced to water (see video of Manganese dioxide below). The video shows Manganese oxide composition and electrolytic manganese dioxide in a lithium manganese dioxide battery.