MnO2 is the chemical formula for manganese (IV) dioxide. It is a naturally occurring blackish-brown solid that is insoluble in water.
Manganese is a transition metal. The pure metal is brittle and relatively soft. It is seldom found in elemental form. The most common natural form of manganese is the mineral pyrolusite, which is manganese (IV) dioxide with small amounts of contaminating elements such as iron. Pyrolusite is widely occurring in the igneous rock where it was originally formed. Particles of pyrolusite that have weathered away from their original locations are also common in sedimentary rock and soil.
Main uses for manganese (IV) dioxide are:
- To convert hydrogen gas to water in dry cell batteries
- As a pigment in ceramics and glassmaking
- To remove the color that can result from iron contamination of glass