What Is the Oxidation Number of Manganese in MnO2?

What Is the Oxidation Number of Manganese in MnO2?

The oxidation number of the manganese ion in the compound with the chemical formula MnO2 is +4. This compound, called manganese dioxide, also contains two oxygen ions, each with an oxidation number of -2.

As the guidelines for nonmetals indicate, oxygen always has an oxidation number of -2 when paired with metals such as manganese. This requires manganese to take a charge of +4, so the MnO2 compound has a neutral total charge.

The manganese ion also exhibits other oxidation numbers, such as +2 and +7. For example, in KMnO4, the potassium ion has a charge of +1 and each of the oxygen ions has a charge of -2, which causes the manganese ion to take a charge of +7.