Manganese (IV) oxide. It is one of the most important oxides of Manganese . According to the IUPAC its chemical formula is MnO 2 . It is also known as manganese dioxide, manganese peroxide and is obtained from the mineral Pyrolusite .
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- 1 History
- 2 Physical properties
- 3 Chemical properties
- 4 Applications
- 5 Effects
- 6 Chemical hazards
- 7 Sources
Manganese (IV) oxide has been found in cave paintings (giving a black color). They have also been used by Egyptians and Romans throughout history, to discolor glass or to color it. Manganese has also been found in the iron ores used by the Spartans, and it is thought that this is perhaps the special hardness of their steels .
In the 17th century , the German chemist Glauber first produced permanganate, a widely used laboratory reagent. In the middle of the 18th century , manganese (IV) oxide was used for the production of chlorine .
It is an unstable compound, solid at normal temperature and pressure.
- Appearance: Solid
- Density: 5026 kg / m3; 5,026 g / cm3
- Molar mass: 86.94 g / mol
- Melting point: 808.15 K (535 ° C)
- Boiling point: 2235 K (1962 ° C
- NFPA: 704.
It is soluble in water and reacts with hydrogen peroxide and breaks it down:
2H 2 O 2 + MnO 2 → 2H 2 O + MnO 2 + O 2
Here manganese (IV) oxide acts as a catalyst .
Manganese (IV) oxide is used as a depolarizer in dry cells. It can also be used to discolor glass that is green due to the presence of traces of iron. This oxide is also used to give amethyst color to glass (a variety of quartz ). Furthermore, it is used in the production of chlorine , iodine and oxygen . It is used in the manufacture of paints and varnishes for painting crystals and ceramics.
Prolonged exposures to manganese compounds, inhaled or oral, can cause adverse effects on the nervous and respiratory system, as well as contact with the eyes .
The substance decomposes when heated intensively above 553 ° C, producing manganese (III) oxide and oxygen, which increases the danger of fire . It is a strong oxidant and reacts violently with combustible and reducing materials, creating a fire and explosion hazard. Reacts violently with aluminum in the presence of intense heat.