Manganese: the metal that served in the army
Manganese reactions, properties and areas of application
Manganese is a silvery-white metal that gradually dulls in air. Its melting point is 1246°C (2275°F). It is fragile enough to break with a hammer.
Manganese is the 12th most common chemical element on Earth. It is most often obtained from an ore known as pyrolusite (manganese dioxide).
Manganese(IV) oxide has been known to humans since time immemorial. The cave drawings in Lascaux Cave (France), which are more than 10,000 years old, contain manganese in their composition.
Manganese compounds were used by glass blowers to bleach glass, and 18th-century chemists used manganese dioxide to produce chlorine. Manganese was obtained as a separate element by Johann Gann in 1774.
Manganese reacts with oxygen to form a durable oxide film of manganese dioxide. The reaction speeds up if heated.
Mn + O₂ = MnO₂
Manganese actively dissolves in acids, such as hydrochloric acid.
Mn + 2HCl = MnCl₂ + H₂
When manganese dioxide is fused with potassium hydroxide, green potassium manganate is formed.
2MnO₂ + 4KOH + O₂ = 2K₂MnO₄ + 2H₂O
Violet potassium permanganate can be obtained via reactions between acids (such as hydrochloric acid) and potassium permanganate.
K₂MnO₄ + 4HCl = 2KMnO₄ + MnO₂ + 2H₂O + 4KCl
Potassium permanganate is a strong oxidizing agent. It can oxidize glucose in an alkaline solution, turning first green (manganate form), then yellow (fine manganese dioxide), and ultimately colorless (divalent manganese ions form).
5C₆H₁₂O₆ + 24KMnO₄ + 36H₂SO₄ → 30CO₂ + 24MnSO₄ + 12K₂SO₄ + 66H₂O
Concentrated sulfuric acid and potassium permanganate form green manganese oxide (VII), a strong oxidizing agent. When brought into contact with alcohol, it ignites and explodes.
C₂H₅OH + 2Mn₂O₇ = 4MnO₂ + 2CO₂ + 3H₂O
Manganese dioxide is used to make alkaline and zinc-carbon batteries. An alloy of bismuth and manganese, bismanol, has been used to make magnets. Adding manganese increases steel’s strength. An alloy known as mangalloy was used to make military helmets due to its impact resistance and durability. Potassium permanganate is used in medicine to treat wounds, dermatitis, and fungal infections.