Potassium Permanganate Formula - Potassium Permanganate Uses, Properties, Structure and Formula

Potassium permanganate, also called as Condy's crystals or hypermangan, is a very useful inorganic chemical with disinfectant properties.

Formula and structure: The chemical formula of potassium permanganate is KMnO₄ and its molar mass is 158.034 g/mol. It is an ionic compound composed of the potassium cation (K⁺) and the permanganate anion (MnO₄^-), in which the manganese atom is attached to four oxygen atoms through three double bonds and one single bond. The manganese metal is in the +7 oxidation state in this salt. Solid KMnO₄ has an orthorhombic crystal structure.

Preparation: Potassium permanganate is prepared industrially in a two-step process by reacting manganese dioxide (MnO₂) with potassium hydroxide in air at high temperatures to give potassium manganate (K₂MnO₄), which is then subjected to electrolytic oxidation to give the potassium permanganate product:

2 MnO₂ + 4 KOH + O₂ → 2 K₂MnO₄ + 2 H₂O

2 K₂MnO₄ + H₂O → 2 KMnO₄ + 2 KOH + H₂

Physical properties: KMnO₄ is found as a bright purple colored crystalline solid. It is odorless and has a density of 2.70 g/mL, and a melting point of 240 °C. It is available commercially as powder, crystals or tablets.

Chemical properties: Potassium permanganate readily dissolves in water to give a characteristic bright purple, dark pink or magenta colored solution. It is a strong oxidizer that stains most organic materials (including skin and clothing) that come into contact with it, due to the formation of a dark brown reduced product, MnO ₂. It is stable at normal conditions, but decomposes upon heating to give MnO₂. Solid KMnO₄ reacts violently with concentrated sulfuric acid, glycerol and some simple alcohols.

Uses: KMnO₄ is a strong oxidant which has powerful antiseptic properties and is non-toxic in dilute concentrations. It is thus used for treating sores, ulcers, eczema, dermatitis, fungal infections and other skin conditions. It is also used widely in water treatment, fruit preservation, organic synthesis, photography, rocket propellants and in analytical chemistry as an important titrant.

Health effects/safety hazards: For its antiseptic and medical uses, it should be used in extremely dilute solutions only. Potassium permanganate is corrosive at high concentrations, and skin contact can cause irritation, redness and even burns. Swallowing high concentrations of potassium permanganate can be very dangerous, and can cause abdominal pain, throat burning, cardiovascular collapse, kidney damage and even death.