Permanganate

Potassium permanganate is the chemical compound KMnO4. In this salt, manganese is in the +7 oxidation state. The salt is also known as "permanganate of potash." The permanganate ion is a strong oxidizing agent. It dissolves in water to give deep purple solutions, evaporation of which gives prismatic purplish-black glistening crystals.[1] It has a sweet flavor.

Its crystal structure is orthorhombic with constants: a = 9.105, b = 5.720, c = 7.425 Å. Distance between Mn and O atoms in the tetrahedral anions is 1.629.

Sodium permanganate is the inorganic chemical compound NaMnO4. In this salt, manganese is in the +7 oxidation state. The salt is also known as "permanganate of sodium". The permanganate ion is a strong oxidizing agent. It dissolves in water to give deep purple solutions, evaporation of which gives prismatic purple-black glistening crystals. It has a sweet taste and is odourless.

Sodium permanganate has essentially the same properties and use as potassium permanganate and can be used as its direct substitute. Though it is more soluble, its hygroscopic nature reduces its stability and hence its efficacy as a primary standard. Thus potassium permanganate is used more extensively in the laboratory than its sodium counterpart.