Potassium

**Symbol:** K

**Atomic number:** 19

**International title:** kalium

**Relative Atomic Weight:** 39,098 g/mol

**Information:** Potassium is a very reactive, glossy, light and very soft (can be cut by a knife) silver-coloured metal. There is a risk of self-ignition in the air, so it must be kept under a kerosene layer. It conducts very well electricity and heat. The compound exists only in the form of potassium K⁺.

**Use:** Moreover, pure metallic potassium is more known for its compounds. E.g. potassium hydroxide is used to make soaps (liquid potassium soaps), pharmaceuticals, paper and other substances.

**Occurrence:** Potassium is among the top ten most widespread elements on Earth. It occurs mainly in seawater. In nature, it only exists bounded in compounds. Its most important minerals are KCl silyl or KNO₃. It is part of all living organisms (it is a biogenic element).

**Structure:** Potassium crystallizes into a cubic (cubic) system (a spatially centered cell).