Overview
Potassium chloride is an inorganic white crystalline salt with the chemical formula KCl. It is an ionic compound made of potassium cations and chloride anions. In its common form it looks like table salt and dissolves readily in water, producing an electrically conductive solution.
Structure and properties
KCl consists of K+ (potassium ion) and Cl− (chloride ion) arranged in a cubic, rock‑salt type lattice at ambient conditions. Physically it is similar to sodium chloride but differs in ionic radius and some solubility and melting characteristics. In flame tests, potassium compounds commonly produce a violet to lilac flame color.
Occurrence and production
Potassium chloride occurs naturally in evaporite minerals such as sylvite and carnallite and is mined as part of potash deposits. It is also recovered by evaporating saline brines. Large quantities are produced for agricultural and industrial use; see industrial production for more on extraction routes.
Uses and importance
- Fertilizer: the principal source of potassium in agriculture, vital for plant growth.
- Food and medicine: used as a low‑sodium salt substitute and as a pharmaceutical potassium supplement under medical supervision.
- Laboratory and industrial reagent: serves as a source of potassium or chloride in chemical processes and analyses.
Safety and notable facts
While commonly handled as a bulk commodity, concentrated or medical doses can affect heart rhythm and must be used with care to avoid hyperkalemia. The element symbol K comes from the historical name kalium, and products derived from potash have been economically important for centuries.