Potassium chloride (KCl), ionic compound whose molecules consist of one potassium atom and one chlorine atom. It is a white-to-colourless face-centred cubic crystal. Potassium chloride produces a lavender or light purple color when burned in a flame test.

Potassium chloride can be extracted from sylvinite, a mineral mixture of sodium chloride (halite) and potassium chloride (sylvite), mined for potash, a mixture of potassium chloride and other potassium compounds.

Uses of potassium chloride

Potassium chloride is most often used in potash as part of an effective fertilizer for plants. Approximately 90 percent of all potassium chloride manufactured is used in the fertilizer industry. Other uses include industrial, pharmaceutical, and food and beverage applications.

In medicine it is used to treat or prevent low levels of potassium (hypokalemia) in the human body. Potassium ions are needed for proper functioning of the heart, muscles, kidneys, and nervous and digestive systems.

Potassium chloride can be substituted for salt (sodium chloride) in water softeners and in processes related to food processing. For people with high blood pressure, potassium chloride can be used as a salt substitute in food. Potassium chloride is added to sodium chloride in table salt instead of using pure potassium chloride. (Potassium chloride does not have as salty a taste as sodium chloride.) A small substitution of potassium chloride into table salt helps reduce sodium intake for people worried about the health effects of too much sodium in their diet.

Potassium chloride readily dissolves in water, and the aqueous solution that forms is a good conductor of electricity. Potassium chloride produces a lilac or pale violet colour when it burns. While it is not directly used in fireworks, potassium chloride is used to manufacture other chemicals used in pyrotechnics, such as potassium chlorate and potassium perchlorate.