What is the chemical formula of Carnallite?

Carnallite is a hydrated potassium magnesium chloride mineral with the chemical formula KCl·MgCl₂·6H₂O. It is commonly found in evaporite deposits and is an important source of potassium and magnesium for industrial and agricultural applications.

The mineral is composed of potassium chloride (KCl) and magnesium chloride (MgCl₂), combined with six molecules of water of crystallization. The presence of water makes Carnallite a hydrated salt, which can lose water upon heating, forming anhydrous salts. This hydration plays a key role in its physical and chemical properties.

Carnallite is primarily used in the production of potash fertilizers, which supply essential potassium to crops. It also serves as a source of magnesium and is used in chemical industries to prepare magnesium compounds.

Other compounds listed in the options are different. KCl is simple potassium chloride without magnesium or water. Na₂B₄O₇·10H₂O is borax, a hydrated sodium borate used in detergents and glassmaking. CaCO₃·MgCO₃ is dolomite, a calcium-magnesium carbonate mineral.

Understanding the chemical formula of Carnallite is important in inorganic chemistry for identifying mineral salts, studying hydration in salts, and learning about industrial applications of these compounds. Its unique combination of potassium, magnesium, chloride ions, and water of crystallization distinguishes it from other salts and makes it a key compound in fertilizer and chemical industries.

Carnallite’s formula, KCl·MgCl₂·6H₂O, reflects its composition and hydration, illustrating how mineral chemistry and industrial chemistry are interconnected through naturally occurring salts.