Crystalline salts are salts that contain a fixed amount of water molecules in their crystal structure, known as water of crystallisation. These water molecules are chemically bonded and give the salt its specific crystalline shape and properties. Many salts we use daily, such as washing soda (Na₂CO₃·10H₂O) and gypsum (CaSO₄·2H₂O), have water of crystallisation. This property is essential in determining their physical and chemical behaviour, such as solubility, melting points, and reactions. These salts are commonly used in industries, households, and laboratories for various purposes.
Some substances in our daily use contain water of crystallisation
- Alum (Potash alum—K₂SO₄·Al₂(SO₄)₃·24H₂O)
- Borax (Na₂B₄O₇·10H₂O)
- Epsom salt (Magnesium sulphate MgSO₄·7H₂O)
- Barium chloride (BaCl₂·2H₂O)
- Sodium sulphate (Glauber’s salt Na₂SO₄·10H₂O)
