Aluminium sulfate, with the chemical formula Al2(SO4)3, is a chemical compound composed of aluminium (Al) and sulfate ions (SO4^2-). It is an ionic compound and belongs to the family of sulfates.

Aluminium sulfate is a white crystalline solid that is highly soluble in water. It is commonly encountered in its hydrated form, as aluminum sulfate hydrate (Al2(SO4)3·xH2O), where x represents the number of water molecules associated with the compound.

Some key properties and uses of aluminium sulfate include:

1. Water Treatment: Aluminium sulfate is widely used in water treatment processes, particularly in the purification of drinking water and wastewater treatment. It acts as a coagulant to remove impurities and suspended particles, helping to clarify the water.
2. Paper Manufacturing: Aluminium sulfate is used in the paper industry as a sizing agent, which improves the water resistance and printability of paper.
3. Dyeing and Printing: It is used in the textile industry as a mordant to enhance the colorfastness of dyes.
4. Soil Conditioner: Aluminium sulfate can be used to lower soil pH and make it more acidic. It is employed as a soil conditioner to enhance the growth of acid-loving plants like azaleas, rhododendrons, and blueberries.
5. Flame Retardant: In some applications, aluminium sulfate is used as a flame retardant to reduce the flammability of materials.

Aluminium sulfate is considered safe for its intended uses, but like any chemical compound, it should be handled with care, and safety precautions must be followed during its application. It is widely used in various industrial and commercial applications due to its effectiveness in water treatment, paper manufacturing, and other processes where its properties are beneficial.