Ammoniumalum

Ammonium alum, also known as ammonium aluminum sulfate or diammonium aluminum sulfate, is a double salt with the chemical formula (NH₄)₂SO₄·Al₂(SO₄)₃·24H₂O. It belongs to the class of compounds called alums, which are characterized by their crystalline structure and solubility in water. Ammonium alum is a white, odorless, crystalline solid that dissolves readily in water, forming a clear solution.

This compound is commonly used in various applications due to its astringent, antiseptic, and coagulating properties. Historically, it has been employed in medicine as an astringent for treating skin irritations, wounds, and minor burns. In the textile industry, ammonium alum serves as a mordant, helping to fix dyes onto fabrics. It is also utilized in water treatment processes to clarify turbid water by precipitating suspended particles.

Ammonium alum can be synthesized through the reaction of aluminum sulfate and ammonium sulfate in a solution. The crystals form upon cooling the saturated solution. It is stable under normal conditions but decomposes upon heating, releasing ammonia and forming aluminum sulfate. The compound is generally considered safe for most uses, though prolonged or excessive exposure may cause skin irritation or drying effects.

In addition to its practical applications, ammonium alum has been studied for its potential in other fields, such as food preservation and laboratory chemistry. However, its use in food has been restricted in many regions due to regulatory concerns. Despite its utility, proper handling is recommended to avoid skin contact or inhalation of dust, as it may cause discomfort.