Ammonium alum

A chemical compound used in various applications

Overview

Ammonium alum crystals

Ammonium alum, also known as ammonium aluminum sulfate, is a chemical compound with the formula (NH_)Al(SO_)_·12H_O. It is a type of alum, a class of double sulfate salts, and is commonly used in various industrial and laboratory applications.

Chemical Properties

Ammonium alum is a white crystalline solid that is soluble in water. It crystallizes in the cubic crystal system and forms large, transparent crystals. The compound is known for its astringent properties and is often used in water purification, in the textile industry, and as a food additive.

Uses

Ammonium alum has several applications:

• Water Purification: It is used as a coagulant to remove impurities from water by causing them to clump together and settle out of the solution.
• Textile Industry: It is used in dyeing and printing textiles to fix dyes onto fabrics.
• Food Industry: It is used as a food additive, particularly in baking powder and pickling.
• Cosmetics: It is used in deodorants and as an astringent in aftershave products.

Production

Ammonium alum is typically produced by the reaction of aluminum sulfate with ammonium sulfate in an aqueous solution. The solution is then allowed to crystallize, forming ammonium alum crystals.

Safety

Ammonium alum is generally considered safe for use in food and cosmetics, but it should be handled with care in industrial settings to avoid inhalation or prolonged skin contact.

Related Compounds

Ammonium alum is part of a larger family of alum compounds, which include:

• Potassium alum
• Sodium alum
• Chrome alum

Related Pages

• Alum
• Aluminum sulfate
• Ammonium sulfate