Alum

Alum

An alum is a type of chemical compound, usually a hydrated double sulfate salt of aluminium with the general formula XAl₂·12H₂O, such that X is a monovalent cation such as potassium or ammonium. By itself, alum often refers to potassium alum, with the formula KAl₂·12H₂O. Other alums are named after the monovalent ion, such as sodium alum and ammonium alum. The name alum is also used, more generally, for salts with the same formula and structure, except that aluminium is replaced by another trivalent metal ion like chromiumᴵᴵᴵ, or sulfur is replaced by another chalcogen like selenium. The most common of these analogs is chrome alum KCr₂·12H₂O. In most industries, the name alum is used to refer to aluminium sulfate, Al₂₃·nH₂O, which is used for most industrial flocculation. For medicine, the word alum may also refer to aluminium hydroxide gel used as a vaccine adjuvant.

Data Source : Wikipedia

• Related Topics:  Alunite - Alunite Is A Hydroxylated Aluminium Potassium Sulfate Mineral, Formula Kal₃₂₆. It Was First Observed In The 15Th Century At Tolfa, Near Rome, Where It Was Mined For The Manufacture Of Alum., Gum Bichromate – Photo Prints And Other Similar Processes Use Alums, Sometimes As Colloid (Gelatin, Albumen) Hardeners., Astringent Flavors, Sulfates, Traditional Medicine, Sulfate Minerals, Food Additives