About Ammonium Sulfates

Ammonium Sulfate Formula Diagram (NH4)2SO4

Ammonium Sulfates are double salts in the class of alums, compounds which contain a monovalent cation such as ammonium and a multivalent metal ion such as aluminum. Many alums occur in various hydrated forms as various rare minerals, but they are generally produced synthetically for commercial use. Many alums have common names: ammonium aluminum sulfate is often referred to as ammonium alum or just alum, ammonium iron(III) sulfate is sometimes known as iron alum, and ammonium iron(II) sulfate is known as Mohr’s salt.

Ammonium alum is an inexpensive and nontoxic chemical with many niche applications, including in water purification, vegetable glues, porcelain cements, deodorants, and textile finishing applications. Iron alum finds similar uses as aluminum alum, and additionally has been used as an etching agent and a reagent in organic synthesis. Mohr’s salt acquired its name from the German chemist Karl Friedrich Mohr, who worked extensively with the salt in his work improving the methodology of titration in the 19th century, and it remains a common chemical laboratory reagent.