Ammonium Ferric Sulphate

Ammonium ferric sulphate, also known as ferric ammonium sulfate or iron alum, is a double salt in the class of alums. It has the appearance of weakly violet, octahedrical crystals.

Ammonium ferric sulphate is used as a mordant in dyeing and printing of fabrics and textiles. It is also used as an analytical reagent; and is used in medicine.

Ammonium ferric sulphate is prepared by mixing an equimolar solution offerric sulfate, Fe2(SO4)3, and ammonium sulfate, (NH4)2SO4. Hydrated crystals are obtained following evaporation and cooling of the solution.