FAS is paramagnetic, acidic and toxic towards microorganisms. It is a weak oxidizing agent, capable of being reduced to Mohr's salt, ferrous ammonium sulfate.It is use as loboratory reagent.
Ferric ammonium sulfate dodecahydrate also known as ferric ammonium sulfate (FAS) or iron alum is a double salt in the class of alums,It has the appearance of weakly violet, octahedrical crystals.FAS can be prepared by crystallization from a solution of ferric sulfate and ammonium sulfate