Ammonium sulfate, (NH4)2SO4open paren cap N cap H sub 4 close paren sub 2 cap S cap O sub 4(𝑁𝐻4)2𝑆𝑂4, is a highly soluble inorganic salt primarily used as a Nitrogen (21%) and Sulfur (24%) fertilizer, particularly for alkaline soils to lower pH. It is essential in agriculture for enhancing crop yields and in biochemical research for protein precipitation and purification.