Ammonium II Sulphate Extra Pure, commonly known as ammonium sulfate ((NH4)2SO4)(\text{(NH}_4)_2\text{SO}_4)((NH4​)2​SO4​), is a high-purity, white crystalline solid widely used in laboratory settings for biochemical, analytical, and inorganic chemistry applications. It is especially valued for protein precipitation and purification through salting-out techniques due to its high solubility and ability to stabilize proteins. Additionally, it serves as a reliable source of nitrogen and sulfate ions in analytical reactions and standard solution preparations. The extra pure grade ensures minimal interference from contaminants, making it ideal for sensitive experimental procedures. It should be stored in a cool, dry place in well-sealed containers to prevent moisture absorption and caking.