Sodium sulfate, also known as sodium sulphate, is a chemical compound with the formula Na2SO4. It is an inorganic salt that consists of sodium (Na) ions and sulfate (SO4) ions. Sodium sulfate can occur in several forms, including anhydrous (containing no water molecules) and hydrated forms, the most common of which is the decahydrate (with ten water molecules), often referred to as Glauber's salt. The decahydrate form is commonly found in nature and is used in various industrial applications.