barium sulfate
Natural barium sulfate is called barite. It is an important raw material for making other barium salts. Barium sulfate is not easily transmitted by X-ray. It can be used as an oral medicine to examine the intestines and stomach in medical treatment, commonly known as "barium meal". Barium sulfate can also be used as white pigments and as raw materials and fillers for high-grade paints, inks, papermaking, plastics and rubber.
ferrous sulfate
The crystalline hydrate of ferrous sulfate is commonly known as alum (FeSO4.7H2O). Ferrous sulphate can be used in medicine to prevent and cure iron deficiency anemia. Ferrous sulphate is also used in industry as raw material to produce iron series water purifier and red iron oxide (the main ingredient is Fe2O3).
Copper sulphate
Copper sulfate, commonly known as alum, has the molecular formula CuSO4.5H2O. The molecular weight is 249.68. Water content is 36%. It is formed by absorbing water from anhydrous copper sulfate. Bile alum is a chemical raw material for pigments, batteries, pesticides, wood preservation, etc. Copper sulfate pentahydrate is very stable under normal temperature and pressure. It does not decompose. It gradually weathers in dry air. When heated to 45 C, it loses bimolecular crystalline water. When heated to 110 C, it loses tetramolecular crystalline water. It is called copper sulfate monohydrate. All crystalline water is lost and anhydrous at 200 C. Anhydrous substances are also easy to absorb water and convert to copper sulfate pentahydrate. Anhydrous copper sulfate (white or gray-white powder) reacts with water to form copper sulfate pentahydrate (blue). This property is often used to test whether some liquid organic substances contain trace water. Attention should be paid to the distinction between the two. The anhydrous copper sulfate can be decomposed into black copper oxide, sulphur dioxide and oxygen (or sulphur trioxide) by heating it to 650 C.