Ferrous chloride, FeCl2. Green to yellow. Soluble in water, ethanol and methanol. FeCl2·4H2O is a clear blue-green monoclinic crystal. Density 1.93 g/cm 3. Easy deliquescence. Soluble in water, ethanol, acetic acid, slightly soluble in acetone, insoluble in ether. Some oxidation in the air turns grassy green. Gradually oxidized to ferric chloride in air. Anhydrous ferrous chloride is a yellow-green hygroscopic crystal, dissolved in water to form a light green solution. Four salt water. Salt dihydrate when heated to 36.5℃. It is widely used in textile dyeing, pigment dyeing, manufacturing and other industries. It is also used in ultra-high pressure lubricating oil components. It is also used in medicine, metallurgy and photography.

Ferrous chloride can be used as wastewater decolorizing agent in sewage treatment in printing and dyeing, paper making industry. Ferrous chloride has obvious treatment effect for all kinds of wastewater, electroplating, leather, paper making wastewater. Ferrous chloride can be directly used for sewage and waste water processing. As a reducing agent and coal dyeing agent, it can be widely used in textile printing and dyeing, pigment printing and dyeing, manufacturing and other industries. It can also be used in ultra-high pressure lubricating oil components, medicine, metallurgy and photography fields.