Apperance: Blue monoclinic crystals.

Nature: Relative density 1. 899(14.8°C, heptahydrate), melting point 64°C (heptahydrate). Soluble in water and glycerol, practically insoluble in ethanol. Lose six molecules of crystal water at 90°C, lose all crystal water at 300°C, in the air gradually weathered, and oxidized to yellow-brown. The interaction of the water-free substance with the water changed back to blue-green. Corrosive. Moisture absorption in dry air.

Use: Used as feed additive. Feed grade ferrous sulfate is an iron salt additive, used as an iron supplement in feed processing, and has a detoxification effect on the toxins contained in the cottonseed cake in the feed. It is used as fertilizer, pesticide and herbicide in agriculture, and is used to treat wheat smut. It is used as a local astringent and a blood tonic in medicine. In addition, it is also used in the manufacture of iron salt, ink, iron oxide red and indigo, etc., and used as mordant, tanning agent, water purification agent, disinfectant and wood preservative. It can also be used for photography.