Ferric trichloride is the most common solid in the market, and the solid of ferric trichloride can be divided into hexahydrate ferric trichloride and anhydrous ferric trichloride. From a strict chemical point of view, there are two different substances. However, because the functional effects are almost the same, most people will recognize it as a kind of ferric trichloride.

Anhydrous ferric chloride is generally a black crystalline solid, exposed to the air for a period of time will deliquescence, produce deterioration, become red. Ferric chloride is easily soluble in water, ethanol, etc., and the aqueous solution is generally acidic, and has strong oxidation and corrosion.

At present, anhydrous ferric chloride is mainly used in industrial water treatment, circuit board etching, mordant in dye industry, catalyst and oxidant in organic chemical industry and raw material of ferric salt in industrial production.

Ferric chloride hexahydrate is generally brownish yellow crystal, which will form a block after being affected by moisture. It is also very easy to dissolve in water and presents brownish black liquid after being dissolved. At present, ferric chloride hexahydrate is mostly used in photographic and printing industries, and can also be used in sewage treatment industry and printing and dyeing industry.

Compared with sewage ferric chloride, ferric chloride hexahydrate is not much different except for its price and purity. However, it should be noted that no matter what industry ferric chloride is used in, it is necessary to select the appropriate type and take certain protective measures when it is used.