Ferric Chloride

In its raw form, ferric chloride is a hygroscopic crystal. Its color is dependent on the viewing angle. In reflected light, the crystals appear to be dark green. By transmitted light, they appear purple-red. Ferric chloride is readily soluble in liquids with donor properties, such as alcohols, ketones, ethers, nitriles, amines, and liquid sulfur dioxide, but sparingly soluble in nonpolar solvents like benzene and hexane according to Ulmann’s Encyclopedia of Industrial Chemistry.

Ferric chloride is harmful, highly corrosive, and acidic. The anhydrous material is a powerful dehydrating agent. Although poisoning in humans is rare, ingestion of ferric chloride can result in serious morbidity and mortality.

The most common use of ferric chloride is in solution. When dissolved it forms a light brown aqueous solution with a faint hydrochloric acid odor. It is highly corrosive to most metals and probably corrosive to tissue. It is noncombustible and primarily used in sewage treatment and water purification.

Industrial uses include the manufacture of pigments, plating agents and surface treating agents, process regulators, and solids separation agents.

Ferris chloride is produced industrially by a process called direct chlorination, the reaction of dry chlorine with scrap iron at 500-700 degrees Centigrade.