ferricloride

Ferric chloride, also known as iron(III) chloride, is a chemical compound with the formula FeCl3. It is a common salt of iron in its +3 oxidation state. Anhydrous ferric chloride is a crystalline solid, ranging in color from dark brown to black. It readily absorbs moisture from the air, forming a hydrated compound, typically ferric chloride hexahydrate (FeCl3·6H2O), which is yellowish-brown in color. This hydrated form is more commonly encountered.

Ferric chloride is highly soluble in water, producing an acidic solution due to hydrolysis. It is also soluble in many organic solvents, such as alcohols and ethers. The compound exhibits strong oxidizing properties.

Industrially, ferric chloride is widely used as a flocculant in wastewater treatment and drinking water purification. It reacts with impurities in the water to form larger particles that can be easily removed. It also serves as a etchant in the electronics industry for printed circuit boards, and in historical photography as a print toner. In laboratories, it is used as a catalyst in organic synthesis, particularly in Friedel-Crafts reactions. Ferric chloride can also be used as a mordant in dyeing fabrics. While useful, it is corrosive and should be handled with appropriate safety precautions.