Name: Ferric chloride
Synonyms: Iron(III) chloride anhydrous; Iron(III) chloride
Molecular Formula: FeCl3
Molecular Weight: 162.20
CAS Number: 7705-08-0
Iron(III) chloride, also called ferric chloride, is an industrial scale commodity chemical compound, with the formula FeCl3. The colour of iron(III) chloride crystals depends on the viewing angle: by reflected light the crystals appear dark green, but by transmitted light they appear purple-red. Anhydrous iron(III) chloride is deliquescent, forming hydrated hydrogen chloride mists in moist air. It is rarely observed in its natural form, mineral molysite, known mainly from some fumaroles.
When dissolved in water, iron(III) chloride undergoes hydrolysis and gives off heat in an exothermic reaction. The resulting brown, acidic, and corrosive solution is used as a coagulant in sewage treatment and drinking water production, and as an etchant for copper-based metals in printed circuit boards. Anhydrous iron(III) chloride is a fairly strong Lewis acid, and it is used as a catalyst in organic synthesis.
Iron(III) chloride is mainly used for the engraving etching of electronic circuit board or purify drink water and treat waste water. Iron(III) chloride is also used to make other iron salts, oxidant, catalyst, mordant and ink. In addition, Iron(III) chloride is used in construction field.