Ferric chloride, reagent grade, 97% Cas 7705-08-0 - used for sewerage treatment of industrial wastes, chloride hydrometallurgy (Silgarin process for the production of silicon), drinking water production, production of precursor for polyvinyl chloride (PVC), and copper-based metals in printed circuit boards. Iron (III) chloride is used as catalyst for the reaction of ethylene with chlorine, as a leaching agent, and as a drying reagent in certain reactions.