Iron(III) chloride is used as a coagulant in water and wastewater treatment to remove impurities, suspended particles, and to precipitate phosphates, thereby reducing nutrient pollution. It is commonly employed in etching copper-based materials in printed circuit board (PCB) manufacturing. As a catalyst, it plays a key role in organic synthesis, particularly in Friedel-Crafts alkylation and acylation reactions. It is also utilized in the production of pigments and dyes. In analytical chemistry, it serves as a reagent for the qualitative detection of phenols. Additionally, it is applied in the leather industry for dyeing and tanning processes, and as a precursor for synthesizing other iron compounds used in agriculture and pharmaceuticals.