Ferric chloride hexahydrate (CAS No. 10025‑77‑1; formula FeCl₃·6H₂O; MW ≈ 270.3 g/mol) is a yellowish‑brown crystalline solid (lumps) with 97–102% purity. It is highly soluble and acidic in water, serving as a cost-effective, stable reagent widely used in water treatment, catalysis, etching, and dyeing.