Ferrous Sulfate Heptahydrate: Properties, Uses, and Applications Ferrous sulfate heptahydrate, chemically represented as FeSO₄·7H₂O, is a hydrated form of ferrous sulfate (iron(II) sulfate). It is a blue-green crystalline solid widely recognized for its role as a source of iron in various industrial, agricultural, and pharmaceutical applications. Physical and Chemical Properties Ferrous sulfate heptahydrate appears as translucent, bluish-green crystals or granules with a slightly metallic taste. It is highly soluble in water, forming a pale green solution, but insoluble in alcohol. The compound is stable under normal storage conditions but gradually oxidizes in moist air, turning yellowish-brown due to the formation of ferric sulfate (iron(III) sulfate). It has a molecular weight of 278.02 g/mol and a melting point of around 60–70°C, where it loses water molecules to form the anhydrous or monohydrate form. Production and Sources Ferrous sulfate heptahydrate is commonly obtained as a byproduct of the steel industry, where it forms during the pickling of iron or steel with sulfuric acid. It can also be synthesized through the reaction of iron with sulfuric acid under controlled conditions. Applications 1. Nutritional Supplement - A key application is in treating and preventing iron-deficiency anemia. It serves as an effective dietary supplement due to its high bioavailability of iron, which is essential for hemoglobin production. 2. Agriculture - Used as a soil amendment to correct iron deficiencies in crops, promoting healthy plant growth. It also acts as a moss killer in lawns. 3. Water Treatment - Functions as a reducing agent and coagulant in wastewater treatment, helping remove phosphates and heavy metals. 4. Industrial Uses - Employed in the manufacture of inks, dyes, and pigments, such as iron gall ink and Prussian blue. - Acts as a reducing agent in chemical processes, including the production of ferric compounds. 5. Other Uses - Historically used in wood preservation and as a component in some types of concrete. Safety and Handling While generally safe when used appropriately, ferrous sulfate heptahydrate can be hazardous if ingested in large quantities, causing gastrointestinal distress or iron toxicity. Proper storage in airtight containers away from moisture and oxidizing agents is essential to maintain stability. Conclusion Ferrous sulfate heptahydrate is a versatile compound with significant applications in healthcare, agriculture, and industry. Its role as an iron source and reducing agent makes it indispensable across multiple sectors, though careful handling is required to ensure safety and efficacy.