Ferrous Sulfate Heptahydrate Powder: Description and Applications Ferrous sulfate heptahydrate powder is a blue-green crystalline compound with the chemical formula FeSO₄·7H₂O. It is one of the most common and widely used forms of iron(II) sulfate, valued for its high solubility in water and its role as a cost-effective source of bioavailable iron. The heptahydrate form contains seven molecules of water per molecule of ferrous sulfate, giving it a distinct crystalline structure and hygroscopic nature. Physical and Chemical Properties Ferrous sulfate heptahydrate powder appears as fine, granular crystals or a free-flowing powder with a pale blue-green color. It is highly soluble in water, forming a light green solution that may oxidize to a yellowish-brown hue upon prolonged exposure to air due to the formation of ferric ions. The compound has a molecular weight of 278.02 g/mol, a melting point of around 64°C (where it loses water molecules), and a density of approximately 1.89 g/cm³. When exposed to dry air, ferrous sulfate heptahydrate gradually effloresces, losing water to form the monohydrate (FeSO₄·H₂O) or anhydrous ferrous sulfate (FeSO₄). It decomposes upon heating, releasing sulfur dioxide (SO₂) and forming iron(III) oxide (Fe₂O₃). Applications 1. Nutritional Supplement Ferrous sulfate heptahydrate is widely used in dietary supplements and fortified foods to prevent or treat iron-deficiency anemia. It provides a highly bioavailable form of iron, essential for hemoglobin synthesis and oxygen transport in the blood. 2. Agriculture In agriculture, it serves as a soil amendment to correct iron deficiencies in crops, particularly in alkaline soils where iron becomes less available to plants. It is also used in fertilizers and as a moss killer in lawns. 3. Water Treatment The compound is employed in wastewater treatment to reduce chromate and phosphate levels, as well as to precipitate heavy metals. It acts as a reducing agent and flocculant, aiding in the removal of contaminants. 4. Industrial Uses Ferrous sulfate heptahydrate is used in the production of iron-based pigments, inks, and dyes. It also serves as a reducing agent in chemical processes, including the synthesis of other iron compounds. 5. Pharmaceuticals In medicine, it is formulated into oral iron supplements and occasionally used in topical treatments for certain skin conditions. Handling and Storage Due to its hygroscopic nature, ferrous sulfate heptahydrate should be stored in airtight containers in a cool, dry place to prevent moisture absorption and oxidation. Prolonged exposure to air can lead to the formation of ferric sulfate, reducing its efficacy. Proper handling with protective equipment is recommended to avoid inhalation or skin contact. Conclusion Ferrous sulfate heptahydrate powder is a versatile and essential compound with applications spanning nutrition, agriculture, water treatment, and industrial processes. Its high solubility and bioavailability make it a preferred choice for iron supplementation, while its chemical properties enable diverse industrial uses. Proper storage and handling ensure its stability and effectiveness in various applications.