Iron(II) sulfate

Chemical compound

Structural formula of Iron(II) sulfate

Iron(II) sulfate, also known as ferrous sulfate, is a chemical compound with the formula FeSO₄. It is commonly encountered as the heptahydrate, FeSO₄·7H₂O, which is a blue-green crystalline solid. Iron(II) sulfate is used in various applications, including as a precursor to other iron compounds, in water treatment, and as a nutritional supplement.

Chemical Properties

Iron(II) sulfate is a sulfate salt of iron in the +2 oxidation state. The compound is typically found in its heptahydrate form, which is known as green vitriol or copperas. The anhydrous form is a white crystalline solid, while the heptahydrate is blue-green.

3D model of Iron(II) sulfate heptahydrate

Hydration States

Iron(II) sulfate can exist in several hydrated forms, including the monohydrate, tetrahydrate, pentahydrate, and heptahydrate. The heptahydrate is the most common form and is often used in industrial applications. The hydration state affects the compound's solubility and stability.

Reactivity

Iron(II) sulfate is soluble in water and forms a pale green solution. It is a reducing agent and can be oxidized to iron(III) sulfate in the presence of oxidizing agents. The compound decomposes upon heating, releasing sulfur dioxide and leaving behind iron(III) oxide.

Production

Iron(II) sulfate is produced as a byproduct of the steel pickling process, where iron is treated with sulfuric acid. It can also be synthesized by reacting iron with sulfuric acid:

Fe + H₂SO₄ → FeSO₄ + H₂

This reaction produces hydrogen gas and iron(II) sulfate.

Applications

Industrial Uses

Iron(II) sulfate is used in the production of iron(III) oxide pigments, as a reducing agent in the treatment of chromate-containing effluents, and in the manufacture of other iron compounds.

Sample of Iron(II) sulfate heptahydrate

Water Treatment

In water treatment, iron(II) sulfate is used as a coagulant to remove impurities and as a flocculant to improve the sedimentation of suspended solids. It is also used to treat sewage and industrial waste.

Agriculture

Iron(II) sulfate is used as a soil amendment to correct iron chlorosis, a condition caused by iron deficiency in plants. It is also used as a moss killer in lawns and gardens.

Medicine

In medicine, iron(II) sulfate is used as an iron supplement to treat iron-deficiency anemia. It is available in various forms, including tablets and liquid solutions.

Safety

Iron(II) sulfate is generally considered safe when used as directed. However, it can be harmful if ingested in large quantities, leading to iron poisoning. It should be handled with care to avoid skin and eye irritation.

Iron(II) sulfate crystals

Related Compounds

• Iron(III) sulfate
• Iron(II) chloride
• Iron(III) chloride

Related Pages

• Iron
• Sulfate
• Anemia