Iron Sulfate

Team Chemistry -
Created by: Team Chemistry -, Last Updated: May 23, 2024

Iron Sulfate

Iron sulfate is a chemistry compound that combines iron and sulfur to form a salt. It appears as a blue-green crystalline solid and is commonly used in various applications, such as in fertilizers to supply essential nutrients to plants. Iron sulfate is also used in water treatment processes to remove impurities. This compound plays a vital role in the production of iron pigments and can be found in some medical treatments for iron deficiency. Its versatility makes it an important substance in both industrial and agricultural chemistry.

What is Iron Sulfate?

Iron sulfate is also known as ferrous sulfate. It is a chemical compound with the formula FeSO₄. It consists of iron in the +2 oxidation state combined with sulfate ions. Iron sulfate often appears as blue-green crystals and is commonly used to treat iron-deficiency anemia, as it provides a source of iron that the body can easily absorb. In gardening, it helps correct iron chlorosis in plants, which is a condition caused by a lack of available iron in the soil.

Chemical Names and Formulas

Hill FormulaFeH14O11S
IUPAC NameIron(+2) Cation Sulfate Heptahydrate
Alternate NamesFerrous Sulfate, Ferrous Sulfate Heptahydrate, Haemofort, Iron(II) Sulfate

Structure of Iron Sulfate


The structure of iron sulfate consists of one iron ion (Fe²⁺) and one sulfate ion (SO₄²⁻). In this compound, the iron ion is positively charged, while the sulfate ion is negatively charged, allowing them to bond together through ionic bonds. The sulfate ion has a tetrahedral shape, where one sulfur atom is centrally located and surrounded by four oxygen atoms. These ions form a crystalline structure when solid, often appearing as blue-green crystals.

Preparation of Iron Sulfate

To prepare iron sulfate, you can react iron with sulfuric acid. This process involves placing a piece of iron into a container with diluted sulfuric acid. As the reaction occurs, iron dissolves and forms iron sulfate and hydrogen gas. You can observe bubbles of hydrogen gas forming as the reaction proceeds. The chemical equation for this reaction is:

Fe + H₂SO₄ → FeSO₄ + H₂

After the reaction completes, you can evaporate the remaining liquid to obtain solid iron sulfate crystals. This method is commonly used in laboratories to produce iron sulfate for various experiments and applications.

Physical Properties of Iron Sulfate

AppearanceIron sulfate appears as blue-green crystals.
SolubilityIt dissolves easily in water.
Melting PointIron sulfate has a melting point of 64°C (147°F).
DensityThe density of iron sulfate is about 1.898 g/cm³.
OdorIt does not have a significant odor.
Molecular WeightThe molecular weight of iron sulfate is 151.91 g/mol.

Chemical Properties of Iron Sulfate

Reacts with Water

Iron sulfate dissolves in water, forming a pale green solution. This solution is often used for various industrial and medical applications.

FeSO₄ → Fe²⁺ +SO₄²⁻


When exposed to air, iron sulfate oxidizes to form iron(III) sulfate and a brownish-yellow coating of iron(III) oxide. This reaction shows the change in the oxidation state of iron from +2 to +3.

4FeSO₄ + O₂ + 2H₂O → 2Fe₂(SO₄)₃ + 2H₂O

Reacts with Alkalis

Iron sulfate reacts with alkalis, such as sodium hydroxide, to form iron(II) hydroxide, which precipitates as a green solid.

FeSO₄ + 2NaOH → Fe(OH)₂ + Na₂SO₄


When heated, iron sulfate decomposes to form iron(III) oxide, sulfur dioxide, and sulfur trioxide. This reaction releases gases and changes the chemical composition of iron sulfate.

2FeSO₄ → Fe₂O₃ + SO₂ + SO₃

Iron Sulfate Chemical Compound Information

Chemical Identifiers

CAS Registry Number7782-63-0
PubChem Compound ID62662
SMILES IdentifierO.O.O.O.O.O.O.[O-]S(=O)(=O)[O-].[Fe+2]
InChI IdentifierInChI=1/Fe.H2O4S.7H2O/c;1-5(2,3)4;;;;;;;/h;(H2,1,2,3,4);7*1H2/q+2;;;;;;;;/p-2/fFe.O4S.7H2O/qm;-2;;;;;;;
EU Number231-753-5
Gmelin Number105946
RTECS NumberNO8510000

NFPA Label

NFPA Health Rating1
NFPA Fire Rating0
NFPA Reactivity Rating0

Uses of Iron Sulfate

Treats Iron-Deficiency Anemia

Doctors prescribe iron sulfate to treat iron-deficiency anemia. It provides the necessary iron for the body to produce red blood cells.

Corrects Iron Chlorosis in Plants

Gardeners use iron sulfate to correct iron chlorosis in plants. It helps plants develop healthy green leaves by supplying essential iron.

Acts as a Coagulant in Water Treatment

Iron sulfate acts as a coagulant in water treatment plants. It helps remove impurities from water by clumping particles together for easier filtration.

Used in Dyeing Processes

The textile industry uses iron sulfate in dyeing processes. It helps fix dyes to fabrics, ensuring vibrant and long-lasting colors.

Serves as a Moss Killer

Iron sulfate is effective as a moss killer on lawns. It helps eliminate moss, promoting healthier grass growth.

Utilized in Making Other Iron Compounds

Chemists use iron sulfate to produce other iron compounds. It serves as a starting material for synthesizing various chemicals in laboratories.

Benefits of Iron Sulfate

  1. Treats Anemia: Iron sulfate effectively treats iron-deficiency anemia by increasing red blood cell production.
  2. Improves Plant Health: It corrects iron chlorosis, helping plants grow healthier and greener.
  3. Purifies Water: Iron sulfate acts as a coagulant, making water treatment processes more efficient.
  4. Enhances Fabric Dyeing: It helps fix dyes to fabrics, ensuring colors are vibrant and durable.
  5. Controls Moss Growth: Iron sulfate kills moss on lawns, promoting healthier grass.
  6. Produces Other Chemicals: It serves as a starting material for making various iron compounds in laboratories.

Iron Sulfate: Effects on Human Body

  1. Boosts Hemoglobin Production: Iron sulfate increases hemoglobin levels, improving oxygen transport in the blood.
  2. Treats Anemia: It effectively treats iron-deficiency anemia, reducing symptoms like fatigue and weakness.
  3. Improves Energy Levels: By increasing iron levels, iron sulfate enhances overall energy and reduces tiredness.
  4. Supports Immune Function: Adequate iron levels boost the immune system, helping the body fight infections.
  5. Enhances Cognitive Function: Iron is crucial for brain health, and iron sulfate can improve concentration and memory.
  6. Potential Side Effects: Some people may experience side effects like stomach upset, constipation, or nausea when taking iron sulfate.

Side Effects of Iron Sulfate

  1. Stomach Upset: Some individuals may experience discomfort or pain in the stomach.
  2. Constipation: Iron sulfate can cause constipation, leading to difficulty in bowel movements.
  3. Nausea: Taking iron sulfate may result in feelings of nausea or queasiness.
  4. Diarrhea: In some cases, it can cause loose or frequent bowel movements.
  5. Dark Stools: Iron sulfate often causes stools to appear darker in color.
  6. Metallic Taste: Some people may notice a metallic taste in their mouth after taking iron sulfate.

When Should You Take Ferrous Sulfate?

Take ferrous sulfate on an empty stomach, preferably one hour before or two hours after meals, to enhance absorption. If stomach upset occurs, take it with food.

Why is Ferrous Sulfate in Food?

Ferrous sulfate is added to food as a fortificant to prevent iron deficiency, ensuring adequate iron intake, especially in populations at risk for anemia.

What Medication is Ferrous Sulfate?

Ferrous sulfate is an iron supplement used to treat or prevent iron-deficiency anemia by providing the body with essential iron needed for red blood cell production.

What Foods Should You Avoid When Taking Iron Sulfate?

Avoid dairy products, coffee, tea, eggs, and high-fiber foods when taking iron sulfate, as they can interfere with iron absorption.

How Much of Ferrous Sulfate Should a Human Take?

Adults typically take 100-200 mg of elemental iron daily, divided into two or three doses. Always follow your healthcare provider’s recommendations for dosage.

Why is Iron Sulfate Used in Water Treatment?

Iron sulfate acts as a coagulant, helping to remove impurities from water by clumping particles together for easier filtration.

How Does Iron Sulfate Help Plants?

Iron sulfate corrects iron chlorosis in plants, promoting healthy green leaves and overall plant health by providing essential iron.

Is Iron Sulfate Safe to Use?

Iron sulfate is safe when used as directed but can cause side effects. Consult a healthcare provider for medical use and follow guidelines for gardening or industrial applications.

Can Ferrous Sulfate Stain Teeth?

Ferrous sulfate liquid can stain teeth. To prevent this, mix the liquid with water or juice, drink through a straw, and brush teeth afterwards.

Can You Take Ferrous Sulfate with Vitamin C?

Yes, taking ferrous sulfate with vitamin C can enhance iron absorption. Vitamin C helps convert iron into a form that is easier for the body to absorb.

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