Difference Between Ferrous Fumarate and Ferrous Sulfate

Ferrous Fumarate vs Ferrous Sulfate

Iron is a metal in the d block with the symbol Fe. It is one of the most common elements forming the earth and has large amounts in the inner and outer core of the earth. It is the fourth most common element in the earth’s crust. Iron has oxidation states ranging from −2 to +8. Among these +2 and the +3 forms are the most common. +2 oxidation form of iron is known as ferrous and +3 form is known as ferric. These ions are in the form of ionic crystals, which are formed with various anions. Iron is needed to biological systems for various purposes. For example in humans, ferrous is found as a chelating agent in hemoglobin. It is also important for the chlorophyll synthesis in plants. Hence, when there is a deficiency of this ion, biological systems show various diseases. Ferrous fumarate and ferrous sulfate are two ionic compounds, which can be given as ferrous supplements, to overcome iron deficiencies in living systems.

Ferrous Fumarate

Ferrous fumarate or iron(II) fumarate is the salt of fumaric acid. Molecular mass of this compound is C4H2FeO4, and it has a molar mass of 169.9. Following is the structure of ferrous fumarate.

Ferrous fumarate is a reddish orange powder. It is a good iron supplement. It has 32.87% of iron in one molecule. This is used to treat iron deficiency anemia. However, if it is taken in large amounts, side effects like drowsiness, severe nausea or stomach pain, vomiting, bloody diarrhea can result.

Ferrous Sulfate

Ferrous sulfate is an ionic compound with the chemical formula FeSO4. It may exist in different crystal types depending on the amount of water molecules attached. It has the anhydrous form, monohydrate, tetrahydrate, pentahydrate, hexahydrate and heptahydrate forms. Among these, the blue, green color heptahydrate form is the common. Monohydrate, pentahydrate and hexahydrate forms are relatively rare.  Other than the blue, green color crystals, other forms of ferrous sulfate are mostly white colored crystals.  When heated, the hydrated crystals loose water and become anhydrous solid. Upon further heating, it is decomposed into sulfur dioxide, sulfur trioxide and iron(III) oxide (reddish brown color). They are odorless crystals. Ferrous sulfate readily dissolves in water and, in that case, ferrous ion forms the hexa aqua complex, [Fe(H2O)6]2+. Ferrous sulfate is used to treat conditions of iron deficiencies like iron deficiency anemia. Not only for humans, it is added to plants, as well. In conditions like iron chlorosis, where plant leaves become yellow, pale color ferrous is given.  Other than that, it is used as a precursor, to synthesize other compounds. Since it is a reduction agent, it is used for redox reactions, as well.


What is the difference between Ferrous Fumarate and Ferrous Sulfate?

• In ferrous fumarate ferrous anion is combined with an organic anion. In ferrous sulfate, the anion is inorganic.

• Ferrous fumarate is a large compound compared to ferrous sulfate.

• Ferrous sulfate is abundant in nature compared to ferrous fumarate.


  • kathy

    Can I take a daily vitamin with ferrous fumarate and a single tablet of ferrous sulfate?