The key difference between ferrous fumarate and ferrous sulfate is that in ferrous fumarate, the ferrous anion is combined with an organic anion, while in ferrous sulfate, the anion is inorganic.
Iron is a d block metal with the symbol Fe. It is one of the most common element forming the earth and is present in large amounts at the inner and outer core of the earth. Iron has oxidation states ranging from −2 to +8. +2 and the +3 forms are the most common among these. +2 oxidation form of iron is known as ferrous while +3 form is known as ferric. These ions are in the form of ionic crystals, which are formed with various anions. Moreover, ferrous fumarate and ferrous sulfate are two ionic compounds we use as ferrous supplements to overcome iron deficiencies in living systems.
CONTENTS
1. Overview and Key Difference
2. What is Ferrous Fumarate
3. What is Ferrous Sulfate
4. Side by Side Comparison – Ferrous Fumarate vs Ferrous Sulfate in Tabular Form
5. Summary
What is Ferrous Fumarate?
Ferrous fumarate or iron(II) fumarate is the salt of fumaric acid. The chemical formula of this compound is C4H2FeO4, and it has a molar mass of 169.9 g/mol. Following is the structure of ferrous fumarate.
Figure 01: Chemical Structure of Ferrous Fumarate
Ferrous fumarate is a reddish-orange powder. It is very useful as an iron supplement. It has 32.87% of iron per molecule. This is important in treating iron-deficiency anaemia. However, if we take it in large amounts, there will be side effects like drowsiness, severe nausea or stomach pain, vomiting, bloody diarrhoea.
What is Ferrous Sulfate?
Ferrous sulfate is an ionic compound with the chemical formula FeSO4. It may exist in different crystal types depending on the number of water molecules attached. It has an anhydrous form (no attached water molecules), as well as monohydrate (one water molecule), tetrahydrate (four water molecules), pentahydrate (five water molecules), hexahydrate (six water molecules) and heptahydrate (seven water molecules) forms. Among these, the blue-green colour heptahydrate form is common. Monohydrate, pentahydrate and hexahydrate forms are relatively rare. In addition to blue-green colour crystals, other forms of ferrous sulfate are mostly white colour crystals. When heated, the hydrated crystals lose water and become anhydrous solid. Upon further heating, it decomposes into sulfur dioxide, sulfur trioxide and iron(III) oxide (reddish-brown colour). They are odourless crystals.
Figure 02: Appearance of the Heptahydrate Form of Ferrous Sulfate
Ferrous sulfate readily dissolves in water; in that case, ferrous ion forms the hexaaqua complex, [Fe(H2O)6]2+. Moreover, this compound is useful in treating conditions of iron deficiencies like iron deficiency anaemia. It can be also added to plants, as well, i.e. in conditions like iron chlorosis where plant leaves become yellow, pale colour ferrous is given. In addition, it is important as a precursor to synthesize other compounds. Moreover, we can use it as a reduction agent in redox reactions.
What is the Difference Between Ferrous Fumarate and Ferrous Sulfate?
Both ferrous fumarate and ferrous sulfate are important as iron supplements. The key difference between ferrous fumarate and ferrous sulfate is that in ferrous fumarate ferrous anion is combined with an organic anion while in ferrous sulfate, the anion is inorganic. Ferrous fumarate appears as a reddish-orange powder while the hydrates forms of ferrous sulfate have different colours. However, the most common form of ferrous sulfate is the heptahydrate form, and it appears in blue-green colour.
Summary – Ferrous Fumarate vs Ferrous Sulfate
Both ferrous fumarate and ferrous sulfate are important as iron supplements. The key difference between ferrous fumarate and ferrous sulfate is that, in ferrous fumarate, the ferrous anion is combined with an organic anion, while in ferrous sulfate, the anion is inorganic.
Reference:
1. “Iron(II) Fumarate.” Wikipedia, Wikimedia Foundation, 17 May 2019, Available here.
Image Courtesy:
1. “Iron(II)fumarate” By Ilgom – Own work (Public Domain) via Commons Wikimedia
2. “Ferrous sulfate” By W. Oelen – (CC BY-SA 3.0) via Commons Wikimedia