Difference Between Magnesium Chloride and Magnesium Sulfate

Main Difference – Magnesium Chloride vs Magnesium Sulfate

Magnesium chloride and magnesium sulfate are inorganic, ionic compounds of the chemical element magnesium. Magnesium is a group 2 element. Therefore, it has two valence electrons that can be removed to make magnesium divalent cation. This cation can form ionic compounds by binding with different divalent or monovalent anions. Both these compounds are well-known for their health benefits. The main difference between magnesium chloride and magnesium sulfate is that magnesium chloride has a chloride ion as the anion whereas magnesium sulfate has sulfate as the anion.

Key Areas Covered

1. What is Magnesium Chloride
     – Definition, Chemical Formula, Properties, Health Benefits
2. What is Magnesium Sulfate
     – Definition, Chemical Formula, Properties, Health Benefits
3. What is the Difference Between Magnesium Chloride and Magnesium Sulfate
     – Comparison of Key Differences

Key Terms: Anion, Cation, Ionic Compound, Magnesium Chloride, Sulfate, Valence Electrons

Difference Between Magnesium Chloride and Magnesium Sulfate - Comparison Summary

What is Magnesium Chloride

Magnesium chloride is an ionic compound that has the chemical formula MgCl2. Magnesium is a group 2 element and has two valence electrons. It can form a stable divalent cation by removing these two electrons. Chloride ion is a monovalent ion. Therefore, two chloride ions can combine with one magnesium ion. There are many hydrates of magnesium chloride as well. Hydrates are composed of water molecules along with magnesium chloride molecules. The molar mass of anhydrous magnesium chloride is 95.205 g/mol.

Magnesium chloride is colorless and odorless. The boiling point of anhydrous magnesium chloride is about 1412oC. The melting point is about 712oC. When this compound is heated until it decomposes, it produces the toxic gas of hydrochloric acid.

Magnesium chloride is highly soluble in water. When solid magnesium chloride is added to water, it dissolves forming magnesium ions and chloride ions surrounded by water molecules. Hydrated magnesium chloride can be obtained from seawater as a byproduct of salt production. Anhydrous magnesium chloride is considered as a weak Lewis acid.

Difference Between Magnesium Chloride and Magnesium Sulfate

Figure 1: Magnesium Chloride

There are health benefits of magnesium chloride as well. It is used as a magnesium supplement. Magnesium is essential for muscle and nerve function. Magnesium chloride is given when an adult person is having a magnesium deficiency. However, our diet, most of the times, have enough magnesium.

What is Magnesium Sulfate

Magnesium sulfate is an inorganic, ionic compound having the chemical formula MgSO4. Magnesium ion is a divalent cation. Sulfate is a divalent anion. Therefore, one magnesium ion combines with one sulfate ion, forming the ionic compound. The molar mass of anhydrous magnesium sulfate is about 120.36 g/mol.

Magnesium sulfate is a transparent solid. It is highly soluble in water. The anhydrous magnesium sulfate crystals are highly hygroscopic. When these crystals are exposed to normal air, they can absorb water from the atmosphere. Therefore, this solid can be used as a desiccant. Magnesium sulfate is colorless and odorless. It has a bitter taste. The melting point of magnesium sulfate is about 1124oC. At this temperature, it decomposes. In its decomposition, magnesium sulfate produces toxic gases such as sulfur dioxide.

Main Difference - Magnesium Chloride vs Magnesium Sulfate_Figure 2

Figure 2: Magnesium Sulfate

The most common form of magnesium sulfate is magnesium sulfate heptahydrate. Here, one magnesium molecule is in association with 7 water molecules. The common name for this compound is Epsom salt. Since Epsom salt is easily absorbed via the skin, it is used for salt baths. Some health benefits of Epsom salt include easing muscle strain, relaxing the nervous system, drawing toxins out of the body.

Difference Between Magnesium Chloride and Magnesium Sulfate

Definition

Magnesium Chloride: Magnesium chloride is an ionic compound that has the chemical formula MgCl2.

Magnesium Sulfate: Magnesium sulfate is an inorganic, ionic compound having the chemical formula MgSO4.

Molar Mass

Magnesium Chloride: The molar mass of magnesium chloride is about 95.205 g/mol.

Magnesium Sulfate: The molar mass of magnesium sulfate is about 120.36 g/mol.

Melting Point and Boiling Point

Magnesium Chloride: The boiling point of anhydrous magnesium chloride is about 1412oC. The melting point is about 712oC.

Magnesium Sulfate: Melting point of magnesium sulfate is about 1124oC. At this temperature, it decomposes.

Decomposition

Magnesium Chloride: Magnesium chloride decomposition produces toxic gases such as hydrogen chloride.

Magnesium Sulfate: Magnesium sulfate decomposition produces toxic gases such as sulfur dioxide.

Anion

Magnesium Chloride: The anion of magnesium chloride is chloride ion.

Magnesium Sulfate: The anion of magnesium sulfate is sulfate ion.

Conclusion

Magnesium chloride and magnesium sulfate are very important compounds due to their health benefits. The main difference between magnesium chloride and magnesium sulfate is that magnesium chloride has a chloride ion as the anion whereas magnesium sulfate has sulfate as the anion.

References:

 1. Cherney, Kristeen. “Benefits of Magnesium Chloride.” LIVESTRONG.COM, Leaf Group, 3 Oct. 2017, Available here.
2. “Magnesium sulfate.” Wikipedia, Wikimedia Foundation, 16 Nov. 2017, Available here.
3. “MAGNESIUM SULFATE.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available here.

Image Courtesy:

1. “Magnesium chloride” (Public Domain) via Commons Wikimedia
2. “Magnesium sulfate heptahydrate” (Public Domain) via Commons Wikimedia

About the Author: Madhusha

Madhusha is a BSc (Hons) graduate in the field of Biological Sciences and is currently pursuing for her Masters in Industrial and Environmental Chemistry. Her interest areas for writing and research include Biochemistry and Environmental Chemistry.

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