The key difference between magnesium chloride and magnesium sulfate is that magnesium chloride molecule has one magnesium cation associated with two chloride anions whereas magnesium sulfate molecule has one magnesium cation associated with one sulfate anion.
Magnesium is an alkaline earth metal that can form a divalent stable cation. This cation can form many ionic compounds such as magnesium chloride and magnesium sulfate. Both these are solid compounds at room temperature that can exist in different hydrated forms. This article discusses more details about these two compounds and other differences between them.
CONTENTS
1. Overview and Key Difference
2. What is Magnesium Chloride
3. What is Magnesium Sulfate
4. Side by Side Comparison – Magnesium Chloride vs Magnesium Sulfate in Tabular Form
5. Summary
What is Magnesium Chloride?
Magnesium chloride is an inorganic compound having the chemical formula MgCl2. It can exist in various hydrate forms. These compounds are ionic halides and are highly water soluble. We can obtain the hydrated forms from seawater via different extractions. The molar mass of the anhydrous form is 95.211 g/mol. It is a white to colorless crystalline solid.
Figure 01: Magnesium Chloride Crystals
The melting point of this is 714◦C, and the boiling point is 1412◦C. The crystallization of this compound resembles the cadmium chloride crystallization. It has octahedral Mg centers. The most common hydrates include magnesium chloride associated with 2, 4, 6, 8 and 12 water molecules.
Magnesium Chloride has one Magnesium Cation associated with two Chloride Anions
We can produce this compound via Dow process in which magnesium hydroxide is treated with HCl acid to obtain magnesium chloride and water.
Mg(OH)2 + HCl → MgCl2 + H2O
The applications of this compound include the production of magnesium metal via electrolysis, dust control, soil stabilization, as catalyst support for Ziegler-Natta catalyst, etc.
What is Magnesium Sulfate?
Magnesium sulfate is an inorganic compound having the chemical formula MgSO4. It is a salt of magnesium and can exist in several hydrated forms as well. The molar mass of the anhydrous form is 120.36 g/mol. It appears as a white crystalline solid at room temperature. This compound is odorless. It has no melting point. Instead, it decomposes at 1124◦C.
Figure 02: Anhydrous Magnesium Sulfate
Unlike magnesium sulfate, this compound is not that much water soluble. The hydrated forms include magnesium sulfate associated with 1, 4, 5, 6 and 7 water molecules.
Magnesium Sulfate Molecule has one Magnesium Cation associated with one Sulfate Anion
The applications of this compound are in the field of medicine as the mineral for the pharmaceutical production of magnesium, the paste of this compound is useful in treating skin inflammations, etc. moreover, it is useful in agriculture to increase the levels of magnesium and sulfur in the soil.
What is the Difference Between Magnesium Chloride and Magnesium Sulfate?
Considering the molecular structure of both, the magnesium chloride molecule has one magnesium cation associated with two chloride anions whereas magnesium sulfate molecule has one magnesium cation associated with one sulfate anion. This is the key difference between magnesium chloride and magnesium sulfate.
Furthermore, the magnesium chloride is an inorganic compound having the chemical formula MgCl2. The molar mass of the anhydrous form is 95.211 g/mol. In addition, the most common hydrates include magnesium chloride associated with 2, 4, 6, 8 and 12 water molecules. Magnesium sulfate is an inorganic compound having the chemical formula MgSO4. The molar mass of the anhydrous form is 120.36 g/mol. Moreover, the common hydrated forms include magnesium sulfate associated with 1, 4, 5, 6 and 7 water molecules.
Summary – Magnesium Chloride vs Magnesium Sulfate
Magnesium is a group 2 chemical element that can form stable, divalent cations that are capable of forming ionic compounds. Magnesium chloride is an ionic halide, and magnesium sulfate is a magnesium salt. The difference between magnesium chloride and magnesium sulfate is that magnesium chloride molecule has one magnesium cation associated with two chloride anions whereas magnesium sulfate molecule has one magnesium cation associated with one sulfate anion.
Reference:
1. “Magnesium Chloride.” Wikipedia, Wikimedia Foundation, 19 June 2018.Available here
2. “Magnesium Sulfate.” Wikipedia, Wikimedia Foundation, 19 June 2018. Available here
Image Courtesy:
1.’Magnesium chloride’ (Public Domain ) via Commons Wikimedia
2.’Magnesium sulfate anhydrous’ (Public Domain) via Commons Wikimedia