Magnesium Chloride Formula

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How to Write the Chemical Formula of Magnesium Chloride?

Magnesium Chloride is an ionic compound. The molecular formula of magnesium chloride is MgCl₂. It is generally used in industrial, food, and medical industries. It is mainly used for dust control and road stabilization and de-icing of highways, sidewalks in snowy places. Apart from the production of magnesium metal, magnesium chloride is also used for a variety of other applications, fertilizers, and mineral supplements for animals, wastewater treatment, fireproofing agents, types of cement, and refrigeration brine. 

What are Ionic Compounds?

An Ionic compound is a chemical compound that is composed of both metals and nonmetals. The bond is formed on the basis of electrostatic forces between negatively (anion) and positively (cation) charged ions. Ionic bonding occurs when one or more electrons from one atom get transferred to another. The Magnesium Chloride formula is derived when Magnesium and Chloride ions combine to form the ionic compound MgCl₂ (Magnesium Chloride).

What is a Structural Formula?

The formula that shows how the atoms in a molecule are bonded together and by what kinds of bonds is called a structural formula. It indicates the arrangement of atoms within a molecule by connecting atoms with a line or lines to represent a chemical bond.

Example: H – Cl,        H-O-H, O=C= O, H-N-H



The structural formula gives the bonding sequence of atoms in the molecule. Example: The 3 atoms in CO₂ (Carbon dioxide) are bonded O=C=O, not O=O=C.

The Symbols in the Magnesium Chloride Formula

Magnesium (solid) = Mg

Chlorine (gas) = Cl

Deriving the Magnesium and Chlorine Formula

Let us look into the steps to write the chemical formula of Magnesium Chloride.

  1. Write the symbols for each element. 

  2. Look at the molecular formula of magnesium chloride and charge for each element using the Periodic table. Write it above each element.

Valency of Mg = 2+

Valency of Cl = 1-

Mg2+ Cl-1

  1. See, if the charges are balanced. 

  2. Add subscripts to the elements if necessary so the charge for the entire compound becomes zero.

  3. Use the crisscross method to check whether it is done correctly. 

Mg2+ Cl-1 

Mg1 Cl2

  • Therefore, MgCl2  is the chemical formula of Magnesium Chloride.

Note: We really do not have to write the subscript 1. Then we can remove the charges. To verify whether the method is correct, we need to go through the following steps:

  1. Remember Mg has two positive charges and chlorine has one negative charge. 

  2. After doing the crisscross method, we have two chlorine atoms, which is two times the one minus to get a negative two there, and in magnesium, one time the two-plus to get positive two. Therefore, plus two minus two add up to zero. Hence the net charge is 0. 

Thus, we conclude that the derivation of the formula for Magnesium Chloride is correct. Therefore, the Magnesium Chloride equation can be written as 

Mg (S) + Cl2 (g)  \[\rightarrow\] MgCl₂(S)

The method of crisscross is the foundation of Chemistry. This method can be used in deriving formulas for any other compound. Understanding the periodic table and learning the valency of each element is important. 

Magnesium chloride-An Alkaline Earth metal.

Magnesium is the element found in the second column of the periodic table. It is from the family of alkaline earth metals. The other members of the same family are calcium and beryllium. Magnesium is a very light and silvery metal in pure form. 

Magnesium chloride is a chemical substance with a chemical formulas of MgCl₂ and its various hydrates MgCl₂ₓ. Anhydrous MgCl₂ consists of 25.5% elemental magnesium by mass. These salts are mainly ionic halides and are highly soluble in water. The hydrated magnesium chloride can be obtained from brine or sea water.

Ionic compound

MgCl₂ is an ionic compound because magnesium is a metal and it has a positive charge of 2. 

Properties of Magnesium Chloride

  • The molecular weight/molar mass of MgCl₂ is 95.211 g/mol in anhydrous state.

  • Density of magnesium chloride is 2.32 g/cm3 in anhydrou state

  • The boiling point of magnesium is 1,412 0C

  • The melting point is 7140C

Cl- Cl- Mg2+

Magnesium Chloride Structure - MgCl2

Applications of Magnesium

Magnesium chloride may be used as a supplement to recover the deficiency of magnesium. It is also helpful for diabetic people and also for high blood pressure.It is also useful in fighting depression and cancer disease.

Magnesium supplements also help sports people. Athletes or sports people can take magnesium supplements for boosting energy and athletic performance.

Intake of magnesium also has some drawbacks.

Intake of magnesium can also produce certain side effects such as nausea, vomiting, diarrhea, and stomach problems. Such problems can be avoided by taking magnesium supplements with food. Generally, nuts, seeds, dark leafy vegetables, whole grains, and low fat dairy products are the best sources of magnesium.

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FAQs (Frequently Asked Questions)

1. Why is it important for students to learn about the formula of magnesium chloride?

The formula of magnesium chloride is important because magnesium occurs naturally and it is used in different industries, medical fields, and it is also an important mineral for human beings. Magnesium chloride is a salt and it is highly soluble in water. It is available either in the anhydrous form or multiple hydrated crystal forms. 

2. What are various uses of magnesium chloride?

MgCl₂ Uses (Magnesium Chloride)

  • Magnesium Chloride is used as a precursor of magnesium metals.

  • For controlling dust and wind erosion magnesium chloride is used.

  • It is also used in fire extinguishers.

  • It is also used in  manufacturing paper , making disinfectants.

  • It is also used as a catalyst to attain new elements.

3. What health benefits are present in magnesium chloride?

Magnesium chloride is useful in the preparation of various drugs. Magnesium chloride is basically used as a supplement and it helps to treat the deficiency of magnesium in the human body. It is also used in the medicines that help to treat the symptoms of excess acid in the stomach, heartburn, and indigestion.

4. What is magnesium chloride used for?

Magnesium is important to many body systems, particularly to the muscles and nerves of the human body. Magnesium chloride is used in supplements which may be taken by people whose body is deficient in magnesium. 

5. What are some good and bad forms of magnesium?

There are some good and bad forms of magnesium.

Good Forms:

  • Magnesium citrate

  • Magnesium palate

  • Magnesium chloride 

  • Magnesium carbonate.

Bad Forms

  • Magnesium oxide

  • Magnesium sulfate.

6. Define an ionic compound. State any two physical properties of an ionic compound. Give an example of an ionic compound with its chemical formula. 

An ionic compound is a chemical compound that is composed of both metals and nonmetals. Two physical properties of an ionic compound are:

i. They are hard and brittle.

ii. They have high boiling and melting points. 

Magnesium chloride is an ionic compound since it comprises one metallic atom (Mg) or cation and two non-metallic atoms (Cl) or anions.  The chemical formula for Magnesium Chloride is Mg (S) + Cl₂ (g) \[\rightarrow\] MgCl₂ (S).

7. Write the formula of magnesium chloride and sodium sulfate.

Both magnesium chloride and sodium sulfate are ionic compounds. While the chemical formula of magnesium chloride is MgCl₂, the chemical formula of sodium sulfate or sodium sulphate is Na₂SO₄. 

In the chemical formula of sodium sulfate, Na is sodium (2 atoms) and SO₄ is the sulfate component wherein S is sulphur (1 atom) and O is oxygen (4 atoms). 

8. What do you understand by the structural formula of a compound?

The structural formula of a compound is the arrangement of atoms within a molecule. It is represented by connecting the atoms with a straight line or lines that are symbolic of the chemical bond(s) between them.