Magnesium Chloride

Since you have started studying chemistry, you are aware of both of these chemical elements called magnesium and chlorine. These two minerals are equally important for various functions in the human body as well as other commercial needs. Magnesium or Mg and chlorine or Cl combine to form magnesium chloride. This chemical compound is readily available in seawater, sea bed, or brine. This mineral can also be extracted by the process of solution mining and evaporation of seawater. Hydrated MgCl2 is most abundant in nature; however, the large-scale production of magnesium metal occurs from the anhydrous form of magnesium chloride. From the below content, you can learn the structure, property, preparation, and usages of this compound. 

Benefits of Referring to Vedantu for Magnesium Chloride 

Magnesium Chloride is just as important a topic for the chemistry students as its components, Magnesium, and Chlorine. And hence to understand this topic in as great detail as possible, students need to have a good explanation of the same, because otherwise, even the simplest of the topic can become the worst nightmare of the students. Therefore, Vedantu provides to the students of Chemistry the complete explanation of the Magnesium Chloride, which includes all the aspects related to it, such as its physical and chemical properties, its formula, as well as its structure and preparation.

An Overview of the Magnesium Chloride

MgCl2 suggests magnesium chloride chemical formula in chemistry. Some other chemical names of this salt are magnesium dichloride, chloromagnesite, and magnesium (II) chloride. One magnesium – Mg+2 and two ions of chloride Cl- form magnesium chloride.

Chloromagnesite and all their salts belong to the ionic halides group with a whitish-grey granule appearance. This compound is utilized in medicine and regarded as a high source of Mg ions, a vital component for various cellular activities.

The chemical compound with the formula MgCl₂ along with its various hydrates is regarded as Magnesium Chloride. In Jordan Valley, Magnesium Chloride is extracted from the Dead Sea, while in North America, it is, for the most part, produced from the Great Salt Lake brine. Also, from brine and Sea, the hydrated Magnesium chloride can be extracted. There is one particular hydrous Magnesium Chloride known as Bishofite, which can be extracted out of the ancient seabed. For instance, in northwest Europe, there is a Zechstein seabed, which is made from the solar evaporation of seawater. Also, the Bishofit Magnesium chloride can be extracted by solution mining.

There are a few more chemical names by which Magnesium Chloride is referred, such as Magnesium Dichloride, Chloromagnesite, and Magnesium ii chloride.

Physical Properties

• Colour – White, light grey, colorless.

• Structure – Granule, crystalline.

• Geometrical Structure – Octahedral with a 6-coordination point.

• State – Solid at standard temperature.

• Water- Solubility – Extremely high.

• Solubility – Ethanol, also partially soluble in pyridine and acetone.

• Odor – Odourless.

Following are the main physical properties of magnesium Chloride.

• Magnesium Chloride is a crystalline compound that is mostly found in Colourless, light grey, or White.

• It is an odourless mineral.

• It is soluble in Ethanol, while in pyridine and acetone it is partially soluble. Also, in water, its solubility is extremely high.

• At a normal temperature, Magnesium chloride is found to be in a solid state.

• As said earlier, it is a crystalline compound, and also a Granule compound, with the shape of octahedral molecular geometry, that has six points.

Chemical Properties

The Main Chemical Properties of Magnesium Chloride are Highlighted Below.

• The Chemical formula for Magnesium Chloride is MgCl₂.

• 95.211 g/mol anhydrous, and 203.31 g/mol hexahydrate, is the molar mass of the Magnesium Chloride.

• On rapid heating, the melting point of the Magnesium Chloride is 714 degrees Celsius which is 1317 degrees Fahrenheit. While, to reach the decomposition in the slow heating it requires 300 degrees Celsius, which is 572 degrees Fahrenheit.

• Its boiling point is 1412 degrees Celsius, which in Fahrenheit becomes 2574 degrees.

• Its water solubility for anhydrous is as under:

• 52.9 grams at 0 degrees Celsius.

• 54.3 gram at 20 degrees Celsius.

• 72.6 gram at 100 degrees Celsius.

• All the measurements, as well as temperatures given, are for 100 ml of water.

• The water solubility of Magnesium Chloride for hexahydrate was 235 grams per 100 ml of water at 20 degrees Celsius.

• The refractive index of the magnesium chloride I anhydrous is 1.675, while in the hexahydrate it is 1.569.

Structure of Magnesium Chloride

Magnesium chloride has a crystalline structure. The positively charged magnesium ion - Mg+2 and negatively charged chlorine ions Cl- create the ionic bond by attracting each other. Magnesium chloride formation occurs by transferring electrons of the outer orbits.

This ionic bond helps to complete the electron transferring process between atoms. Magnesium chloride solution can conduct electricity due to its electrolytic nature. In its solid state at room temperature, every anion is encircled by cations and vice versa. One magnesium cation holds a 2+ charge and one chlorine anion holds a 1- charge. However, like a compound, magnesium chloride is neutral. So, magnesium ions form the ionic bond with two chlorine ions.

Thus, the ratio of magnesium ion: chloride ion is 1: 2 and the simplest magnesium chloride chemical formula is MgCl2. Look at the following diagram of the magnesium chloride structure to understand their chemical and molecular bonding.

Preparation of Magnesium Chloride

Due to various usages for different industrial and commercial purposes, this ionic salt is produced in large amounts. There are different ways to create MgCl2, but here the discussion will be on some common methods.

In hexahydrate state, the magnesium ion is octahedral; however, it coordinates with 6 water ligands. The heating process of magnesium chloride hexahydrate is not straightforward. The hydrous form of this salt is heated along with alcohol and gradually distilled off the H2O. This way, anhydrous MgCl2 is extracted from its hydrous state.

Magnesium chloride in its anhydrous form is generated by heating hexamine-complex chloride salt as well. The most preferred method of anhydrous magnesium chloride preparation is the chemical reaction between magnesium and mercury (II) chloride.

Mg + HgCl2 🡪 MgCl2 + Hg

Another most common method of producing MgCl2 is by the Dow process. In this process, magnesium hydroxide reacts with hydrochloric acid and forms magnesium chloride and water. Following is the chemical formula of this reaction-

Mg(OH)2 (s) + 2 HCl (aq) 🡪 MgCl2 (aq) + 2 H2O (l)

Magnesium carbonate can substitute magnesium hydroxide in a similar reaction. However, as a by-product, carbon dioxide will also be produced along with water. Here is the chemical formula-

MgCO3 (s) + 2 HCl (aq) 🡪 MgCl2 (aq) + CO2 (g) + 2 H2O (l)

Another alternative way to produce MgCl2 is by the chemical reaction between aluminum chloride and magnesium with aluminum as a by-product.

3 Mg (s) + 2 AlCl3 (aq) 🡪 3 MgCl2 (aq) + 2 Al (s)

Other Important Reactions

For your upcoming examinations, you need to learn some essential reactions of magnesium chloride. If you can check previous question papers of your board exam, NEET, JEE, etc., you will come across some MgCl2 reactions repetitively.

Silicon Tetrachloride and Magnesium

In this reaction, magnesium chloride and silicon are produced.

SiCl4 (l) + 2 Mg (s) 🡪 Si (s) + 2 MgCl2 (s)

Titanium Tetrachloride and Magnesium

At the end of this chemical reaction, titanium and magnesium chloride are generated.

TiCl4 (g) + 2 Mg (l) 🡪 Ti (s) + 2 MgCl2 (l) 

Magnesium and Hydrochloric Acid 

It is one of the most common reactions of MgCl2, where the by-product is hydrogen.

Mg (s) + 2 HCl (aq) 🡪 MgCl2 (aq) + H2 (g)

Magnesium Bicarbonate and Hydrochloric Acid

3 Mg(HCO3)2 (l) + HCl (l) 🡪 MgCl2 (aq) + H2O (l) + CO2 (g)

• s - Solid

• g – Gas

• l – Liquid

• aq – Aqueous solution

Uses of Magnesium Chloride

MgCl2 is found in various medicines to prevent or treat magnesium deficiency in human bodies. Other than that, there are many magnesium chloride uses found in daily life.

A Precursor to Magnesium Metal

Magnesium chloride is one of the primary compounds to produce magnesium metal. This reaction is accomplished by electrolysis.

MgCl2 🡪 Mg + Cl2

This method of magnesium production occurs on a large scale industrially.

Erosion and Dust Control

This ionic salt is one of the most important components used to control dust, wind erosion, and soil stabilization. However, there are both positive and negative impacts of applying magnesium chloride to bare soil and roads.

Ice Control

The use of MgCl2 is also found in de-icing parking lots, sidewalks, and highways in low-temperature areas. Places that are typically struck by extreme snowstorms use magnesium chloride to treat the icy conditions of various transport ways. As a prevention to ice control, an anti-icing process is practiced. Nonetheless, there are some other processes like pre-wetting and pre-treating to clear the show and ice bonds off the roadways.

Catalyst Support

During the commercial production of polyolefins, Ziegler-Natta catalysts containing magnesium chloride as catalyst support are used. MgCl2 helps to develop high-quality stereospecific catalysts for commercial purposes.

Cuisine

This salt is mostly found in Japanese and Chinese cuisine. Tofu, a preparation from soya milk, contains a high amount of magnesium chloride. This preparation is one of the major dishes in these cuisines.

Nutrition

MgCl2 is also present in various nutraceutical products like diet supplements, food additives, etc. Furthermore, this chemical compound is also available in different pharmaceutical preparations, such as medication. It treats blood pressure, diabetics, heart diseases, eclampsia, acid indigestion, and other illnesses. 

Horticulture

Similar to the human body, plants also need magnesium for their cellular activities. Magnesium chloride flakes are effectively used as an alternative to Epsom salt or magnesium sulfate in horticulture or gardening. However, the recommended amount of MgCl2 is always lower than magnesium sulfate. This is because of the presence of chlorine in MgCl2, and an excess amount of chlorine can be toxic for plants.

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Quiz

1. What type of Bond is Found in Magnesium Chloride Atoms?

1. Polar covalent

2. Covalent

3. Ionic bond

4. None of the above

Ans: c. Due to the ionic bond of magnesium ion and chlorine ion, magnesium chloride forms.

2. How Many Water Molecules Can be Coordinated by One Magnesium Chloride Hexahydrate?

1. 8

2. 6

3. 4

4. 2

Ans: b. One hexahydrate magnesium chloride coordinates with six water molecules.

3. Where Is MgCl2 (Natural) Found the Most?

1. North America

2. South America

3. Brazil

4. Canada

Ans: a. In North America, MgCl2 is naturally abundant in the largest amount.

4. What Percentage of Elemental Magnesium Mass is Found in Anhydrous MgCl2?

1. 30.2%

2. 28.4%

3. 26.2%

4. 25.5%

Ans: d. 25.5% of the elemental mass of magnesium is found in anhydrous magnesium chloride.

5. What Will Come in the Blank?

MgCO3 (s) + 2 HCl (aq) 🡪 MgCl2 (aq) + ___ + 2 H2O (l)

1. CO3

2. CO

3. CO2

4. C2

Ans: c. CO2.