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Aluminium Chloride

Last updated date: 17th Apr 2024
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Aluminum Chloride Formula

Aluminum chloride is sometimes referred to as Aluminum trichloride. Aluminum chloride (\[AlCl_{3}\]) is a pure compound formed by the exothermic reaction of metallic aluminum and chlorine. The Aluminum Chloride formula is written as \[AlCl_{3}\]. As for physical appearance, it is usually white in color. However, due to the presence of contaminants (iron(III) chloride), it acquires a yellowish color.

More about Aluminum Chloride

Aluminum chloride is a well-known catalyst for organic reactions. This compound is soluble in water, hydrogen chloride, ethanol, chloroform, \[CCl_{4}\] and is slightly soluble in benzene. It is a silvery-white powder but sometimes turns yellow if it is contaminated by ferric chloride. It tends to absorb water easily (hygroscopic) to form monohydrate or hexahydrate. Aluminum chloride is a corrosive substance and it is also very toxic. It can cause high damage to the eyes, skin, and respiratory systems if inhaled or upon contact.

\[AlCl_{3}\] Structure is represented as

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Properties of Aluminum Chloride 

The chemical formula of Aluminum Chloride


The molecular weight of Aluminum Chloride

133.341 g/mol (anhydrous)

The density of Aluminum Chloride

2.48 g/cm3 (anhydrous)

The boiling point of Aluminum Chloride

192.6 °C

The melting point of Aluminum Chloride

180 °C

The chemical and physical properties of aluminum chloride are as follows.

Physical Properties of \[AlCl_{3}\]

  • Aluminum chloride has a very low melting and boiling point. It sublimes at a temperature of 180°C.

  • \[AlCl_{3}\] in the molten state is a poor conductor of electricity 

  • The color of aluminum chloride is white, but often it is contaminated with iron trichloride, which makes it yellow in color.

  • It is in a liquid state only at pressures above 2.5 atm and temperature above 190°C.

Chemical Properties of \[AlCl_{3}\]       

  • Aluminum chloride is a powerful Lewis acid. 

  • It is a major industrial catalyst.

  • \[AlCl_{3}\]   Is anhydrous, non-explosive, non-flammable but a corrosive solid

  • It reacts violently when it comes in contact with water.

Uses of Aluminum Chloride 

Aluminum Chloride is often regarded as a versatile chemical compound and therefore finds application in many areas. The uses of aluminum chloride are discussed below.

  • Aluminum Chloride (\[AlCl_{3}\]) is used mainly as a catalyst for different chemical reactions. It is used extensively in Friedel-Crafts reaction including both acylations and alkylations. It is used during the preparation of anthraquinone from phosgene and benzene.

  • Aluminum chloride can be used to bring in or attach aldehyde groups on aromatic series or rings.   

  • It is also used in polymerization and isomerization reactions of light molecular weight hydrocarbons. Some of the common examples include the production of ethylbenzene or the manufacture of dodecylbenzene for detergents.

  • Aluminum chloride can be mixed with aluminum along with arene to synthesize bis(arene) metal complexes.    

Industrial uses of Aluminum Chloride (\[AlCl_{3}\])

  • Aluminum chloride is used widely in manufacturing rubber, lubricants, wood preservatives, and paints.

  • It is used in pesticides and pharmaceuticals.

  • As a flux in melting and Aluminum,

  • It is used in antiperspirants.

Aluminum Chloride Reaction with Water

Aluminum chloride is hygroscopic, and it can absorb moisture from the air. Usually, this chemical compound fumes in the air containing moisture. It creates a hissing sound when it comes in contact with water. When the reaction occurs the Cl– ions are replaced with \[H_{2}O\] molecules and form hexahydrate \[Al((H_{2}O)6)Cl_{3}\]. The anhydrous state of\[AlCl_{3}\] is lost and when the heat is applied HCl also dissipates and the final product that is obtained is aluminum hydroxide.

\[Al(H_{2}O)6Cl_{3} \rightarrow  Al(OH)_{3} + 3HCl +3H_{2}O\]

When the temperature is further increased to about 400°C, aluminum oxide is formed from the hydroxide.    


\[2Al(OH)_{3} \rightarrow Al_{2}O_{3} + 3H_{2}O\]

One distinct characteristic of the \[AlCl_{3}\] aqueous. The solution is that it is ionic. Due to this, it is a good conductor of electricity. It is also acidic and this can lead to partial hydrolysis in \[Al^{3+}\] ions. 

The reaction can be written as:

\[(Al(H_{2}O)_{6})_{3} + (aq) \rightleftharpoons  (Al(OH)(H_{2}O_{5})_{2} + (aq) + H + (aq)\]

Aluminum salts that contain hydrated \[Al^{3+}\] ions are similar to the aqueous solution of aluminum chloride. They also behave in a similar manner. For example, it gives a thick precipitate of \[Al(OH)_{3}\] on reaction with dilute sodium hydroxide.

\[AlCl_{3} + 3NaOH \rightarrow  Al(OH)_{3} + 3NaCl\]

Precautions should be taken to keep anhydrous aluminum chloride away from water or bases. Aluminum chloride can explode on coming in contact with water because of the high heat of hydration. It also fumes in the air. Safety items like glasses, gloves, faceguards, etc. should be worn during chemical reactions. This chemical compound should be stored in a tightly sealed container and protected from moisture.

When it comes in contact with moist air, \[AlCl_{3}\] can absorb the moisture present in the air to become highly acidic and it turns into a sticky substance. It can furiously corrode materials such as stainless steel and rubber.

Prolonged exposure to this chemical can cause irritation to the skin, eyes, and respiratory tract.

In some studies, aluminum chloride has been found to be a neurotoxin that can be destructive to nerve tissues and can cause permanent damage.

Aluminum Chloride Reactions

Anhydrous aluminum chloride is a powerful Lewis acid. It means that it is capable of forming Lewis Acid-base adducts even with bases that are weak in nature. For example, mesitylene and benzophenone. Some of the common reactions are given below. \[AlCl_{3}\] can form tetrachloroaluminate (\[AlCl{_{4}}^{-}\]) when chloride ions are present. Aluminum chloride can react with magnesium and calcium hydride in tetrahydrofuran to form tetrahydridoaluminate.      

Relevance of Aluminum Chloride in Chemistry

Aluminum chloride is a chemical substance used to make the metal, aluminum, and reacts strongly in the presence of water. It is a white compound composed of aluminum and chloride. It needs to be kept away from hydrogen because of its high reactivity.  Even a bit of moisture can lead to strong reactions.  It is mainly used in industries and in manufacturing. All students of Chemistry need to know about aluminum chloride so as to answer all questions that come from the topic.

Does Vedantu have anything on Aluminum Chloride?

Vedantu has ample study material on Aluminum Chloride if the students read from Aluminum Chloride - Formula, Structure, Properties, Uses, and Reactions.

This page has explained the formula, physical and chemical properties, uses, and reactions with certain compounds. This page is available on Vedantu’s platform completely free of cost. Vedantu aims to educate as many students as it possibly can through its platform. It employs the most seasoned of teachers to write for its platform. This way, it has only the most useful material on its platform for the students to read from. The study matter can be downloaded in a PDF format too and then be gone through.

FAQs on Aluminium Chloride

1.  What is the melting and boiling point of aluminum chloride?

The melting point of aluminum chloride is 180 degrees centigrade and its boiling point is 192.6 degrees centigrade. These chemical properties of aluminum chloride have been elaborated upon in Aluminum Chloride on Vedantu. It is an ideal reference book for all students of Chemistry who wish to know about aluminum chloride in depth. Its other chemical properties such as its density, molecular weight, and chemical formula have also been explained here. Students need to read from here if they wish to revise for a test that’s on aluminum chloride.

2. How does aluminum chloride react with water?

Aluminum chloride reacts strongly when it comes in contact with water. Even a tiny amount of moisture can cause it to react in a volatile manner. More about this has been included on Vedantu’s online tutoring platform if students read Aluminium Chloride. This page has solid explanations on aluminum chloride which are sufficient for the students to be aware of. Its nature when it comes in contact with water has also been discussed so that students understand its reaction with the different compounds.

3. What are the uses of aluminum chloride?

Aluminum chloride is versatile and has uses across many industries. It is used as a catalyst in many reactions because of its nature.  It can also be used to attach aldehyde groups to the aromatic series of rings. It has other chemical uses as well which will be better understood once the students check out Aluminum Chloride on Vedantu. This page has the answer to all their queries. It is important to know about the uses of aluminum chloride so that students do not remain confused.

4. Is aluminum chloride a Lewis Acid?

Yes, aluminum chloride is a powerful Lewis acid, which means it forms lewis acid-base adducts even with bases that are weak in nature. Some examples of which are contained in Aluminum Chloride. This page must be read by all students of Chemistry before a test on the same. It has been created by expert Chemistry teachers who are well versed in the subject and so, contains only the most relevant inputs. The information contained here has been created as per the student’s level of understanding.

5. Is the chapter on Aluminum Chloride difficult to understand?

The chapter on aluminum chloride is not difficult to understand. In fact, it is quite interesting as the students find out about the nature of the metal and its properties. Once they have known its characteristics, they will no longer find it challenging. All those students who need to get a crash course on Aluminum Chloride done can read from Aluminum Chloride on Vedantu. This page has simplified explanations so that the students can relate to what they’re studying.