Aluminium Oxide Formula

A chemical oxide of aluminium and oxygen, aluminium oxide is also known as alumina or aloxide. It is basically an odourless, white amorphous material that is amphoteric in nature. Aluminium oxide finds its place in various industrial, commercial and chemical enterprises. It is also present in some essential naturally occurring minerals like Bauxite and Corundum of which corundum is a naturally occurring crystalline form of aluminium oxide which is most commonly found to be in use. 


Properties of Aluminium Oxide

The symbol of aluminium oxide is given as - Al2O3. Its molar mass is denoted as 101.96 g/mol. Its boiling point is presented at 2977 degrees celsius and its melting point is presented at 2072 degrees celsius. Its density is 3.95 g/cm3.


Chemical Formula of Aluminium Oxide

Aluminium oxide is an ionic compound. Its formula is written as Al2O3 which tells us that it has aluminium atoms with +3 charge and oxygen atoms with -2 charge. Now, what does this mean? In this chemical process, aluminium loses three electrons whereas oxygen gains two electrons. This is how we derive the chemical formula for aluminium oxide. 


Structure of Aluminium Oxide

The structure of aluminium oxide is formed when two aluminium atoms bond with two oxygen atoms each, which means it has three oxygen atoms. 


How do we Derive Equations of Aluminium Oxide?

As we have seen earlier, aluminium oxide is amphoteric by nature. Now we also call amphoteric oxides metal oxides because they can form reactions with both acids as well as bases to produce salt and water. Zinc Oxide (ZnO), SnO and PbO are other common examples of amphoteric or metallic oxides.


Following are the chemical properties or chemical reactions of Aluminium Oxide - 

  • When Aluminium Oxide reacts with hot and dilute hydrochloric acid, it gives aluminium chloride solution and water as its products. We must bear in mind that sodium and magnesium oxides also produce similar reactions because all three of them contain oxide ions. Here Aluminium oxide acts as a base. 

Al2O3 + 6HCl → 2AICl3 + 3H2

  • When aluminium oxide reacts with sodium hydroxide at a temperature of 900-1100 degrees celsius, it gives sodium aluminate and water as its products. In this reaction, aluminium oxide behaves like an acid. The reaction is as follows - 

Al(OH)3 + NaOH  →  NaAlO2 + 2H2O


In a neutralisation reaction, aluminium oxide reacts with sulphuric acid to produce aluminium sulphate and water. Here aluminium oxide acts as a base.

Al2O3 + H2SO4 -> Al2 (SO4) 3 + H2O. 


Various Uses of Aluminium Oxide

As a popular and commonly found metallic oxide, aluminium oxide has the following uses - 

  • In the Claus process, it is used as a catalyst

  • It is used to dehydrate alcohols to alkenes

  • It can be used as a purificatory material to separate water from a gas stream

  • It finds its place in paints, making spark plug insulators and in cosmetic industries.

  • In chromatography, it is used as a medium

Aluminium oxide is strong yet light in weight. Hence it is used regularly to create body armours and in bulletproof windows. It also finds applications in the medical industry. 


Prepare for this Topic Well with Vedantu

Students can employ various techniques to study not just this topic but the subject of chemistry as a whole. They will not only score higher but also enhance their understanding of concepts, reactions, properties and equations in this subject. For this purpose, Vedantu has many invaluable free resources available! Students can utilise resources such as articles, FAQs, important concepts and revision notes all put together by some of the best teachers in the country. Students can also book personalised tutoring sessions to get their doubts solved or deepen their knowledge of the subject. We suggest you bookmark the website for ease of access! 


Aside from this students can and should ideally be preparing their own revision notes because it improves concentration and memory by ensuring you study as an active learner. You can keep different books for structures and reactions that come up in topics such as aluminium oxides. It will make it much easier and organised for revision. 


The key to preparation is only consistency and innovation. And of course interest in the subject itself!

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FAQs (Frequently Asked Questions)

1. Write Some Properties of Aluminium Oxide.

Some properties of Aluminium oxides are:

  • It is an Electrical insulator with High thermal conductivity and low density.
  • Wear and corrosion resistant, due to its strength and lightweight it is suitable for preparing body armors, and bulletproof windows. 
  • High compression strength and stiffness.
  • Chemical and thermal stability, high melting and boiling point.

2. Aluminium Oxide is Acidic or Basic in Nature?

Aluminum oxide is acidic and basic in nature. This type of oxide is known as amphoteric oxides, the balanced equation for aluminum oxide is shown below.


Al2O3 + 6HF → 2AIF3 + 3H2O


Al2O3 + 2NaOH +  3H2O   →  2NaAl(OH)4

3. Aluminium Oxide is Soluble in Water?

Aluminum oxide has high lattice energy and low heat of hydration and is not soluble in water.

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