Aluminium oxide is a chemical compound that contains two atoms of aluminium for every three oxygen atoms. It has the systematic IUPAC name Al2O3.
In order to form aluminium oxide, two aluminium atoms lose their outer electrons to three oxygen atoms. They then bond to form an ionic compound which is called aluminum oxide or alumina.
It is an amphoteric substance, meaning that it can react with both acids and bases. It is used as a catalyst for many industrial catalysts, including hydrodesulfurization and some Ziegler-Natta polymerizations.
The crystalline forms of aluminium oxide include the mineral corundum which is the most common. It can also be found in a variety of other phases, such as the cubic g-phase, monoclinic th phase, hexagonal kh phase and orthorhombic d-phase.
Alumina is a material that is extremely hard and strong and is often used in abrasive applications. It is used in the manufacture of emery boards, sandpaper, and abrasive grinding and polishing wheels.
It has high melting and boiling points and is a good electrical insulator. It is also useful for manufacturing ceramics.
Unlike other metals, aluminium does not corrode because a thin layer of oxide forms on its surface when exposed to atmospheric oxygen. This prevents further oxidation and adds strength to the material.
It is also a valuable element in the formation of rubies and sapphires. These precious gems owe their deep red or green colors to trace impurities like chromium.