Aluminium oxide
Description
Aluminium oxide (
Al
2
O
3
Al
2
O
3
), also known as alumina, is a white, odourless, crystalline or amorphous substance composed of aluminium and oxygen atoms, with significant industrial and technological applications.
Chemical and Physical Properties
Chemical Formula:
Al
2
O
3
Al
2
O
3
.
Molar Mass: 101.96 g/mol.
Density: ~3.95 to 4.1 g/cm³ (depends on crystal structure).
Melting Point: ~2,072°C.
Boiling Point: ~2,977°C.
Appearance: White, odourless, solid; insoluble in water and most organic solvents.
Structure: Most stable crystalline form is corundum, where oxygen ions form a hexagonal close-packed structure, and aluminium ions occupy two-thirds of octahedral sites.
Polymorphism: Exists in several forms, with alpha (corundum) being the hardest and most stable; gamma alumina is porous and used in catalysis.
Chemical Behaviour
Amphoteric Nature: Reacts with acids (acts as a base) and with bases (acts as an acid), forming salts and water in both cases.
Redox Properties: Typically features aluminium in the +3 oxidation state; participates in redox reactions, such as electrolytic reduction to produce metallic aluminium.
Major Uses
Abrasives: Due to its high hardness, alpha alumina is used as abrasive materials (sandpaper, grinding wheels).
Refractories: Used for lining furnaces, kilns, and reactors due to its thermal stability.
Ceramics and Electrical Insulators: Essential in producing advanced ceramics and as a dielectric material in electronics.
Catalyst Supports: Gamma alumina, with a highly porous structure and large surface area, is widely used as a catalyst support in petrochemicals and chemical industry.
Gemstones: The naturally occurring crystalline forms corundum, ruby, and sapphire are all varieties of alumina.
Specifications
| Model No. | N-CH1170 |
|---|