Product Details
Alumina, chemically represented as Al₂O₃, is widely known as bauxite. This white, heat-resistant powder does not dissolve in water. It has a melting point of 2015 °C, a boiling point of 2980 °C, a specific gravity of 4.0, and a Mohs hardness of 8.8. The compound exists in several crystalline forms, with α and γ being the predominant ones.
Production occurs through the thermal dehydration of aluminum hydroxide. In nature, the α form is known as corundum, a mineral surpassed in hardness only by diamond. When containing trace impurities, corundum develops various colors, creating precious stones such as ruby (with traces of Cr³⁺) and sapphire (containing Ti³⁺, Fe²⁺, and Fe³⁺).
Modern technology enables the production of synthetic gems through the controlled crystallization of molten alumina. These man-made gemstones match natural ones in quality and find extensive industrial applications. They serve as bearings in high-speed machinery, jewel bearings in timepieces, grinding materials, and heat-resistant components. Corundum crucibles, capable of withstanding temperatures up to 1800 °C, represent another important application.
Chemical Properties
| Melting point | 2040 °C(lit.) |
| Boiling point | 2980°C |
| density | 3.97 |
| bulk density | 950-1100g/L |
| vapor pressure | 17 mm Hg ( 20 °C) |
| refractive index | 1.765 |
| Fp | 2980°C |
| storage temp. | Sealed in dry,Room Temperature |
| solubility | Miscible with ethanol. |
| form | powder |
| color | White to pink |
| Specific Gravity | 3.97 |
| Odor | Odorless |
| PH Range | 3.5 - 4.5 |
| PH | 7.0±0.5 ( in H2O) |
| Water Solubility | INSOLUBLE |
| semiconductor properties | <0001> |
| Crystal Structure | Trigonal |
| crystal system | Three sides |
| Merck | 14,356 |
| Space group | R3c |
| Lattice constant | a/nmb/nmc/nmα/oβ/oγ/oV/nm30.475890.475891.299190901200.2548 |
| Exposure limits | ACGIH: TWA 1 mg/m3 OSHA: TWA 15 mg/m3; TWA 5 mg/m3 |
| Dielectric constant | 4.5（Ambient） |
| InChIKey | PNEYBMLMFCGWSK-UHFFFAOYSA-N |
| CAS Database Reference | 1344-28-1(CAS Database Reference) |
| NIST Chemistry Reference | Aluminum oxide(1344-28-1) |
| EPA Substance Registry System | Alumina (1344-28-1) |
Safety Information
| Hazard Codes | Xi,F |
| Risk Statements | 36/37/38-67-36/38-11-36 |
| Safety Statements | 26-24/25-16-7-36 |
| WGK Germany | - |
| RTECS | BD1200000 |
| F | 3 |
| TSCA | Yes |
| HazardClass | 8 |
| HS Code | 28181010 |
| Hazardous Substances Data | 1344-28-1(Hazardous Substances Data) |
| Toxicity | Chronic inhalation of Al2O3 dusts may cause lung damage. |
