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Aluminium oxide
(Aluminum oxide)
Corundum-3D-balls.png
Aluminium oxide2.jpg
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.014.265
PubChem CID
RTECS number BD120000
UNII
Properties
Al2O3
Molar mass 101.960 g·mol−1
Appearance white solid
Odor odorless
Density 3.987g/cm3
Melting point 2,072 °C (3,762 °F; 2,345 K)
Boiling point 2,977 °C (5,391 °F; 3,250 K)
insoluble
Solubility insoluble in diethyl ether
practically insoluble in ethanol
log P 0.31860
−37.0×10−6 cm3/mol
Thermal conductivity 30 W·m−1·K−1
nω=1.768–1.772
nε=1.760–1.763
Birefringence 0.008
Structure
Trigonal, hR30, space group = R3c, No. 167
a = 478.5 pm, c = 1299.1 pm
octahedral
Thermochemistry
50.92 J·mol−1·K−1
−1675.7 kJ/mol
Pharmacology
D10AX04 (WHO)
Hazards
Safety data sheet See: data page
Not listed.
NFPA 704
Flammability code 0: Will not burn. E.g., waterHealth code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentineReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
0
1
0
Flash point Non-flammable
US health exposure limits (NIOSH):
PEL (Permissible)
OSHA 15 mg/m3 (Total Dust)
OSHA 5 mg/m3 (Respirable Fraction)
ACGIH/TLV 10 mg/m3
REL (Recommended)
none
IDLH (Immediate danger)
N.D.
Related compounds
Other anions
aluminium hydroxide
Other cations
boron trioxide
gallium oxide
indium oxide
thallium oxide
Supplementary data page
Refractive index (n),
Dielectric constantr), etc.
Thermodynamic
data
Phase behaviour
solid–liquid–gas
UV, IR, NMR, MS

Aluminium oxide (IUPAC name) or aluminum oxide (American English) is a chemical compound of aluminium and oxygen with the chemical formula Al2O3. It is the most commonly occurring of several aluminium oxides, and specifically identified as aluminium(III) oxide. It is commonly called alumina and may also be called aloxide, aloxite, or alundum depending on particular forms or applications. It occurs naturally in its crystalline polymorphic phase α-Al2O3 as the mineral corundum, varieties of which form the precious gemstones ruby and sapphire. Al2O3 is significant in its use to produce aluminium metal, as an abrasive owing to its hardness, and as a refractory material owing to its high melting point.

Natural occurrence