Constituent Aluminum oxide | SSHADE

Constituent

Name: Aluminum oxide
Official name: alpha-Aluminium(III) oxide

Family: ionic solid
Class: tridimentional covalent network solid
Compound type: oxide
Comments: Aluminium oxide also exist in a number of other crystalline phases

Constituent abundance in material

Relevance: main - major
Arrangement: single phase
Mass fraction: 0.9945 $\pm$ 0.0001

Chemical composition

Formula: $Al^{3+}_2O^{2-}_3$
Chemical formula: Al2O3
Elemental formula: Al2 O3
Isotope mixture type: terrestrial abundance

	Formula	Name	Family	Number min-max	Mole fraction	Isotope mole fraction	State	Relevance
	$Al^{3+}$	Aluminium(III) cation	element	2	0.4	1	constituent cation	main
	$O^{2-}$	Oxide anion	element	3	0.6	1	constituent anion	main

Composition comments: partly ionic and covalent bond network

Chemical functions and bonds

Chemical bonds

	Bond	Number
	$\cdot (\cdot) Al^{3+} \cdot O^{2-} \cdot$	6

Class: tridimensional covalent networks (11)
Type: metal homonuclear tridimensional networks (elemental) (11.02)

Phase name: $\alpha\-Al_2O_3$
Phase type: crystalline

Crystallography

Crystal system: trigonal
Crystal class: ditrigonal-scalenohedral
Crystal class symbol: -3m (D3d)
Crystal spacegroup: R-3c
Composition order: ordered

Texture: polycrystalline

Physical properties

Molar mass: 101.96 $g/mol$
Density: 3.987 $g/cm^3$

Optical properties

Refringence type: uniaxial
Refringence sign: negative
Birefringence: 0.008
Refraction index $n_{\alpha}$: 1.768 - 1.772
Refraction index $n_{\beta}$: 1.760 - 1.763