AlO3

AlO3 is a semiconducting, thermodynamically unstable oxide phase that belongs to the broader category of spinel-related catalytic materials.

AlO
Crystal structure of AlO3 (monoclinic, P21/c (No. 14))
Ground-state structure · Materials Project
Overview

About AlO3

AlO3 is a semiconducting oxide material categorized within the spinel oxide catalyst class. Despite its structural complexity and the significant number of reported configurations, it is characterized as thermodynamically unstable, sitting above the energy hull in standard computational models.

Its identity as a potential catalyst makes it a subject of interest for researchers investigating non-equilibrium oxide phases. While it shares elemental components with more stable oxides, its specific electronic character and metastable nature distinguish it as a unique candidate for specialized catalytic studies.

At a glance

Key Properties

Cross-validated computational properties for AlO3, aggregated across 6 databases.

Band Gap

1.68–2.65 eV
Range across DFT structures · ground state: wide gap

Energy Above Hull

0.251 eV/atom
Best (lowest) across sources

Stability

Unstable
4 DFT sources

Structures

188
6 databases, 26 space groups
Validation

Cross-Source DFT Agreement

How well independent DFT databases agree on the thermodynamics of AlO3. Tight agreement means computed properties can be trusted without re-running calculations.

Agreement Score

0.00 / 1.00
Trust tier: low

Hull Spread

0.336 eV
EAH spread across sources

Sources Compared

3
jarvis, materials_project, oqmd

Space Group Consensus

Mixed (most: P21/c (No. 14))
Crystallography

Reported Structures

Lowest-energy structures reported for AlO3, ranked by energy above hull.

Space GroupCrystal SystemBand Gap (eV)E above hull (eV/atom)E/atom (eV)Density (g/cm³)
——2.650.2514-1.789—
——0.000.2797-1.761—
C2 (No. 5)monoclinic2.320.3860-6.4033.04
——1.680.5534-1.487—
R-3c (No. 167)trigonal0.000.5539-6.2352.45
R-3c (No. 167)trigonal0.000.5544-6.2352.45
Amm2 (No. 38)orthorhombic0.000.5871-1.488—
P-31m (No. 162)trigonal0.000.6550-6.1342.43
P21/c (No. 14)monoclinic0.000.6655-6.1232.21
C2/c (No. 15)monoclinic0.000.6797-6.1092.22
P-1 (No. 2)triclinic0.000.6801-6.1092.17
——0.000.8091-1.232—
Synthesis

Synthesis Routes

Literature-extracted synthesis procedures targeting AlO3.

Sol Gel
Procedure available · ceder_sol_gel
Uses

Applications

Where AlO3 is used.

Catalysis researchMaterials science explorationSolid-state chemistry studies
Reference

Frequently Asked Questions

Common questions about AlO3, answered from cross-validated data.

What is AlO3?

AlO3 is a semiconducting, thermodynamically unstable oxide phase that belongs to the broader category of spinel-related catalytic materials.

More questions
What is AlO3 used for?
AlO3 is used in catalysis research, materials science exploration, and solid-state chemistry studies.
What is the band gap of AlO3?
AlO3 has a DFT-computed band gap of 1.68–2.65 eV across 188 reported structures. Standard DFT underestimates band gaps, so the measured gap is typically larger.
Is AlO3 a metal, semiconductor, or insulator?
DFT predicts a band gap of up to 2.65 eV (a semiconductor). Measured gaps are typically larger.
Is AlO3 thermodynamically stable?
AlO3 has a lowest energy above hull of 0.251 eV/atom (unstable).
What is the crystal structure of AlO3?
The reference structure of AlO3 is monoclinic symmetry, space group P21/c (No. 14).
What is the density of AlO3?
The computed density of the ground-state structure of AlO3 is 2.21 g/cm³.
How many polymorphs of AlO3 are known?
188 structures of AlO3 are reported across 6 databases, spanning 26 distinct space groups.
How is AlO3 synthesized?
Literature-reported routes for AlO3 include sol gel.
What elements does AlO3 contain?
AlO3 contains Al and O (2 elements).
Where does the data for AlO3 come from?
AlO3 data is cross-referenced from oqmd, materials_project, jarvis, mpaloe.
Comparison

How It Compares

Unlike the highly stable and widely utilized MgAl2O4 or the common Al2O3, AlO3 exists as a metastable phase, making it significantly more challenging to synthesize and maintain than its more robust siblings like ZnO or NiO.

Data sources & attribution
  • oqmd — Data from the OQMD (oqmd.org). Cite: Saal et al., JOM 65, 1501 (2013); Kirklin et al., npj Comp. Mater. 1, 15010 (2015). (CC-BY-4.0)
  • materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
  • jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
  • mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.

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