Al2FeO4
Hercynite · Iron aluminate, Iron aluminum oxide
Hercynite is a naturally occurring mineral belonging to the spinel group. It is primarily used in geological research and as a refractory material due to its stability at elevated conditions.
Overview
Key Properties
Cross-validated computational properties for Hercynite, aggregated across 3 databases.
Band GapEnergy needed to move an electron from the valence band to the conduction band. Lower or zero values tend to behave more metallic; larger gaps are more insulating or semiconducting.
0.04–2.82 eV
Range across DFT structures
Energy Above HullThermodynamic distance from the most stable set of competing phases. 0 eV/atom is on the convex hull; small positive values may still be experimentally accessible.
0.000 eV/atom
Best (lowest) across sources
StabilityA plain-language summary of the best reported energy-above-hull result. It reflects whether the lowest-energy structure is on, near, or far from the stability hull.
On hull (stable)
2 DFT sources
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
19
3 databases, 6 space groups
Crystallography
Reported Structures
Lowest-energy structures reported for Al2FeO4, ranked by energy above hull.
| Space GroupSymmetry classification of the crystal arrangement. The number is the international space-group index. | Crystal SystemBroad lattice family, such as cubic, tetragonal, monoclinic, or triclinic, derived from unit-cell symmetry. | Band Gap (eV)Electronic gap calculated for this specific reported structure, measured in electronvolts. | E above hull (eV/atom)Thermodynamic distance from the convex hull for this structure, normalized per atom. Lower is generally more stable. | E/atom (eV)Computed total energy normalized per atom. Use energy above hull, not this value alone, when comparing stability. | Density (g/cm³)Mass per relaxed crystal volume, reported in grams per cubic centimeter. |
|---|---|---|---|---|---|
| Fd-3m (No. 227) | cubic | 0.00 | 0.0000 | -8.011 | 4.30 |
| Cm (No. 8) | monoclinic | 2.53 | 0.0146 | -7.997 | 4.12 |
| C2/m (No. 12) | monoclinic | 2.82 | 0.0224 | -7.989 | 4.11 |
| P3m1 (No. 156) | trigonal | 0.52 | 0.0334 | -7.978 | 4.11 |
| Imma (No. 74) | orthorhombic | 2.63 | 0.0642 | -7.947 | 4.17 |
| P3m1 (No. 156) | trigonal | 0.00 | 0.0664 | -7.945 | 4.12 |
| R3m (No. 160) | trigonal | 0.04 | 0.1619 | -7.849 | 4.13 |
| R3m (No. 160) | trigonal | 0.00 | 0.4820 | -7.529 | 4.12 |
| Imma (No. 74) | Orthorhombic | — | — | — | 4.33 |
| Fd-3m (No. 227) | — | — | — | — | — |
| Imma (No. 74) | Orthorhombic | — | — | — | 4.17 |
| Imma (No. 74) | Orthorhombic | — | — | — | 4.46 |
Uses
Applications
Where Hercynite is used.
Refractory ceramicsGeological indicator mineralMaterials science research
Reference
Frequently Asked Questions
Common questions about Hercynite, answered from cross-validated data.
What is Al2FeO4?
Hercynite is a naturally occurring mineral belonging to the spinel group. It is primarily used in geological research and as a refractory material due to its stability at elevated conditions.
More questions
What is Al2FeO4 used for?
Hercynite (Al2FeO4) is used in refractory ceramics, geological indicator mineral, and materials science research.
What is the band gap of Al2FeO4?
Hercynite (Al2FeO4) has a DFT-computed band gap of 0.04–2.82 eV across 19 reported structures.
Is Al2FeO4 a metal, semiconductor, or insulator?
With a band gap up to 2.82 eV it is a semiconductor.
Is Al2FeO4 thermodynamically stable?
Yes — Hercynite (Al2FeO4) sits on the convex hull (energy above hull 0 eV/atom), i.e. on hull (stable).
What is the crystal structure of Al2FeO4?
The lowest-energy reported polymorph of Hercynite (Al2FeO4) is cubic symmetry, space group Fd-3m (No. 227).
What is the density of Al2FeO4?
The computed density of the ground-state structure of Hercynite (Al2FeO4) is 4.30 g/cm³.
How many polymorphs of Al2FeO4 are known?
19 structures of Al2FeO4 are reported across 3 databases, spanning 6 distinct space groups.
What elements does Al2FeO4 contain?
Hercynite (Al2FeO4) contains Al, Fe, and O (3 elements).
Where does the data for Al2FeO4 come from?
Al2FeO4 data is cross-referenced from materials_project, mpaloe, jarvis.
Explore
Related Compounds
Other Oxide Oxygen-Evolution Catalysts in the database.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- mpaloe — Data from mpaloe.
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
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