FeAs
FeAs has a DFT band gap of Metallic / not reported across 88 reported structures in 17 space groups; its reference structure is orthorhombic (Pnma (No. 62)). Cross-validated across 3 computational databases.
At a glance
Key Properties
Cross-validated computational properties for FeAs, 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.
Metallic / not reported
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.
Stable
3 DFT sources
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
88
3 databases, 17 space groups
Validation
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of FeAs. Tight agreement means computed properties can be trusted without re-running calculations.
Agreement ScoreA normalized confidence score summarizing how closely independent DFT databases agree. Higher scores mean tighter cross-source agreement.
0.98 / 1.00
Trust tier: high
Hull SpreadDifference between the highest and lowest energy-above-hull values reported by comparable sources. Smaller spread means less thermodynamic disagreement.
0.004 eV
EAH spread across sources
Sources ComparedNumber and names of computational sources with comparable entries for this formula.
3
jarvis, materials_project, oqmd
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
All match
Crystallography
Reported Structures
Lowest-energy structures reported for FeAs, 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. |
|---|---|---|---|---|---|
| — | — | 0.00 | 0.0000 | -0.213 | — |
| Pnma (No. 62) | orthorhombic | 0.00 | 0.0000 | -6.768 | 7.61 |
| — | — | 0.00 | 0.0000 | -0.213 | — |
| Pnma (No. 62) | orthorhombic | 0.00 | 0.0038 | -0.186 | — |
| — | — | 0.00 | 0.0760 | -0.137 | — |
| — | — | 0.00 | 0.1427 | -0.071 | — |
| — | — | 0.00 | 0.2188 | 0.005 | — |
| — | — | 0.00 | 0.3326 | 0.119 | — |
| — | — | 0.00 | 0.3381 | 0.125 | — |
| — | — | 0.00 | 0.3387 | 0.125 | — |
| — | — | 0.00 | 0.3650 | 0.152 | — |
| — | — | 0.00 | 0.4225 | 0.209 | — |
Synthesis
Synthesis Routes
Literature-extracted synthesis procedures targeting FeAs.
Solid State
Procedure available · ceder_solid_state
Intellectual Property
Patent Landscape
1 patent reference FeAs or close compositional variants.
| Patent | Title | Assignee | Granted |
|---|---|---|---|
| 11060167 | Layered FeAs, method of preparing same, and FeAs nanosheet exfoliated from same | — | — |
Reference
Frequently Asked Questions
Common questions about FeAs, answered from cross-validated data.
What is the band gap of FeAs?
The reported DFT structures of FeAs show no band gap. Standard DFT often misses gaps (especially in transition-metal oxides), so this is not proof the real material is a metal.
More questions
Is FeAs a metal, semiconductor, or insulator?
DFT calculations predict no band gap. Standard DFT can miss gaps, so measurements are needed to confirm metallic behavior.
Is FeAs thermodynamically stable?
Yes — FeAs sits on the convex hull (energy above hull 0 eV/atom), i.e. stable.
What is the crystal structure of FeAs?
The reference structure of FeAs is orthorhombic symmetry, space group Pnma (No. 62).
What is the density of FeAs?
The computed density of the ground-state structure of FeAs is 7.61 g/cm³.
How many polymorphs of FeAs are known?
88 structures of FeAs are reported across 3 databases, spanning 17 distinct space groups.
How is FeAs synthesized?
Literature-reported routes for FeAs include solid state.
What elements does FeAs contain?
FeAs contains As and Fe (2 elements).
Where does the data for FeAs come from?
FeAs data is cross-referenced from oqmd, materials_project, jarvis, mpaloe.
Explore
Related Compounds
Other Skutterudite Thermoelectrics in the database.
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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