FeAsS
Arsenopyrite · Mispickel
Arsenopyrite is a stable, naturally occurring iron arsenic sulfide mineral that functions as a semiconductor.
About Arsenopyrite
Arsenopyrite is a naturally occurring iron arsenic sulfide that serves as the most common arsenic-bearing mineral. Its structure is characterized by high thermodynamic stability, placing it firmly on the convex hull of the iron-arsenic-sulfur system. As a semiconducting material, it represents a fundamental building block in the study of iron-based chemical systems.
Beyond its geological significance, this compound is a critical subject for understanding phase stability and structural transitions in iron-based compounds. Its widespread occurrence and structural robustness make it a primary reference point for researchers investigating the complex interplay between iron, arsenic, and sulfur in solid-state chemistry.
Key Properties
Cross-validated computational properties for Arsenopyrite, 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.
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.
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.
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of FeAsS. 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.
Hull SpreadDifference between the highest and lowest energy-above-hull values reported by comparable sources. Smaller spread means less thermodynamic disagreement.
Sources ComparedNumber and names of computational sources with comparable entries for this formula.
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
Reported Structures
Lowest-energy structures reported for FeAsS, 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. |
|---|---|---|---|---|---|
| — | — | 0.84 | 0.0000 | -0.550 | — |
| P21/c (No. 14) | monoclinic | 0.74 | 0.0000 | -6.373 | 6.35 |
| P21/c (No. 14) | monoclinic | 0.66 | 0.0000 | -0.512 | — |
| — | — | 0.84 | 0.0002 | -0.550 | — |
| — | — | 0.00 | 0.0720 | -0.478 | — |
| — | — | 0.00 | 0.0726 | -0.478 | — |
| — | — | 0.00 | 0.1332 | -0.417 | — |
| P-1 (No. 2) | triclinic | 0.00 | 0.3013 | -0.211 | — |
| P-1 (No. 2) | triclinic | — | — | — | 6.20 |
| Cm (No. 8) | monoclinic | — | — | — | 5.58 |
| P-1 (No. 2) | triclinic | — | — | — | 6.20 |
| P21/c (No. 14) | monoclinic | — | — | — | 6.27 |
Applications
Where Arsenopyrite is used.
Frequently Asked Questions
Common questions about Arsenopyrite, answered from cross-validated data.
What is FeAsS?
Arsenopyrite is a stable, naturally occurring iron arsenic sulfide mineral that functions as a semiconductor.
What is FeAsS used for?
What is the band gap of FeAsS?
Is FeAsS a metal, semiconductor, or insulator?
Is FeAsS thermodynamically stable?
What is the crystal structure of FeAsS?
How many polymorphs of FeAsS are known?
What elements does FeAsS contain?
Where does the data for FeAsS come from?
How It Compares
Within the iron-based superconductors class.
Unlike the metallic or superconducting phases often explored in the iron-based class, such as FeSe, arsenopyrite exhibits a distinct semiconducting electronic character. While many iron-chalcogenides like FeSe2 or FeTe2 are studied for their potential in thin-film photovoltaics or magnetic applications, FeAsS remains a remarkably stable, naturally occurring benchmark that contrasts with the more synthetic, highly reactive members of the iron-based family.
Related Compounds
Other Iron-Based Superconductors 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)
- cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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