AsS
Realgar · Arsenic monosulfide, Ruby arsenic
AsS is a thermodynamically stable, semiconducting arsenic sulfide mineral known for its historical use in pigments and industrial applications.
About Realgar
AsS is a naturally occurring arsenic sulfide that maintains a stable position on the convex hull. As a semiconducting material, it exhibits unique electronic properties that distinguish it from simple metallic or insulating sulfides. Its structural complexity is evidenced by the extensive number of reported crystal arrangements across various databases.
Beyond its fundamental material science interest, this compound has a long history of human use due to its vibrant color and reactivity. It serves as a primary source of arsenic and remains a subject of study for its potential roles in specialized semiconductor applications and chemical synthesis.
Key Properties
Cross-validated computational properties for Realgar, aggregated across 6 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 AsS. 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 AsS, 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. |
|---|---|---|---|---|---|
| P21/c (No. 14) | monoclinic | 1.96 | 0.0000 | -11.530 | 3.26 |
| — | — | 1.80 | 0.0000 | -0.279 | — |
| P21/c (No. 14) | monoclinic | 1.50 | 0.0000 | -0.154 | — |
| C2/c (No. 15) | monoclinic | 2.01 | 0.0032 | -11.527 | 3.26 |
| C2/c (No. 15) | monoclinic | 1.47 | 0.0034 | -0.151 | — |
| — | — | 1.88 | 0.0035 | -0.275 | — |
| — | — | 2.00 | 0.0218 | -0.257 | — |
| P21/c (No. 14) | monoclinic | 2.03 | 0.0247 | -11.506 | 3.29 |
| P21/c (No. 14) | monoclinic | 2.09 | 0.0247 | -11.506 | 3.32 |
| — | — | 2.01 | 0.0251 | -0.253 | — |
| — | — | 0.62 | 0.0510 | -0.228 | — |
| Pca21 (No. 29) | orthorhombic | 0.61 | 0.0563 | -11.474 | 3.67 |
Synthesis Routes
Literature-extracted synthesis procedures targeting AsS.
Applications
Where Realgar is used.
Frequently Asked Questions
Common questions about Realgar, answered from cross-validated data.
What is AsS?
AsS is a thermodynamically stable, semiconducting arsenic sulfide mineral known for its historical use in pigments and industrial applications.
What is AsS used for?
What is the band gap of AsS?
Is AsS a metal, semiconductor, or insulator?
Is AsS thermodynamically stable?
What is the crystal structure of AsS?
What is the density of AsS?
How many polymorphs of AsS are known?
How is AsS synthesized?
What elements does AsS contain?
Where does the data for AsS come from?
How It Compares
As a standalone representative of arsenic-sulfur compounds, AsS serves as a critical benchmark for understanding the stability and electronic behavior of chalcogenides. Without direct structural siblings in this specific dataset, it acts as a primary reference point for the bonding characteristics and thermodynamic favorability of arsenic-based semiconductors.
Data sources & attribution
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- 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)
- 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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