As2Se
As2Se is a metallic arsenic selenide compound that exists in a metastable state and has been extensively documented in structural research.
About As2Se
As2Se is a binary compound composed of arsenic and selenium. It exhibits a metallic electronic character, distinguishing it from many of its semiconducting or insulating chalcogenide counterparts. Due to its position above the thermodynamic hull, it is considered a metastable phase that requires specific synthesis conditions to stabilize.
Despite its thermodynamic instability, the material has been the subject of significant investigation, with numerous structural configurations documented across various databases. This extensive data richness highlights its role as a complex system in materials science research, often studied to understand the phase space of arsenic-selenium alloys.
Key Properties
Cross-validated computational properties for As2Se, aggregated across 5 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.
Reported Structures
Lowest-energy structures reported for As2Se, 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. |
|---|---|---|---|---|---|
| I41/amd (No. 141) | tetragonal | 0.00 | 0.1349 | -14.520 | 5.75 |
| Cm (No. 8) | Monoclinic | — | — | — | 5.86 |
| P-1 (No. 2) | Triclinic | — | — | — | 4.44 |
| P-1 (No. 2) | Triclinic | — | — | — | 2.79 |
| P-1 (No. 2) | Triclinic | — | — | — | 8.28 |
| P1 (No. 1) | Triclinic | — | — | — | 8.93 |
| P1 (No. 1) | Triclinic | — | — | — | 3.93 |
| P1 (No. 1) | Triclinic | — | — | — | 5.90 |
| Amm2 (No. 38) | Orthorhombic | — | — | — | 4.96 |
| P-1 (No. 2) | Triclinic | — | — | — | 3.54 |
| P-1 (No. 2) | Triclinic | — | — | — | 5.34 |
| C2/m (No. 12) | Monoclinic | — | — | — | 4.30 |
Frequently Asked Questions
Common questions about As2Se, answered from cross-validated data.
What is As2Se?
As2Se is a metallic arsenic selenide compound that exists in a metastable state and has been extensively documented in structural research.
What is the band gap of As2Se?
Is As2Se a metal, semiconductor, or insulator?
Is As2Se thermodynamically stable?
What is the crystal structure of As2Se?
What is the density of As2Se?
How many polymorphs of As2Se are known?
What elements does As2Se contain?
Where does the data for As2Se come from?
How It Compares
As a binary chalcogenide, As2Se represents a unique case within the arsenic-selenium system, characterized by its metallic nature and metastable state compared to more stable, glass-forming compositions in the same chemical family.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- mpaloe — Data from mpaloe.
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