Cd2Se2
Cd2Se2 has a DFT band gap of 0.51–0.57 eV across 55 reported structures in 15 space groups; its lowest-energy polymorph is hexagonal (P63mc (No. 186)). Cross-validated across 5 computational databases.
At a glance
Key Properties
Cross-validated computational properties for Cd2Se2, 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.
0.51–0.57 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)
3 DFT sources
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
55
5 databases, 15 space groups
Crystallography
Reported Structures
Lowest-energy structures reported for Cd2Se2, 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. |
|---|---|---|---|---|---|
| P63mc (No. 186) | hexagonal | 0.57 | 0.0000 | -3.066 | 5.48 |
| F-43m (No. 216) | cubic | 0.51 | 0.0006 | -3.065 | 5.49 |
| Fm-3m (No. 225) | cubic | 0.00 | 0.1458 | -2.920 | 6.69 |
| P63mc (No. 186) | — | — | — | — | — |
| — | — | — | — | — | 7.06 |
| P63mc (No. 186) | — | — | — | — | — |
| Fd-3m (No. 227) | — | — | — | — | — |
| P63mc (No. 186) | — | — | — | — | — |
| Fm-3m (No. 225) | — | — | — | — | — |
| P63mc (No. 186) | — | — | — | — | — |
| P63mc (No. 186) | — | — | — | — | — |
| P4/nmm (No. 129) | — | — | — | — | — |
Reference
Frequently Asked Questions
Common questions about Cd2Se2, answered from cross-validated data.
What is the band gap of Cd2Se2?
Cd2Se2 has a DFT-computed band gap of 0.51–0.57 eV across 55 reported structures.
More questions
Is Cd2Se2 a metal, semiconductor, or insulator?
With a band gap up to 0.57 eV it is a semiconductor.
Is Cd2Se2 thermodynamically stable?
Yes — Cd2Se2 sits on the convex hull (energy above hull 0 eV/atom), i.e. on hull (stable).
What is the crystal structure of Cd2Se2?
The lowest-energy reported polymorph of Cd2Se2 is hexagonal symmetry, space group P63mc (No. 186).
What is the density of Cd2Se2?
The computed density of the ground-state structure of Cd2Se2 is 5.48 g/cm³.
How many polymorphs of Cd2Se2 are known?
55 structures of Cd2Se2 are reported across 5 databases, spanning 15 distinct space groups.
What elements does Cd2Se2 contain?
Cd2Se2 contains Cd and Se (2 elements).
Where does the data for Cd2Se2 come from?
Cd2Se2 data is cross-referenced from materials_project, aflow, omat24, nomad.
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Related Compounds
Other II-VI Semiconductors in the database.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- aflow — Data from AFLOW. Cite: Curtarolo et al., Comp. Mater. Sci. 58, 218 (2012).
- omat24 — Data from OMat24 (Meta FAIR). Cite: Barroso-Luque et al., arXiv 2410.12771 (2024).
- nomad — Data from NOMAD. Cite: Draxl & Scheffler, J. Phys. Mater. 2, 036001 (2019).
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