KNbSe2
KNbSe2 is a metastable semiconducting compound composed of potassium, niobium, and selenium.
About KNbSe2
KNbSe2 is a ternary selenide characterized by its semiconducting electronic nature. As a metastable compound, it represents a complex structural arrangement of potassium, niobium, and selenium atoms that requires specific conditions for synthesis and stabilization.
This material is of significant interest to researchers investigating the structural diversity of chalcogenides. Its existence across multiple databases highlights its role in the study of metastable phases and their potential utility in specialized electronic device architectures.
Key Properties
Cross-validated computational properties for KNbSe2, 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 KNbSe2. 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 KNbSe2, 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. |
|---|---|---|---|---|---|
| P63/mmc (No. 194) | hexagonal | 0.80 | 0.0000 | -1.067 | — |
| — | — | 0.82 | 0.0151 | -0.996 | — |
| P63/mmc (No. 194) | hexagonal | 0.69 | 0.0290 | -5.771 | 5.14 |
| — | — | 0.00 | 0.2512 | -0.760 | — |
| I-42d (No. 122) | tetragonal | — | — | — | 3.71 |
| P63/mmc (No. 194) | hexagonal | — | — | — | 5.14 |
| R-3m (No. 166) | trigonal | — | — | — | 4.15 |
| P63/mmc (No. 194) | hexagonal | — | — | — | 5.19 |
| P63/mmc (No. 194) | hexagonal | — | — | — | 5.23 |
| P63/mmc (No. 194) | hexagonal | — | — | — | 5.39 |
Applications
Where KNbSe2 is used.
Frequently Asked Questions
Common questions about KNbSe2, answered from cross-validated data.
What is KNbSe2?
KNbSe2 is a metastable semiconducting compound composed of potassium, niobium, and selenium.
What is KNbSe2 used for?
What is the band gap of KNbSe2?
Is KNbSe2 a metal, semiconductor, or insulator?
Is KNbSe2 thermodynamically stable?
What is the crystal structure of KNbSe2?
How many polymorphs of KNbSe2 are known?
What elements does KNbSe2 contain?
Where does the data for KNbSe2 come from?
How It Compares
As a unique ternary compound, KNbSe2 occupies a distinct niche within the landscape of niobium-based selenides, serving as a subject of investigation for how stoichiometry and atomic arrangement influence semiconducting behavior in metastable systems.
Data sources & attribution
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- 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)
- alexandria — Data from Alexandria. Cite: Schmidt et al., npj Comput. Mater. 10, 200 (2024). (CC-BY-4.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
- cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)
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