KNaS
KNaS is a thermodynamically stable semiconducting ternary sulfide composed of potassium, sodium, and sulfur.
About KNaS
KNaS is a ternary sulfide that exhibits semiconducting electronic behavior. As a thermodynamically stable phase located on the convex hull, it represents a robust configuration of potassium, sodium, and sulfur atoms that maintains structural integrity under standard conditions. The compound is characterized by a notable degree of structural diversity, with multiple reported configurations across various materials databases. This versatility makes it an intriguing subject for researchers investigating the interplay between alkali metal cations and chalcogenide frameworks in solid-state chemistry.
Key Properties
Cross-validated computational properties for KNaS, aggregated across 4 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 KNaS. 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 KNaS, 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. |
|---|---|---|---|---|---|
| Pnma (No. 62) | orthorhombic | 2.77 | 0.0000 | -1.254 | — |
| Pnma (No. 62) | orthorhombic | 2.49 | 0.0000 | -7.158 | 2.10 |
| — | — | 2.77 | 0.0004 | -1.215 | — |
| — | — | 2.60 | 0.0012 | -1.214 | — |
| — | — | 2.24 | 0.0331 | -1.182 | — |
| — | — | 2.58 | 0.0387 | -1.176 | — |
| — | — | 2.43 | 0.0500 | -1.165 | — |
| — | — | 2.57 | 0.0532 | -1.162 | — |
| — | — | 2.43 | 0.0690 | -1.146 | — |
| — | — | 2.14 | 0.0779 | -1.137 | — |
| — | — | 1.69 | 0.1824 | -1.033 | — |
| — | — | 2.90 | 0.2057 | -1.009 | — |
Applications
Where KNaS is used.
Frequently Asked Questions
Common questions about KNaS, answered from cross-validated data.
What is KNaS?
KNaS is a thermodynamically stable semiconducting ternary sulfide composed of potassium, sodium, and sulfur.
What is KNaS used for?
What is the band gap of KNaS?
Is KNaS a metal, semiconductor, or insulator?
Is KNaS thermodynamically stable?
What is the crystal structure of KNaS?
How many polymorphs of KNaS are known?
What elements does KNaS contain?
Where does the data for KNaS come from?
How It Compares
As a ternary sulfide, KNaS occupies a distinct niche in the landscape of alkali-metal chalcogenides, serving as a foundational example of how combining different alkali cations can stabilize specific lattice arrangements in sulfur-based 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)
- 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)
- alexandria — Data from Alexandria. Cite: Schmidt et al., npj Comput. Mater. 10, 200 (2024). (CC-BY-4.0)
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