KS
KS is a stable semiconducting compound formed from potassium and sulfur atoms.
About KS
KS is a binary inorganic compound composed of potassium and sulfur. As a thermodynamically stable material residing on the convex hull, it represents a robust phase within the chemical space of alkali metal chalcogenides.
This material exhibits semiconducting electronic character, making it a subject of interest for fundamental studies in solid-state physics. Its structural complexity is highlighted by a significant number of reported configurations across multiple databases, indicating a rich landscape for potential phase exploration.
Key Properties
Cross-validated computational properties for KS, 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.
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of KS. 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 KS, 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. |
|---|---|---|---|---|---|
| — | — | 1.55 | 0.0000 | -1.083 | — |
| P-62m (No. 189) | hexagonal | 1.49 | 0.0000 | -8.126 | 1.93 |
| P-62m (No. 189) | hexagonal | 1.48 | 0.0000 | -1.082 | — |
| Pm-3m (No. 221) | cubic | 0.00 | 0.3833 | -0.699 | — |
| P4/mmm (No. 123) | tetragonal | 0.00 | 0.4145 | -7.711 | 2.32 |
| Pm-3m (No. 221) | cubic | 0.00 | 0.4699 | -7.656 | 2.09 |
| — | — | 0.00 | 0.4801 | -0.603 | — |
| — | — | 0.00 | 0.4984 | -0.585 | — |
| Fm-3m (No. 225) | cubic | 0.00 | 0.5377 | -0.544 | — |
| Fm-3m (No. 225) | cubic | 0.00 | 0.5867 | -7.539 | 1.71 |
| — | — | 0.00 | 0.5895 | -0.494 | — |
| — | — | 0.00 | 0.5990 | -0.484 | — |
Frequently Asked Questions
Common questions about KS, answered from cross-validated data.
What is KS?
KS is a stable semiconducting compound formed from potassium and sulfur atoms.
What is the band gap of KS?
Is KS a metal, semiconductor, or insulator?
Is KS thermodynamically stable?
What is the crystal structure of KS?
How many polymorphs of KS are known?
What elements does KS contain?
Where does the data for KS come from?
How It Compares
As a standalone entry in this context, KS serves as a foundational example of a stable alkali metal sulfide. Its position on the convex hull distinguishes it as a reliable reference point for understanding the bonding and electronic behavior of potassium-sulfur systems.
Data sources & attribution
- 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)
- 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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