Cs2S
cesium sulfide
Cesium sulfide is a stable semiconducting compound formed from cesium and sulfur that is primarily used in specialized chemical synthesis and materials research.
About cesium sulfide
Cesium sulfide is a binary inorganic compound composed of cesium and sulfur. As a thermodynamically stable material situated on the convex hull, it represents a well-defined chemical phase that maintains structural integrity under standard conditions.
This semiconducting material is of interest for its unique electronic properties and its role as a precursor in the synthesis of complex chalcogenide systems. Its stability makes it a reliable subject for fundamental studies in solid-state chemistry and materials research.
Key Properties
Cross-validated computational properties for cesium sulfide, 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 Cs2S. 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 Cs2S, 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. |
|---|---|---|---|---|---|
| — | — | 2.12 | 0.0000 | -1.107 | — |
| Pnma (No. 62) | orthorhombic | 2.10 | 0.0000 | -20.609 | 4.03 |
| — | — | 2.13 | 0.0006 | -1.107 | — |
| — | — | 2.21 | 0.0222 | -1.085 | — |
| — | — | 2.31 | 0.0227 | -1.085 | — |
| — | — | 7.08 | 0.0229 | -1.084 | — |
| — | — | 2.03 | 0.0310 | -1.076 | — |
| P63/mmc (No. 194) | hexagonal | 2.08 | 0.0667 | -20.543 | 4.06 |
| — | — | 2.08 | 0.0779 | -1.029 | — |
| — | — | 1.18 | 0.0783 | -1.029 | — |
| — | — | 2.35 | 0.0890 | -1.018 | — |
| — | — | 2.23 | 0.0892 | -1.018 | — |
Applications
Where cesium sulfide is used.
Frequently Asked Questions
Common questions about cesium sulfide, answered from cross-validated data.
What is Cs2S?
Cesium sulfide is a stable semiconducting compound formed from cesium and sulfur that is primarily used in specialized chemical synthesis and materials research.
What is Cs2S used for?
What is the band gap of Cs2S?
Is Cs2S a metal, semiconductor, or insulator?
Is Cs2S thermodynamically stable?
What is the crystal structure of Cs2S?
What is the density of Cs2S?
How many polymorphs of Cs2S are known?
What elements does Cs2S contain?
Where does the data for Cs2S come from?
How It Compares
As a binary sulfide of an alkali metal, cesium sulfide serves as a fundamental reference point for understanding the bonding and structural trends within the broader family of alkali metal chalcogenides.
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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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