CaS
calcium sulfide · oldhamite
Calcium sulfide is a stable, semiconducting inorganic material known for its structural diversity and utility in phosphor technology.
About calcium sulfide
Calcium sulfide is a thermodynamically stable binary compound that exhibits semiconducting electronic behavior. Its structural versatility is highlighted by a vast array of reported configurations, marking it as a significant subject of study in solid-state chemistry and materials science.
Because of its inherent stability and electronic properties, this compound serves as a critical building block in various industrial and research contexts. It is frequently utilized in the development of phosphors and specialized materials where its unique electronic character can be leveraged for performance optimization.
Key Properties
Cross-validated computational properties for calcium sulfide, 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 CaS. 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 CaS, 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. |
|---|---|---|---|---|---|
| Fm-3m (No. 225) | cubic | 2.38 | 0.0000 | -9.972 | 2.58 |
| Fm-3m (No. 225) | cubic | 2.35 | 0.0000 | -2.382 | — |
| — | — | 2.40 | 0.0002 | -2.314 | — |
| — | — | 2.49 | 0.0002 | -2.314 | — |
| — | — | 2.39 | 0.0003 | -2.313 | — |
| — | — | 2.67 | 0.0902 | -2.223 | — |
| — | — | 2.64 | 0.0903 | -2.223 | — |
| — | — | 2.97 | 0.1192 | -2.194 | — |
| — | — | 2.86 | 0.1193 | -2.194 | — |
| — | — | 2.59 | 0.1394 | -2.174 | — |
| — | — | 2.04 | 0.1412 | -2.172 | — |
| — | — | 2.44 | 0.1874 | -2.126 | — |
Synthesis Routes
Literature-extracted synthesis procedures targeting CaS.
Applications
Where calcium sulfide is used.
Frequently Asked Questions
Common questions about calcium sulfide, answered from cross-validated data.
What is CaS?
Calcium sulfide is a stable, semiconducting inorganic material known for its structural diversity and utility in phosphor technology.
What is CaS used for?
What is the band gap of CaS?
Is CaS a metal, semiconductor, or insulator?
Is CaS thermodynamically stable?
What is the crystal structure of CaS?
What is the density of CaS?
How many polymorphs of CaS are known?
How is CaS synthesized?
What elements does CaS contain?
Where does the data for CaS come from?
How It Compares
As a thermodynamically stable binary sulfide, this compound represents a foundational material within its chemical class. It serves as a primary reference point for understanding the behavior of alkaline earth chalcogenides, providing a stable baseline for comparing the structural and electronic trends observed in more complex or less stable related compounds.
Data sources & attribution
- 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)
- 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)
Analyze CaS in the Lattice Graph platform
Polymorph comparison, confidence scoring, supply-chain risk, and patent monitoring — across 85 source databases.
Explore the Platform →