Na2S
sodium sulfide · disodium sulfide
Sodium sulfide is a stable, semiconducting inorganic compound widely used as a reactive chemical precursor in industrial and laboratory settings.
About sodium sulfide
Sodium sulfide is a thermodynamically stable inorganic compound that serves as a fundamental building block in chemical synthesis. Its semiconducting electronic character makes it an interesting subject for materials research and industrial processing applications. The compound is well-characterized, with a significant number of structural configurations documented across major materials databases. Its stability on the convex hull underscores its reliability as a precursor in various chemical reactions and material development pathways. This compound plays a vital role in industrial chemistry, particularly in processes requiring efficient sulfur delivery and reactive inorganic components. Its ability to maintain structural integrity under diverse conditions allows it to be utilized effectively in manufacturing and specialized chemical production.
Key Properties
Cross-validated computational properties for sodium 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 Na2S. 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 Na2S, 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. |
|---|---|---|---|---|---|
| — | — | 2.63 | 0.0000 | -1.247 | — |
| C2/m (No. 12) | monoclinic | 2.51 | 0.0000 | -1.223 | — |
| Fm-3m (No. 225) | cubic | 2.44 | 0.0000 | -6.323 | 1.89 |
| — | — | 2.65 | 0.0028 | -1.244 | — |
| Fm-3m (No. 225) | cubic | 2.59 | 0.0111 | -1.212 | — |
| Pnma (No. 62) | orthorhombic | 2.12 | 0.0350 | -6.288 | 2.06 |
| Pnma (No. 62) | orthorhombic | 2.36 | 0.0419 | -1.181 | — |
| — | — | 2.37 | 0.0424 | -1.204 | — |
| — | — | 2.40 | 0.0446 | -1.202 | — |
| — | — | 2.15 | 0.0465 | -1.200 | — |
| — | — | 2.28 | 0.0794 | -1.167 | — |
| — | — | 2.29 | 0.0804 | -1.166 | — |
Applications
Where sodium sulfide is used.
Frequently Asked Questions
Common questions about sodium sulfide, answered from cross-validated data.
What is Na2S?
Sodium sulfide is a stable, semiconducting inorganic compound widely used as a reactive chemical precursor in industrial and laboratory settings.
What is Na2S used for?
What is the band gap of Na2S?
Is Na2S a metal, semiconductor, or insulator?
Is Na2S thermodynamically stable?
What is the crystal structure of Na2S?
What is the density of Na2S?
How many polymorphs of Na2S are known?
What elements does Na2S contain?
Where does the data for Na2S come from?
How It Compares
As a primary inorganic sulfide, this compound serves as a foundational reference point for the study of alkali metal chalcogenides. It occupies a central role in the class of simple binary sulfides, providing a benchmark for stability and electronic behavior against which more complex or doped sulfide materials are often evaluated.
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)
- 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)
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