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.

NaS
Crystal structure of Na2S (cubic, Fm-3m (No. 225))
Ground-state structure · Materials Project
Overview

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.

At a glance

Key Properties

Cross-validated computational properties for sodium sulfide, aggregated across 3 databases.

Band Gap

1.68–2.44 eV
Range across DFT structures

Energy Above Hull

0.000 eV/atom
Best (lowest) across sources

Stability

On hull (stable)
2 DFT sources

Structures

29
3 databases, 10 space groups
Crystallography

Reported Structures

Lowest-energy structures reported for Na2S, ranked by energy above hull.

Space GroupCrystal SystemBand Gap (eV)E above hull (eV/atom)E/atom (eV)Density (g/cm³)
Fm-3m (No. 225)cubic2.440.0000-6.3231.89
Pnma (No. 62)orthorhombic2.120.0350-6.2882.06
P63/mmc (No. 194)hexagonal1.680.1031-6.2202.07
Fm-3m (No. 225)Cubic1.88
Cm (No. 8)Monoclinic1.46
P1 (No. 1)Triclinic1.58
P63/mmc (No. 194)Hexagonal2.07
Fm-3m (No. 225)Cubic1.87
C2/m (No. 12)Monoclinic1.77
C2/m (No. 12)Monoclinic2.03
P63/mmc (No. 194)Hexagonal2.12
P63/mmc (No. 194)Hexagonal2.13
Uses

Applications

Where sodium sulfide is used.

Paper and pulp manufacturingWater treatmentChemical synthesisOre flotationDye production
Reference

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.

More questions
What is Na2S used for?
sodium sulfide (Na2S) is used in paper and pulp manufacturing, water treatment, chemical synthesis, ore flotation, and dye production.
What is the band gap of Na2S?
sodium sulfide (Na2S) has a DFT-computed band gap of 1.68–2.44 eV across 29 reported structures.
Is Na2S a metal, semiconductor, or insulator?
With a band gap up to 2.44 eV it is a semiconductor.
Is Na2S thermodynamically stable?
Yes — sodium sulfide (Na2S) sits on the convex hull (energy above hull 0 eV/atom), i.e. on hull (stable).
What is the crystal structure of Na2S?
The lowest-energy reported polymorph of sodium sulfide (Na2S) is cubic symmetry, space group Fm-3m (No. 225).
What is the density of Na2S?
The computed density of the ground-state structure of sodium sulfide (Na2S) is 1.89 g/cm³.
How many polymorphs of Na2S are known?
29 structures of Na2S are reported across 3 databases, spanning 10 distinct space groups.
What elements does Na2S contain?
sodium sulfide (Na2S) contains Na and S (2 elements).
Where does the data for Na2S come from?
Na2S data is cross-referenced from materials_project, mpaloe, jarvis.
Comparison

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
  • materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
  • mpaloe — Data from mpaloe.
  • jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).

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