Na2SO3
Sodium sulfite · Sodium sulphite
Sodium sulfite is a white, water-soluble inorganic salt commonly used as a preservative and antioxidant in food processing and industrial water treatment.
About Sodium sulfite
Sodium sulfite is a versatile inorganic compound characterized by its wide-band-gap insulating electronic structure. It is recognized for its role as a chemical reducing agent, frequently utilized in water treatment and the pulp and paper industry to manage oxygen levels and bleaching processes.
While this compound is considered metastable, it remains a highly practical substance in various chemical synthesis pathways. Its ability to act as a scavenger for reactive species makes it a staple in laboratory and commercial settings where oxidative degradation must be strictly controlled.
Key Properties
Cross-validated computational properties for Sodium sulfite, aggregated across 3 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 Na2SO3. 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 Na2SO3, 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. |
|---|---|---|---|---|---|
| P-3 (No. 147) | trigonal | 5.24 | 0.0210 | -1.810 | — |
| — | — | 5.07 | 0.0412 | -1.975 | — |
| — | — | 0.00 | 0.0556 | -1.960 | — |
| P-3 (No. 147) | trigonal | 4.92 | 0.0616 | -5.631 | 2.56 |
| Cmcm (No. 63) | orthorhombic | 0.00 | 0.5839 | -1.247 | — |
| C2221 (No. 20) | orthorhombic | 0.48 | 0.6246 | -5.068 | 2.09 |
| P-3 (No. 147) | trigonal | — | — | — | 2.66 |
| P-3 (No. 147) | trigonal | — | — | — | 2.56 |
| P-3 (No. 147) | trigonal | — | — | — | 2.60 |
| P-3 (No. 147) | trigonal | — | — | — | 2.68 |
Applications
Where Sodium sulfite is used.
Frequently Asked Questions
Common questions about Sodium sulfite, answered from cross-validated data.
What is Na2SO3?
Sodium sulfite is a white, water-soluble inorganic salt commonly used as a preservative and antioxidant in food processing and industrial water treatment.
What is Na2SO3 used for?
What is the band gap of Na2SO3?
Is Na2SO3 a metal, semiconductor, or insulator?
Is Na2SO3 thermodynamically stable?
What is the crystal structure of Na2SO3?
How many polymorphs of Na2SO3 are known?
What elements does Na2SO3 contain?
Where does the data for Na2SO3 come from?
How It Compares
As a standalone representative of its chemical class, sodium sulfite serves as a primary benchmark for sulfite-based chemistry, demonstrating the essential reactivity profile required for effective oxygen scavenging and industrial bleaching applications.
Data sources & attribution
- 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)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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