K2S2O5
Potassium metabisulfite · Potassium pyrosulfite
Potassium metabisulfite is an insulating, metastable salt primarily utilized as a food additive and industrial preservative.
About Potassium metabisulfite
Potassium metabisulfite is a chemical compound characterized by its wide-band-gap insulating electronic nature. As a metastable substance, it serves as a critical source of sulfur dioxide in various industrial and culinary settings.
Its utility is largely driven by its ability to act as an effective preservative and reducing agent. The compound is widely recognized for its role in inhibiting microbial growth and preventing oxidation in sensitive products.
Key Properties
Cross-validated computational properties for Potassium metabisulfite, 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 K2S2O5. 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 K2S2O5, 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. |
|---|---|---|---|---|---|
| — | — | 3.38 | 0.0580 | -1.886 | — |
| P21/m (No. 11) | monoclinic | 3.19 | 0.0753 | -5.896 | 2.18 |
| P21/m (No. 11) | monoclinic | 3.25 | 0.0772 | -1.679 | — |
| P21/m (No. 11) | monoclinic | 3.25 | 0.1326 | -5.839 | 1.94 |
| — | — | 0.68 | 0.2807 | -1.663 | — |
| P21/m (No. 11) | monoclinic | — | — | — | 2.33 |
| P21/m (No. 11) | monoclinic | — | — | — | 2.04 |
| P21/m (No. 11) | monoclinic | — | — | — | 2.34 |
| P21/m (No. 11) | monoclinic | — | — | — | 2.30 |
| P21/m (No. 11) | monoclinic | — | — | — | 1.97 |
| P21/m (No. 11) | monoclinic | — | — | — | 1.94 |
| P21/m (No. 11) | monoclinic | — | — | — | 2.18 |
Applications
Where Potassium metabisulfite is used.
Frequently Asked Questions
Common questions about Potassium metabisulfite, answered from cross-validated data.
What is K2S2O5?
Potassium metabisulfite is an insulating, metastable salt primarily utilized as a food additive and industrial preservative.
What is K2S2O5 used for?
What is the band gap of K2S2O5?
Is K2S2O5 a metal, semiconductor, or insulator?
Is K2S2O5 thermodynamically stable?
What is the crystal structure of K2S2O5?
What is the density of K2S2O5?
How many polymorphs of K2S2O5 are known?
What elements does K2S2O5 contain?
Where does the data for K2S2O5 come from?
How It Compares
As a distinct chemical entity, this compound functions as a versatile sulfite source. While it lacks direct structural siblings in this specific dataset, it remains a fundamental reference point for understanding the behavior of alkali metal sulfur-oxygen salts in metastable states.
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)
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- 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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