SO2
Sulfur dioxide · Sulfurous anhydride
Sulfur dioxide is a stable, semiconducting oxide of sulfur that is widely recognized for its industrial utility and presence in atmospheric processes.
About Sulfur dioxide
Sulfur dioxide is a thermodynamically stable oxide that occupies a prominent position on the convex hull, reflecting its robust chemical nature. As a semiconducting compound, it plays a critical role in atmospheric chemistry and various industrial synthesis pathways.
With extensive structural data available across multiple databases, this compound is highly characterized. Its unique electronic configuration makes it a vital subject of study for understanding sulfur-based inorganic materials and their reactivity in diverse environments.
Key Properties
Cross-validated computational properties for Sulfur dioxide, 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 SO2. 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 SO2, 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. |
|---|---|---|---|---|---|
| Aea2 (No. 41) | orthorhombic | 3.15 | 0.0000 | -6.200 | 2.04 |
| Aea2 (No. 41) | orthorhombic | 2.65 | 0.0000 | -1.087 | — |
| — | — | 2.63 | 0.0000 | -1.393 | — |
| — | — | 2.29 | 0.0373 | -1.356 | — |
| — | — | 0.00 | 1.0911 | -0.302 | — |
| — | — | 0.00 | 1.5582 | 0.165 | — |
| — | — | 0.00 | 3.0121 | 1.619 | — |
| P1 (No. 1) | triclinic | — | — | — | 4.12 |
| P1 (No. 1) | triclinic | — | — | — | 2.27 |
| P1 (No. 1) | triclinic | — | — | — | 2.38 |
| P1 (No. 1) | triclinic | — | — | — | 3.03 |
| P1 (No. 1) | triclinic | — | — | — | 2.61 |
Applications
Where Sulfur dioxide is used.
Patent Landscape
96 patents reference SO2 or close compositional variants.
| Patent | Title | Assignee | Granted |
|---|---|---|---|
| 11710849 | SO2-based electrolyte for a rechargeable battery cell, and rechargeable battery cells | — | — |
| 6117403 | Barrier discharge conversion of Hg, SO.sub.2 and NOx | — | — |
| 4428921 | Process for recovery of sulfur from SO.sub.2 -containing gas | — | — |
| 6027704 | Process for the reduction of SO.sub.2 from wet lime/limestone tailgas in power plant desulfurization processes | — | — |
| 7132093 | Mesoporous mixed oxide materials as a new class of SO2 resistant catalysts for hydrocarbon oxidation | — | — |
| 6132692 | Barrier discharge conversion of SO.sub.2 and NOx to acids | — | — |
| 6500402 | Catalyst for oxidizing SO2 to SO3 and utilization of the catalyst in a method for producing sulfuric acid | — | — |
| 10307741 | Shaped catalyst body for the catalytic oxidation of SO2 into SO3 | — | — |
| 5186914 | Process for removing NO.sub.x and SO.sub.2 utilizing activated carbon | — | — |
| 12017180 | Improving sulfur recovery operations with processes based on novel CO2 over SO2 selective membranes and its co | — | — |
Frequently Asked Questions
Common questions about Sulfur dioxide, answered from cross-validated data.
What is SO2?
Sulfur dioxide is a stable, semiconducting oxide of sulfur that is widely recognized for its industrial utility and presence in atmospheric processes.
What is SO2 used for?
What is the band gap of SO2?
Is SO2 a metal, semiconductor, or insulator?
Is SO2 thermodynamically stable?
What is the crystal structure of SO2?
What is the density of SO2?
How many polymorphs of SO2 are known?
What elements does SO2 contain?
Where does the data for SO2 come from?
How It Compares
As a fundamental inorganic oxide, sulfur dioxide serves as a primary reference point for sulfur-based compounds. Its thermodynamic stability and well-documented structural landscape establish it as a cornerstone for evaluating the behavior of similar chalcogen-based materials.
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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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