IO2
IO2 is a semiconducting iodine oxide that exists in a near-hull state, indicating potential for experimental synthesis.
About IO2
IO2 is an intriguing inorganic oxide characterized by its semiconducting electronic nature. As a near-hull compound, it occupies a unique position in the phase space, suggesting that it is likely synthesizable under the right experimental conditions.
Its structural complexity is highlighted by the vast number of reported configurations found across multiple databases. This high data richness makes it a compelling subject for researchers investigating the bonding behavior and stability of iodine-based oxides.
Key Properties
Cross-validated computational properties for IO2, 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 IO2. 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 IO2, 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. |
|---|---|---|---|---|---|
| P21/c (No. 14) | monoclinic | 1.50 | 0.0000 | -0.308 | — |
| — | — | 1.31 | 0.0017 | -0.551 | — |
| P21/c (No. 14) | monoclinic | 1.46 | 0.0096 | -4.503 | 5.37 |
| — | — | 1.33 | 0.0179 | -0.534 | — |
| P1 (No. 1) | triclinic | 0.00 | 0.3696 | 0.061 | — |
| — | — | 0.00 | 0.4751 | -0.077 | — |
| Pmmm (No. 47) | orthorhombic | 0.00 | 0.5954 | 0.287 | — |
| Pmmm (No. 47) | orthorhombic | 0.00 | 0.7516 | 0.443 | — |
| — | — | 0.00 | 1.8790 | 1.327 | — |
| P1 (No. 1) | triclinic | — | — | — | 6.44 |
| P1 (No. 1) | triclinic | — | — | — | 4.26 |
| P1 (No. 1) | triclinic | — | — | — | 6.54 |
Frequently Asked Questions
Common questions about IO2, answered from cross-validated data.
What is IO2?
IO2 is a semiconducting iodine oxide that exists in a near-hull state, indicating potential for experimental synthesis.
What is the band gap of IO2?
Is IO2 a metal, semiconductor, or insulator?
Is IO2 thermodynamically stable?
What is the crystal structure of IO2?
How many polymorphs of IO2 are known?
What elements does IO2 contain?
Where does the data for IO2 come from?
How It Compares
As a standalone entry in this specific chemical space, IO2 represents a critical data point for understanding the structural diversity of iodine oxides. Its status as a near-hull material provides a benchmark for evaluating the stability and potential synthesis pathways of similar high-oxidation-state halogen compounds.
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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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