SeI2
Selenium diiodide is a stable semiconducting material formed from selenium and iodine that is frequently studied for its structural and electronic characteristics.
About SeI2
Selenium diiodide is a semiconducting compound composed of selenium and iodine. As a thermodynamically stable phase located on the convex hull, it represents a well-defined chemical arrangement that maintains structural integrity under standard conditions.
With extensive data available across multiple structural databases, this compound serves as a significant subject for researchers investigating chalcogen-halide interactions. Its electronic character suggests potential utility in specialized electronic or optoelectronic applications where specific semiconductor properties are required.
Key Properties
Cross-validated computational properties for SeI2, 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 SeI2. 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 SeI2, 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. |
|---|---|---|---|---|---|
| P42/mnm (No. 136) | tetragonal | 0.91 | 0.0000 | -2.367 | 4.11 |
| — | — | 0.00 | 0.0211 | -0.129 | — |
| C2 (No. 5) | monoclinic | 0.40 | 0.0599 | 0.060 | — |
| — | — | 0.91 | 0.1044 | -0.045 | — |
| P42/mnm (No. 136) | tetragonal | 0.84 | 0.1129 | 0.113 | — |
| Pmmm (No. 47) | orthorhombic | 0.00 | 0.1380 | 0.138 | — |
| P2/m (No. 10) | monoclinic | 0.00 | 0.1916 | 0.192 | — |
| — | — | 0.00 | 1.0483 | 0.899 | — |
| P1 (No. 1) | triclinic | — | — | — | 3.49 |
| P1 (No. 1) | triclinic | — | — | — | 6.76 |
| P1 (No. 1) | triclinic | — | — | — | 3.27 |
| P1 (No. 1) | triclinic | — | — | — | 3.54 |
Applications
Where SeI2 is used.
Frequently Asked Questions
Common questions about SeI2, answered from cross-validated data.
What is SeI2?
Selenium diiodide is a stable semiconducting material formed from selenium and iodine that is frequently studied for its structural and electronic characteristics.
What is SeI2 used for?
What is the band gap of SeI2?
Is SeI2 a metal, semiconductor, or insulator?
Is SeI2 thermodynamically stable?
What is the crystal structure of SeI2?
What is the density of SeI2?
How many polymorphs of SeI2 are known?
What elements does SeI2 contain?
Where does the data for SeI2 come from?
How It Compares
As a unique binary chalcogen-halide, Selenium diiodide occupies a distinct position in materials research, serving as a fundamental reference point for understanding the bonding and stability trends within selenium-iodine systems.
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)
- 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)
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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