CrI2
CrI2 is a metastable semiconducting material consisting of chromium and iodine used primarily in fundamental materials science research.
About CrI2
CrI2 is a semiconducting compound composed of chromium and iodine. As a metastable material, it represents a unique phase that requires specific synthesis conditions to maintain its structural integrity, making it a subject of interest for fundamental solid-state chemistry studies.
Because of its electronic character, this material is primarily investigated for its potential in specialized semiconductor applications. Its existence across numerous reported structures highlights its complexity and the ongoing efforts to characterize its behavior in various crystalline forms.
Key Properties
Cross-validated computational properties for CrI2, 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 CrI2. 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 CrI2, 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. |
|---|---|---|---|---|---|
| R-3m (No. 166) | trigonal | 0.00 | 0.0000 | -0.276 | — |
| P63mc (No. 186) | hexagonal | 0.00 | 0.0011 | -0.275 | — |
| Cmc21 (No. 36) | orthorhombic | 0.00 | 0.0018 | -0.274 | — |
| R-3m (No. 166) | trigonal | 0.00 | 0.0180 | -0.258 | — |
| — | — | 0.00 | 0.0838 | -0.411 | — |
| C2/m (No. 12) | monoclinic | 0.26 | 0.0854 | -4.791 | 4.47 |
| Cmc21 (No. 36) | orthorhombic | 0.00 | 0.0938 | -4.783 | 4.36 |
| — | — | 0.00 | 0.0939 | -0.401 | — |
| — | — | 0.00 | 0.0939 | -0.401 | — |
| — | — | 0.00 | 0.0944 | -0.400 | — |
| — | — | 0.39 | 0.0946 | -0.400 | — |
| — | — | 0.00 | 0.0966 | -0.398 | — |
Applications
Where CrI2 is used.
Frequently Asked Questions
Common questions about CrI2, answered from cross-validated data.
What is CrI2?
CrI2 is a metastable semiconducting material consisting of chromium and iodine used primarily in fundamental materials science research.
What is CrI2 used for?
What is the band gap of CrI2?
Is CrI2 a metal, semiconductor, or insulator?
Is CrI2 thermodynamically stable?
What is the crystal structure of CrI2?
How many polymorphs of CrI2 are known?
What elements does CrI2 contain?
Where does the data for CrI2 come from?
How It Compares
As a unique chromium-based halide, CrI2 occupies a distinct position in materials research, serving as a critical case study for understanding the stability and electronic properties of transition metal dihalides in the absence of more common structural analogs.
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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