CsI3
Cesium triiodide
Cesium triiodide is a thermodynamically stable semiconducting compound formed from cesium and iodine that is studied for its diverse structural configurations.
About Cesium triiodide
Cesium triiodide is a semiconducting compound composed of cesium and iodine. As a thermodynamically stable member of the triiodide family, it sits securely on the convex hull, indicating a robust structural configuration that makes it a subject of significant interest for materials research.
Its electronic character allows it to function within semiconductor-based technologies. Given its structural diversity, with numerous reported configurations, it serves as a versatile candidate for exploring halide-based materials in various optoelectronic and sensing applications.
Key Properties
Cross-validated computational properties for Cesium triiodide, aggregated across 4 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 CsI3. 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 CsI3, 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. |
|---|---|---|---|---|---|
| — | — | 2.03 | 0.0000 | -0.969 | — |
| Pnma (No. 62) | orthorhombic | 1.92 | 0.0000 | -2.484 | 4.24 |
| — | — | 1.96 | 0.0303 | -0.938 | — |
| — | — | 0.00 | 0.2835 | -0.685 | — |
| — | — | 0.00 | 0.3530 | -0.616 | — |
| — | — | 0.00 | 0.3819 | -0.587 | — |
| — | — | 0.00 | 0.4197 | -0.549 | — |
| C2/m (No. 12) | monoclinic | — | — | — | 4.92 |
| P-1 (No. 2) | triclinic | — | — | — | 3.21 |
| P-1 (No. 2) | triclinic | — | — | — | 3.12 |
| Pm (No. 6) | monoclinic | — | — | — | 2.98 |
| Pm (No. 6) | monoclinic | — | — | — | 2.77 |
Applications
Where Cesium triiodide is used.
Frequently Asked Questions
Common questions about Cesium triiodide, answered from cross-validated data.
What is CsI3?
Cesium triiodide is a thermodynamically stable semiconducting compound formed from cesium and iodine that is studied for its diverse structural configurations.
What is CsI3 used for?
What is the band gap of CsI3?
Is CsI3 a metal, semiconductor, or insulator?
Is CsI3 thermodynamically stable?
What is the crystal structure of CsI3?
What is the density of CsI3?
How many polymorphs of CsI3 are known?
What elements does CsI3 contain?
Where does the data for CsI3 come from?
How It Compares
As a distinct halide-based semiconductor, cesium triiodide represents a stable structural archetype within its chemical class. It serves as a foundational example of how alkali metal cations interact with polyiodide networks to create stable, semiconducting solid-state architectures.
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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
- cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)
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