CsI
Cesium iodide · Caesium iodide
Cesium iodide is an inorganic salt that is highly valued for its ability to convert high-energy radiation into visible light. It is widely utilized in sensitive detection equipment due to its excellent transparency and scintillation properties.
CsI
Overview
Key Properties
Cross-validated computational properties for Cesium iodide, 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.
3.12–3.87 eV
Range across DFT structures
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.
0.000 eV/atom
Best (lowest) across sources
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.
On hull (stable)
2 DFT sources
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
64
4 databases, 17 space groups
Validation
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of CsI. 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.
1.00 / 1.00
Trust tier: medium
Hull SpreadDifference between the highest and lowest energy-above-hull values reported by comparable sources. Smaller spread means less thermodynamic disagreement.
0.000 eV
EAH spread across sources
Sources ComparedNumber and names of computational sources with comparable entries for this formula.
2
materials_project, nomad
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
All match
Crystallography
Reported Structures
Lowest-energy structures reported for CsI, 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. |
|---|---|---|---|---|---|
| Fm-3m (No. 225) | cubic | 3.86 | 0.0000 | -2.945 | 3.62 |
| Pmmn (No. 59) | orthorhombic | 3.87 | 0.0111 | -2.934 | 3.64 |
| Pmmn (No. 59) | orthorhombic | 3.84 | 0.0114 | -2.934 | 3.63 |
| Pm-3m (No. 221) | cubic | 3.68 | 0.0325 | -2.913 | 4.25 |
| Pnma (No. 62) | orthorhombic | 3.12 | 0.1131 | -2.832 | 3.59 |
| F-43m (No. 216) | — | 3.57 | — | — | — |
| Cmc21 (No. 36) | Orthorhombic | — | — | — | 3.13 |
| Cmcm (No. 63) | Orthorhombic | — | — | — | 4.10 |
| C2/m (No. 12) | Monoclinic | — | — | — | 1.38 |
| P1 (No. 1) | Triclinic | — | — | — | 2.42 |
| P1 (No. 1) | Triclinic | — | — | — | 2.72 |
| P1 (No. 1) | Triclinic | — | — | — | 4.01 |
Uses
Applications
Where Cesium iodide is used.
Scintillation detectorsX-ray imaging screensInfrared optical windowsRadiation spectroscopy
Reference
Frequently Asked Questions
Common questions about Cesium iodide, answered from cross-validated data.
What is CsI?
Cesium iodide is an inorganic salt that is highly valued for its ability to convert high-energy radiation into visible light. It is widely utilized in sensitive detection equipment due to its excellent transparency and scintillation properties.
More questions
What is CsI used for?
Cesium iodide (CsI) is used in scintillation detectors, x-ray imaging screens, infrared optical windows, and radiation spectroscopy.
What is the band gap of CsI?
Cesium iodide (CsI) has a DFT-computed band gap of 3.12–3.87 eV across 64 reported structures.
Is CsI a metal, semiconductor, or insulator?
With a wide band gap up to 3.87 eV it is an insulator / wide-band-gap material.
Is CsI thermodynamically stable?
Yes — Cesium iodide (CsI) sits on the convex hull (energy above hull 0 eV/atom), i.e. on hull (stable).
What is the crystal structure of CsI?
The lowest-energy reported polymorph of Cesium iodide (CsI) is cubic symmetry, space group Fm-3m (No. 225).
What is the density of CsI?
The computed density of the ground-state structure of Cesium iodide (CsI) is 3.62 g/cm³.
How many polymorphs of CsI are known?
64 structures of CsI are reported across 4 databases, spanning 17 distinct space groups.
What elements does CsI contain?
Cesium iodide (CsI) contains Cs and I (2 elements).
Where does the data for CsI come from?
CsI data is cross-referenced from materials_project, nomad, mpaloe.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- nomad — Data from NOMAD. Cite: Draxl & Scheffler, J. Phys. Mater. 2, 036001 (2019).
- mpaloe — Data from mpaloe.
Analyze CsI in the Lattice Graph platform
Polymorph comparison, confidence scoring, supply-chain risk, and patent monitoring — across 53 integrated data sources.
Explore the Platform →