CaI2
Calcium iodide · calcium diiodide
Calcium iodide is a stable, insulating salt composed of calcium and iodine that is primarily used in chemical synthesis and specialized industrial processes.
About Calcium iodide
Calcium iodide is a stable inorganic halide compound that functions as a wide-gap insulator. Its electronic structure is characterized by a significant energy separation between the valence and conduction bands, making it a subject of interest for specialized optical and electronic applications.
Due to its thermodynamic stability on the convex hull, this material maintains structural integrity under standard conditions. It is frequently utilized in chemical synthesis and as a precursor for various calcium-containing materials in laboratory research.
Key Properties
Cross-validated computational properties for Calcium iodide, 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 CaI2. 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 CaI2, 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. |
|---|---|---|---|---|---|
| P-3m1 (No. 164) | trigonal | 3.90 | 0.0000 | -3.579 | 3.81 |
| P-3m1 (No. 164) | trigonal | 3.45 | 0.0000 | -1.716 | — |
| — | — | 3.72 | 0.0005 | -1.761 | — |
| — | — | 3.81 | 0.0012 | -1.760 | — |
| — | — | 3.62 | 0.0014 | -1.760 | — |
| — | — | 3.83 | 0.0021 | -1.759 | — |
| — | — | 3.69 | 0.0046 | -1.757 | — |
| — | — | 3.53 | 0.0434 | -1.718 | — |
| — | — | 3.71 | 0.0452 | -1.716 | — |
| — | — | 3.44 | 0.0452 | -1.716 | — |
| — | — | 3.43 | 0.0458 | -1.716 | — |
| — | — | 3.43 | 0.0665 | -1.695 | — |
Applications
Where Calcium iodide is used.
Frequently Asked Questions
Common questions about Calcium iodide, answered from cross-validated data.
What is CaI2?
Calcium iodide is a stable, insulating salt composed of calcium and iodine that is primarily used in chemical synthesis and specialized industrial processes.
What is CaI2 used for?
What is the band gap of CaI2?
Is CaI2 a metal, semiconductor, or insulator?
Is CaI2 thermodynamically stable?
What is the crystal structure of CaI2?
What is the density of CaI2?
How many polymorphs of CaI2 are known?
What elements does CaI2 contain?
Where does the data for CaI2 come from?
How It Compares
As a primary calcium-based halide, calcium iodide serves as a representative example of alkaline earth metal iodides, providing a baseline for understanding the structural and chemical behavior of this group in solid-state chemistry.
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)
- 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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
Analyze CaI2 in the Lattice Graph platform
Polymorph comparison, confidence scoring, supply-chain risk, and patent monitoring — across 85 source databases.
Explore the Platform →