RbI
rubidium iodide
Rubidium iodide is a stable, insulating alkali halide salt used primarily in optical and scientific research applications.
About rubidium iodide
Rubidium iodide is a thermodynamically stable inorganic salt 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 classic example of a robust ionic solid.
Due to its structural reliability and chemical stability, this compound is frequently utilized in specialized optical and radiation detection applications. It serves as a foundational material for researchers investigating the fundamental properties of alkali halides.
Key Properties
Cross-validated computational properties for rubidium iodide, 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 RbI. 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 RbI, 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 | 3.97 | 0.0000 | -1.592 | — |
| Fm-3m (No. 225) | cubic | 3.78 | 0.0000 | -2.948 | 3.51 |
| — | — | 3.87 | 0.0000 | -1.601 | — |
| — | — | 3.99 | 0.0004 | -1.600 | — |
| — | — | 3.86 | 0.0006 | -1.600 | — |
| Pm-3m (No. 221) | cubic | 3.75 | 0.0030 | -1.589 | — |
| P-6m2 (No. 187) | hexagonal | 3.54 | 0.0199 | -1.572 | — |
| — | — | 3.86 | 0.0199 | -1.581 | — |
| Pm-3m (No. 221) | cubic | 3.35 | 0.0297 | -2.918 | 4.02 |
| — | — | 0.00 | 0.0399 | -1.561 | — |
| — | — | 3.54 | 0.0408 | -1.560 | — |
| — | — | 3.45 | 0.0494 | -1.551 | — |
Applications
Where rubidium iodide is used.
Frequently Asked Questions
Common questions about rubidium iodide, answered from cross-validated data.
What is RbI?
Rubidium iodide is a stable, insulating alkali halide salt used primarily in optical and scientific research applications.
What is RbI used for?
What is the band gap of RbI?
Is RbI a metal, semiconductor, or insulator?
Is RbI thermodynamically stable?
What is the crystal structure of RbI?
How many polymorphs of RbI are known?
What elements does RbI contain?
Where does the data for RbI come from?
How It Compares
As a member of the alkali halide family, rubidium iodide represents a highly stable, well-characterized crystalline system. It is recognized for its structural versatility, supported by a vast array of reported experimental and computational configurations that highlight its consistent behavior within this class of insulating materials.
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)
- 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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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