NaI
Sodium iodide · NaI
Sodium iodide is an inorganic compound that exists as a white, water-soluble salt. It is widely utilized in medical imaging and as a chemical reagent in organic synthesis.
INa
Overview
Key Properties
Cross-validated computational properties for Sodium 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.
2.75–3.57 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.
47
4 databases, 12 space groups
Crystallography
Reported Structures
Lowest-energy structures reported for NaI, 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 | 3.57 | 0.0000 | -2.883 | 3.73 |
| Pmma (No. 51) | orthorhombic | 2.75 | 0.1182 | -2.765 | 3.23 |
| I41/amd (No. 141) | tetragonal | 3.08 | 0.1470 | -2.736 | 3.03 |
| P1 (No. 1) | triclinic | — | — | — | 2.72 |
| Cm (No. 8) | Monoclinic | — | — | — | 2.66 |
| P-6m2 (No. 187) | — | — | — | — | — |
| P-6m2 (No. 187) | Hexagonal | — | — | — | 3.78 |
| P-1 (No. 2) | Triclinic | — | — | — | 4.29 |
| Pmma (No. 51) | Orthorhombic | — | — | — | 3.23 |
| Pmma (No. 51) | Orthorhombic | — | — | — | 3.28 |
| C2/m (No. 12) | Monoclinic | — | — | — | 3.76 |
| P-1 (No. 2) | Triclinic | — | — | — | 2.87 |
Uses
Applications
Where Sodium iodide is used.
Scintillation detectorsRadiopharmaceuticalsOrganic synthesisNutritional supplements
Reference
Frequently Asked Questions
Common questions about Sodium iodide, answered from cross-validated data.
What is NaI?
Sodium iodide is an inorganic compound that exists as a white, water-soluble salt. It is widely utilized in medical imaging and as a chemical reagent in organic synthesis.
More questions
What is NaI used for?
Sodium iodide (NaI) is used in scintillation detectors, radiopharmaceuticals, organic synthesis, and nutritional supplements.
What is the band gap of NaI?
Sodium iodide (NaI) has a DFT-computed band gap of 2.75–3.57 eV across 47 reported structures.
Is NaI a metal, semiconductor, or insulator?
With a wide band gap up to 3.57 eV it is an insulator / wide-band-gap material.
Is NaI thermodynamically stable?
Yes — Sodium iodide (NaI) sits on the convex hull (energy above hull 0 eV/atom), i.e. on hull (stable).
What is the crystal structure of NaI?
The lowest-energy reported polymorph of Sodium iodide (NaI) is cubic symmetry, space group Fm-3m (No. 225).
What is the density of NaI?
The computed density of the ground-state structure of Sodium iodide (NaI) is 3.73 g/cm³.
How many polymorphs of NaI are known?
47 structures of NaI are reported across 4 databases, spanning 12 distinct space groups.
What elements does NaI contain?
Sodium iodide (NaI) contains I and Na (2 elements).
Where does the data for NaI come from?
NaI data is cross-referenced from materials_project, cod, mpaloe, jarvis.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- cod — Data from the Crystallography Open Database. Cite: Grazulis et al., Nucleic Acids Res. 40, D420 (2012).
- mpaloe — Data from mpaloe.
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
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