NaAlH4
NaAlH4 has a DFT band gap of 1.87–4.67 eV across 12 reported structures in 3 space groups; its lowest-energy polymorph is tetragonal (I41/a (No. 88)). Cross-validated across 3 computational databases.
At a glance
Key Properties
Cross-validated computational properties for NaAlH4, 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.
1.87–4.67 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.
12
3 databases, 3 space groups
Crystallography
Reported Structures
Lowest-energy structures reported for NaAlH4, 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. |
|---|---|---|---|---|---|
| I41/a (No. 88) | tetragonal | 4.67 | 0.0000 | -4.232 | 1.34 |
| Cmc21 (No. 36) | orthorhombic | 1.87 | 0.0221 | -4.210 | 1.48 |
| I41/a (No. 88) | — | — | — | — | — |
| I41/a (No. 88) | Tetragonal | — | — | — | 1.30 |
| Cmc21 (No. 36) | Orthorhombic | — | — | — | 1.45 |
| Cmc21 (No. 36) | — | — | — | — | — |
| I41/a (No. 88) | Tetragonal | — | — | — | 1.32 |
| Cmc21 (No. 36) | — | — | — | — | — |
| I41/a (No. 88) | Tetragonal | — | — | — | 1.32 |
| Cmc21 (No. 36) | Orthorhombic | — | — | — | 1.43 |
| Cmc21 (No. 36) | Orthorhombic | — | — | — | 1.46 |
| P4/mmm (No. 123) | — | — | — | — | — |
Reference
Frequently Asked Questions
Common questions about NaAlH4, answered from cross-validated data.
What is the band gap of NaAlH4?
NaAlH4 has a DFT-computed band gap of 1.87–4.67 eV across 12 reported structures.
More questions
Is NaAlH4 a metal, semiconductor, or insulator?
With a wide band gap up to 4.67 eV it is an insulator / wide-band-gap material.
Is NaAlH4 thermodynamically stable?
Yes — NaAlH4 sits on the convex hull (energy above hull 0 eV/atom), i.e. on hull (stable).
What is the crystal structure of NaAlH4?
The lowest-energy reported polymorph of NaAlH4 is tetragonal symmetry, space group I41/a (No. 88).
What is the density of NaAlH4?
The computed density of the ground-state structure of NaAlH4 is 1.34 g/cm³.
How many polymorphs of NaAlH4 are known?
12 structures of NaAlH4 are reported across 3 databases, spanning 3 distinct space groups.
What elements does NaAlH4 contain?
NaAlH4 contains Al, H, and Na (3 elements).
Where does the data for NaAlH4 come from?
NaAlH4 data is cross-referenced from materials_project, jarvis, mpaloe.
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Related Compounds
Other Hydrogen Storage Hydrides in the database.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
- mpaloe — Data from mpaloe.
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