CaAlH5
CaAlH5 has a DFT band gap of 2.65–3.39 eV across 4 reported structures in 1 space group; its reference structure is monoclinic (P21/c (No. 14)). Cross-validated across 2 computational databases.
At a glance
Key Properties
Cross-validated computational properties for CaAlH5, aggregated across 2 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.
2.65–3.39 eV
Range across DFT structures · ground state: insulator
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.
Stable
3 DFT sources
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
4
2 databases, 1 space group
Validation
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of CaAlH5. 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: high
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.
3
jarvis, materials_project, oqmd
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
Mixed (most: P21/c (No. 14))
Crystallography
Reported Structures
Lowest-energy structures reported for CaAlH5, 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. |
|---|---|---|---|---|---|
| P212121 (No. 19) | orthorhombic | 3.35 | 0.0000 | -0.382 | — |
| P21/c (No. 14) | monoclinic | 2.69 | 0.0000 | -4.810 | 1.72 |
| — | — | 2.65 | 0.0000 | -0.289 | — |
| P212121 (No. 19) | orthorhombic | 3.31 | 0.0085 | -4.801 | 1.83 |
| — | — | 3.39 | 0.0103 | -0.279 | — |
| P212121 (No. 19) | orthorhombic | 3.35 | 0.0242 | -3.629 | 1.79 |
| — | — | 2.67 | 0.0434 | -0.246 | — |
| P21/c (No. 14) | monoclinic | 2.94 | 0.1167 | -4.693 | 1.33 |
| P21/c (No. 14) | monoclinic | — | — | — | 1.68 |
Synthesis
Synthesis Routes
Literature-extracted synthesis procedures targeting CaAlH5.
Solid State
Procedure available · ceder_solid_state
Reference
Frequently Asked Questions
Common questions about CaAlH5, answered from cross-validated data.
What is the band gap of CaAlH5?
CaAlH5 has a DFT-computed band gap of 2.65–3.39 eV across 4 reported structures. Standard DFT underestimates band gaps, so the measured gap is typically larger.
More questions
Is CaAlH5 a metal, semiconductor, or insulator?
DFT predicts a wide band gap of up to 3.39 eV (an insulator or wide-band-gap material).
Is CaAlH5 thermodynamically stable?
Yes — CaAlH5 sits on the convex hull (energy above hull 0 eV/atom), i.e. stable.
What is the crystal structure of CaAlH5?
The reference structure of CaAlH5 is monoclinic symmetry, space group P21/c (No. 14).
What is the density of CaAlH5?
The computed density of the ground-state structure of CaAlH5 is 1.72 g/cm³.
How many polymorphs of CaAlH5 are known?
4 structures of CaAlH5 are reported across 2 databases, spanning 1 distinct space group.
How is CaAlH5 synthesized?
Literature-reported routes for CaAlH5 include solid state.
What elements does CaAlH5 contain?
CaAlH5 contains Al, Ca, and H (3 elements).
Where does the data for CaAlH5 come from?
CaAlH5 data is cross-referenced from jarvis, materials_project, oqmd, cod.
Explore
Related Compounds
Other Hydrogen Storage Hydrides in the database.
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)
- cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)
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