CaHN
CaHN is a stable, semiconducting ternary hydride material investigated for its potential utility in solid-state hydrogen storage technologies.
About CaHN
CaHN is a semiconducting ternary hydride that exists as a thermodynamically stable phase on the convex hull. Its unique composition of calcium, hydrogen, and nitrogen positions it as a specialized candidate for solid-state hydrogen storage applications, where structural stability is a critical requirement for reversible cycling.
As a member of the broader class of hydrogen storage hydrides, this compound is subject to significant interest due to its structural diversity, with multiple reported configurations across crystallographic databases. Its electronic character and stable nature make it a compelling subject for researchers aiming to optimize hydrogen density and release kinetics in next-generation energy systems.
Key Properties
Cross-validated computational properties for CaHN, 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 CaHN. 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 CaHN, 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. |
|---|---|---|---|---|---|
| I4mm (No. 107) | tetragonal | 2.50 | 0.0000 | -0.883 | — |
| — | — | 2.45 | 0.0000 | -0.864 | — |
| I4mm (No. 107) | tetragonal | 2.19 | 0.0000 | -7.434 | 2.59 |
| P-1 (No. 2) | triclinic | — | — | — | 1.61 |
| P-1 (No. 2) | triclinic | — | — | — | 1.83 |
| P21/m (No. 11) | monoclinic | — | — | — | 2.46 |
| Pmma (No. 51) | orthorhombic | — | — | — | 1.92 |
| Fm-3 (No. 202) | cubic | — | — | — | 2.71 |
| Pmma (No. 51) | orthorhombic | — | — | — | 3.46 |
| Pmma (No. 51) | orthorhombic | — | — | — | 2.20 |
| Fm-3m (No. 225) | cubic | — | — | — | 2.92 |
Applications
Where CaHN is used.
Frequently Asked Questions
Common questions about CaHN, answered from cross-validated data.
What is CaHN?
CaHN is a stable, semiconducting ternary hydride material investigated for its potential utility in solid-state hydrogen storage technologies.
What is CaHN used for?
What is the band gap of CaHN?
Is CaHN a metal, semiconductor, or insulator?
Is CaHN thermodynamically stable?
What is the crystal structure of CaHN?
What is the density of CaHN?
How many polymorphs of CaHN are known?
What elements does CaHN contain?
Where does the data for CaHN come from?
How It Compares
Within the hydrogen storage hydrides class.
Within the class of hydrogen storage hydrides, CaHN occupies a distinct niche compared to binary counterparts like CaH2 or LiH. While binary hydrides are often the primary focus for weight-efficient storage, CaHN introduces nitrogen into the lattice, offering a different chemical environment that can influence the thermodynamic pathways of hydrogen desorption compared to simpler systems like MgH2 or AlH3.
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)
- 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)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
- 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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