CaH2
calcium hydride · hydrolith
Calcium hydride is a stable, insulating inorganic compound widely used as a drying agent and a source of hydrogen in chemical applications.
About calcium hydride
Calcium hydride is a robust, wide-band-gap insulating compound that serves as a critical member of the hydrogen storage hydride class. Its position on the thermodynamic convex hull highlights its exceptional stability, making it a reliable candidate for hydrogen containment and chemical processing.
Beyond its storage potential, the compound is widely utilized as a powerful drying agent and a versatile reducing agent in industrial chemistry. Its structural diversity, evidenced by numerous reported configurations, underscores its fundamental importance in inorganic materials research.
Key Properties
Cross-validated computational properties for calcium hydride, 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.
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 CaH2. 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 CaH2, 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. |
|---|---|---|---|---|---|
| Pnma (No. 62) | orthorhombic | 3.03 | 0.0000 | -5.316 | 1.96 |
| Pnma (No. 62) | orthorhombic | 0.70 | 0.0555 | -5.261 | 2.06 |
| Cmcm (No. 63) | orthorhombic | 0.65 | 0.0562 | -5.260 | 2.08 |
| P63/mmc (No. 194) | hexagonal | 0.65 | 0.0609 | -5.255 | 2.09 |
| P1 (No. 1) | Triclinic | — | — | — | 1.40 |
| C2/m (No. 12) | Monoclinic | — | — | — | 1.09 |
| Cmcm (No. 63) | Orthorhombic | — | — | — | 1.84 |
| P21/m (No. 11) | Monoclinic | — | — | — | 1.00 |
| P21/m (No. 11) | Monoclinic | — | — | — | 1.05 |
| P63/mmc (No. 194) | — | — | — | — | — |
| C2/c (No. 15) | Monoclinic | — | — | — | 1.16 |
| P1 (No. 1) | Triclinic | — | — | — | 1.52 |
Applications
Where calcium hydride is used.
Frequently Asked Questions
Common questions about calcium hydride, answered from cross-validated data.
What is CaH2?
Calcium hydride is a stable, insulating inorganic compound widely used as a drying agent and a source of hydrogen in chemical applications.
What is CaH2 used for?
What is the band gap of CaH2?
Is CaH2 a metal, semiconductor, or insulator?
Is CaH2 thermodynamically stable?
What is the crystal structure of CaH2?
What is the density of CaH2?
How many polymorphs of CaH2 are known?
What elements does CaH2 contain?
Where does the data for CaH2 come from?
How It Compares
Within the hydrogen storage hydrides class.
Compared to other hydrogen storage materials like LiH or MgH2, calcium hydride offers a distinct balance of thermodynamic stability and reactivity. While complex hydrides like NaBH4 are often explored for high-capacity storage, calcium hydride remains a foundational benchmark for stability and practical utility in chemical drying and synthesis.
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).
- mpaloe — Data from mpaloe.
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
Analyze CaH2 in the Lattice Graph platform
Polymorph comparison, confidence scoring, supply-chain risk, and patent monitoring — across 53 integrated data sources.
Explore the Platform →