HPd
Palladium hydride
Palladium hydride is a non-stoichiometric material formed by the absorption of hydrogen gas into a palladium metal lattice. It is primarily studied for its role in hydrogen storage technologies and as a catalyst in various chemical hydrogenation processes.
HPd
Overview
Key Properties
Cross-validated computational properties for HPd, 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.
Metallic / not reported
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)
3 DFT sources
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
34
5 databases, 9 space groups
Validation
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of HPd. 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, nomad
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
All match
Crystallography
Reported Structures
Lowest-energy structures reported for HPd, 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. |
|---|---|---|---|---|---|
| P63mc (No. 186) | hexagonal | 0.00 | 0.0000 | -13.297 | 9.53 |
| Fm-3m (No. 225) | cubic | 0.00 | 0.0331 | -13.264 | 10.29 |
| No. 0 | unknown | — | — | — | 2.75 |
| Fm-3m (No. 225) | — | — | — | — | — |
| P212121 (No. 19) | Orthorhombic | — | — | — | 9.61 |
| Fm-3m (No. 225) | Cubic | — | — | — | 10.05 |
| P212121 (No. 19) | Orthorhombic | — | — | — | 7.92 |
| Cm (No. 8) | Monoclinic | — | — | — | 9.95 |
| P212121 (No. 19) | Orthorhombic | — | — | — | 9.73 |
| R3m (No. 160) | Trigonal | — | — | — | 9.18 |
| Fm-3m (No. 225) | Cubic | — | — | — | 10.41 |
| P1 (No. 1) | Triclinic | — | — | — | 8.56 |
Uses
Applications
Where HPd is used.
Hydrogen storage researchCatalytic hydrogenationHydrogen purification membranesElectrochemical sensors
Reference
Frequently Asked Questions
Common questions about HPd, answered from cross-validated data.
What is HPd?
Palladium hydride is a non-stoichiometric material formed by the absorption of hydrogen gas into a palladium metal lattice. It is primarily studied for its role in hydrogen storage technologies and as a catalyst in various chemical hydrogenation processes.
More questions
What is HPd used for?
HPd is used in hydrogen storage research, catalytic hydrogenation, hydrogen purification membranes, and electrochemical sensors.
What is the band gap of HPd?
HPd is computed to be metallic (no band gap) in the reported DFT structures.
Is HPd a metal, semiconductor, or insulator?
Computed band structures report no gap, so it is metallic.
Is HPd thermodynamically stable?
Yes — HPd sits on the convex hull (energy above hull 0 eV/atom), i.e. on hull (stable).
What is the crystal structure of HPd?
The lowest-energy reported polymorph of HPd is hexagonal symmetry, space group P63mc (No. 186).
What is the density of HPd?
The computed density of the ground-state structure of HPd is 9.53 g/cm³.
How many polymorphs of HPd are known?
34 structures of HPd are reported across 5 databases, spanning 9 distinct space groups.
What elements does HPd contain?
HPd contains H and Pd (2 elements).
Where does the data for HPd come from?
HPd data is cross-referenced from materials_project, cod, jarvis, mpaloe, nomad.
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).
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
- mpaloe — Data from mpaloe.
- nomad — Data from NOMAD. Cite: Draxl & Scheffler, J. Phys. Mater. 2, 036001 (2019).
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