Ba4Pd
Ba4Pd is a semimetallic intermetallic compound composed of barium and palladium that serves as a research subject in the study of platinum-group alloy catalysts.
About Ba4Pd
Ba4Pd is a complex intermetallic compound belonging to the platinum-group alloy catalyst class. Characterized by a near-zero-gap electronic structure, it exhibits semimetallic behavior that is of significant interest for fundamental studies in solid-state physics and materials science. Although it is currently classified as thermodynamically unstable, its existence across multiple structural databases highlights its importance in understanding phase stability within barium-palladium systems. The material is primarily investigated for its unique bonding characteristics and potential as a precursor or model system in catalytic research. Its electronic nature suggests potential utility in specialized electronic or chemical applications where semimetallic properties are advantageous.
Key Properties
Cross-validated computational properties for Ba4Pd, 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.
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 Ba4Pd. 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 Ba4Pd, 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. |
|---|---|---|---|---|---|
| Fd-3m (No. 227) | cubic | 0.06 | 0.1557 | -2.635 | 3.62 |
| Fd-3m (No. 227) | cubic | 0.00 | 0.1862 | -0.096 | — |
| C2/m (No. 12) | monoclinic | — | — | — | 3.84 |
| C2/m (No. 12) | monoclinic | — | — | — | 4.20 |
| C2/m (No. 12) | monoclinic | — | — | — | 3.37 |
Applications
Where Ba4Pd is used.
Frequently Asked Questions
Common questions about Ba4Pd, answered from cross-validated data.
What is Ba4Pd?
Ba4Pd is a semimetallic intermetallic compound composed of barium and palladium that serves as a research subject in the study of platinum-group alloy catalysts.
What is Ba4Pd used for?
What is the band gap of Ba4Pd?
Is Ba4Pd a metal, semiconductor, or insulator?
Is Ba4Pd thermodynamically stable?
What is the crystal structure of Ba4Pd?
What is the density of Ba4Pd?
How many polymorphs of Ba4Pd are known?
What elements does Ba4Pd contain?
Where does the data for Ba4Pd come from?
How It Compares
Within the platinum-group alloy catalysts class.
Within the broader class of platinum-group alloys, Ba4Pd stands out due to its high barium content compared to more common stoichiometric phases like BaPd. While many members of this group, such as GeRu or IrSe2, exhibit robust thermodynamic stability, Ba4Pd exists in a more precarious state above the hull, making it a subject of interest for researchers studying metastable phases in transition metal alloys.
Related Compounds
Other Platinum-Group Alloy Catalysts in the database.
Data sources & attribution
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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