HfIr
HfIr is a stable, metallic intermetallic compound composed of hafnium and iridium that serves as a specialized platinum-group alloy catalyst.
About HfIr
HfIr is a metallic intermetallic compound belonging to the class of platinum-group alloy catalysts. Its position on the convex hull confirms that it is a thermodynamically stable phase, making it a robust candidate for materials research and industrial applications requiring high structural integrity. The compound is supported by a significant volume of structural data, reflecting its status as a well-documented material in contemporary databases. Its metallic nature suggests excellent conductivity and potential for surface-mediated chemical processes. This alloy leverages the unique catalytic properties of iridium combined with the structural stability provided by hafnium, positioning it as a specialized material for demanding catalytic environments where traditional noble metal catalysts might be insufficient.
Key Properties
Cross-validated computational properties for HfIr, 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 HfIr. 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 HfIr, 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. |
|---|---|---|---|---|---|
| P21/m (No. 11) | monoclinic | 0.00 | 0.0000 | -10.346 | 17.04 |
| P21/m (No. 11) | monoclinic | 0.00 | 0.0000 | -49.817 | 17.55 |
| Pmma (No. 51) | orthorhombic | 0.00 | 0.0191 | -10.327 | 17.76 |
| P4/mmm (No. 123) | tetragonal | 0.00 | 0.0378 | -10.308 | 17.55 |
| Pm-3m (No. 221) | cubic | 0.00 | 0.0424 | -10.303 | 17.73 |
| Cm (No. 8) | Monoclinic | — | — | — | 18.88 |
| Pmma (No. 51) | Orthorhombic | — | — | — | 17.39 |
| Pmma (No. 51) | Orthorhombic | — | — | — | 17.75 |
| P21/m (No. 11) | Monoclinic | — | — | — | 18.65 |
| P21/m (No. 11) | Monoclinic | — | — | — | 15.30 |
| P21/m (No. 11) | Monoclinic | — | — | — | 17.16 |
| Cmm2 (No. 35) | Orthorhombic | — | — | — | 14.99 |
Applications
Where HfIr is used.
Frequently Asked Questions
Common questions about HfIr, answered from cross-validated data.
What is HfIr?
HfIr is a stable, metallic intermetallic compound composed of hafnium and iridium that serves as a specialized platinum-group alloy catalyst.
What is HfIr used for?
What is the band gap of HfIr?
Is HfIr a metal, semiconductor, or insulator?
Is HfIr thermodynamically stable?
What is the crystal structure of HfIr?
What is the density of HfIr?
How many polymorphs of HfIr are known?
What elements does HfIr contain?
Where does the data for HfIr come from?
How It Compares
Within the platinum-group alloy catalysts class.
Within the diverse group of platinum-group alloy catalysts, HfIr stands out for its thermodynamic stability compared to more complex or less stable members like As2Ir or Ga2Ru. While many alloys in this class are explored for their specific surface reactivity, HfIr is distinguished by its structural prevalence, having been identified in a vast number of reported configurations that highlight its versatility compared to more niche compounds like BaPd.
Related Compounds
Other Platinum-Group Alloy Catalysts 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.
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