HfTa
HfTa is a metallic binary compound of hafnium and tantalum that is frequently observed in structural studies despite being thermodynamically metastable.
About HfTa
HfTa is a binary intermetallic compound formed from the transition metals hafnium and tantalum. As a metallic system, it lacks a band gap and exhibits the characteristic electronic behavior associated with transition metal alloys.
While this compound appears frequently in structural databases, its thermodynamic profile indicates it sits above the stability hull. This suggests that while it can be synthesized or modeled in various configurations, it may be metastable under standard conditions.
Key Properties
Cross-validated computational properties for HfTa, aggregated across 6 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 HfTa. 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 HfTa, 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. |
|---|---|---|---|---|---|
| Cmmm (No. 65) | orthorhombic | 0.00 | 0.1359 | 0.136 | — |
| Cmmm (No. 65) | orthorhombic | 0.00 | 0.1571 | -46.714 | 14.98 |
| Pm-3m (No. 221) | cubic | 0.00 | 0.1658 | 0.166 | — |
| — | — | 0.00 | 0.1906 | 0.191 | — |
| — | — | 0.00 | 0.2075 | 0.207 | — |
| P-6m2 (No. 187) | hexagonal | 0.00 | 0.2080 | 0.208 | — |
| — | — | 0.00 | 0.2113 | 0.211 | — |
| — | — | 0.00 | 0.2263 | 0.226 | — |
| — | — | 0.00 | 1.1706 | 1.171 | — |
| — | — | 0.00 | 2.8709 | 2.871 | — |
| P1 (No. 1) | triclinic | — | — | — | 10.23 |
| P1 (No. 1) | triclinic | — | — | — | 14.73 |
Frequently Asked Questions
Common questions about HfTa, answered from cross-validated data.
What is HfTa?
HfTa is a metallic binary compound of hafnium and tantalum that is frequently observed in structural studies despite being thermodynamically metastable.
What is the band gap of HfTa?
Is HfTa a metal, semiconductor, or insulator?
Is HfTa thermodynamically stable?
What is the crystal structure of HfTa?
How many polymorphs of HfTa are known?
What elements does HfTa contain?
Where does the data for HfTa come from?
How It Compares
As a binary alloy of hafnium and tantalum, HfTa represents a specific point in the vast landscape of refractory metal systems. Without a stable ground-state configuration, it serves as an important case study for understanding the phase space and structural diversity of transition metal combinations.
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)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- 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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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