Y2Hf2O7
Yttrium hafnate · YHO
Yttrium hafnate is a stable, insulating oxide-ion conductor used in high-temperature materials and protective coatings.
About Yttrium hafnate
Yttrium hafnate is a thermodynamically stable oxide that crystallizes in a fluorite-related structure. As a wide-band-gap insulator, it exhibits excellent chemical and structural integrity, making it a robust candidate for high-temperature environments where ionic conductivity and thermal stability are required.
This compound is primarily utilized in advanced materials science for its ability to withstand extreme conditions. Its role as an oxide-ion conductor is highly valued in the development of protective coatings and electrolyte components, where its structural reliability ensures long-term performance in demanding industrial applications.
Key Properties
Cross-validated computational properties for Yttrium hafnate, 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 Y2Hf2O7. 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 Y2Hf2O7, 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 | 3.45 | 0.0000 | -3.835 | — |
| Fd-3m (No. 227) | cubic | 3.34 | 0.0003 | -10.132 | 7.57 |
| — | — | 3.53 | 0.0069 | -3.822 | — |
| C2/m (No. 12) | monoclinic | 4.43 | 0.0472 | -10.085 | 5.90 |
| P41212 (No. 92) | tetragonal | 4.13 | 0.0762 | -10.056 | 6.41 |
| C2/m (No. 12) | monoclinic | 4.39 | 0.0953 | -3.740 | — |
| — | — | 0.55 | 0.3122 | -3.517 | — |
| C2/m (No. 12) | monoclinic | — | — | — | 6.04 |
| C2/m (No. 12) | monoclinic | — | — | — | 6.26 |
| Fd-3m (No. 227) | cubic | — | — | — | 7.37 |
| C2/m (No. 12) | monoclinic | — | — | — | 5.90 |
| Fd-3m (No. 227) | cubic | — | — | — | 7.85 |
Synthesis Routes
Literature-extracted synthesis procedures targeting Y2Hf2O7.
Applications
Where Yttrium hafnate is used.
Frequently Asked Questions
Common questions about Yttrium hafnate, answered from cross-validated data.
What is Y2Hf2O7?
Yttrium hafnate is a stable, insulating oxide-ion conductor used in high-temperature materials and protective coatings.
What is Y2Hf2O7 used for?
What is the band gap of Y2Hf2O7?
Is Y2Hf2O7 a metal, semiconductor, or insulator?
Is Y2Hf2O7 thermodynamically stable?
What is the crystal structure of Y2Hf2O7?
How many polymorphs of Y2Hf2O7 are known?
How is Y2Hf2O7 synthesized?
What elements does Y2Hf2O7 contain?
Where does the data for Y2Hf2O7 come from?
How It Compares
Within the fluorite oxide-ion conductors class.
Within the family of fluorite oxide-ion conductors, Yttrium hafnate stands out for its exceptional stability compared to counterparts like Y2Zr2O7. While many zirconate-based members of this class are widely studied for their ionic transport properties, the hafnate variant provides a distinct alternative that often offers superior thermal resistance, positioning it as a critical material for high-performance engineering tasks.
Related Compounds
Other Fluorite Oxide-Ion Conductors in the database.
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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