Ca2HfO4
calcium hafnate
Calcium hafnate is a ceramic oxide material known for its high thermal stability and refractory properties. It is primarily investigated for use in advanced electronics and as a protective coating in extreme environments.
At a glance
Key Properties
Cross-validated computational properties for Ca2HfO4, 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.
3.84–4.53 eV
Range across DFT structures
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.
0.004 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.
Near hull (likely stable)
2 DFT sources
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
10
3 databases, 2 space groups
Crystallography
Reported Structures
Lowest-energy structures reported for Ca2HfO4, 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. |
|---|---|---|---|---|---|
| Pbam (No. 55) | orthorhombic | 3.84 | 0.0039 | -8.493 | 5.85 |
| Pbca (No. 61) | orthorhombic | 4.53 | 0.0251 | -8.472 | 5.43 |
| Pbam (No. 55) | — | — | — | — | — |
| Pbca (No. 61) | — | — | — | — | — |
| Pbca (No. 61) | Orthorhombic | — | — | — | 5.43 |
| Pbca (No. 61) | Orthorhombic | — | — | — | 5.70 |
| Pbca (No. 61) | Orthorhombic | — | — | — | 5.56 |
| Pbam (No. 55) | Orthorhombic | — | — | — | 5.73 |
| Pbam (No. 55) | Orthorhombic | — | — | — | 5.96 |
| Pbam (No. 55) | Orthorhombic | — | — | — | 5.83 |
Uses
Applications
Where Ca2HfO4 is used.
high-k dielectric materialsthermal barrier coatingsgate insulators in semiconductors
Reference
Frequently Asked Questions
Common questions about Ca2HfO4, answered from cross-validated data.
What is Ca2HfO4?
Calcium hafnate is a ceramic oxide material known for its high thermal stability and refractory properties. It is primarily investigated for use in advanced electronics and as a protective coating in extreme environments.
More questions
What is Ca2HfO4 used for?
Ca2HfO4 is used in high-k dielectric materials, thermal barrier coatings, and gate insulators in semiconductors.
What is the band gap of Ca2HfO4?
Ca2HfO4 has a DFT-computed band gap of 3.84–4.53 eV across 10 reported structures.
Is Ca2HfO4 a metal, semiconductor, or insulator?
With a wide band gap up to 4.53 eV it is an insulator / wide-band-gap material.
Is Ca2HfO4 thermodynamically stable?
Ca2HfO4 has a lowest energy above hull of 0.004 eV/atom (near hull (likely stable)).
What is the crystal structure of Ca2HfO4?
The lowest-energy reported polymorph of Ca2HfO4 is orthorhombic symmetry, space group Pbam (No. 55).
What is the density of Ca2HfO4?
The computed density of the ground-state structure of Ca2HfO4 is 5.85 g/cm³.
How many polymorphs of Ca2HfO4 are known?
10 structures of Ca2HfO4 are reported across 3 databases, spanning 2 distinct space groups.
What elements does Ca2HfO4 contain?
Ca2HfO4 contains Ca, Hf, and O (3 elements).
Where does the data for Ca2HfO4 come from?
Ca2HfO4 data is cross-referenced from materials_project, jarvis, mpaloe.
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Related Compounds
Other Fluorite Oxide-Ion Conductors in the database.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
- mpaloe — Data from mpaloe.
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