Ca2Nb2O7
calcium niobate · calcium diniobium heptaoxide
Ca2Nb2O7 is a stable, insulating perovskite oxide used primarily in advanced dielectric and electronic material research.

About calcium niobate
Ca2Nb2O7 is a thermodynamically stable perovskite oxide characterized by its wide-gap insulating electronic structure. As a member of the niobate family, it exhibits robust structural integrity, making it a reliable candidate for high-performance electronic and optical applications.
Its inherent stability and insulating nature allow it to function effectively in environments where charge carrier management is critical. The material is frequently investigated for its potential in dielectric components and as a substrate for thin-film growth in complex oxide electronics.
Key Properties
Cross-validated computational properties for calcium niobate, aggregated across 5 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 Ca2Nb2O7. 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 Ca2Nb2O7, 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 (No. 4) | monoclinic | 3.01 | 0.0000 | -8.647 | 4.41 |
| Pna21 (No. 33) | orthorhombic | 3.06 | 0.0001 | -8.647 | 4.31 |
| Fd-3m (No. 227) | cubic | 1.44 | 0.0415 | -8.606 | 4.24 |
| Fd-3m (No. 227) | — | — | — | — | — |
| No. 0 | unknown | — | — | — | 1.12 |
| Fd-3m (No. 227) | Cubic | — | — | — | 4.24 |
| Fd-3m (No. 227) | Cubic | — | — | — | 4.41 |
| Fd-3m (No. 227) | Cubic | — | — | — | 4.30 |
| — | — | — | — | — | 3.43 |
Applications
Where calcium niobate is used.
Frequently Asked Questions
Common questions about calcium niobate, answered from cross-validated data.
What is Ca2Nb2O7?
Ca2Nb2O7 is a stable, insulating perovskite oxide used primarily in advanced dielectric and electronic material research.
What is Ca2Nb2O7 used for?
What is the band gap of Ca2Nb2O7?
Is Ca2Nb2O7 a metal, semiconductor, or insulator?
Is Ca2Nb2O7 thermodynamically stable?
What is the crystal structure of Ca2Nb2O7?
What is the density of Ca2Nb2O7?
How many polymorphs of Ca2Nb2O7 are known?
What elements does Ca2Nb2O7 contain?
Where does the data for Ca2Nb2O7 come from?
How It Compares
Within the perovskite oxides class.
Unlike the metallic or semi-metallic behavior seen in members like LaNiO3, Ca2Nb2O7 is a distinct wide-gap insulator. While compounds such as BaTiO3 are widely utilized for their prominent ferroelectric properties, Ca2Nb2O7 offers a unique structural framework that provides a stable alternative for specialized dielectric applications within the broader perovskite oxide class.
Related Compounds
Other Perovskite Oxides 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).
- cod — Data from the Crystallography Open Database. Cite: Grazulis et al., Nucleic Acids Res. 40, D420 (2012).
- mpaloe — Data from mpaloe.
- omat24 — Data from OMat24 (Meta FAIR). Cite: Barroso-Luque et al., arXiv 2410.12771 (2024).
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