Ca4Nb2O9
Ca4Nb2O9 has a DFT band gap of 2.42–3.26 eV across 4 reported structures in 3 space groups; its reference structure is monoclinic (P21/c (No. 14)). Cross-validated across 1 computational databases.
Key Properties
Cross-validated computational properties for Ca4Nb2O9, aggregated across 1 database.
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 Ca4Nb2O9. Tight agreement means computed properties can be trusted without re-running calculations.
Only 1 independent DFT source (materials_project) reports a hull energy for Ca4Nb2O9, so cross-source agreement can't be assessed yet.
Reported Structures
Lowest-energy structures reported for Ca4Nb2O9, 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/c (No. 14) | monoclinic | 3.26 | 0.0000 | -8.186 | 4.18 |
| P21/c (No. 14) | monoclinic | 2.98 | 0.0163 | -8.169 | 4.12 |
| P-1 (No. 2) | triclinic | 2.42 | 0.0202 | -8.165 | 4.08 |
| P1 (No. 1) | triclinic | 2.43 | 0.0208 | -8.165 | 4.08 |
Synthesis Routes
Literature-extracted synthesis procedures targeting Ca4Nb2O9.
Frequently Asked Questions
Common questions about Ca4Nb2O9, answered from cross-validated data.
What is the band gap of Ca4Nb2O9?
Ca4Nb2O9 has a DFT-computed band gap of 2.42–3.26 eV across 4 reported structures. Standard DFT underestimates band gaps, so the measured gap is typically larger.
Is Ca4Nb2O9 a metal, semiconductor, or insulator?
Is Ca4Nb2O9 thermodynamically stable?
What is the crystal structure of Ca4Nb2O9?
What is the density of Ca4Nb2O9?
How many polymorphs of Ca4Nb2O9 are known?
How is Ca4Nb2O9 synthesized?
What elements does Ca4Nb2O9 contain?
Where does the data for Ca4Nb2O9 come from?
Related Compounds
Other Perovskite Oxides in the database.
Data sources & attribution
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
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