Ca4Bi2O
Ca4Bi2O is a stable, semiconducting ternary compound containing calcium, bismuth, and oxygen.
About Ca4Bi2O
Ca4Bi2O is a semiconducting compound composed of calcium, bismuth, and oxygen. As a thermodynamically stable phase located on the convex hull, it represents a well-defined structural configuration within its chemical system.
This material is of interest for fundamental research into complex ternary oxides. Its electronic character and stability profile make it a subject of investigation for those studying the interplay between alkaline earth metals and heavy pnictogens.
Key Properties
Cross-validated computational properties for Ca4Bi2O, 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 Ca4Bi2O. 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 Ca4Bi2O, 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. |
|---|---|---|---|---|---|
| — | — | 0.99 | 0.0000 | -1.594 | — |
| I4/mmm (No. 139) | tetragonal | 0.84 | 0.0000 | -1.673 | — |
| I4/mmm (No. 139) | tetragonal | 0.81 | 0.0000 | -4.567 | 5.28 |
| I4/mmm (No. 139) | tetragonal | — | — | — | 5.21 |
| I4/mmm (No. 139) | tetragonal | — | — | — | 5.29 |
| I4/mmm (No. 139) | tetragonal | — | — | — | 5.30 |
Frequently Asked Questions
Common questions about Ca4Bi2O, answered from cross-validated data.
What is Ca4Bi2O?
Ca4Bi2O is a stable, semiconducting ternary compound containing calcium, bismuth, and oxygen.
What is the band gap of Ca4Bi2O?
Is Ca4Bi2O a metal, semiconductor, or insulator?
Is Ca4Bi2O thermodynamically stable?
What is the crystal structure of Ca4Bi2O?
How many polymorphs of Ca4Bi2O are known?
What elements does Ca4Bi2O contain?
Where does the data for Ca4Bi2O come from?
How It Compares
As a stable ternary compound, Ca4Bi2O serves as a distinct representative of its chemical family, providing a benchmark for structural and electronic studies in systems involving calcium and bismuth oxides.
Data sources & attribution
- 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)
- 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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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