Ca4P2O
Ca4P2O is a stable semiconducting inorganic compound containing calcium, phosphorus, and oxygen.
About Ca4P2O
Ca4P2O is a distinct inorganic compound composed of calcium, phosphorus, and oxygen. As a thermodynamically stable phase located on the convex hull, it represents a robust structural arrangement that is of significant interest for fundamental materials research.
Exhibiting semiconducting electronic character, this material offers potential for specialized electronic or optoelectronic applications. Its existence across multiple structural databases highlights its importance as a well-defined phase within the broader landscape of calcium-based phosphides and oxides.
Key Properties
Cross-validated computational properties for Ca4P2O, 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 Ca4P2O. 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 Ca4P2O, 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. |
|---|---|---|---|---|---|
| — | — | 1.39 | 0.0000 | -1.824 | — |
| I4/mmm (No. 139) | tetragonal | 1.27 | 0.0000 | -5.171 | 2.60 |
| I4/mmm (No. 139) | tetragonal | 1.27 | 0.0000 | -1.878 | — |
| — | — | 1.39 | 0.0005 | -1.824 | — |
| — | — | 1.52 | 0.0009 | -1.824 | — |
| I4/mmm (No. 139) | tetragonal | — | — | — | 2.60 |
| I4/mmm (No. 139) | tetragonal | — | — | — | 2.60 |
| I4/mmm (No. 139) | tetragonal | — | — | — | 2.57 |
Frequently Asked Questions
Common questions about Ca4P2O, answered from cross-validated data.
What is Ca4P2O?
Ca4P2O is a stable semiconducting inorganic compound containing calcium, phosphorus, and oxygen.
What is the band gap of Ca4P2O?
Is Ca4P2O a metal, semiconductor, or insulator?
Is Ca4P2O thermodynamically stable?
What is the crystal structure of Ca4P2O?
What is the density of Ca4P2O?
How many polymorphs of Ca4P2O are known?
What elements does Ca4P2O contain?
Where does the data for Ca4P2O come from?
How It Compares
As a unique phase within the calcium-phosphorus-oxygen system, Ca4P2O serves as a stable reference point for understanding the interplay between alkaline earth metals and pnictide-oxide frameworks in the solid state.
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)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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