Ca2As2O7
Ca2As2O7 is a thermodynamically stable, wide-gap insulating compound composed of calcium, arsenic, and oxygen.
About Ca2As2O7
Ca2As2O7 is a thermodynamically stable inorganic compound that exists as a wide-gap insulator. Its presence on the convex hull indicates a high level of structural stability, making it a reliable subject for fundamental materials research. The compound is characterized by its distinct arrangement of calcium, arsenic, and oxygen atoms, which contributes to its insulating electronic nature.
With multiple reported structures across major databases, this material is well-documented in the scientific literature. Its stability and electronic properties make it an important reference point for understanding the behavior of calcium-based arsenate systems in various solid-state environments.
Key Properties
Cross-validated computational properties for Ca2As2O7, 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 Ca2As2O7. 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 Ca2As2O7, 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. |
|---|---|---|---|---|---|
| — | — | 3.61 | 0.0000 | -2.342 | — |
| C2/m (No. 12) | monoclinic | 3.55 | 0.0000 | -2.191 | — |
| C2/m (No. 12) | monoclinic | 3.34 | 0.0000 | -6.872 | 3.56 |
| C2/m (No. 12) | monoclinic | — | — | — | 3.52 |
| C2/m (No. 12) | monoclinic | — | — | — | 3.69 |
| C2/m (No. 12) | monoclinic | — | — | — | 3.44 |
Applications
Where Ca2As2O7 is used.
Frequently Asked Questions
Common questions about Ca2As2O7, answered from cross-validated data.
What is Ca2As2O7?
Ca2As2O7 is a thermodynamically stable, wide-gap insulating compound composed of calcium, arsenic, and oxygen.
What is Ca2As2O7 used for?
What is the band gap of Ca2As2O7?
Is Ca2As2O7 a metal, semiconductor, or insulator?
Is Ca2As2O7 thermodynamically stable?
What is the crystal structure of Ca2As2O7?
How many polymorphs of Ca2As2O7 are known?
What elements does Ca2As2O7 contain?
Where does the data for Ca2As2O7 come from?
How It Compares
As a stable member of the calcium arsenate family, Ca2As2O7 serves as a benchmark for structural integrity within its class. It occupies a favorable position on the thermodynamic landscape, providing a clear reference for researchers studying the phase stability and insulating characteristics of similar complex oxide materials.
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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