Ca2Al2O5
dicalcium aluminate · C2A
Ca2Al2O5 is a stable, insulating calcium aluminate ceramic used primarily in materials research and as a precursor in specialized oxide synthesis.
About dicalcium aluminate
Ca2Al2O5 is a wide-gap insulating oxide that exists in a near-hull state, indicating it is a thermodynamically stable phase suitable for synthesis. Its structural characteristics make it a subject of interest for researchers studying complex oxide systems and their potential for catalytic applications. The material is recognized for its structural versatility, supported by multiple reported crystalline arrangements across major databases. As an aluminate, it plays a specific role in high-temperature material science and serves as a foundational component in various mineralogical and synthetic ceramic studies.
Key Properties
Cross-validated computational properties for dicalcium aluminate, 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 Ca2Al2O5. 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 Ca2Al2O5, 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. |
|---|---|---|---|---|---|
| Ima2 (No. 46) | orthorhombic | 3.90 | 0.0000 | -3.327 | — |
| — | — | 3.83 | 0.0120 | -3.273 | — |
| — | — | 3.82 | 0.0125 | -3.273 | — |
| Ima2 (No. 46) | orthorhombic | 3.57 | 0.0228 | -7.438 | 3.40 |
| C2/m (No. 12) | monoclinic | 3.40 | 0.0478 | -7.413 | 3.36 |
| — | — | 2.33 | 0.1070 | -3.178 | — |
| — | — | 2.24 | 0.3552 | -2.930 | — |
| — | — | 2.18 | 0.3689 | -2.917 | — |
| — | — | 2.54 | 0.3997 | -2.886 | — |
| — | — | 1.80 | 0.4040 | -2.881 | — |
| — | — | 2.49 | 0.4045 | -2.881 | — |
| — | — | 1.22 | 0.6729 | -2.613 | — |
Synthesis Routes
Literature-extracted synthesis procedures targeting Ca2Al2O5.
Applications
Where dicalcium aluminate is used.
Frequently Asked Questions
Common questions about dicalcium aluminate, answered from cross-validated data.
What is Ca2Al2O5?
Ca2Al2O5 is a stable, insulating calcium aluminate ceramic used primarily in materials research and as a precursor in specialized oxide synthesis.
What is Ca2Al2O5 used for?
What is the band gap of Ca2Al2O5?
Is Ca2Al2O5 a metal, semiconductor, or insulator?
Is Ca2Al2O5 thermodynamically stable?
What is the crystal structure of Ca2Al2O5?
How many polymorphs of Ca2Al2O5 are known?
How is Ca2Al2O5 synthesized?
What elements does Ca2Al2O5 contain?
Where does the data for Ca2Al2O5 come from?
How It Compares
Within the spinel oxide catalysts class.
Within the diverse class of spinel and related oxide catalysts, Ca2Al2O5 occupies a distinct niche compared to transition-metal-heavy counterparts like CuO or NiO. While those materials are often prized for their redox activity, Ca2Al2O5 acts more as a stable, insulating structural host or support material, sharing more functional commonalities with the robust MgAl2O4 or the insulating Al2O3 than with the highly conductive perovskites like LaNiO3.
Related Compounds
Other Spinel Oxide Catalysts in the database.
Data sources & attribution
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- 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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
- cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)
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