Ca2Fe2O5
Brownmillerite · Dicalcium ferrite
Ca2Fe2O5 is a stable, semiconducting oxide mineral used in research for oxygen-evolution catalysis and electrochemical energy conversion.
About Brownmillerite
Ca2Fe2O5, known as brownmillerite, is a semiconducting oxide that holds a significant position within the family of oxygen-evolution catalysts. Its thermodynamic stability on the convex hull and its ability to adopt numerous structural configurations make it a highly studied material for electrochemical applications.
This compound is primarily investigated for its catalytic potential in water splitting and oxygen production. Its unique crystal lattice allows for oxygen vacancy mobility, which is a critical feature for enhancing performance in energy conversion and storage technologies.
Key Properties
Cross-validated computational properties for Brownmillerite, aggregated across 4 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 Ca2Fe2O5. 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 Ca2Fe2O5, 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. |
|---|---|---|---|---|---|
| Pnma (No. 62) | orthorhombic | 0.86 | 0.0000 | -7.533 | 4.06 |
| Ima2 (No. 46) | orthorhombic | 0.00 | 0.0465 | -7.486 | 3.89 |
| C2/m (No. 12) | monoclinic | 0.48 | 0.0571 | -7.476 | 3.87 |
| Pbam (No. 55) | orthorhombic | 0.57 | 0.0986 | -7.434 | 4.00 |
| Pmn21 (No. 31) | orthorhombic | 0.00 | 0.1725 | -7.360 | 3.70 |
| P-1 (No. 2) | triclinic | 1.10 | 0.1928 | -7.340 | 3.92 |
| C2/m (No. 12) | Monoclinic | — | — | — | 3.87 |
| No. 0 | unknown | — | — | — | 1.12 |
| Ima2 (No. 46) | Orthorhombic | — | — | — | 4.11 |
| C2/m (No. 12) | Monoclinic | — | — | — | 4.08 |
| Ima2 (No. 46) | Orthorhombic | — | — | — | 4.02 |
| Pmn21 (No. 31) | Orthorhombic | — | — | — | 3.85 |
Applications
Where Brownmillerite is used.
Frequently Asked Questions
Common questions about Brownmillerite, answered from cross-validated data.
What is Ca2Fe2O5?
Ca2Fe2O5 is a stable, semiconducting oxide mineral used in research for oxygen-evolution catalysis and electrochemical energy conversion.
What is Ca2Fe2O5 used for?
What is the band gap of Ca2Fe2O5?
Is Ca2Fe2O5 a metal, semiconductor, or insulator?
Is Ca2Fe2O5 thermodynamically stable?
What is the crystal structure of Ca2Fe2O5?
What is the density of Ca2Fe2O5?
How many polymorphs of Ca2Fe2O5 are known?
What elements does Ca2Fe2O5 contain?
Where does the data for Ca2Fe2O5 come from?
How It Compares
Within the oxide oxygen-evolution catalysts class.
Within the diverse class of oxide oxygen-evolution catalysts, Ca2Fe2O5 distinguishes itself from transition metal-rich oxides like NiO or LaNiO3 through its specific calcium-iron framework. While many members of this class, such as LiCoO2 or LiMn2O4, are primarily optimized for lithium-ion battery cathodes, Ca2Fe2O5 is frequently evaluated for its intrinsic catalytic activity and structural robustness in harsh electrochemical environments.
Related Compounds
Other Oxide Oxygen-Evolution Catalysts in the database.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- mpaloe — Data from mpaloe.
- cod — Data from the Crystallography Open Database. Cite: Grazulis et al., Nucleic Acids Res. 40, D420 (2012).
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
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