Fe7O8
Fe7O8 is a metastable semiconducting iron oxide utilized primarily as an experimental conversion anode material for electrochemical energy storage.
About Fe7O8
Fe7O8 is a semiconducting iron oxide that functions as a conversion anode material. Its metastable nature makes it an intriguing subject for research into advanced battery architectures where structural flexibility and redox activity are critical for performance.
This compound represents a complex phase within the iron-oxygen system, contributing to the broader study of transition metal oxides in electrochemical energy storage. Its electronic properties and structural diversity are essential for understanding how iron-based materials can store charge through conversion reactions.
Key Properties
Cross-validated computational properties for Fe7O8, 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 Fe7O8. 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 Fe7O8, 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. |
|---|---|---|---|---|---|
| P-1 (No. 2) | triclinic | 1.07 | 0.0629 | -8.085 | 5.19 |
| Fm-3m (No. 225) | cubic | 0.00 | 0.0979 | -8.050 | 5.28 |
| Fm-3m (No. 225) | Cubic | — | — | — | 5.28 |
| Fm-3m (No. 225) | Cubic | — | — | — | 6.31 |
| Fm-3m (No. 225) | — | — | — | — | — |
| P-62m (No. 189) | hexagonal | — | — | — | 2.01 |
| Fm-3m (No. 225) | Cubic | — | — | — | 5.82 |
| Fm-3m (No. 225) | — | — | — | — | — |
Applications
Where Fe7O8 is used.
Frequently Asked Questions
Common questions about Fe7O8, answered from cross-validated data.
What is Fe7O8?
Fe7O8 is a metastable semiconducting iron oxide utilized primarily as an experimental conversion anode material for electrochemical energy storage.
What is Fe7O8 used for?
What is the band gap of Fe7O8?
Is Fe7O8 a metal, semiconductor, or insulator?
Is Fe7O8 thermodynamically stable?
What is the crystal structure of Fe7O8?
What is the density of Fe7O8?
How many polymorphs of Fe7O8 are known?
What elements does Fe7O8 contain?
Where does the data for Fe7O8 come from?
How It Compares
Within the conversion oxide anodes class.
Within the family of conversion oxide anodes, Fe7O8 occupies a unique position compared to more common iron oxides like Fe2O3 and Fe3O4. While those siblings are frequently studied for their stable, well-defined phases, Fe7O8 offers a distinct structural profile that differentiates it from the more widely utilized MnO2 or Co3O4, highlighting the diversity of iron-based conversion mechanisms.
Related Compounds
Other Conversion Oxide Anodes 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.
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
- cod — Data from the Crystallography Open Database. Cite: Grazulis et al., Nucleic Acids Res. 40, D420 (2012).
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