FeF4
FeF4 is a semiconducting iron fluoride compound that exists in a metastable state, serving as a significant subject for structural research in inorganic chemistry.
About FeF4
FeF4 is a binary fluoride compound composed of iron and fluorine. As a semiconducting material, it represents a specialized chemical system that has been the subject of extensive structural investigation across various crystallographic databases.
Due to its position above the thermodynamic hull, this compound is considered metastable, making it a focus for researchers studying high-energy pathways and phase stabilization. Its electronic properties and structural complexity provide valuable insights into the behavior of transition metal fluorides.
Key Properties
Cross-validated computational properties for FeF4, aggregated across 2 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 FeF4. 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 FeF4, 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. |
|---|---|---|---|---|---|
| — | — | 0.58 | 0.0000 | -2.135 | — |
| — | — | 0.00 | 0.0101 | -2.125 | — |
| — | — | 0.00 | 0.0246 | -2.110 | — |
| I4/mcm (No. 140) | tetragonal | 1.65 | 0.2009 | -5.182 | 2.92 |
| P2 (No. 3) | monoclinic | — | — | — | 3.70 |
| P1 (No. 1) | triclinic | — | — | — | 3.83 |
| P1 (No. 1) | triclinic | — | — | — | 3.76 |
| P1 (No. 1) | triclinic | — | — | — | 2.78 |
| P1 (No. 1) | triclinic | — | — | — | 3.26 |
| P-1 (No. 2) | triclinic | — | — | — | 3.11 |
| C2/m (No. 12) | monoclinic | — | — | — | 3.92 |
| P-1 (No. 2) | triclinic | — | — | — | 3.94 |
Applications
Where FeF4 is used.
Frequently Asked Questions
Common questions about FeF4, answered from cross-validated data.
What is FeF4?
FeF4 is a semiconducting iron fluoride compound that exists in a metastable state, serving as a significant subject for structural research in inorganic chemistry.
What is FeF4 used for?
What is the band gap of FeF4?
Is FeF4 a metal, semiconductor, or insulator?
Is FeF4 thermodynamically stable?
What is the crystal structure of FeF4?
What is the density of FeF4?
How many polymorphs of FeF4 are known?
What elements does FeF4 contain?
Where does the data for FeF4 come from?
How It Compares
As a unique transition metal fluoride, FeF4 serves as an important case study for understanding the structural diversity of iron-based halides, particularly in instances where thermodynamic stability is limited.
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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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