KFeF4
KFeF4 is a thermodynamically stable semiconducting fluoride compound used in fundamental materials research.
About KFeF4
KFeF4 is a complex inorganic fluoride featuring a stable arrangement of potassium and iron ions. As a thermodynamically stable material located on the convex hull, it exhibits robust structural integrity that makes it a subject of interest for fundamental solid-state studies.
Possessing semiconducting electronic characteristics, this compound serves as a model system for investigating transition metal fluoride interactions. Its presence across multiple structural databases highlights its significance in the broader landscape of functional inorganic materials.
Key Properties
Cross-validated computational properties for KFeF4, 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 KFeF4. 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 KFeF4, 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 | 3.06 | 0.0000 | -5.714 | 3.18 |
| — | — | 0.42 | 0.0000 | -2.695 | — |
| Cmcm (No. 63) | orthorhombic | 0.20 | 0.0000 | -2.551 | — |
| Cmcm (No. 63) | orthorhombic | 2.20 | 0.0025 | -5.711 | 3.13 |
| — | — | 0.28 | 0.0301 | -2.665 | — |
| — | — | 0.57 | 0.0634 | -2.632 | — |
| Pmn21 (No. 31) | orthorhombic | — | — | — | 3.13 |
| Cmcm (No. 63) | orthorhombic | — | — | — | 3.11 |
| Cmcm (No. 63) | orthorhombic | — | — | — | 2.96 |
| Cmcm (No. 63) | orthorhombic | — | — | — | 3.06 |
Applications
Where KFeF4 is used.
Frequently Asked Questions
Common questions about KFeF4, answered from cross-validated data.
What is KFeF4?
KFeF4 is a thermodynamically stable semiconducting fluoride compound used in fundamental materials research.
What is KFeF4 used for?
What is the band gap of KFeF4?
Is KFeF4 a metal, semiconductor, or insulator?
Is KFeF4 thermodynamically stable?
What is the crystal structure of KFeF4?
What is the density of KFeF4?
How many polymorphs of KFeF4 are known?
What elements does KFeF4 contain?
Where does the data for KFeF4 come from?
How It Compares
As a distinct inorganic fluoride, KFeF4 occupies a unique position in materials science where its thermodynamic stability and semiconducting nature provide a baseline for exploring the properties of complex iron-based fluoride frameworks.
Data sources & attribution
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- 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)
- cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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