CrF2
Chromium(II) fluoride · Chromous fluoride
Chromium(II) fluoride is a stable, metallic inorganic compound composed of chromium and fluorine atoms.
About Chromium(II) fluoride
Chromium(II) fluoride is a robust inorganic compound that occupies a stable position on the thermodynamic convex hull. Its metallic electronic character distinguishes it from many typical insulating metal halides, marking it as a subject of significant interest in solid-state chemistry.
With extensive structural documentation across multiple databases, this compound serves as a fundamental reference point for chromium-based fluorides. Its stability and unique electronic profile make it a valuable material for researchers investigating the interplay between transition metal oxidation states and halide coordination environments.
Key Properties
Cross-validated computational properties for Chromium(II) fluoride, aggregated across 6 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 CrF2. 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 CrF2, 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. |
|---|---|---|---|---|---|
| P21/c (No. 14) | monoclinic | 0.00 | 0.0000 | -7.316 | 3.84 |
| — | — | 0.40 | 0.0898 | -2.491 | — |
| — | — | 0.67 | 0.1116 | -2.469 | — |
| P21/c (No. 14) | monoclinic | 0.55 | 0.1194 | -2.328 | — |
| — | — | 0.00 | 0.1208 | -2.460 | — |
| — | — | 0.00 | 0.1303 | -2.451 | — |
| — | — | 0.00 | 0.1352 | -2.446 | — |
| — | — | 0.00 | 0.1539 | -2.427 | — |
| — | — | 0.00 | 0.3033 | -2.278 | — |
| — | — | 0.00 | 0.3755 | -2.206 | — |
| Pnnm (No. 58) | orthorhombic | 0.00 | 0.5829 | -1.864 | — |
| — | — | 0.00 | 1.9178 | -0.663 | — |
Applications
Where Chromium(II) fluoride is used.
Frequently Asked Questions
Common questions about Chromium(II) fluoride, answered from cross-validated data.
What is CrF2?
Chromium(II) fluoride is a stable, metallic inorganic compound composed of chromium and fluorine atoms.
What is CrF2 used for?
What is the band gap of CrF2?
Is CrF2 a metal, semiconductor, or insulator?
Is CrF2 thermodynamically stable?
What is the crystal structure of CrF2?
What is the density of CrF2?
How many polymorphs of CrF2 are known?
What elements does CrF2 contain?
Where does the data for CrF2 come from?
How It Compares
As a thermodynamically stable metallic fluoride, this compound represents a well-defined benchmark within the broader family of chromium halides, serving as a primary reference for studying the structural and electronic evolution of the chromium-fluorine system.
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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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