CuF
CuF is a metallic, thermodynamically unstable copper fluoride compound that is primarily studied for its extensive structural complexity.
About CuF
CuF is a binary inorganic compound composed of copper and fluorine. It exhibits a metallic electronic character, distinguishing it from many typical insulating metal halides. Because it resides above the thermodynamic hull, it is considered an unstable phase that presents significant challenges for experimental synthesis and long-term storage.
Despite its instability, the compound is a subject of intense theoretical interest due to its structural diversity. With nearly two hundred reported structures across major materials databases, it serves as a critical case study for researchers investigating the complex phase space of transition metal halides.
Key Properties
Cross-validated computational properties for CuF, aggregated across 5 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 CuF. 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 CuF, 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. |
|---|---|---|---|---|---|
| — | — | 1.12 | 0.1293 | -1.168 | — |
| C2/m (No. 12) | monoclinic | 0.02 | 0.1612 | -1.067 | — |
| — | — | 1.13 | 0.1638 | -1.134 | — |
| — | — | 0.00 | 0.2097 | -1.088 | — |
| — | — | 0.00 | 0.2197 | -1.078 | — |
| — | — | 0.00 | 0.2293 | -1.068 | — |
| — | — | 0.00 | 0.2512 | -1.047 | — |
| — | — | 0.00 | 0.2788 | -1.019 | — |
| — | — | 0.00 | 0.2814 | -1.016 | — |
| — | — | 0.00 | 0.2932 | -1.005 | — |
| — | — | 0.00 | 0.2998 | -0.998 | — |
| — | — | 0.00 | 0.3027 | -0.995 | — |
Frequently Asked Questions
Common questions about CuF, answered from cross-validated data.
What is CuF?
CuF is a metallic, thermodynamically unstable copper fluoride compound that is primarily studied for its extensive structural complexity.
What is the band gap of CuF?
Is CuF a metal, semiconductor, or insulator?
Is CuF thermodynamically stable?
What is the crystal structure of CuF?
How many polymorphs of CuF are known?
What elements does CuF contain?
Where does the data for CuF come from?
How It Compares
As a metallic and thermodynamically unstable phase, CuF represents a unique outlier in the broader landscape of copper-based compounds, which are more commonly found in stable, insulating oxidation states.
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)
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- 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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