FeNi
taenite · iron-nickel alloy
FeNi is a thermodynamically stable metallic alloy of iron and nickel that is widely studied for its structural properties and natural occurrence in meteorites.
About taenite
FeNi is a metallic alloy composed of iron and nickel that exhibits robust thermodynamic stability. As a material that sits directly on the convex hull, it represents a highly favorable structural state for these two transition metals, reflecting a deep-seated chemical compatibility that facilitates its formation in various environments.
Beyond its fundamental scientific interest, this compound is a subject of extensive structural investigation, with numerous reported configurations across major databases. Its metallic nature and stability make it a cornerstone for understanding phase transitions in planetary science and advanced alloy design.
Key Properties
Cross-validated computational properties for taenite, 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 FeNi. 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 FeNi, 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. |
|---|---|---|---|---|---|
| P4/mmm (No. 123) | tetragonal | 0.00 | 0.0000 | -7.192 | 8.54 |
| — | — | 0.00 | 0.0000 | -0.069 | — |
| — | — | 0.00 | 0.0045 | -0.064 | — |
| P4/mmm (No. 123) | tetragonal | 0.00 | 0.0068 | -0.054 | — |
| P4/mmm (No. 123) | tetragonal | 0.00 | 0.0068 | -0.054 | — |
| — | — | 0.00 | 0.0425 | -0.026 | — |
| P-6m2 (No. 187) | hexagonal | 0.00 | 0.0659 | 0.005 | — |
| R-3m (No. 166) | trigonal | 0.00 | 0.0686 | -7.124 | 8.40 |
| — | — | 0.00 | 0.0700 | 0.001 | — |
| — | — | 0.00 | 0.0738 | 0.005 | — |
| Cmmm (No. 65) | orthorhombic | 0.00 | 0.0832 | -7.109 | 8.46 |
| — | — | 0.00 | 0.1469 | 0.078 | — |
Synthesis Routes
Literature-extracted synthesis procedures targeting FeNi.
Applications
Where taenite is used.
Patent Landscape
10 patents reference FeNi or close compositional variants.
| Patent | Title | Assignee | Granted |
|---|---|---|---|
| 9821372 | FeNi binder having universal usability | — | — |
| 10920292 | FeNi ordered alloy and method for manufacturing FeNi ordered alloy | — | — |
| 11313004 | FeNi ordered alloy and method for manufacturing FeNi ordered alloy | — | — |
| 11207730 | FeNi binder having universal usability | — | — |
| 12146210 | FeNi ordered alloy, method for manufacturing FeNi ordered alloy, and magnetic material including FeNi ordered | — | — |
| 10724112 | FeNi ordered alloy and method for manufacturing FeNi ordered alloy | — | — |
| 11361887 | Magnetic material comprising FeNi ordered alloy and manufacturing method for the same | — | — |
| 11244776 | L10-FeNi magnetic powder and bond magnet | — | — |
| 11427895 | FeNi ordered alloy, FeNi ordered alloy magnet, and method for manufacturing FeNi ordered alloy | — | — |
| 9142350 | Synthesis of ordered L10-type FeNi nanoparticles | — | — |
Frequently Asked Questions
Common questions about taenite, answered from cross-validated data.
What is FeNi?
FeNi is a thermodynamically stable metallic alloy of iron and nickel that is widely studied for its structural properties and natural occurrence in meteorites.
What is FeNi used for?
What is the band gap of FeNi?
Is FeNi a metal, semiconductor, or insulator?
Is FeNi thermodynamically stable?
What is the crystal structure of FeNi?
What is the density of FeNi?
How many polymorphs of FeNi are known?
How is FeNi synthesized?
What elements does FeNi contain?
Where does the data for FeNi come from?
How It Compares
As a foundational binary metallic system, FeNi serves as a primary reference point for the study of iron-nickel intermetallics and their diverse structural behaviors under varying conditions.
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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