FeCl2
Ferrous chloride · Iron(II) chloride
Ferrous chloride is a stable, semimetallic iron halide widely used as a precursor in chemical synthesis and industrial catalysis.
About Ferrous chloride
Ferrous chloride is a robust, thermodynamically stable inorganic compound that sits firmly on the convex hull of its chemical system. Its electronic character is defined as near-zero-gap, placing it in a semimetallic regime that distinguishes it from typical insulating metal halides.
This material is highly valued for its versatility in laboratory and industrial settings. Due to its structural stability and well-documented nature, it serves as a fundamental precursor in the synthesis of diverse iron-based complexes and as a reliable reagent in various chemical transformations.
Key Properties
Cross-validated computational properties for Ferrous chloride, 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 FeCl2. 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 FeCl2, 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. |
|---|---|---|---|---|---|
| — | — | 0.78 | 0.0000 | -0.966 | — |
| P-3m1 (No. 164) | trigonal | 0.61 | 0.0000 | -5.203 | 3.17 |
| P-3m1 (No. 164) | trigonal | 0.00 | 0.0000 | -0.750 | — |
| — | — | 0.00 | 0.0010 | -0.965 | — |
| — | — | 0.00 | 0.0013 | -0.964 | — |
| — | — | 0.00 | 0.0091 | -0.957 | — |
| — | — | 0.00 | 0.0104 | -0.955 | — |
| R-3m (No. 166) | trigonal | 0.00 | 0.0117 | -0.738 | — |
| R-3m (No. 166) | trigonal | 0.63 | 0.0218 | -5.181 | 3.21 |
| — | — | 0.00 | 0.0348 | -0.931 | — |
| — | — | 0.00 | 0.0351 | -0.931 | — |
| — | — | 0.28 | 0.0422 | -0.923 | — |
Applications
Where Ferrous chloride is used.
Patent Landscape
2 patents reference FeCl2 or close compositional variants.
| Patent | Title | Assignee | Granted |
|---|---|---|---|
| 5064632 | Process for partial oxidation of FeCl.sub.2 to FeCl.sub.3 | — | — |
| 10615407 | Na—FeCl2 ZEBRA type battery | — | — |
Frequently Asked Questions
Common questions about Ferrous chloride, answered from cross-validated data.
What is FeCl2?
Ferrous chloride is a stable, semimetallic iron halide widely used as a precursor in chemical synthesis and industrial catalysis.
What is FeCl2 used for?
What is the band gap of FeCl2?
Is FeCl2 a metal, semiconductor, or insulator?
Is FeCl2 thermodynamically stable?
What is the crystal structure of FeCl2?
How many polymorphs of FeCl2 are known?
What elements does FeCl2 contain?
Where does the data for FeCl2 come from?
How It Compares
As a primary iron halide, FeCl2 serves as a foundational reference point for the study of iron-based chemical systems, representing a stable and highly accessible form of divalent iron that facilitates a wide array of synthetic pathways.
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)
- 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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