CoCl2
Cobalt(II) chloride · Cobaltous chloride
Cobalt(II) chloride is a stable, semimetallic inorganic compound widely utilized as a chemical reagent and precursor in industrial manufacturing.
About Cobalt(II) chloride
Cobalt(II) chloride is a well-characterized inorganic compound that exhibits near-zero-gap electronic behavior. As a thermodynamically stable phase located on the convex hull, it represents a robust material with significant structural versatility, evidenced by the high volume of reported experimental and theoretical structures.
This compound serves as a critical precursor in various chemical synthesis pathways and industrial processes. Its unique electronic character and stability make it a focal point for research into coordination chemistry and the development of functional materials, particularly where precise control over cobalt oxidation states is required.
Key Properties
Cross-validated computational properties for Cobalt(II) 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 CoCl2. 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 CoCl2, 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. |
|---|---|---|---|---|---|
| R-3m (No. 166) | trigonal | 0.08 | 0.0000 | -4.585 | 3.34 |
| — | — | 0.00 | 0.0000 | -0.815 | — |
| R-3m (No. 166) | trigonal | 0.00 | 0.0000 | -0.567 | — |
| P-3m1 (No. 164) | trigonal | 0.08 | 0.0012 | -4.584 | 3.33 |
| — | — | 0.00 | 0.0105 | -0.804 | — |
| P-3m1 (No. 164) | trigonal | 0.09 | 0.0116 | -4.573 | 1.21 |
| — | — | 0.00 | 0.0246 | -0.790 | — |
| — | — | 0.28 | 0.0254 | -0.789 | — |
| — | — | 0.00 | 0.0302 | -0.785 | — |
| — | — | 0.00 | 0.0878 | -0.727 | — |
| — | — | 0.00 | 0.0893 | -0.725 | — |
| P-3m1 (No. 164) | trigonal | 0.54 | 0.1312 | -0.436 | — |
Applications
Where Cobalt(II) chloride is used.
Patent Landscape
2 patents reference CoCl2 or close compositional variants.
| Patent | Title | Assignee | Granted |
|---|---|---|---|
| 4508798 | Cell with CoCl.sub.2 cathode | — | — |
| 4394366 | Process for production of CoCl.sub.2 solution from cobaltic oxide-hydrate | — | — |
Frequently Asked Questions
Common questions about Cobalt(II) chloride, answered from cross-validated data.
What is CoCl2?
Cobalt(II) chloride is a stable, semimetallic inorganic compound widely utilized as a chemical reagent and precursor in industrial manufacturing.
What is CoCl2 used for?
What is the band gap of CoCl2?
Is CoCl2 a metal, semiconductor, or insulator?
Is CoCl2 thermodynamically stable?
What is the crystal structure of CoCl2?
What is the density of CoCl2?
How many polymorphs of CoCl2 are known?
What elements does CoCl2 contain?
Where does the data for CoCl2 come from?
How It Compares
As a highly studied inorganic halide, Cobalt(II) chloride stands out for its structural reliability and accessibility. It serves as a benchmark material within the broader landscape of cobalt-based halides, providing a foundational reference point for understanding the electronic and thermodynamic trends of transition metal chlorides.
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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