Co
Cobalt · metallic cobalt
Cobalt is a stable, metallic transition element widely utilized for its magnetic properties and its role in creating durable, heat-resistant alloys.

About Cobalt
Cobalt is a fundamental metallic element recognized for its exceptional thermodynamic stability. As a pure metal, it exhibits characteristic metallic electronic behavior, serving as a critical building block in materials science due to its robust structural integrity and unique magnetic properties.
Its importance spans across heavy industry and high-tech manufacturing, where it is prized for its ability to maintain strength and magnetic performance under demanding conditions. With a vast array of documented structural phases, it remains one of the most extensively studied elements in modern metallurgy.
Key Properties
Cross-validated computational properties for Cobalt, 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 Co. 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 Co, 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. |
|---|---|---|---|---|---|
| Fm-3m (No. 225) | cubic | 0.00 | 0.0000 | -13.234 | 9.03 |
| P-3m1 (No. 164) | trigonal | 0.00 | 0.0101 | -13.224 | 8.99 |
| P63/mmc (No. 194) | hexagonal | 0.00 | 0.0106 | -13.224 | 9.16 |
| P63/mmc (No. 194) | hexagonal | 0.00 | 0.0251 | -13.209 | 9.20 |
| Im-3m (No. 229) | cubic | 0.00 | 0.0896 | -13.145 | 8.87 |
| P63mc (No. 186) | hexagonal | 0.00 | 0.1177 | -13.117 | 8.69 |
| P42/mnm (No. 136) | tetragonal | 0.00 | 0.1192 | -13.115 | 8.77 |
| Fd-3m (No. 227) | cubic | 0.00 | 0.1993 | -13.035 | 8.82 |
| No. 0 | unknown | — | — | — | 4.42 |
| No. 0 | unknown | — | — | — | 1.72 |
| No. 0 | unknown | — | — | — | 4.25 |
| No. 0 | unknown | — | — | — | 4.35 |
Synthesis Routes
Literature-extracted synthesis procedures targeting Co.
Applications
Where Cobalt is used.
Frequently Asked Questions
Common questions about Cobalt, answered from cross-validated data.
What is Co?
Cobalt is a stable, metallic transition element widely utilized for its magnetic properties and its role in creating durable, heat-resistant alloys.
What is Co used for?
What is the band gap of Co?
Is Co a metal, semiconductor, or insulator?
Is Co thermodynamically stable?
What is the crystal structure of Co?
What is the density of Co?
How many polymorphs of Co are known?
How is Co synthesized?
What elements does Co contain?
Where does the data for Co come from?
How It Compares
As a pure elemental metal, cobalt serves as a foundational reference point for metallic systems, providing the essential magnetic and structural characteristics that define its utility in high-strength alloys compared to other transition metal elements.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- cod — Data from the Crystallography Open Database. Cite: Grazulis et al., Nucleic Acids Res. 40, D420 (2012).
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