27 Co Cobalt 58.933
Transition metal
Cobalt 钴
[Ar] 3d⁷ 4s²
- Period 4
- Group 9
- Block d
- Solid
Electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁷ 4s²
Orbital diagram (valence)
3d ↑↓↑↓↑↑↑
4s ↑↓
- Electrons per shell
- 2, 8, 15, 2
- Unpaired electrons
- 3
- Zeff (Slater)
- 3.90
Properties
- Atomic weight
- 58.933
- Electronegativity (Pauling)
- 1.88
- First ionization energy
- 760.4 kJ/mol
- Electron affinity
- 63.78 kJ/mol
- Covalent radius
- 126 pm
- van der Waals radius
- 192 pm
- Melting point
- 1768 K
- Boiling point
- 3200 K
- Density
- 8.86 g/cm³
- Melting / boiling point
- 1494.8 °C / 2926.8 °C
- Common oxidation states
- +3, +2
- Discovered
- 1735
Natural isotopes
| Mass number A | Abundance |
|---|---|
| 59Co | 100.00 % |
Isotope masses: AME2020; abundances: IUPAC/CIAAW representative values.
Cobalt in the course
The lessons that discuss this element most (ranked by mentions).
- Complexes and ligands Coordination chemistry
- Geometry and isomerism Coordination chemistry
- Le Chatelier’s principle: how equilibria respond Chemical equilibrium
- Batteries: chemistry that stores charge Redox and electrochemistry
- Symmetry, distortion and the Jahn–Teller effect Coordination chemistry
- Colour and the spectrochemical series Coordination chemistry
- Ligand substitution: labile and inert Coordination chemistry
- Catalysts and materials Transition metals
Lab experiments with Cobalt
Periodic trend
Group 9
Data: PubChem periodic table (public domain); atomic weights are IUPAC abridged standard values; covalent radii from Cordero et al. (2008).