Cobalt
Cobalt (钴, symbol Co) is chemical element number 27, a Transition Metal in period 4, group 9 of the periodic table, with a standard atomic weight of about 58.933. Hard, lustrous, silver-gray metal. Used in rechargeable batteries and superalloys.
Properties
| Atomic number | 27 |
|---|---|
| Symbol | Co |
| Atomic mass | 58.933 u |
| Category | Transition Metal |
| Period | 4 |
| Group | 9 |
| Electron configuration | [Ar] 3d⁷ 4s² |
| Electronegativity | 1.88 |
| Covalent radius | 126 pm |
| Density | 8.86 g/cm³ |
| Melting point | 1768 K |
| Boiling point | 3200 K |
| Discovery | Georg Brandt, 1735 |
Overview
Hard, lustrous, silver-gray metal. Used in rechargeable batteries and superalloys. Cobalt (Co) holds position 27 in the periodic table, a Transition Metal in period 4, group 9. As a transition metal it commonly shows several oxidation states, forms coloured compounds, and is widely used in catalysts and alloys.
It has the configuration [Ar] 3d⁷ 4s² and an electronegativity near 1.88; its 2 outer-shell electrons drive its bonding. Under standard conditions it exists as a solid; it melts near 1768 K (1494.9 °C), boils near 3200 K (2926.9 °C), has a density around 8.86 g/cm³.
It is widely used in Energy / Batteries, Pigments / Glass and Medical / Pharma. On the safety side, it carries a moderate hazard rating. It was first described by Georg Brandt in 1735. See more trends in the visualization center.
Electron shells
Electrons per shell: 2 · 8 · 15 · 2
Main uses
- Energy / Batteries
- Pigments / Glass
- Medical / Pharma
Hazard
Compounds containing Cobalt
No compounds in this knowledge base contain Cobalt yet.
Data sources
Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.