Cobalt (Co) — Element 27: Properties & Data | Aladdin Scientific
Cobalt(Co) — Element 27
Cobalt (Co) is a transition metal with atomic number 27 and atomic mass 58.9332. It has melting point 1768 K (1495 °C), boiling point 3200 K (2927 °C), density 8.86 g/cm³. It sits in group 9 and period 4 of the periodic table and was discovered in 1735.
Key facts
| Atomic mass | 58.9332 u |
|---|---|
| Electron configuration | [Ar]4s2 3d7 |
| Oxidation states | +3, +2 |
| Electronegativity (Pauling) | 1.88 |
| Atomic radius (van der Waals) | 192 pm |
| Ionization energy | 7.881 eV |
| Electron affinity | 0.661 eV |
| Melting point | 1768 K |
| Boiling point | 3200 K |
| Density | 8.86 g/cm³ |
| Standard state | Solid |
| Year discovered | 1735 |
Frequently asked questions
What is the electron configuration of cobalt?
The ground-state electron configuration of cobalt is [Ar]4s2 3d7.
What group and period is cobalt in?
Cobalt (Co) is in group 9 and period 4 of the periodic table, classified as a transition metal.
What is the melting point of cobalt?
Cobalt melts at 1768 K (1495 °C).
What is the standard state of cobalt?
Cobalt is a solid at standard temperature and pressure.
Related elements
About this data: property values compiled from IUPAC Standard Atomic Weights (2021), the NIST Atomic Spectra Database, and PubChem. Curated by the Aladdin Scientific technical team. Last reviewed: .