Co
Cobalt
Atomic number: 27Mass: 58.933 uCategory: Transition Metal
About Cobalt
Cobalt is a hard, lustrous, silver-grey metal. It is ferromagnetic and is used to make permanent magnets. Cobalt compounds have been used since ancient times as blue pigments in glass and ceramics.
Properties
Period
4
Group
9
Block
D
Category
Transition Metal
Electronegativity
1.88 (Pauling)
Ionization Energy
760.4 kJ/mol
Melting Point
1768 K (1495°C)
Boiling Point
3143 K (2870°C)
Density
8.9 g/cm³
Oxidation States
+2, +3
Electron Configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁷ 4s²
[Ar] 3d⁷ 4s²
Shell 1:2e⁻
Shell 2:8e⁻
Shell 3:15e⁻
Shell 4:2e⁻
Real-World Uses
Lithium-ion batteries
Magnets
Blue pigment
Superalloys (jet engines)
Cancer radiation therapy
Fun Fact
Vitamin B12 — essential for your nervous system — contains cobalt at its core. It's the only vitamin with a metal in it!