27
Co
cobalt
58.933

General properties

Group
group 9
Period
period 4
Category
transition metals
Standard atomic weight
58.933 194(3)
Melting point
1768 K (1495 °C)
Boiling point
3200 K (2927 °C)
Phase at STP
solid

Additional properties

Block
d-block
Electron configuration
[Ar] 3d⁷ 4s²
Electrons per shell
2, 8, 15, 2
Electronegativity
1.88
Density
8.90 g/cm³
Oxidation states
−3, −1, 0, +1, +2, +3, +4, +5 (an amphoteric oxide)
CAS Number
7440-48-4