Periodic Table of Elements

27

Cobalt

58.933

Cobalt was first discovered by Georg Brandt, a Swedish chemist, in 1735.

Name: Cobalt
Symbol: Co
Atomic number: 27
Atomic weight: 58.933
State: solid
Group, period, block: 9, 4, d
Color: hard lustrous gray metal
Classification: transition metal
Electron configuration: 4s2 3d7
2,8,15,2

Physical properties

Density: 8.90 g/cm-3
Melting point: 1768 K, 1495 C, 2723 F
Boiling point: 3200 K, 2927 C, 5301 F

Atomic properties

Oxidation states: 5, 4, 3, 2, 1, -1[2]
Electronegativity: 1.88 (Pauling scale)
Ionization energies: 1st: 760.4 kJmol-1
Covalent radius: 1263 (low spin), 1507 (high spin) pm
Van der Waals radius: no data
  • Co
  • Electron Configuration

Isotopes

There is only one naturally occurring isotope of cobalt exists, 59Co.