cobalt

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Symbol:

Co

Atomic Number:

27

Relative Atomic Mass:

58.933200 g mol^-1

Natural Abundance in Lithosphere, hydrosphere and atmosphere:

4 x 10^-3% (mass fraction)

Electron Configuration:

[Ar]3d⁷4s²

Oxidation States:

III, II, 0, -I

Atomic Radius:

125.3pm

Covalent Radius:

116pm

Ionic Radius:

61pm (for +3 oxidation state)

75pm (for +2 oxidation state)

(Values are for high-spin complexes)

Melting Point:

1495°C

Density:

8.89 g cm^-3 (at 20°C)

First Ionisation Energy:

7.86 eV

Reduction Potential:

-0.28V

for Co²⁺ +2e^- a Co_(s)

Electronegativity (Allred and Rochow):

1.7

Number of Natural Isotopes:

1

Mass Number of the Most Abundant Isotopes:

59 g mol^-1 a 100% abundance