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| General
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| Name, symbol, number
| cobalt, Co, 27
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| Chemical series | transition metals |
| Group, period, block
| 9, 4, d
|
| Appearance | metallic with gray tinge
Image:Cobalt-sample.jpg
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| Standard atomic weight | 58.933195(5) g·mol−1
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| Electron configuration | [Ar] 3d7 4s2
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| Electrons per shell | 2, 8, 15, 2
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| Density (near r.t.) | 8.90 g·cm−3 |
| Liquid density at m.p. | 7.75 g·cm−3 |
| Melting point | 1768 K
(1495 °C, 2723 °F) |
| Boiling point | 3200 K
(2927 °C, 5301 °F) |
| Heat of fusion | 16.06 kJ·mol−1 |
| Heat of vaporization | 377 kJ·mol−1 |
| Heat capacity | (25 °C) 24.81 J·mol−1·K−1 |
Vapor pressure
| P/Pa | 1 | 10 | 100 | 1 k | 10 k | 100 k
|
| at T/K | 1790 | 1960 | 2165 | 2423 | 2755 | 3198
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| Atomic properties
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| Crystal structure | hexagonal |
| Oxidation states | 2, 3
(amphoteric oxide) |
| Electronegativity | 1.88 (Pauling scale) |
Ionization energies
(more)
| 1st: 760.4 kJ·mol−1
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| 2nd: 1648 kJ·mol−1
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| 3rd: 3232 kJ·mol−1
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| Atomic radius | 135 pm |
| Atomic radius (calc.) | 152 pm |
| Covalent radius | 126 pm |
| Miscellaneous
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| Magnetic ordering | ferromagnetic |
| Electrical resistivity | (20 °C) 62.4 nΩ·m |
| Thermal conductivity | (300 K) 100 W·m−1·K−1 |
| Thermal expansion | (25 °C) 13.0 µm·m−1·K−1 |
| Speed of sound (thin rod) | (20 °C) 4720 m/s |
| Young's modulus | 209 GPa |
| Shear modulus | 75 GPa |
| Bulk modulus | 180 GPa |
| Poisson ratio | 0.31 |
| Mohs hardness | 5.0 |
| Vickers hardness | 1043 MPa |
| Brinell hardness | 700 MPa |
| CAS registry number | 7440-48-4 |
| Selected isotopes
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| References
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