Periodic table

 

 

Atomic number:27

Group numbers:9

Period:4

Electronic configuration:[Ar] 3d⁷ 4s²

Formal oxidation number:+2 +3

Electronegativities:1.88

Atomic radius / pm:125.3

Relative atomic mass:58.933195 ± 0.000005

 

Cobalt was discovered by Georg Brandt (DE) in 1739. The origin of the name comes from the German word kobald meaning goblin or evil spirit. It is a hard, ductile, lustrous bluish-grey metal and it's surfaces are stable in air. Cobalt reacts over time with dilute acids and has remarkable magnetic properties. Cobalt occurs in compounds with arsenic and sulfur as in cobaltine (CoAsS) and linneite (Co3S4). Pure cobalt is obtained as a by-product of refining nickel, copper and iron. Cobalt is used in many hard alloys; for magnets, ceramics and special glasses. Radioactive cobalt-60 is used in cancer therapy.

PHYSICAL PROPERTIES

Density / g dm^-3:8900 (293 K)

 7670 (m.p.)

Molar volume / cm³mol^-1:6.62 (293 K)

 7.68 (m.p.)

Electrical resistivity / μΩcm:6.24 (20 °C)

THERMAL PROPERTIES

Thermal conductivity / W m^-1K^-1:100

Melting point / °C:1495

Boiling point / °C:2927

Heat of fusion / kJ mol^-1:15.2

Heat of vaporization / kJ mol^-1:382.4

Heat of atomization / kJ mol^-1:423.082

IONIZATION ENERGIES

First ionization energy / kJ mol^-1:760.41

Second ionization energy / kJ mol^-1:1648.27

Third ionization energy / kJ mol^-1:3232.28

ABUNDANCE OF ELEMENTS

in the atmosphere / ppm:-

in the Earth's crust / ppm:29

in the oceans / ppm:0.0005

CRYSTALLOGRAPHIC DATA

ISOTOPES

REDUCTION POTENTIALS

 

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Citing this page:

Generalic, Eni. "Cobalt." EniG. Periodic Table of the Elements. 16 May 2013. KTF-Split. {Date of access}. <http://www.periodni.com/co.html>.