Relative atomic mass: 58.933195 +- 0.000005

English: Cobalt
French: Cobalt
Croatian: Kobalt
German: Cobalt
Italian: Cobalto
Spanish: Cobalto

Atomic number: 27
Group numbers: 9
Period: 4
Standard state (20 oC): solid

Discovery: 1739 Georg Brandt (DE)
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. The price of 99.9 % pure cobalt pieces is 171.20 for 500 g.
Electronic configuration: [Ar] 3d7 4s2
Formal oxidation number: +2 +3
Atomic radius: 125.3 pm

Electronegativities: 1.88
Thermal conductivity: 100 W/(m K)
Electrical resistivity (20 oC): 6.24 microOhm cm

Melting point: 1495 oC
Boiling point: 2927 oC

Heat of fusion: 15.2 kJ/mol
Heat of vaporization: 382.4 kJ/mol
Heat of atomization: 423.082 kJ/mol

26Fe <= 27Co => 28Ni

ASCII Periodic Table of the Elements
6 Jan. 2020
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