Co
58.933Cobalt
Kobalt
Cobalt is a transition metal with atomic number 27. It is important in vitamin B12, lithium-ion batteries, superalloys, blue pigments, permanent magnets and cobalt-60 radiation sources.
27
58.933 g/mol
[Ar] 3d⁷ 4s²
2 | 8 | 15 | 2
1.88
8.9 g/cm³
1494.8 °C
2926.8 °C
Georg Brandt
Cobalt was identified as a distinct metal by Georg Brandt in the 18th century. Its name comes from the German Kobold, a mining goblin, because cobalt ores confused miners and often released harmful arsenic fumes.
Cobalt-59
Natural abundance: 100%. The only stable naturally occurring isotope of cobalt.Cobalt-60
Natural abundance: Synthetic. Half-life: About 5.27 years. Radioactive gamma emitter used in medicine, sterilization and radiography.CoO
Cobalt(II) OxideCeramic and glass pigment source.CoCl₂
Cobalt(II) ChlorideHumidity indicator that changes color when hydrated.CoAl₂O₄
Cobalt AluminateStable cobalt blue pigment for ceramics, glass and paints.LiCoO₂
Lithium Cobalt OxideRechargeable lithium-ion battery cathode material.Co₂(CO)₈
Dicobalt OctacarbonylOrganometallic catalyst and cobalt carbonyl chemistry reagent.- Lithium cobalt oxide cathodes in rechargeable lithium-ion batteries
- Superalloys for jet engines and high-temperature turbine parts
- Cobalt blue pigments for glass, ceramics and art materials
- Cobalt-60 gamma sources for radiotherapy, sterilization and industrial radiography
- Permanent magnets such as samarium-cobalt and Alnico alloys
Cobalt is essential as the central metal in vitamin B12, also called cobalamin. Vitamin B12 is needed for red blood cell formation, DNA synthesis and nervous system function.
- Vitamin B12 is the best-known cobalt-containing biomolecule.
- Cobalt blue pigments have been valued in glass and ceramics for centuries.
- Anhydrous cobalt(II) chloride is blue, while hydrated cobalt chloride is pink, so it has been used as a humidity indicator.
- Cobalt-60 emits strong gamma rays and must be handled with strict radiation controls.
- Cobalt demand is linked to rechargeable batteries and high-performance alloys.
- Cobalt has atomic number 27 and belongs to group 9.
- Its electron configuration is [Ar] 3d⁷ 4s².
- Common oxidation states include +2 and +3.
- Cobalt in vitamin B12 is an example of a transition metal with a direct biological role.
What is the atomic number of cobalt?
The atomic number of cobalt is 27.
What is the electron configuration of cobalt?
Cobalt has the electron configuration [Ar] 3d⁷ 4s².
What is cobalt used for?
Cobalt is used in lithium-ion batteries, superalloys, blue pigments, magnets, radiotherapy sources and sterilization.
Why is cobalt important in vitamin B12?
Cobalt is the central metal in vitamin B12, which is needed for DNA synthesis, red blood cell formation and nerve function.
What is cobalt-60 used for?
Cobalt-60 is a gamma-emitting radioisotope used in cancer radiotherapy, medical sterilization and industrial radiography.
Why does cobalt chloride change color with humidity?
Anhydrous cobalt(II) chloride is blue, but it turns pink when hydrated, so the color change can indicate moisture.
What is lithium cobalt oxide?
Lithium cobalt oxide, LiCoO₂, is a common cathode material in rechargeable lithium-ion batteries.