It is a chemical element with an atomic number 27. It has a standard atomic weight of 58.933 and it is represented by the symbol Co. It could be found in group 9 and period 4 of the periodic table. It is a d-block element and its electronic configuration is 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d7. There are 27 electrons, 27 protons and 32 neutrons in an electrically neutral cobalt atom. Its electronegativity is 1.88 (Pauling scale). Its oxidation states maybe −3, −1, 0, +1, +2, +3, +4, +5 depending on the bonding atom properties. Cobalt has 28 radioisotopes and only one naturally occurring stable isotope, Cobalt-59.

At STP it is solid while its melting point is 1768 K ?(1495 °C, ?2723 °F) and its boiling point is 3200 K ?(2927 °C, ?5301 °F). It was isolated and discovered by Swedish chemist Georg Brandt in 1735. It has a hard lustrous bluish-grey appearance. In the Earth's crust, it could be chemically bound with other metals and elements. Most of the cobalt ores are coming from the Democratic Republic of Congo and Zambia. They are accounting for 63% of cobalt production. It is used in ion batteries and the manufacture of magnet and high-strength alloys. Other uses can be found in blue ceramics, inks and paints etc. Cobalt-60 is used as a radioactive tracer and high energy gamma rays production. It is a vital part and a cofactor of cobalamins (vitamin B12) and a micronutrient for algae and bacteria.

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What is cobalt used for?

Cobalt has a wide range of uses. Some of the following are,


Cobalt is used in ceramics and paintings for blue colouring. It is used since the Middle ages to make a blue colour cobalt glass called smalt. Other pigments and colouring of cobalt are cerulean blue (cobalt(II) stannate) and cobalt blue (cobalt aluminate) etc.


Cobalt-60 is used in high gamma rays production. It is used in the sterilization of medical waste and medical supplies. It is also used in external beam radiotherapy.


Lithium cobalt oxide (LiCoO2) is used in lithium-ion batteries. The material is layered with cobalt oxide layers. Most cobalt is used in mobile batteries but for electric vehicles, its demand increased 81% since 2018. Most of the cobalt is coming from mines in DRC Congo.


Cobalt alloys are some of the high-performance alloys. It is used in aircraft jet engine and turbine blades. Cobalt alloys are corrosive resistant. Vitallium a special cobalt-chromium-molybdenum alloy is used in prosthetic parts. Other uses of Cobalt alloy can be found in dental prosthetics.