Cobalt

Description

Cobalt was discovered by George Brandt in 1737. Cobalt exists in valence states from 0 to 5, with the most stable (+2 and +3) being the most common. Although there is only one stable isotope of cobalt, there are a number of unstable isotopes. Two of these, cobalt-60 and cobalt-57, are in use commercially. Cobalt-60 is used for cancer treatment and food irradiation. Cobalt-57 has research applications.

The Uses of Cobalt

Cobalt has many practical uses.Historically, as well as today, different compounds of cobalt have been used for their colorsknown as cobalt blue, cerulean, new blue, smalt, cobalt yellow, and green.For many centuries cobalt was used to color glass, pottery, and porcelain and as an enamel.It is also used as a dye and paint pigment.As mentioned, cobalt alloyed with iron and nickel is used to make powerful permanentmagnets that are used in many industries.A major use is as an alloy with chromium to produce high-speed machine-cutting toolsthat are resistant to high temperatures.A cobalt alloy of copper and tungsten, called “stellite,” also maintains its hardness at hightemperatures, making it an ideal alloy for high-speed drills and cutting tools.The radioisotope cobalt-60, with a half-life of 5.27 years (1925.3 days) through beta (β)emission, decays to form the stable element nickel-60. It is used to test welds and metal castsfor flaws, to irradiate food crops to prolong freshness, as a portable source of ionizing gamma(γ) radiation, for radiation research, and for a medical source of radiation to treat cancers andother diseases.Cobalt is an important trace element for proper human nutrition. It is also a natural component of vitamin B12.

Background

A trace element that is a component of vitamin B12. It has the atomic symbol Co, atomic number 27, and atomic weight 58.93. It is used in nuclear weapons, alloys, and pigments. Deficiency in animals leads to anemia; its excess in humans can lead to erythrocytosis. Except for radioactive forms of cobalt and cobalamin, the FDA withdrew its approval for the use of drug products containing cobalt salts.

Metabolism

Not Available