Cobalt, element symbol Co, atomic number 27, atomic weight 58.9332, closely packed hexagonal crystal, located in the 4th period and 8th group of the periodic table, with common valences of +2 and +3.

Cobalt is a shiny steel-gray metal, hard and brittle, and ferromagnetic. When heated to 1 150℃, the magnetism disappears. It does not react with water at room temperature, but oxidizes to generate CoO when heated to above 300℃ in air, and burns to generate Co3O4 when heated in white heat.

1780, Swedish chemist T. Bergman made pure cobalt and determined that cobalt is a metal element.

1789, lavoisier listed it in the periodic table for the first time.

Discover history:

Cobalt About cobalt, China knew about it in the early days, and it was used in pottery glaze. The ancient Greeks and Romans used its compounds to make colored glass and produced beautiful dark blue. The blue color of China Tang Dynasty colored porcelain is also due to the existence of cobalt compounds. CoAsS is a blue ore containing cobalt, which was called kobalt in Europe in the Middle Ages. It first appeared in agricola's works. agricola was a German mineralogist who lived in the Czech Republic in the16th century. The word originally meant "devil" in German.

This may be because it was considered useless at that time, because arsenic in cobalt iron ore was harmful to workers' health. Today, the Latin name of cobaltum and the symbol of Co element come from the word "devil" in German, which is due to people's ignorance of new things at that time. 1753, Swedish chemist G.Brandt separated light rose metal from cobaltate, which is a kind of high-purity metallic cobalt. Therefore, Brent is considered as the discoverer of cobalt.