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- Name : Cobalt
- Symbol : Co
- Atomic # : 27
- Atom weight: 58.9332
- Melting P. : 1857
- Boiling P. : 2672
- Oxidation : +2, +3
- Pronounced : KO-bolt
- From : German kobold, "goblin"
- Identified : Compounds known in anicent times
- Appearance : Hard, ductile, lustrous bluish-gray metal
- Note : A fourth of the world's cobalt production goes into making
- powerful permanent magnets
-
- [Properties]
-
- Cobalt is a silvery-white, brittle metal that has a slight bluish color
- when polished. Cobalt stands between iron (Fe) and nickel (Ni) on the
- periodic table. These three metals are similar in many respects and are
- usually found together in ore deposits.
- This element is best known for its remarkable magnetic properties. Like
- iron, cobalt is easily magnetized and readily retains its magnetism under
- a wide range of environmental conditions. In fact, one-fourth of the
- world's cobalt production is used in a "super magnet" alloy known as
- alnico, aluminum-nickel-cobalt.
- Cobalt has the highest Curie point of any known metal or alloy. The
- Curie point is the temperature at which a metal loses its magnetic
- properties, usually just a bit below the melting point. In the case of
- Cobalt, the Curie point is 1121 degrees.
- Cobalt has two common allotropes. The one that is stable at room
- temperature, the beta form, has a close-packed hexagonal crystalline
- structure. Teh transition to the alpha form, one having a face-centered
- cubic structure, takes place at about 417 degrees.
-