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Cobalt is a chemical element; it has symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, somewhat brittle, gray metal.
Georg Brandt (26 June 1694 – 29 April 1768) [1] [2] was a Swedish chemist and mineralogist who discovered cobalt c. 1735. He was the first person to discover a metal unknown in ancient times. He was the first person to discover a metal unknown in ancient times.
The first elemental metal with a clearly identifiable discoverer is cobalt, discovered in 1735 by Georg Brandt, by which time the Scientific Revolution was in full swing. [6] (Even then, cobalt might have been prepared before the 13th century by alchemists roasting and reducing its ore, but,in any case, its distinct nature was not recognised.) [7]
Perey discovered it as a decay product of 227 Ac. [177] Francium was the last element to be discovered in nature, rather than synthesized in the lab, although four of the "synthetic" elements that were discovered later (plutonium, neptunium, astatine, and promethium) were eventually found in trace amounts in nature as well. [178]
Cobalt(II) azide (Co(N 3) 2) is another binary compound of cobalt and nitrogen that can explode when heated. Cobalt(II) and azide can form Co(N 3) 2− 4 complexes. [9] Cobalt pentazolide Co(N 5) 2 was discovered in 2017, and it exists in the form of the hydrate [Co(H 2 O) 4 (N 5) 2]·4H 2 O. It decomposes at 50~145 °C to form cobalt(II) azide ...
Archaeologists discovered an ancient stone slab with 123 hieroglyphic symbols in Mexico, revealing the founding of a town in 569 AD and details about Maya rulers.
Cobalt is found in steel. Uncontrolled disposal of 60 Co in scrap metal is responsible for the radioactivity in some iron products. [15] [16] Circa 1983, construction was finished of 1700 apartments in Taiwan which were built with steel contaminated with cobalt-60. About 10,000 people occupied these buildings during a 9–20 year period.
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