Cobalt Cobalt Cobalt is a chemical element with symbol Co and atomic number 27. Like nickel, cobalt is found in the Earth's crust only in 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, silver-gray metal. Cobalt-based blue pigments (cobalt blue) have been used since ancient times for jewelry and paints, and to impart a distinctive blue tint to glass, but the color was later thought by alchemists to be due to the known metal bismuth. Miners had long used the name "kobold ore" (German
Cobalt boride Cobalt boride nanoparticless in the size range of 18 to 22 nm have also been produced. When used as a catalyst, cobalt boride is prepared by reducing a cobalt salt, such as Cobalt(II) nitrate, with sodium borohydride. Prior to reduction, the surface area of the catalyst is maximized by supporting the salt on another material; often this material is activated carbon. Cobalt boride Cobalt borides are inorganic compounds with the general formula CoB. The two main cobalt borides CoB and CoB. These are refractory materials. Cobalt boride is known to be exceptionally resistant to oxidation, a chemical property which makes