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(II) nitrate Cobalt(II) nitrate Cobalt Nitrate is the Inorganic compound with the formula Co(NO3)xHO. It is cobalt(II) salt. The most common form is the hexahydrate Co(NO)·6HO, which is a red-brown deliquescent salt that is soluble in water and other polar solvents. As well as the anhydrous compound Co(NO), several hydrates of cobalt(II) nitrate exist. These hydrates have the chemical formula Co(NO)·"n"HO, where "n" = 0, 2, 4, 6. Anhydrous cobalt(II) nitrate adopts a three-dimensional polymeric network structure, with each cobalt(II) atom approximately octahedrally coordinated by six oxygen atoms, each from a different nitrate ion. Each nitrate ion coordinates to three cobalts. The