Cobalt are faced by cobalt miners. Cobalt can be effectively absorbed by charred pigs' bones; however, this process is inhibited by copper and zinc, which have greater affinities to bone char. 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
Cobalt blue), cobalt(II) bromide (CoBr, green), cobalt(II) iodide (CoI, blue-black). These halides exist in anhydrous and hydrated forms. Whereas the anhydrous dichloride is blue, the hydrate is red. The reduction potential for the reaction + e → is +1.92 V, beyond that for chlorine to chloride, +1.36 V. Consequently, cobalt(III) and chloride would result in the cobalt(III) being reduced to cobalt(II). Because the reduction potential for fluorine to fluoride is so high, +2.87 V, cobalt(III) fluoride is one of the few simple stable cobalt(III) compounds. Cobalt(III) fluoride, which is used in some fluorination reactions, reacts vigorously with water. As for all