Cobalt "goblin", a superstitious term used for the ore of cobalt by miners. The first attempts to smelt those ores for copper or nickel failed, yielding simply powder (cobalt(II) oxide) instead. Because the primary ores of cobalt always contain arsenic, smelting the ore oxidized the arsenic into the highly toxic and volatile arsenic oxide, adding to the notoriety of the ore. Swedish chemist Georg Brandt (1694–1768) is credited with discovering cobalt circa 1735, showing it to be a previously unknown element, different from bismuth and other traditional metals. Brandt called it a new "semi-metal". He showed that compounds of cobalt metal
Cobalt(II) nitrate or one of its oxides, hydroxides, or carbonate with nitric acid: 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