Carbonyl Nickel by the Mond Process: Mond, 1891

Ludwig Mond found that finely divided nickel combines with carbon monoxide below 150 °C into a volatile compound, nickel carbonyl (Ni(CO)4, a colourless liquid boiling at 43 °C), while the impurities in the ore are not acted on (not even the cobalt, Mond wrote) and stay behind. Heated to about 180 °C, the gas gives up pure nickel and the carbon monoxide, which is used again. His 1891 patent starts from nickel ores: roasted to oxide, reduced with a gas at 350–400 °C, then volatilised and deposited. The nickel made this way is known as carbonyl nickel. Nickel carbonyl is highly toxic.