 The unusual high volatility of the metal compound nickel tetracarbonyl led Kelvin with the statement that Mond had "given wings to the heavy metals".The following year, Mond and Marcellin Berthelot independently discovered iron pentacarbonyl, which is produced by a similar procedure as nickel tetracarbonyl.Mond recognized the economic potential of this class of compounds, which he commercially used in the Mond process and financed more research on related compounds.