The Two Odors of Iron when Touched or Pickled: (Skin) Carbonyl Compounds and Organophosphines

The smell of money and chemical weapons: The perplexing metallic odor from touching iron tools or coins (see picture) is a type of human body odor linked to the decomposition of skin peroxides. Fe2+ ion containing rust, drinking water, and blood all cause a similar metallic odor. Another "garlic" metallic odor, that of phosphorus-alloyed iron under acid attack, is caused by organophosphines, including C–P compounds which are monitored under the Chemical Weapons Convention.