FGROUP by class
Carbon Carbon skeleton Hydrocarbon ring N-heterocyclic O-heterocyclic S-heterocyclic Mixed-heterocyclic Oxygen Nitrogen Sulfur Sulfenate (F571000) Sulfenic acid (F571100) Sulfenate ester (F571200) Phosphorus Halogen Boron Magnesium Silicon Iron Cobalt Asenic Selenium Tin