FGROUP by class
Carbon Carbon skeleton Hydrocarbon ring N-heterocyclic O-heterocyclic S-heterocyclic Mixed-heterocyclic Oxygen Nitrogen Sulfur Phosphorus Halogen Alkyl halide (F701000) Allyl halide (F702000) Acetylene halide (F703000) Carbonyl halide (F704000) Acyl halide (F704000) Aryl halide (F705000) Halo phosphate (F711000) Sulfenyl halide (F721000) Sulfonyl halide (F722000) Boron Magnesium Silicon Iron Cobalt Asenic Selenium Tin