FGROUP by class
Carbon Carbon skeleton 1 carbon Saturated Unsaturated Acyl Carboxylate Formimino Methenyl Ketimine Hydrocarbon ring N-heterocyclic O-heterocyclic S-heterocyclic Mixed-heterocyclic Oxygen Nitrogen Sulfur Phosphorus Halogen Boron Magnesium Silicon Iron Cobalt Asenic Selenium Tin