FGROUP by class
Carbon Carbon skeleton Hydrocarbon ring Dicyclic 6+6-membered Fully aromatic Naphthalene (F212341) Naphthoquinone (F212342) N-heterocyclic O-heterocyclic S-heterocyclic Mixed-heterocyclic Oxygen Nitrogen Sulfur Phosphorus Halogen Boron Magnesium Silicon Iron Cobalt Asenic Selenium Tin