FGROUP by class
Carbon Carbon skeleton Hydrocarbon ring N-heterocyclic O-heterocyclic Monocyclic 5-membered Saturated Tetrahydrofuran (F231511) Furanose (F231512) S-heterocyclic Mixed-heterocyclic Oxygen Nitrogen Sulfur Phosphorus Halogen Boron Magnesium Silicon Iron Cobalt Asenic Selenium Tin