FGROUP by class
Carbon Carbon skeleton Hydrocarbon ring N-heterocyclic O-heterocyclic S-heterocyclic Mixed-heterocyclic Oxygen Ether (F320000) Alkyl ether (F321000) Hemiacetal Ether (F321400) Acetal (F321400) Hemiketal Ether (F321500) Ketal (F321500) Allyl ether (F322000) Aryl ether (F323000) Acetylene ether (F324000) Nitrogen Sulfur Phosphorus Halogen Boron Magnesium Silicon Iron Cobalt Asenic Selenium Tin