FGROUP by class
Carbon Carbon skeleton Hydrocarbon ring N-heterocyclic O-heterocyclic S-heterocyclic Mixed-heterocyclic Oxygen Nitrogen Amine (F410000) Primary amine (F411000) Secondary amine (F412000) Tertiary amine (F413000) Quaternary ammonium (F414000) Hydroxylamine (F415000) Amine oxide (F416000) Hemiaminal (F419000) Sulfur Phosphorus Halogen Boron Magnesium Silicon Iron Cobalt Asenic Selenium Tin