FGROUP by class
Carbon Carbon skeleton Hydrocarbon ring N-heterocyclic O-heterocyclic S-heterocyclic Mixed-heterocyclic Oxygen Nitrogen Sulfur Phosphorus Phosphite (F630000) Phosphic acid (F631000) Phosphite diester (F632000) Phosphite triester (F633000) Halogen Boron Magnesium Silicon Iron Cobalt Asenic Selenium Tin