SEARCH Articles Figures Tables Aromatic hydrocarbons structure Aromatic structures Aromaticity polycyclic aromatic hydrocarbons Aromatics structure Hydrocarbon structure Nitro polycyclic aromatic hydrocarbons structures Polycyclic aromatic hydrocarbons structural formulas Polycyclic aromatic hydrocarbons structure-activity relationship Polycyclic hydrocarbons aromatic Polycyclic structures