3d image of dibenzo-18-crown-6 skeletal formula

dibenzo-18-crown-6 crown ether solvent 18-crown-6 catechol cyclic ring oligomers complexes cation catalysis complexing agent chelate effect substance matter material compound component stuff reagent functional group precursor reaction production building block molecule molecular formula skeletal structural structure geometry ball stick atom chemistry science scientific research organic chemical 3d iupac nomenclature name cas einecs fema