3d image of chromane skeletal formula

chromane benzodihydropyran benzoxane heterocyclic chemical compound c9h10o vitamins tocopherols tocotrienols dianin's pharmaceutical drugs troglitazone ormeloxifene nebivolol aromatic aromaticity heterocycle polycyclic ring substance matter material component agent stuff reagent functional group precursor synthesis reaction production building block molecule molecular formula skeletal structural structure geometry ball stick chemistry science scientific research organic chemical 3d isomer