. "constitutive isomeric" . "isomers" . "isomer" . "regularity" . "Metamere" . "Photoisomerism" . . "''trans-cis'' isomerism" . "constitution" . "isomeric" . "isomerizing" . "chemical isomer" . "chemical isomerism" . . . . . "isomerism" . "Isomer" . "Isomerism" . "isomeric forms" . "diastereoisomers" . . . "optical isomers" . "isomerizes" . "isomerize" . "Isomer" .