Molecular configuration

The molecular configuration of a molecule is the permanent geometry that results from the spatial arrangement of its bonds.[1] The ability of the same set of atoms to form two or more molecules with different configurations is stereoisomerism.This is distinct from constitutional isomerism which arises from atoms being connected in a different order.Amino acids are designated either L or D depending on relative group arrangements around the stereogenic carbon center.[4] In general, all L designated amino acids are enantiomers of their D counterparts except for isoleucine and threonine which contain two carbon stereocenters, making them diastereomers.
R-S isomerism of thalidomide. Chiral center marked with a star(*). Hydrogen (not drawn) is projecting behind the chiral centre.
Assignment of E and Z isomerism based on group priority.
L vs D configuration of amino acids
moleculespatialstereoisomerismconstitutional isomerismConformersatropisomersEnantiomerschiralR or SDiastereomersZ or EAmino acidsAbsolute configurationStereochemistryChiralityRacemic mixtureConfiguration descriptorscis–trans isomerismE–Z notationArene substitution patternEndo-exo isomerismSyn and anti additionSecondarytertiarySpiro compoundCatenaneAbsolute configurationsCIP (Cahn–Ingold–Prelog) priority rules