3.1: Introduction to stereochemistry Isomerism and the basic classification of isomers are described. 3.2: Confirmations Representing conformations of simple organic molecules, including ethane and butane, by Sawhorse and Newman projections, drawing chair conformations of cyclohexane and substituted cyclohexane, and relative stability of the conformational isomers are described. 3.3: Configurations Perspective drawing, Fisher projections, CIP rules for assigning R/S stereodescriptors, D/S stereodescriptors, and stereochemical relationships, including enantiomers, diastereomers, and meso are described.