6: Stereoisomerism

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6.1: Chirality
Chiral carbons are tetrahedral carbons bonded to four unique groups. At first glance, many carbons may look alike, but upon closer inspection, we can discern their differences.
6.2: Fischer Projections to communicate Chirality
Converting between perspective formula structures (wedges and dashes) and Fischer projections can be useful when evaluating stereochemistry, especially for carbohydrate chemistry.
6.3: Absolute Configuration and the (R) and (S) System
The absolute configuration of chiral centers as R or S is determined by applying the Cahn-Ingold-Prelog rules.
6.4: Diastereomers - more than one chiral center
Diastereomers are stereoisomers with two or more chiral centers that are not enantiomers. Diastereomers have different physical properties (melting points, boiling points, and densities). Depending on the reaction mechanism, diastereomers can produce different stereochemical products.
6.5: Meso Compounds
A meso compound is an achiral compound that has two or more chiral centers. Molecular symmetry allows the mirror images to super-impose so that they are not enantiomers.
6.6: Isomerism Summary Diagram
A simple diagram is helpful in distinguishing between the different types of isomers that are possible.
6.7: Optical Activity and Racemic Mixtures
Optical activity is one of the few ways to distinguish between enantiomers. A racemic mixture is a 50:50 mixture of two enantiomers. Racemic mixtures were an interesting experimental discovery because two optically active samples were combined to create an optically INACTIVE sample.
6.8: Resolution (Separation) of Enantiomers
The most commonly used procedure for separating enantiomers is to convert them to a mixture of diastereomeric salts that can be separated based on their differences in their physical properties. After separation, the isolated D or the L enantiomer can be recovered.