5.1 The First Law of Thermodynamics, Enthalpy, and Phase Changes
|Chiral compounds have nonsuperimposable (non-identical) mirror images called enantiomers. Enantiomers have many of the same physical properties: b.p., m.p., polarity, etc. Chiral compounds are said to be optically active as they rotate plane-polarized light. A racemic mixture is a 50/50 mixture of enantiomers and is optically inactive.|
|Achiral compounds are superimposable (identical) with their mirror images. Achiral compounds are optically inactive as they do not rotate plane-polarized light.|
|Meso compounds are achiral but have chiral centers.|
|Diastereomers are nonsuperimposable (non-identical) non-mirror images. Diastereomers typically have different physical properties: b.p., m.p., polarity, etc.|
Chiral Centers and Chirality
Chiral centers are tetrahedral atoms (sp3 hybridized) with four different substituents.
-(a.k.a. chirality centers, asymmetric centers, stereogenic centers)