Plane of symmetry A plane of symmetry bisects a molecule into two mirror image halves.Chlorodifluoromethane has a plane of symmetry
Plane of symmetry A plane of symmetry bisects a molecule into two mirror image halves. 1-Bromo-1-chloro-2-fluoroethene has a plane of symmetry
Mirror Planes of Symmetry If two groups are the same,carbon is achiral.(animation) A molecule with an internal mirror plane cannot be chiral.* Caution!If there is no plane of symmetry,molecule H may be chiral or H achiral.See if CI mirror image can be CI superimposed. internal mirror plane of symmetry (o)
Center of symmetry A point in the center of the molecule is a center of symmetry if a line drawn from it to any element, when extended an equal distance in the opposite direction,encounters an identical element
手性与分子结构关系 冬手性、对称性与旋光性 ,有反映对称性的分子：物象重合，不具有旋光性，非手性分子 无对称性的分子：物象不重合，有旋光性，手性分子 必手性碳与手性分子二者关系 ,有手性碳的分子不一定就是手性分子 手性分子并不一定就含有手性碳 •只有一个手性碳的分子一定就是手性分子 必构型与旋光性 分子结构的不对称性导致，物象不重合；二者主要差异在于构 型不同； 必对称性、不对称性与手性： 对称因素：对称面（σ）；对称中心() ,凡是没有反映对称性的分子称为手性分子 不对称性：找不到任何一个对称因素的分子；手性是不对称性 之一种