Asymmetrically substituted C atom

In organic stereochemistry the terms center of chirality or center of asymmetry are often used usually they refer to an asymmetrically substituted C atom. These terms should be avoided since they are contradictions in themselves a chiral object by definition has no center (the only kind of center existing in symmetry is the inversion center). 

Chinese gallotannin see Tannins Chirality the necessary and sufficient condition for optical activity (rotation of the plane of polarized light). C. means handedness (from the Greek Kelp = hand). Chiral molecules have no second order symmetry element (center, plane or axis of symmetry) and exist in two mirror-image forms (enantiomers) which cannot be rotated in such a way as to coincide. Most chiral compounds contain an asymmetrically substituted C-atom, i.e. a tetrahedral C-atom with 4 different substituents [E.L.EIiel, S.H.Wilen L.N.Mander Stereochemistry of Organic Compounds, Wiley Sons New York, 1994]... 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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