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Subject - Organic Chemistry
Based on their behavior towards linear-polarized light, chemical compounds can be divided into two groups: they either rotate the plane of the light or they do not. Optically active compounds belong to the first group. Their behavior is caused by special symmetry properties inherent in their crystals or molecules. K. Mislow proposed to use the term chirality (handedness, from the Greek cheir, hand) which was coined in 1904 by Lord Kelvin for the molecular property that gives rise to the optical activity. V. Prelog deserves credit for mathematically embedding chirality into group theory. Like a hand, a molecule is chiral if it is non-superposable on its mirror image. Symmetry considerations are used to decide if a molecule is chiral or achiral.
See also: optical activity
Subject - General Chemistry
Molecular systems and other geometrical objects that exclusively allow rotations as symmetry operations are called dissymmetric or chiral.
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