Chemistry - STEREO ISOMERISM Question with Solution | TestHub
What is meant by operators in terms of elements of symmetry ? What is order of symmetry operation ? Show the symmetry operators of chair form of cyclohexane.
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Ans. The order of the symmetry operations of the chair form of cyclohexane is 12 : E, C31, C32, 3C2, 3σd, i, S61 and S65.
Sol. If a structure of a molecule can be transformed into an identical or indistinguishable structure by a physical movement based on an element of symmetry, without breaking or deforming any part of the molecule, then that manipulation is called a symmetry operation. The order of a symmetry operation is the total number of operations that convert a structure into its equivalent/identical structure.
The chair form of cyclohexane belongs to the point group D3d. Its elements of symmetry are C3, 3C2, 3σd (diagonal planes), i and S6; the identity E is also a symmetry operation. Two successive C3 operations followed by a third give the identity (C33 = E), and five successive S6 operations followed by a sixth give the identity (S66 = E). Therefore the complete set of symmetry operations of chair cyclohexane is E, C31, C32, 3C2, 3σd, i, S61 and S65 : 12 in all.
