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Torsional Strain

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    40044
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    Torsional strain or eclipsing strain is the increase in potential energy of a molecule due to repulsion between electrons in bonds that do not share an atom.

    Consider two conformations of ethane:

    torsionalstrain.png

    The smallest dihedral angle is 60º in 1; it is 0º in 2. Thus, two C-H bonds not sharing a carbon atom that are closest to each other (ex: C-H1 and C-H4) are closer in 2 than in 1. The repulsion between electrons in bonds that do not share a carbon atom is, therefore, greater in 2 than in 1. Consequently, torsional strain is greater in 2 than in 1.


    This page titled Torsional Strain is shared under a All Rights Reserved (used with permission) license and was authored, remixed, and/or curated by Gamini Gunawardena via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.

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