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Torsional Strain

[ "article:topic", "authorname:ggunawardena" ]
  • Page ID
    40044
  • 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:

    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.