I have read that the conformations of butane are as follows:

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I came across a question about number of chiral conformations of butane.

My Attempt :

  1. The total or fully eclipsed is achiral because it has a plane of symmetry passing through the two methyl groups.
  2. The gauche form is chiral as it neither has a plane of symmetry nor a centre of symmetry.
  3. The anti form is also achiral as it has a centre of symmetry

But I am unsure about the eclipsed also known as the partially eclipsed form as it seems chiral to me but on searching on the net, I find that only the gauche form is chiral.

Any help would be greatly appreciated !

  • $\begingroup$ They can’t really be chiral, as they’re not stable. The barrier to rotation is so low that the conformations are constantly changing $\endgroup$
    – NotEvans.
    Aug 1, 2021 at 7:57
  • 1
    $\begingroup$ @NotEvans. they are interchangeable at room temperature but maybe if we could create conditions in which they would not be interchangeable, then I guess we could comment on their chirality. $\endgroup$
    – Nil
    Aug 1, 2021 at 8:17


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