As per my knowledge, hyperconjugation is more dominating over inductive effect, so due to three alpha hydrogen ethyl carbocation should be more stable. In some books, while solving questions I observed that answers can match if I take neopentyl carbocation as more stable.

so which one of them is comparatively more stable?

  • 4
    $\begingroup$ Watch out: the ethyl carbo cation is a nonclassical cation; under certain conditions it is better described as a protonated ethylene. Stability is also a relative concept, which can't be applied to molecular ions/entities in an absolute manner. $\endgroup$ May 25, 2018 at 10:10
  • $\begingroup$ Can you give specific examples? It may be possible that the underlying concept in some questions is not just the stability of the carbonation, for example, a kinetically controlled reaction... $\endgroup$
    – Abhigyan
    May 25, 2018 at 13:34

1 Answer 1


In that case ethyl carbocation has two alpha hydrogen atoms as CH2 is bonded to C+.And in case of neopentynyl carbocation CH3 is attached to C+ .more alpha hydrogen atoms ,more hyperconjugative structures,and more stability.and there are three donating groups in neopentynyl carbocation.these may be the reasons


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