Stability of the carbocation increases with the number of alkyl groups bonded to the charge-bearing carbon. Tertiary carbocations are more stable (and form more readily) than secondary carbocations; primary carbocations are highly unstable because, while ionized higher-order carbons are stabilized by hyperconjugation, unsubstituted (primary) carbons are not. Therefore, reactions such as the SN1 reaction and the E1 elimination reaction normally do not occur if a primary carbocation would be formed. An exception to this occurs when there is a carbon-carbon double bond next to the ionized carbon. Such cations as "allyl" cation CH2=CH–CH2+ and "benzyl" cation C6H5–CH2+ are more stable than most other carbocations. Molecules which can form allyl or benzyl carbocations are especially reactive.
s t ə b ɪ l ɪ t i WORD_BOUNDARY ʌ v ð ə WORD_BOUNDARY k ɑ ɹ b ə k eɪ ʃ ə n WORD_BOUNDARY ɪ ŋ k ɹ iː s ɪ z WORD_BOUNDARY w ɪ ð ð ə WORD_BOUNDARY n ʌ m b ə ɹ ɹ WORD_BOUNDARY ʌ v WORD_BOUNDARY æ l k aɪ l WORD_BOUNDARY ɡ ɹ uː p s WORD_BOUNDARY b ɑ n d ɪ d WORD_BOUNDARY t ə WORD_BOUNDARY ð ə WORD_BOUNDARY t̠ʃ ɑ ɹ d̠ʒ b ɛ ɹ ɪ ŋ WORD_BOUNDARY k ɑ ɹ b ə n WORD_BOUNDARY t ɜː ʃ j ə ɹ ɹ i WORD_BOUNDARY k ɑ ɹ b ə k eɪ ʃ ə n z WORD_BOUNDARY ɑ ɹ WORD_BOUNDARY m ɔ ɹ WORD_BOUNDARY s t eɪ b ə l WORD_BOUNDARY æ n d WORD_BOUNDARY f ɔ ɹ m WORD_BOUNDARY m ɔ ɹ WORD_BOUNDARY ɹ ɛ d i l i WORD_BOUNDARY ð ʌ n WORD_BOUNDARY s ɛ k ə n d ə ɹ ɹ i WORD_BOUNDARY k ɑ ɹ b ə k eɪ ʃ ə n z WORD_BOUNDARY p ɹ aɪ m ə ɹ ɹ i WORD_BOUNDARY k ɑ ɹ b ə k eɪ ʃ ə n z WORD_BOUNDARY ɑ ɹ WORD_BOUNDARY h aɪ l i WORD_BOUNDARY ʌ n s t eɪ b ə l WORD_BOUNDARY b ɪ k ʌ z WORD_BOUNDARY w aɪ l WORD_BOUNDARY aɪ ə n aɪ z d WORD_BOUNDARY h aɪ ə ɹ ɹ ɔ ɹ d ə ɹ WORD_BOUNDARY k ɑ ɹ b ə n z WORD_BOUNDARY ɑ ɹ WORD_BOUNDARY s t eɪ b ɪ l aɪ z d WORD_BOUNDARY b aɪ WORD_BOUNDARY h aɪ p ə ɹ k ɑ n d̠ʒ uː ɡ eɪ ʃ ə n WORD_BOUNDARY ʌ n s ʌ b s t ɪ t uː t ɪ d WORD_BOUNDARY p ɹ aɪ m ə ɹ ɹ i WORD_BOUNDARY k ɑ ɹ b ə n z WORD_BOUNDARY ɑ ɹ WORD_BOUNDARY n ɑ t WORD_BOUNDARY ð ɛ ɹ f ɔ ɹ WORD_BOUNDARY ɹ ɪ æ k ʃ ə n z WORD_BOUNDARY s ʌ t̠ʃ WORD_BOUNDARY ʌ z WORD_BOUNDARY ð ɪ WORD_BOUNDARY ɛ s ɛ n WORD_BOUNDARY w ʌ n WORD_BOUNDARY ɹ ɪ æ k ʃ ə n WORD_BOUNDARY æ n d WORD_BOUNDARY ð ɪ WORD_BOUNDARY iː WORD_BOUNDARY w ʌ n WORD_BOUNDARY ɪ l ɪ m ɪ n eɪ ʃ ə n WORD_BOUNDARY ɹ ɪ æ k ʃ ə n WORD_BOUNDARY n ɔ ɹ m ə l i WORD_BOUNDARY d uː n ɑ t WORD_BOUNDARY ə k ɜː WORD_BOUNDARY ɪ f WORD_BOUNDARY ʌ WORD_BOUNDARY p ɹ aɪ m ə ɹ ɹ i WORD_BOUNDARY k ɑ ɹ b ə k eɪ ʃ ə n WORD_BOUNDARY w ʊ d WORD_BOUNDARY b iː WORD_BOUNDARY f ɔ ɹ m d WORD_BOUNDARY ʌ n WORD_BOUNDARY ɛ k s ɛ p ʃ ə n WORD_BOUNDARY t ə WORD_BOUNDARY ð ɪ s WORD_BOUNDARY ə k ɜː z WORD_BOUNDARY w ɛ n WORD_BOUNDARY ð ɛ ɹ WORD_BOUNDARY ɪ z WORD_BOUNDARY ʌ WORD_BOUNDARY k ɑ ɹ b ə ŋ k ɑ ɹ b ə n WORD_BOUNDARY d ʌ b ə l WORD_BOUNDARY b ɑ n d WORD_BOUNDARY n ɛ k s t WORD_BOUNDARY t ə WORD_BOUNDARY ð ɪ WORD_BOUNDARY aɪ ə n aɪ z d WORD_BOUNDARY k ɑ ɹ b ə n WORD_BOUNDARY s ʌ t̠ʃ WORD_BOUNDARY k æ t aɪ ə n z WORD_BOUNDARY æ z WORD_BOUNDARY æ l aɪ l WORD_BOUNDARY k æ t aɪ ə n WORD_BOUNDARY s iː eɪ t̠ʃ WORD_BOUNDARY t uː WORD_BOUNDARY iː k w ə l z WORD_BOUNDARY s iː eɪ t̠ʃ WORD_BOUNDARY s iː eɪ t̠ʃ WORD_BOUNDARY t uː WORD_BOUNDARY p l ʌ s WORD_BOUNDARY æ n d WORD_BOUNDARY b ɛ n z ɪ l WORD_BOUNDARY k æ t aɪ ə n WORD_BOUNDARY s iː WORD_BOUNDARY s ɪ k s WORD_BOUNDARY eɪ t̠ʃ WORD_BOUNDARY f aɪ v WORD_BOUNDARY s iː eɪ t̠ʃ WORD_BOUNDARY t uː WORD_BOUNDARY p l ʌ s WORD_BOUNDARY ɑ ɹ WORD_BOUNDARY m ɔ ɹ WORD_BOUNDARY s t eɪ b ə l WORD_BOUNDARY ð ʌ n WORD_BOUNDARY m oʊ s t WORD_BOUNDARY ʌ ð ə ɹ WORD_BOUNDARY k ɑ ɹ b ə k eɪ ʃ ə n z WORD_BOUNDARY m ɑ l ɪ k j uː l z WORD_BOUNDARY w ɪ t̠ʃ WORD_BOUNDARY k æ n WORD_BOUNDARY f ɔ ɹ m WORD_BOUNDARY æ l aɪ l WORD_BOUNDARY ɔ ɹ WORD_BOUNDARY b ɛ n z ɪ l WORD_BOUNDARY k ɑ ɹ b ə k eɪ ʃ ə n z WORD_BOUNDARY ɑ ɹ WORD_BOUNDARY ɪ s p ɛ ʃ ə l i WORD_BOUNDARY ɹ ɪ æ k t ɪ v WORD_BOUNDARY