isovalent hyperconjugation

isovalent hyperconjugation

[¦ī·sə¦vā·lənt ‚hī·pər‚kän·jə′gā·shən]
(physical chemistry)
An arrangement of bonds in a hyperconjugated molecule such that the number of bonds is the same in the two resonance structures but the second structure is energetically less favorable than the first structure; examples are H3≡C‒C+H2 and H3≡C‒CH2.