Pentadiene

In organic chemistry, pentadiene is any hydrocarbon with an open chain of five carbons, connected by two single bonds and two double bonds. All those compounds have the same molecular formula C₅H₈. Specifically, it may be

• 1,2-pentadiene, or ethyl allene, H₂C=C=CH−CH₂−CH₃.
• 1,3-pentadiene, H₂C=CH−CH=CH−CH₃ with two isomers:
  • cis-1,3-pentadiene.
  • trans-1,3-pentadiene, or piperylene.
• 1,4-pentadiene, H₂C=CH−CH₂−CH=CH₂.
• 2,3-pentadiene, H₃C−CH=C=CH−CH₃, with two enantiomers (R and S).