C5H8
# C5H8

The molecular formula $C_5H_8$ may refer to any of the following hydrocarbons:

   * 1-Pentyne

   * 2-Pentyne

   * 3-Methyl-1-butyne or isopentyne, CAS 598-23-2

   * 1,2-Pentadiene, two cis-trans isomers, CAS 591-95-7

   * 1,3 Pentadiene, CAS 504-60-9 (racemic mixture)

      * cis-1,3-Pentadiene or (Z)-1,3-pentadiene, CAS 1574-41-0

      * trans-1,3-Pentadiene or (E)-1,3-pentadiene, or Piperylene

   * 1,4-Pentadiene, CAS 591-93-5

   * 2,3-Pentadiene, two axial isomers, CAS 591-96-8 (racemic mixture)

      * $(R_a)-2,3-Pentadiene,$ CAS 20431-56-5

      * $(S_a)-2,3-Pentadiene,$ CAS 23190-25-2

   * 3-Methyl-1,2-butadiene, CAS 598-25-4

   * 2-Methyl-1,3-butadiene or isoprene

   * Methylenecyclobutane, CAS 1120-56-5

   * 1-Methylcyclobutene, CAS 1489-60-7

   * 3-Methylcyclobutene, CAS 1120-55-4 (racemic mixture)

      * (R)-3-Methylcyclobutene, CAS 20476-28-2

      * (S)-3-Methylcyclobutene, CAS 30334-81-7

   * Ethenylcyclopropane or Vinylcyclopropane

   * Ethylidenecyclopropane, CAS 18631-83-9

   * 2-Methyl-1-methylenecyclopropane, CAS 18631-84-0 (racemic mixture)

      * (R)-2-Methyl-1-methylenecyclopropane

      * (S)-2-Methyl-1-methylenecyclopropane

   * 1-Ethylcyclopropene, CAS 34189-00-9

   * 3-Ethylcyclopropene, CAS 203442-62-0

   * 1,2-Dimethylcyclopropene, CAS 14309-32-1

   * 1,3-Dimethylcyclopropene, CAS 82190-83-8 (racemic)

      * (R)-1,3-Dimethylcyclopropene

      * (S)-1,3-Dimethylcyclopropene

   * 3,3-Dimethylcyclopropene, CAS 3907-06-0

   * Bicyclo[1.1.1]pentane, CAS 311-75-1

   * Bicyclo[2.1.0]pentane or housane, CAS 185-94-4

## Functional groups

The formula may also represent a monovalent functional group derived from any hydrocarbon with formula C $_5H$ $_9$ by removal of one hydrogen atom; or a divalent group derived from C $_5H$ $_{10}$ minus two hydrogens; and so on.

