C5H8

The molecular formula C₅H₈ may refer to any of the following hydrocarbons:

• Pentynes:

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

• Pentadienes:

• 1,2-Pentadiene, two cis-z 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

• Butadiene derivatives:

• 3-Methyl-1,2-butadiene, CAS 598-25-4
• 2-Methyl-1,3-butadiene or isoprene

• Cyclopentene

• Cyclobutane derivatives:

• Methylenecyclobutane, CAS 1120-56-5

• Cyclobutene derivatives:

• 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

• Cyclopropane derivatives:

• 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

• Cyclopropene derivatives:

• 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

• Bicyclopentane

• Bicyclo[1.1.1]pentane, CAS 311-75-1
• Bicyclo[2.1.0]pentane or housane, CAS 185-94-4

• Spiro[2.2]pentane or spiropentane, CAS 157-40-4

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.