Gasoline is a complex mixture of over 500 hydrocarbons that may have between 5 to 12 carbons. Alkanes type compounds, either straight chain or branched coupounds are present is greatest amounts. Smaller amounts of alkane cyclic and aromatic compounds are present. Very small or trace amounts of alkenes are present in gasoline. A few examples are given here.

Compound	Octane number	Static Graphic Image
Paraffins or Alkanes
Answer n-butane	113	Graphic
Answer n-pentane	62	Graphic
Answer n-hexane	19	Graphic
n-heptane	0	Graphic
2-methylbutane	99	Graphic
2,2-dimethylpropane	100	Graphic
2,2-dimethylbutane	89	Graphic
2,2-dimethylpentane	89	Graphic
2,2,3-trimethylbutane	113	Graphic
2,2,4-trimethylpentane (isooctane)	100	Graphic
Olefins or Alkenes
1-pentene	152	Graphic
2-methyl-2-butene	176	Graphic
3-methyl-2-pentene	130	Graphic
2,4,4-trimethyl-1-pentene	164	Graphic
Cycloalkanes or Naphthenes
cyclopentane	141	Graphic
methylcyclopentane	107	Graphic
cyclohexane	110	Graphic
1,2-dimethylcyclohexane	104	Graphic
1,4-dimethylcyclohexane	66	Graphic
Aromatics
Benzene	99	Graphic
Toluene or methylbenzene	124	Graphic
m-xylene or 1,3-dimethylbenzene	145	Graphic
Ethylbenzene	124	Graphic
Propylbenzene	127	Graphic
Isopropylbenzene	132	Graphic