Editing Diene (section)

==Classes==
Dienes can be divided into three classes, depending on the relative location of the double bonds:<ref name="IUPAC dienes"/>
#'''Cumulated dienes''' have the double bonds sharing a common atom. The result is more specifically called an [[allene]].
#'''Conjugated dienes''' have [[Conjugated system|conjugated]] double bonds separated by one single bond. Conjugated dienes are more stable than other dienes because of resonance.
#'''Unconjugated dienes''' have the double bonds separated by two or more single bonds. They are usually less stable than [[isomer]]ic conjugated dienes. This can also be known as an '''isolated''' diene.

[[File:Dienes various examples.png|thumb|center|650px|alt=Structure of various alkadienes (also called dienes or diolefins)|Some dienes: '''A''': 1,2-Propadiene, also known as [[allene]], is the simplest cumulated diene. '''B''': [[Isoprene]], also known as 2-methyl-1,3-butadiene, the precursor to natural rubber. '''C''': [[1,3-Butadiene]], a  precursor to synthetic polymers.  '''D''': [[1,5-Cyclooctadiene]], an unconjugated diene (notice that each double bond is two carbons away from the other). '''E''': [[Norbornadiene]], a strained bicyclic and unconjugated  diene.  '''F''': [[Dicyclopentadiene]].]]

According to the ''[[Gold Book]]'' definition, a "diene" could include one or more [[heteroatom]]s which replace unsaturated carbon atoms, giving structures that could more specifically be called ''heterodienes''.<ref name="IUPAC dienes"/>

Compounds that contain more than two double bonds are called [[polyene]]s. Polyenes and dienes share many properties.