Editing Functional group (section)

===Hydrocarbons===
Hydrocarbons are a class of molecule that is defined by functional groups called [[wikt:hydrocarbyl|hydrocarbyl]]s that contain only carbon and hydrogen, but vary in the number and order of double bonds. Each one differs in type (and scope) of reactivity.

{| class="wikitable" style="background: #ffffff; text-align: center;width:550px"
|-
! [[Chemical class]]
! Group
! Formula
! Structural Formula
! Prefix
! Suffix
! Example
|-
| [[Alkane]] ||[[Alkyl]]
| R(CH<sub>2</sub>)<sub>n</sub>H
| [[File:Alkyl-(general)-skeletal.svg|75px|Alkyl]]
| alkyl- || -ane
| [[File:Ethan Keilstrich.svg|135x135px]]<br>[[Ethane]]
|-
| [[Alkene]] || [[Alkene|Alkenyl]]
| R<sub>2</sub>C=CR<sub>2</sub>
| [[File:Alkene-2D-skeletal.svg|75px|Alkene]]
| alkenyl- || -ene
| [[File:Ethylene.svg|75px|ethylene]]<br>[[Ethylene]]<br>''(Ethene)''
|-
| [[Alkyne]] || [[Alkyne|Alkynyl]]
| {{chem2|RC\tCR′}}
| <chem>R-C#C-R'</chem>
| alkynyl- || -yne
| <chem>H-C#C-H</chem><br>[[Acetylene]]<br>''(Ethyne)''
|-
|-
| [[Benzene|Benzene derivative]]
| [[Phenyl]]
| RC<sub>6</sub>H<sub>5</sub><br>RPh
| [[File:Phenyl-group.svg|75px|Phenyl]]
| phenyl- || -benzene
| [[File:Cumene-skeletal.svg|75px]]<br>[[Cumene]]<br>''(Isopropylbenzene)''
|-
|}
There are also a large number of branched or ring alkanes that have specific names, e.g., [[tert-butyl]], [[bornyl]], [[cyclohexyl]], etc. There are several functional groups that contain an alkene such as [[vinyl group]], [[allyl group]], or [[Acryl|acrylic group]]. Hydrocarbons may form charged structures: positively charged [[carbocation]]s or negative [[carbanion]]s. Carbocations are often named ''-um''. Examples are [[tropylium]] and [[triphenylmethyl]] cations and the [[cyclopentadienyl]] anion.