Editing Simple aromatic ring (section)

==Heterocyclic aromatic rings==
{| border="1" cellpadding="0" cellspacing="0" align="right" style="margin-left: 1em"
|
{| border="0" cellpadding="5" cellspacing="0" style="margin: 1em"
! colspan="3" align="center" | Table of simple aromatic rings
|-
! Five-membered rings
! colspan="2" | Fused five-membered rings with six-membered rings
|
|- align="center" valign="bottom"
| [[File:Pyrrole structure.png|70px]]<br>[[Pyrrole]]
| [[File:Indole structure.png|120px]]<br>[[Indole]]
| [[File:Carbazol - Carbazole.svg|170px]]<br>[[Carbazole]]
|- align="center" valign="bottom"
| [[File:Furan structure.png|70px]]<br>[[Furan]]
| [[File:Benzofuran structure.png|120px]]<br>[[Benzofuran]]
| [[File:Dibenzofuran - Dibenzofuran.svg|170px]]<br>[[Dibenzofuran]]
|- align="center" valign="bottom"
| [[File:Thiophene structure.png|70px]]<br>[[Thiophene]]
| [[File:Benzothiophene structure.png|120px]]<br>[[Benzothiophene]]
|[[File:Dibenzothiophen - Dibenzothiophene.svg|170px]]<br>[[Dibenzothiophene]]
|- align="center" valign="bottom"
| [[File:Imidazole structure.png|70px]]<br>[[Imidazole]]
| [[File:Benzimidazole structure.png|120px]]<br>[[Benzimidazole]]
| [[File:Purine structure.png|120px]]<br>[[Purine]]
|- align="center" valign="bottom"
| [[File:Pyrazole structure.png|70px]]<br>[[Pyrazole]]
| [[File:Indazol.svg|120px]]<br>[[Indazole]]
| &nbsp;
|- align="center" valign="bottom"
| [[File:Oxazole structure.png|70px]]<br>[[Oxazole]]
| [[File:Benzoxazole structure.png|120px]]<br>[[Benzoxazole]]
| &nbsp;
|- align="center" valign="bottom"
| [[File:Thiazole structure.png|70px]]<br>[[Thiazole]]
| [[File:Benzothiazole structure.png|120px]]<br>[[Benzothiazole]]
| &nbsp;
|- align="center" valign="bottom"
| [[File:1,2,3-Triazole structure.svg|90px]]<br>[[1,2,3-Triazole]]
| [[File:1,2,4-Triazole structure.svg|90px]]<br>[[1,2,4-Triazole]]
| &nbsp;
|-
! Six-membered rings
! colspan="2" | Fused six-membered rings with six-membered rings
|
|- align="center" valign="bottom"
| [[File:Benzene-Kekule-2D-skeletal.png|70px]]<br>[[Benzene]]
| [[File:Naphthalene-2D-Skeletal.svg|120px]]<br>[[Naphthalene]]
| [[File:Anthracene structure.png|170px]]<br>[[Anthracene]]
|- align="center" valign="bottom"
| [[File:Pyridine structure.png|70px]]<br>[[Pyridine]]
| [[File:Quinoline structure.png|120px]]<br>[[Quinoline]]
| [[File:Acridin.svg|170px]]<br>[[Acridine]]
|- align="center" valign="bottom"
| [[File:Pyrazine structure.png|70px]]<br>[[Pyrazine]]
| [[File:Quinoxaline structure.png|120px]]<br>[[Quinoxaline]]
| [[File:Phenazine.png|170px]]<br>[[Phenazine]]
|- align="center" valign="bottom"
| [[File:Pyrimidine structure.png|70px]]<br>[[Pyrimidine]]
| [[File:Quinazoline structure.png|120px]]<br>[[Quinazoline]]
| [[File:Pteridin - Pteridine.svg|120px]]<br>[[Pteridine]]
|- align="center" valign="bottom"
| [[File:Pyridazine structure.png|70px]]<br>[[Pyridazine]]
| [[File:Cinnoline structure.png|120px]]<br>[[Cinnoline]]
| [[File:Phthalazin - Phthalazine.svg|120px]]<br>[[Phthalazine]]
|- align="center" valign="bottom"
| [[File:1,2,3-Triazin - 1,2,3-triazine.svg|70px]]<br>[[1,2,3-Triazine]]
| [[File:1,2,4-Triazin - 1,2,4-triazine.svg|70px]]<br>[[1,2,4-Triazine]]
| [[File:1,3,5-Triazin - 1,3,5-triazine.svg|70px]]<br>[[1,3,5-Triazine]]
|}
|}

The nitrogen (N)-containing aromatic rings can be separated into [[basic aromatic ring]]s that are easily [[protonation|protonated]], and form aromatic [[cation]]s and [[salts]] (e.g., [[pyridinium]]), and non-basic aromatic rings.

*In the '''basic aromatic rings''', the [[lone pair]] of [[electron]]s is not part of the aromatic system and extends in the plane of the ring. This lone pair is responsible for the basicity of these [[nitrogenous base]]s, similar to the nitrogen atom in [[amine]]s. In these compounds, the nitrogen atom is ''not'' connected to a hydrogen atom. Examples of basic aromatic rings are [[pyridine]] or [[quinoline]]. Several rings contain basic as well as non-basic nitrogen atoms, e.g., [[imidazole]] and [[purine]].
*In the '''non-basic rings''', the lone pair of electrons of the nitrogen atom is delocalized and contributes to the aromatic pi-electron system. In these compounds, the nitrogen atom ''is'' connected to a hydrogen atom. Examples of non-basic nitrogen-containing aromatic rings are [[pyrrole]] and [[indole]].

In the oxygen- and sulfur-containing aromatic rings, one of the electron pairs of the heteroatoms contributes to the aromatic system (similar to the non-basic nitrogen-containing rings), whereas the second lone pair extends in the plane of the ring (similar to the primary nitrogen-containing rings).