Aromatic ion
From Mass Spec Terms
| DRAFT DEFINITION |
| Aromatic ion |
|---|
| A cyclically conjugated ion with a stability (due to delocalization) significantly greater than that of a hypothetical localized structure (e.g. Kekul???????????? structure). If the structure is of higher energy than such a hypothetical classical structure, the ion is antiaromatic. Aromatic ions obey the H?????????????ckel (4n + 2) rule: monocyclic planar (or almost planar) systems of trigonally (or sometimes digonally) hybridized atoms that contain (4n + 2) p-electrons (where n is a non-negative integer generally limited to n = 0??????????????????????????5). Ions containing 4n p-electrons are antiaromatic. Examples of aromatic ions are the cyclopropenyl cation and the cyclopentadienyl anion whereas the cyclopentadienyl cation is antiaromatic. |
| Considered between 2004 and 2006 but not included in the 2006 PAC submission |
| This is an unofficial draft definition presented for information and comment. |
