| |||
Names | |||
---|---|---|---|
Preferred IUPAC name
Pyridin-1-ium | |||
Identifiers | |||
3D model (JSmol)
|
|||
ChemSpider | |||
PubChem CID
|
|||
UNII | |||
CompTox Dashboard (EPA)
|
|||
| |||
| |||
Properties | |||
[C5H5NH]+ | |||
Molar mass | 80.110 g·mol−1 | ||
Acidity (pKa) | ~5 [1][2] | ||
Conjugate base | Pyridine | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|
Pyridinium refers to the cation [C5H5NH]+. It is the conjugate acid of pyridine. Many related cations are known involving substituted pyridines, e.g. picolines, lutidines, collidines. They are prepared by treating pyridine with acids.[3]
As pyridine is often used as an organic base in chemical reactions, pyridinium salts are produced in many acid-base reactions. Its salts are often insoluble in the organic solvent, so precipitation of the pyridinium leaving group complex is an indication of the progress of the reaction.
Pyridinium cations are aromatic, as determined through Hückel's rule.[4] They are isoelectronic with benzene.