<unk>  is a chemical compound with the formula C5H5N. It is a liquid with a distinctively putrid, fishy odour.<unk>  is a simple and fundamentally important heterocyclic aromatic organic compound that is structurally related to benzene, wherein one CH group in the six-membered ring is replaced by a nitrogen atom. The<unk>  ring occurs in many important compounds, including the nicotinamides.<unk>  is sometimes used as a ligand in coordination chemistry. As a ligand, it is usually abbreviated<unk> .
Pyridine
Acetarsol
Nitrazine
Trientine
Monobenzone
8-Hyydroxyquinoline
Citicoline
Hemin