Pyridine
Appearance
Pyridine is one of the most simple heteroaromatic molecules, with the Hill system formula C5H5N.
Pyridine is structurally similar to benzene, with a single nitrogen atom substituting in the six-member aromatic ring for one of the carbon and one of the hydrogen atoms.
Pyridine is a base. Its conjugate acid is a unipositive polyatomic ion called pyridinium, C5H5NH+.
Under conditions of standard temperature and pressure, pyridine is a liquid with a strong odor.