C5H5N, commonly known as pyridine, is an organic compound with a six-membered ring structure containing five carbon atoms and one nitrogen atom. It is a colorless liquid with a distinctive, unpleasant odor and is soluble in water and organic solvents. Pyridine is often used as a solvent and as a precursor in the synthesis of various chemicals, including pharmaceuticals and agrochemicals. Pyridine is classified as a heterocyclic aromatic compound due to the presence of the nitrogen atom in its ring. It is a basic compound, meaning it can accept protons, which makes it useful in various chemical reactions. Pyridine derivatives, such as nicotine and vitamin B6, play important roles in biological systems.