Pyridine

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Pyridine is a basic heterocyclic organic compound with the chemical formula C5H5N. It is structurally related to benzene, with one C-H group replaced by a nitrogen atom. The pyridine ring occurs in many important compounds, including azines and the vitamins niacin and pyridoxal. =====



Pyridine is a colorless liquid that boils at 115.2 °C and freezes at −41.6 °C. Its density, 0.9819 g/cm3, is close to that of water, and its refractive index is 1.5093 at a wavelength of 589 nm and a temperature of 20 °C.[7] Addition of up to 40 mol% of water to pyridine gradually lowers its melting point from −41.6 °C to −65.0 °C.[8] The molecular electric dipole moment is 2.2 Debye.[3] Pyridine is diamagnetic and has a diamagnetic susceptibility of −48.7×10−6 cm3·mol−1.[9] The standard enthalpy of formation is 100.2 kJ·mol−1 in the liquid phase[10] and 140.4 kJ·mol−1 in the gas phase. At 25 °C pyridine has a viscosity[11] of 0.88 mPa/s and thermal conductivity of 0.166 W·m−1·K−1.[12][13] The enthalpy of vaporization is 35.09 kJ·mol−1 at the boiling point and normal pressure.[14] The enthalpy of fusion is 8.28 kJ·mol−1 at the melting point.

Impure pyridine was undoubtedly prepared by early alchemists by heating animal bones and other organic matter

Pyridine is formed through the dry distillation of organic matter containing nitrogen, and can also be used in analytical chemistry as well as in the production of certain drugs or vitamins.

An example of where pyridine would be found in would be in the leaves and roots of belladonna. Oddly enough pyridine has been found in marshmellows and the smoke of tobacco.

Pyridine is a toxic water soluble flammable liquic base C5H5N of pungent odor that is the parent of many naturally occurring organic compounds. It's used as a solvent and a denaturant for alcohol and in the manufacture of pharmaceuticals, like antiseptics and antihistamines, and in waterproofing agents.