Nitric oxide

Written By: Ehsan Jahandarpour

Nitric oxide (nitrogen oxide or nitrogen monoxide) is a colorless gas with the formula NO. It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes denoted by a dot in its chemical formula (•N=O or •NO). Nitric oxide is also a heteronuclear diatomic molecule, a class of molecules whose study spawned early modern theories of chemical bonding. Nitric oxide should not be confused with nitrogen dioxide (NO2), a brown gas and major air pollutant, nor with nitrous oxide (N2O), an anesthetic.