Editing Nitrite (section)

==Production==
[[Sodium nitrite]] is made industrially by passing a mixture of nitrogen oxides into aqueous [[sodium hydroxide]] or [[sodium carbonate]] solution:<ref name=p461/><ref name=Ullmann/>
:{{chem2|NO + NO2  + 2 NaOH  -> 2 NaNO2 + H2O}}
:{{chem2|NO + NO2  +  Na2CO3  -> 2 NaNO2 +  CO2}}
The product is purified by recrystallization. Alkali metal nitrites are thermally stable up to and beyond their melting point (441&nbsp;°C for KNO<sub>2</sub>). [[Ammonium nitrite]] can be made from [[dinitrogen trioxide]], N<sub>2</sub>O<sub>3</sub>, which is formally the [[anhydride]] of nitrous acid:
:2 NH<sub>3</sub> + H<sub>2</sub>O + N<sub>2</sub>O<sub>3</sub> → 2 NH<sub>4</sub>NO<sub>2</sub>