Sodium nitrite
Sodium nitrite (NaNO₂) is an inorganic salt used to cure foods and as a reagent and precursor in chemical synthesis.
Nitrous acid: Nitrous acid (HNO₂) is a weak, unstable acid containing nitrogen in the +3 oxidation state. Acidifying nitrite forms nitrous acid, which generates reactive species involved in curing and other reactions.
Curing (food preservation): Curing preserves food by using salt, nitrite, drying, or related treatments to inhibit spoilage and alter flavor. Sodium nitrite is a central curing agent in many processed meats.
Nitrite: Nitrite is the polyatomic ion NO₂⁻, containing nitrogen in the +3 oxidation state. Sodium nitrite is the sodium salt of this ion.
Methemoglobinemia: Methemoglobinemia is a condition in which excess methemoglobin reduces the blood’s capacity to carry oxygen. It is the principal acute toxic effect associated with excessive nitrite exposure.
Nitrosation: Nitrosation is the transfer of a nitroso group, –NO, to an atom or molecule. Nitrite-derived nitrosating agents can modify food molecules and form N-nitroso compounds.
Sodium nitrite poisoning: Sodium nitrite poisoning is toxic exposure that can cause methemoglobinemia and impair oxygen delivery. The same nitrite chemistry useful in preservation can dangerously disrupt blood oxygen transport at high exposure.
Sodium nitrate: Sodium nitrate (NaNO₃) is an inorganic salt containing the nitrate ion, NO₃⁻. It is a closely related sodium salt, but nitrate has one more oxygen atom and different chemistry.
N-nitroso compounds: N-nitroso compounds are chemicals containing an N–N=O group; some are carcinogenic. Nitrite can contribute to their formation when it reacts with amines under suitable conditions.
Diazotization: Diazotization converts a primary aromatic amine into an aromatic diazonium salt, usually using nitrous acid. Sodium nitrite supplies the nitrous acid commonly used to make diazonium salts.
Azo dyes: Azo dyes are colored compounds containing a nitrogen–nitrogen double bond between organic groups. Diazonium salts made with sodium nitrite are key intermediates in many azo-dye syntheses.