Nitrite

The nitrite ion, which has the chemical formula NO₂⁻, is a symmetric anion with equal N–O bond lengths and an O–N–O bond angle of approximately 120°. Upon protonation, the unstable weak acid nitrous acid is produced. Nitrite can be oxidized or reduced, with the product somewhat dependent on the oxidizing/reducing agent and its strength. The nitrite ion is an ambidentate ligand, and is known to bond to metal centers in at least five different ways. Nitrite is also important in biochemistry as a source of the potent vasodilator nitric oxide. In organic chemistry the NO₂ group is present in nitrous acid esters and nitro compounds. Nitrites are also used in the food production industry for curing meat.

The nitrite ion

Nitrite salts

Sodium nitrite made industrially by passing "nitrous fumes" into aqueous sodium hydroxide or sodium carbonate solution:

The product is purified by recrystallization. Alkali metal nitrites are thermally stable up to and beyond their melting point (441 °C for KNO₂). Ammonium nitrite can be made from dinitrogen trioxide, N₂O₃, which is formally the anhydride of nitrous acid:

Nitro compound

Nitro compounds are organic compounds that contain one or more nitro functional groups (–NO₂). They are often highly explosive, especially when the compound contains more than one nitro group and is impure. The nitro group is one of the most common explosophores (functional group that makes a compound explosive) used globally. This property of both nitro and nitrate groups is because their thermal decomposition yields molecular nitrogen N₂ gas plus considerable energy, due to the high strength of the bond in molecular nitrogen.

The nitro group is also strongly electron-withdrawing. This makes the C-H bonds alpha to the nitro group acidic. The pKas of nitromethane and isopropyl nitrate, reported by Matthews and Bordwell respectively, are 17.2 and 16.9.

Aromatic nitro compounds are typically synthesized by the action of a mixture of nitric and sulfuric acids on an organic molecule. The one produced on the largest scale, by far, is nitrobenzene. Many explosives are produced by nitration including trinitrophenol (picric acid), trinitrotoluene (TNT), and trinitroresorcinol (styphnic acid).

NO2

NO₂ is nitrogen dioxide.

NO2 or NO₂ may also refer to:

See also