Nitrogen oxide

For the air pollutants, see Nitrogen oxides.

Nitrogen oxide may refer to a binary compound of oxygen and nitrogen, or a mixture of such compounds:

Charge-neutral

• Nitric oxide (NO), nitrogen(II) oxide, or nitrogen monoxide
• Nitrogen dioxide (NO₂), nitrogen(IV) oxide
• Nitrogen trioxide (NO₃), or nitrate radical
• Nitrous oxide (N₂O), nitrogen(0,II) oxide
• Dinitrogen dioxide (N₂O₂), nitrogen(II) oxide dimer
• Dinitrogen trioxide (N₂O₃), nitrogen(II,IV) oxide
• Dinitrogen tetroxide (N₂O₄), nitrogen(IV) oxide dimer
• Dinitrogen pentoxide (N₂O₅), nitrogen(V) oxide, or nitronium nitrate [NO₂]⁺[NO₃]⁻
• Nitrosyl azide (N₄O), nitrogen(−I,0,I,II) oxide
• Nitryl azide (N₄O₂)
• Oxatetrazole (N₄O)
• Trinitramide (N(NO₂)₃ or N₄O₆), nitrogen(0,IV) oxide

Anions

Name	Formula
Nitroxide	O=N^− or NO^−
Nitrite	O=N−O^− or NO−2
Nitrate	O2N−O^− or NO−3
Peroxynitrite	O=N−O−O^− or NO−3
Peroxynitrate	O2N−O−O^− or NO−4
Orthonitrate	^+N(−O^−)4 or NO3−4
Hyponitrite	^−O−N=N−O^− or N2O2−2
Trioxodinitrate or hyponitrate	O=N−N(−O^−)2 or N2O2−3
Nitroxylate	(^−O−)2N−N(−O^−)2 or N2O4−4
Dinitramide	O2N−N^−−NO2 or N3O−4

Cations

• Nitrosonium (N≡O⁺ or [NO]⁺)
• Nitronium (O=N⁺=O or [NO₂]⁺)

Atmospheric sciences

In atmospheric chemistry:

• NO_x (or NOx) refers to the sum of NO and NO₂.^[1][2]
• NO_y (or NOy) refers to the sum of NO_x and all oxidized atmospheric odd-nitrogen species (e.g. the sum of NO_x, HNO₃, HNO₂, etc.)
• NO_z (or NOz) = NO_y − NO_x
• Mixed Oxides of Nitrogen ("MON"): solutions of nitric oxide in dinitrogen tetroxide/nitrogen dioxide.

• 
  Nitric oxide, NO
• 
  Nitrogen dioxide, NO₂
• 
  Nitrous oxide, N₂O
• 
  Dinitrogen trioxide, N₂O₃
• 
  Dinitrogen tetroxide, N₂O₄
• 
  Dinitrogen pentoxide, N₂O₅
• 
  Trinitramide, N₄O₆

Stability

Due to relatively weak N–O bonding, all nitrogen oxides are unstable with respect to N₂ and O₂, which is the principle behind the catalytic converter, and prevents the oxygen and nitrogen in the atmosphere from combusting.

See also

• Nitrate
• Nitrogen oxide sensor
• Sulfur nitrides, which are valence isoelectronic with nitrogen oxides

References

1. United States Clean Air Act, 42 U.S.C. § 7602
2. Seinfeld, John H.; Pandis, Spyros N. (1997), Atmospheric Chemistry and Physics: From Air Pollution to Climate Change, Wiley-Interscience, ISBN 0-471-17816-0