Nitrogen Oxide

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 (NO
2), nitrogen(IV) oxide
Nitrogen trioxide (NO
3), or nitrate radical
Nitrous oxide (N
2O), nitrogen(0,II) oxide
Dinitrogen dioxide (N
2O
2), nitrogen(II) oxide dimer
Dinitrogen trioxide (N
2O
3), nitrogen(II,IV) oxide
Dinitrogen tetroxide (N
2O
4), nitrogen(IV) oxide dimer
Dinitrogen pentoxide (N
2O
5), nitrogen(V) oxide, or nitronium nitrate [NO
2]+
[NO
3]−
Nitrosylazide (N
4O), nitrogen(−I,0,I,II) oxide
Oxatetrazole (N
4O)
Trinitramide (N(NO
2)
3 or N
4O
6), nitrogen(0,IV) oxide

Anions

Nitroxide (O=N−
)
Nitrite (O=N–O−
or NO−
2)
Nitrate (NO−
3)
Peroxynitrite (O=N–O–O−
or NO−
3)
Peroxynitrate (O
2N–O–O−
or NO−
4)
Orthonitrate (NO3−
4, analogous to phosphate PO3−
4)
Hyponitrite (−
O–N=N–O−
or N
2O2−
2)
Trioxodinitrate or hyponitrate ([O
2NNO]²⁻ or [N
2O
3]²⁻)
Nitroxylate ((−
O–)
2N–N(–O−
)
2 or N
2O4−
4)
Dinitramide (O
2N–N−
–NO
2 or N
3O−
4)

Cations

Nitrosonium (N≡O+
or [NO]+
)
Nitronium (O=N+
=O or [NO
2]+
)

Atmospheric sciences

In atmospheric chemistry:

NO {x} (or NOx) refers to the sum of NO and NO
2.^[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, HNO
3, HNO
2, etc.)
NO
z (or NOz) = NO
y − NO
x

Nitric oxide, NO
Nitrogen dioxide, NO
2
Nitrous oxide, N
2O
Dinitrogen trioxide, N
2O
3
Dinitrogen tetroxide, N
2O
4
Dinitrogen pentoxide, N
2O
5
Trinitramide, N
4O
6

Stability

Due to relatively weak N–O bonding, all nitrogen oxides are unstable with respect to N
2 and O
2, which is the principle behind the catalytic converter and prevents the combustion of the atmosphere.