- 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]−
- Nitrosylazide (N4O), nitrogen(−I,0,I,II) oxide
- Oxatetrazole (N4O)
- Trinitramide (N(NO2)3 or N4O6), nitrogen(0,IV) oxide
In atmospheric chemistry:
- NOx (or NOx) refers to the sum of NO and NO2.
- NOy (or NOy) refers to the sum of NOx and all oxidized atmospheric odd-nitrogen species (e.g. the sum of NOx, HNO3, HNO2, etc.)
- NOz (or NOz) = NOy − NOx
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 combustion of the atmosphere.