Nitrogen reacts with oxygen to form a number of nitrogen oxides. It exhibits different oxidation states in its oxides, ranging from +1 to +5. Oxides of nitrogen having nitrogen in the higher oxidation state are more acidic than that in lower oxidation state. Some of the oxides of nitrogen are enlisted below:

### Dinitrogen oxide, $N_2O$

Dinitrogen oxide is a colourless non-flammable gaseous compound with neutral properties. It is commonly known as laughing gas. Dinitrogen oxide is prepared by the decomposition of ammonium nitrate under high temperature.

$NH_4NO_3 ~\rightarrow~ N_2O~ + ~2H_2O$

### Nitrogen monoxide, NO:

Nitrogen monoxide is a colourless gaseous compound. It’s bonding structure includes an unpaired electron and it belongs to the class of heteronuclear diatomic molecules. Nitrogen monoxide is prepared by the reduction of dilute nitric acid with copper.

$2~ NaNO_2 ~+~ 2 ~FeSO_4 ~+~ 3~ H_2SO_4 ~→ ~Fe_2(SO4)_3 ~+ ~2 NaHSO_4~ +~ 2 H_2O~ + ~2 ~NO$

### Dinitrogen trioxide, $N_2O_3$:

Dinitrogen trioxide is a deep blue solid with an acidic nature. It is only isolable at low temperatures, i.e. in the liquid and solid phases. As the temperature increases, the equilibrium favours the formation of constituent gases. Dinitrogen trioxide is prepared by mixing equal parts of nitric oxide and nirogen dioxide and further cooling the mixture below −21 °C (−6 °F).

$NO~ +~ NO_2 ~\rightarrow~ N_2O_3$

### Nitrogen dioxide, $NO_2$:

Nitrogen dioxide is a reddish-brown toxic gas and has a characteristic sharp, biting odor and is a prominent air pollutant. It is acidic in nature having +4 oxidation state of nitrogen. Nitrogen dioxide is prepared by thermal decomposition of metal nitrates, for example lead nitrate:

$2~ Pb(NO_3)_2~ →~ 2 ~PbO ~+ ~4 ~NO_2~ +~ O_2$

### Dinitrogen tetroxide, $N_2O_4$:

Dinitrogen tetroxide is a colourless solid existing in equilibrium with nitrogen dioxide. It is a powerful oxidizer and is used as a reagent in the synthesis of many chemical compounds.

$N_2O_4 ~⇌ ~2 ~NO_2$

### Dinitrogen Pentoxide, $N_2O_5$:

Dinitrogen pentoxide is a colourless solid that sublimes slightly above room temperature. It is an unstable and potentially dangerous oxidizer and was used as a reagent, dissolved in chloroform for nitration. Dinitrogen pentoxide is prepared by dehydrating nitric acid (HNO3) with phosphorus (V) oxide:

$P_4O_{10}~ +~ 12~ HNO_3 ~→~ 4 ~H_3PO_4~ +~ 6~ N_2O_5$