Nitrogen and oxygen and their interaction

How these gases react with each other

[Deposit Photos]

In this ar­ti­cle, you will find out about oxy­gen and ni­tro­gen – 2 gas­es which suc­cess­ful­ly in­ter­act with each oth­er.


Ni­tro­gen it­self was dis­cov­ered in the sec­ond half of the 18th cen­tu­ry, in 1772, by the chemist Hen­ry Cavendish. In his lab­o­ra­to­ry, Cavendish passed air over heat­ed coals with a spe­cial de­vice. He re­peat­ed this process many time, then treat­ed the air with al­ka­lis. Cavendish called the sub­stance ob­tained in the ex­per­i­ment a “suf­fo­cat­ing” gas be­cause of its prop­er­ties. But the sci­en­tist could not un­der­stand what the suf­fo­cat­ing gas was. If we study mod­ern chem­istry, how­ev­er, it be­comes clear that pass­ing air over heat­ed coals gives car­bon diox­ide, and that al­ka­li neu­tral­izes it. Cavendish re­port­ed his ex­per­i­ment to his ac­quain­tance Joseph Priest­ley.

It is in­ter­est­ing that this is not the first case when sci­en­tists did not un­der­stand the sub­stance that they had cre­at­ed in their ex­per­i­ments. For ex­am­ple, Priest­ley once bond­ed oxy­gen and ni­tro­gen us­ing an elec­tric cur­rent, but did not un­der­stand that he had ob­tained ar­gon in the ex­per­i­ment, which is an in­ert gas.

Phys­i­cal prop­er­ties of ni­tro­gen

In stan­dard con­di­tions, ni­tro­gen is an in­ert, col­or­less gas, with­out smell or taste. It is harm­less to hu­man be­ings, and lighter than air, but not as light as he­li­um or hy­dro­gen. The gas is also vir­tu­al­ly in­sol­u­ble in wa­ter, and does not re­act with it chem­i­cal­ly.

The sev­enth el­e­ment on the pe­ri­od­ic ta­ble also has liq­uid and sol­id ag­gre­gate states.

Liquid nitrogen [Deposit Photos]

In a liq­uid state, the boil­ing tem­per­a­ture of ni­tro­gen is -195.8 de­grees Cel­sius, and in a sol­id state it is -209.86 Cel­sius.

Chem­i­cal prop­er­ties of ni­tro­gen

The col­or­less gas it­self has very sta­ble mol­e­cules, they are di­atom­ic and form a triple bond. So the mol­e­cules prac­ti­cal­ly do not break apart. It is be­cause of this prop­er­ty that the sev­enth el­e­ment shows low chem­i­cal ac­tiv­i­ty. All ni­tro­gen com­pounds are high­ly un­sta­ble, be­cause when they are heat­ed, free ni­tro­gen is formed.

Re­ac­tion of ni­tro­gen with met­als

Molec­u­lar ni­tro­gen can only en­ter into a re­ac­tion only with a small group of met­als, which dis­play re­duc­ing prop­er­ties. For ex­am­ple, N₂ can en­ter into a re­ac­tion with lithi­um:

6Li + N₂ = 2Li₃N

It also re­acts with the light sil­very met­al of mag­ne­sium, but for the chem­i­cal process it must be heat­ed to 300 de­grees Cel­sius. The re­sult of the re­ac­tion will be mag­ne­sium ni­tride – yel­low-green crys­tals which on heat­ing break down into mag­ne­sium and free ni­tro­gen:

3Mg + N₂ = Mg₃N₂.

Mg₃N₂ → 3Мg + N₂ — at a tem­per­a­ture of 1000 de­grees Cel­sius and high­er.

If the ni­tride of an ac­tive met­al is added to wa­ter, the process of hy­drol­y­sis be­gins, and am­mo­ni­um forms.

Ni­tro­gen and hy­dro­gen

The re­ac­tion of ni­tro­gen and hy­dro­gen takes place at a tem­per­a­ture of around 400 de­grees Cel­sius, with a pres­sure of 200 at­mos­pheres, and also in the pres­ence of iron act­ing as a cat­a­lyst:

3H₂ + N₂ = 2NH₃.

[Deposit Photos]

Re­ac­tion of ni­tro­gen and oth­er non-met­als

Again, all in­ter­ac­tions of sub­stances with ni­tro­gen take place at high tem­per­a­tures, for ex­am­ple with boron:

2B + N₂ = 2BN.

It does not in­ter­act with many halo­gens, or with sul­fur, but sul­fides and halo­genides may be ob­tained in­di­rect­ly.

Re­ac­tion of ni­tro­gen with oxy­gen

Oxy­gen is an el­e­ment with the atom­ic num­ber 8. It is a trans­par­ent gas with­out smell or col­or, and in liq­uid form it has a bluish col­or.

Liquid oxygen [Wikimedia]

Oxy­gen can also ex­ist in a sol­id ag­gre­gate state, and takes the form of blue crys­tals. It has a di­atom­ic mol­e­cule.

An in­ter­est­ing fact is that Priest­ley did not ini­tial­ly un­der­stand that he had dis­cov­ered oxy­gen, and be­lieved that in he had ob­tained a cer­tain com­po­nent of oxy­gen. Priest­ley ob­served the break­down of mer­cury ox­ide in a her­met­ic de­vice. The sci­en­tist used a lens to di­rect the rays of the sun at the ox­ide.

As for the in­ter­ac­tion of ni­tro­gen and oxy­gen, the sub­stances en­ter into a re­ac­tion in the pres­ence of an elec­tric cur­rent, be­cause ni­tro­gen is a very sta­ble mol­e­cule, which re­acts very un­will­ing­ly with oth­er sub­stances:

O₂ + N₂ = 2NO

There are sev­er­al ox­ides of the col­or­less gas, the va­lence of which varies from one to five.

There are sev­er­al com­pounds which can form in the re­ac­tion of ni­tro­gen and oxy­gen:

  • N₂O — ni­trous ox­ide;

  • NO — ni­tric ox­ide;

  • N₂O₃ — dini­tro­gen tri­ox­ide;

  • NO₂ — ni­tro­gen diox­ide;

  • N₂O₅ — ni­tro­gen pen­tox­ide.

Click here for do­ing an in­ter­est­ing ex­per­i­ment on ob­tain­ing ni­tro­gen diox­ide and learn­ing its prop­er­ties.

Ni­trous ox­ide, which is an anes­thet­ic, is ob­tained with the break­down of am­mo­ni­um ni­trate. It is a col­or­less gas with a char­ac­ter­is­tic pleas­ant smell. The ox­ide dis­solves well in wa­ter.

Molecule of nitrous oxide [Wikimedia]

N₂O is also a con­stant com­po­nent of air. The process takes place at a tem­per­a­ture of 200 de­grees Cel­sius. The re­ac­tion is:

NH₄NO₃ = 2Н₂О + N₂O

Ni­tric ox­ide, NO, is also a col­or­less gas which is prac­ti­cal­ly in­sol­u­ble in wa­ter. This com­pound does not read­i­ly give up oxy­gen, but it is known for its com­bi­na­tion re­ac­tions, for ex­am­ple with the green-yel­low tox­ic gas of chlo­rine:

2NO + Сl₂ = 2N­O­Cl.