N
Carbon Nitrogen Oxygen - 7 N N P Full table Table range
General Information
Name , Symbol, Number	N, N, 7
Chemical series	Nonmetals
Group , Period , Block	15 (VA) , 2 , p
Density	1.2506 g l -1
Van der Waals radius	150 pm
Electronic configuration
1st:14.5341 eV	2 nd: 29.6013 eV
3 rd: 47.44924 eV	4 th:77.4735 eV
5 th:97.8902 eV	6 th:552.0718 eV
7 th:667.046 eV
Isotopes
iso NA Period MD Ed PD MeV 13 N {Syn.} 9.965 min 2,22 13C 14 N 99.634% stable with 7 neutrons 15 N 0.366% stable with 8 neutrons 16 N {Syn.} 7.13 s - 10,419 16O
Units of SI & STP unless otherwise stated.

Nitrogen is a chemical element in the family pnicogen of symbol N and atomic number 7. In common parlance, means the nitrogen diatomic gas dinitrogen N _2, a major component of Earth's atmosphere, accounting for almost 4 / 5 ^th of the air (78.06%, by volume).

Nitrogen is ^the 34th element constituting the crust in order of importance.

"Minerals" containing nitrogen are mainly nitrate : potassium nitrate KNO ₃ (constituent of saltpetre ) or "niter" which was once used to make explosive powder, sodium nitrate NaNO ₃ (component of Chile saltpetre).

The Latin name "nitrogenium" comes from the Greek Nitron gennan, which means "trainer of saltpetre ( nitrate of potassium ). The chemical symbol N is from that origin.

The English term for nitrogen is nitrogen.

There is also the name nitrogen in French, but the name is the most common nitrogen.

Antoine Lavoisier chose the name nitrogen compound a-(privative) and radical -Greek, "living" and therefore means "private life", because unlike the oxygen , it does not sustain life animals.

Nitrogen was isolated by Daniel Rutherford in 1772 , however, nitrogen compounds are known since antiquity. It is prepared by extracting the oxygen from the air and carbon dioxide.

It has been used mainly as nitrate in fertilizers and explosives for munitions of war and civilian explosives or hunting.

Operation and usage

Nitrogen compounds

Paradoxically, despite its name, the chemical element "N" is (with the carbon , the oxygen and hydrogen ) one of the main components of the Life and ecosystems as well as agro-ecosystems. It enters the composition of protein (about 15%). Nitrogen is present in many chemicals, including certain pesticides known to (substituted ureas).

Nitrogen was used and is still as' fertilizer naturally in the urea animal (or human) and guano (feces dry with bird or bat ), particularly in Chile , in Peru , in India , in Bolivia , in Spain , in Italy and Russia. The nitre (nitrate natural mineral) was once harvested to produce gunpowder.

Today, its compounds are mainly produced industrially by chemical synthesis for many uses, including for example:

• agricultural fertilizers ( fertilizer ) ammonium salts are absorbed by plants, which are then forced to absorb more water (osmotic balance). These salts and forcing the plant to grow. If other minerals are present in sufficient (phosphorus, potassium in particular) that nitrogen boosts plant growth under cultivation. Nitrogen is therefore used as nitrate of ammonium , NH ₄ NO _3,ammonium sulfate , (NH _{4) 2} SO _4,ammonium monophosphate , NH ₄ H ₂ PO _4, or Urea, CO (NH _{2) 2.} Today the main use of nitrogen in the world, which is also responsible for widespread pollution ( eutrophication , dystrophisation ) the environment (water aquifers, estuaries, some coasts, with the appearance of vast dead zones in the oceans a great concern by the UN ).
• Pharmaceuticals
  • some nitrates' s organic ", such as nitroglycerin , are used to treat certain cardiovascular diseases;
  • the nitrous oxide (laughing gas) is used as an anesthetic ;
• the ammonia NH _3, used as raw material for production of polymers , explosives, fertilizer, or as a refrigerant in certain industrial facilities;
• fuels (the hydrazine and other derivatives as fuel rocket);
• Explosives (organic chemical compounds that have more-or-ONO ₂ NO _2:dynamite );
• propellants for aerosol sprays (N ₂ O) or guns;
• preservative ( E250 , NaNO _2);
• sodium azide, used to instantly inflate airbags (eg a car) crash.

By reaction with oxygen, nitrogen forms three stable oxides: the nitrous oxide N ₂ O, nitric oxide NO and dinitrogen pentoxide N ₂ O _5.

The nitrogen cycle.

Dinitrogen

Today, nitrogen gas or nitrous is generally obtained by liquefaction of air , which is the main component with a concentration of 78.06% in volume and 75.5% by mass. World production is about 150 million tons per year.

Dinitrogen gas itself particularly following applications:

• Packaging of foodstuffs ( MAP ): The inerting packaged foods increases their shelf life by replacing the ambient air (containing oxygen) with nitrogen (purity of 95 to 99.5%) * gas "neutral" used to protect (through the formation of an inert atmosphere confined) products, objects or containers (eg tanks) in the industry, museums or other places: protection against corrosion, insects, fungi ... ;
• gas used as a pesticide to eliminate mild asphyxia by wood worms or some organisms (eg small beetle ) that colonized ancient fragile objects (frames, sculptures and wooden objects, incunabula, scrolls, prints, etc.).
• gas blowing tires. Although the air already contains 78% nitrogen ( dinitrogen to be precise), some professionals in the aviation or a formula (for example), increase this proportion and inflate tires with nitrogen almost pure. This gas has the property of being inert and maintains a stable pressure more constant even when intense heating of the tire. A controversy also exists regarding the introduction of this method for passenger cars. Indeed, they are constrained much less what makes the difference look less noticeable. Cons by inflating the price goes and is often criticized for having a price not justified (the inflation air is often free and found satisfactory). Those who use it should, in principle, to correct the inflation rarely, but they must still monitor the pressure regularly.
• useful gas for inflating the hydraulic accumulators because of its passivity vis--vis oils.
• Mechanical Engineering: Many modern cutting machines operate with a laser beam, it requires nitrogen as driving gas or inert gas such as .
• control agent against fire: ally to 50% of argon and sometimes with carbon dioxide , it is present in certain fire sprinkler systems in gas protecting computer rooms where storage individuals should not be damaged by the powder or water. Stored in metal cylinders at a pressure of 200 bars, and released in an area where an outbreak of fire was detected. The volume of nitrous injected replaces part of the atmosphere of the room and causes a drop in oxygen levels in the air. The generally accepted 15% of combustion breaks the phenomenon of combustion ineffective lethal to human respiration;
• liquid nitrogen coolant.
• Metallurgy: nitrogen is regularly injected into the furnaces to produce highly oxidized metals (eg aluminum and its alloys) to prevent reaction with oxygen from the air. It is also used to prevent corrosion during brazing (eg solder Copper) .

Dinitrogen, unlike gas and chemical inhibitors halogenated CFCs does a priori any harm to the environment (no impact on the greenhouse or on the ozone layer ). But it requires large tanks, pipelines and suitable constructive measures to deal with the sudden expansion of an equivalent of 40 to 50% of the protected volume.

Danger dinitrogen gas: the use of nitrous to create inert atmospheres is confined to several deaths caused by suffocation when a person enters unwittingly into a chamber rendered inert, it is necessary to verify the presence a sufficient proportion of oxygen in such confined spaces before entering, or to acquire a self-contained breathing apparatus.

Diving, nitrogen content in the air breathed under pressure is causing the phenomenon of narcosis. The partial pressure of nitrogen is indeed "toxic" to the body from PpN2 = 3.6 bar and the narcosis is real PpN2 Bars = 4.6 (a dive to about 50 m deep). It is also the main element dictating the length of decompression stops.

References

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