Nitrogen

Nitrogen is a trivalent in most compounds. The triple bond in molecular nitrogen (N₂) is one of the strongest in nature. The resulting difficulty of converting (N₂) into other compounds, and the ease (and associated high energy release) of converting nitrogen compounds into elemental N₂, have dominated the role of nitrogen in both nature and human economic activities.

At cryogen.

Unstable allotropes of nitrogen consisting of more than two nitrogen atoms have been produced in the laboratory, like N₃ and N₄.^[1] Under extremely high pressures (1.1 million atm) and high temperatures (2000 K), as produced under diamond crystal structure, an allotrope nicknamed "nitrogen diamond."^[2]

Occurrence

Nitrogen is the largest single constituent of the Earth's chemical element by mass in the universe.

Molecular nitrogen and nitrogen compounds have been detected in interstellar space by astronomers using the Far Ultraviolet Spectroscopic Explorer.^[3] Molecular nitrogen is a major constituent of the Saturnian moon Titan's thick atmosphere, and occurs in trace amounts in other planetary atmospheres.^[4]

Nitrogen is present in all living organisms in proteins, nucleic acids and other molecules. It is a large component of animal waste (for example, fix atmospheric nitrogen.

See also: Ammonium minerals

Isotopes

See also: Isotopes of nitrogen

There are two stable CNO cycle in stars and the remaining is ¹⁵N. Of the ten isotopes produced synthetically, ¹³N has a half life of ten minutes and the remaining isotopes have half lives on the order of seconds or less. Biologically-mediated reactions (e.g., assimilation, substrate and depletion of the product.

0.73% of the molecular nitrogen in Earth's atmosphere is comprised of the isotopologue ¹⁴N¹⁵N and almost all the rest is ¹⁴N₂.

Electromagnetic spectrum

Molecular nitrogen (¹⁴N₂) is largely transparent to infrared and visible radiation because it is a homonuclear molecule and thus has no dipole moment to couple to electromagnetic radiation at these wavelengths. Significant absorption occurs at extreme ultraviolet wavelengths, beginning around 100 nanometers. This is associated with electronic transitions in the molecule to states in which charge is not distributed evenly between nitrogen atoms. Nitrogen absorption leads to significant absorption of ultraviolet radiation in the Earth's upper atmosphere as well as in the atmospheres of other planetary bodies. For similar reasons, pure molecular nitrogen lasers typically emit light in the ultraviolet range.

Nitrogen also makes a contribution to visible air glow from the Earth's upper atmosphere, through electron impact excitation followed by emission. This visible blue air glow (seen in the polar nitric oxide (NO).

History

Nitrogen (Latin nitrogenium, where nitrum (from Greek nitron) means "saltpetre" (see Antoine Lavoisier referred to it as azote, from the Greek word αζωτος meaning "lifeless". Animals died in it, and it was the principal component of air in which animals had suffocated and flames had burned to extinction. This term has become the French word for "nitrogen" and later spread out to many other languages.

Argon was discovered when it was noticed that nitrogen from air is not identical to nitrogen from chemical reactions.

Compounds of nitrogen were known in the Middle Ages. The fertilizer,

Applications

Nitrogen gas is acquired for industrial purposes by the fractional distillation of liquid air, or by mechanical means using gaseous air (i.e. pressurised reverse osmosis membrane or pressure swing adsorption). Commercial nitrogen is often a byproduct of air-processing for industrial concentration of oxygen for steelmaking and other purposes.

Nitrogen gas has a wide variety of applications, including serving as an oxidation is undesirable;

To preserve the freshness of packaged or bulk foods (by delaying rancidity and other forms of oxidative damage)
In ordinary incandescent light bulbs as an inexpensive alternative to argon
On top of liquid explosives for safety measures
The production of electronic parts such as transistors, diodes, and integrated circuits
gas for high voltage equipment
The manufacturing of stainless steel
Use in military aircraft fuel systems to reduce fire hazard, see inerting system
Filling automotive and aircraft tires^[5] due to its air, though this is not necessary for consumer automobiles.^[6]^[7]

Nitrogen molecules are less likely to escape from the inside of a tire compared with the traditional air mixture used. substances more slowly.^[8]

Molecular nitrogen, a diatomic gas, is apt to dimerize into a linear four nitrogen long polymer. This is an important phenomenon for understanding high-voltage nitrogen dielectric switches because the process of polymerization can continue to lengthen the molecule to still longer lengths in the presence of an intense electric field. A nitrogen polymer fog is thereby created. The second virial coefficient of nitrogen also shows this effect as the compressibility of nitrogen gas is changed by the dimerization process at moderate and low temperatures.^{[citation needed]}

Nitrogen tanks are also replacing carbon dioxide as the main power source for paintball guns. The downside is that nitrogen must be kept at higher pressure than CO2, making N2 tanks heavier and more expensive.

Nitrogenated beer

A further example of its versatility is its use as a preferred alternative to pressurize kegs of some beers, particularly stouts and British ales, due to the smaller bubbles it produces, which make the dispensed beer smoother and headier. A modern application of a pressure sensitive nitrogen capsule known commonly as a "widget" now allows nitrogen charged beers to be packaged in cans and bottles.^[9]

Liquid nitrogen

Main article: Liquid nitrogen

Liquid nitrogen is a cryogenic liquid. At atmospheric pressure, it boils at −196.5 °C. When insulated in proper containers such as evaporative losses.

Like cold traps for certain laboratory equipment. It has also been used to cool central processing units and other devices in computers which are overclocked, and which produce more heat than during normal operation.

Biological role

See also: nitrogen cycle

Nitrogen is an essential part of amino acids and nucleic acids, both of which are essential to all life on Earth.

Molecular nitrogen in the atmosphere cannot be used directly by either plants or animals, and needs to be converted into nitrogen compounds, or "fixed," in order to be used by life. Precipitation often contains substantial quantities of ammonium is preferentially retained by the forest canopy relative to atmospheric nitrate, most of the fixed nitrogen that reaches the soil surface under trees is in the form of nitrate. Soil nitrate is preferentially assimilated by tree roots relative to soil ammonium.

Specific bacteria (e.g. Glycine max). Nitrogen-fixing bacteria can be symbiotic with a number of unrelated plant species. Common examples are legumes, alders (Alnus) spp., lichens, Casuarina, Myrica, liverworts, and Gunnera.

As part of the symbiotic relationship, the plant subsequently converts the ammonium ion to nitrogen oxides and amino acids to form proteins and other biologically useful molecules, such as alkaloids. In return for the usable (fixed) nitrogen, the plant secretes sugars to the symbiotic bacteria.

Some plants are able to assimilate nitrogen directly in the form of nitrates which may be present in soil from natural mineral deposits, artificial fertilizers, animal waste, or organic decay (as the product of bacteria, but not bacteria specifically associated with the plant). Nitrates absorbed in this fashion are converted to nitrites by the enzyme nitrate reductase, and then converted to ammonia by another enzyme called nitrite reductase.

Nitrogen compounds are basic building blocks in animal biology. Animals use nitrogen-containing amino acids from plant sources, as starting materials for all nitrogen-compound animal biochemistry, including the manufacture of proteins and nucleic acids. Some plant-feeding insects are so dependent on nitrogen in their diet, that varying the amount of nitrogen fertilizer applied to a plant can affect the rate of reproduction of the insects feeding on it.^[10]

Soluble nitrate is an important limiting factor in the growth of certain bacteria in ocean waters. In many places in the world, artificial "dead zone" areas in the U.S. Gulf Coast and the Black Sea are due to this important polluting process.

Many saltwater fish manufacture large amounts of trimethylamine oxide to protect them from the high amino acid, serves as an important regulatory molecule for circulation.

Animal metabolism of NO results in production of cadaverine.

Decay of organisms and their waste products may produce small amounts of nitrate, but most decay eventually returns nitrogen content to the atmosphere, as molecular nitrogen.

Reactions

Nitrogen is generally considered unreactive. N₂ reacts spontaneously with few reagents, being resilient to acids and bases as well as oxidants and most reductants. It does however react with elemental lithium at 1 atmosphre and room temperature.^[11] Lithium burns in an atmosphere of N₂ to give lithium nitride:

6 Li + N₂ → 2 Li₃N

Magnesium also reacts in a similar manner, forming magnesium nitride.

3 Mg + N₂ → Mg₃N₂

N₂ forms a variety of molybdenum complex in the presence of a proton source was published in 2005.^[11]

Certain other flammable metals (e.g., magnesium) will also react with nitrogen gas, especially at high temperatures, or when the metal has already been ignited before the nitrogen atmosphere is introduced.

Nitrogen compounds in industry

Simple compounds

See also the category Nitrogen compounds.

The main neutral amphiphilic, compound). Larger chains, rings and structures of nitrogen hydrides are also known, but are generally unstable. N₂²⁺ is another polyatomic cation as in hydrazine.

Other classes of nitrogen anions (negatively charged ions) are the poisonous electron and is an important component of smog. Nitrogen molecules containing unpaired electrons show an understandable tendency to dimerize (thus pairing the electrons), and are generally highly reactive.

The more standard oxides, oxidizing agent.

Nitrogen can also be found in Kjeldahl method.

Nitrogen compounds of notable economic importance

Molecular nitrogen (N₂) in the atmosphere is relatively non-reactive due to its strong bond, and N₂ plays an inert role in the human body, being neither produced or destroyed. In nature, nitrogen is converted into biologically (and industrially) useful compounds by some living organisms, notably certain bacteria (i.e. Ostwald process.

The organic and inorganic monopropellants. In most of these compounds, the basic instability and tendency to burn or explode is derived from the fact that nitrogen is present as an oxide, and not as the far more stable nitrogen molecule (N₂) which is a product of the compounds' thermal decomposition. When nitrates burn or explode, the formation of the powerful triple bond in the N₂ which results, produces most of the energy of the reaction.

Nitrogen is a constituent of molecules in every major drug class in pharmacology and medicine. nitric oxide.

Dangers

Rapid release of nitrogen gas into an enclosed space can displace oxygen, and therefore represents an asphyxiation hazard. This may happen with few warning symptoms, since the human carotid body is a relatively slow and a poor low-oxygen (hypoxia) sensing system.^[13] An example occurred shortly before the launch of the first Space Shuttle mission in 1981, when two technicians lost consciousness and died after they walked into a space located in the Shuttle's Mobile Launcher Platform that was pressurized with pure nitrogen as a precaution against fire. The technicians would have been able to exit the room if they had experienced early symptoms from nitrogen-breathing.

When inhaled at high partial pressures (more than about 3 atmospheres, encountered at depths below about 30 m in scuba diving) nitrogen begins to act as an anesthetic agent. It can cause nitrous oxide.

Nitrogen also dissolves in the bloodstream and body fats, and rapid decompression (particularly in the case of divers ascending too quickly, or astronauts decompressing too quickly from cabin pressure to spacesuit pressure) can lead to a potentially fatal condition called decompression sickness (formerly known as caisson sickness or more commonly, the "bends"), when nitrogen bubbles form in the bloodstream, nerves, joints, and other sensitive or vital areas.

Direct skin contact with liquid nitrogen causes severe frostbite (cryogenic burns) within seconds, though not instantly on contact, depending on form of liquid nitrogen (liquid vs. mist) and surface area of the nitrogen-soaked material (soaked clothing or cotton causing more rapid damage than a spill of direct liquid to skin, which for a few seconds is protected by the Leidenfrost effect).

References

^ A new molecule and a new signature - Chemistry - tetranitrogen. Science News (February 162002). Retrieved on 2007-08-18.
^ Polymeric nitrogen synthesized. physorg.com (August 52004). Retrieved on 2007-08-18.
^ Daved M. Meyer, Jason A. Cardelli, and Ulysses J. Sofia (1997). Abundance of Interstellar Nitorgen. arXiv. Retrieved on 2007-12-24.
^ Calvin J. Hamilton. Titan (Saturn VI). Solarviews.com. Retrieved on 2007-12-24.
^ Why don't they use normal air in race car tires?. Howstuffworks. Retrieved on 2006-07-22.
^ Diffusion, moisture and tyre expansion. Car Talk. Retrieved on 2006-07-22.
^ Is it better to fill your tires with nitrogen instead of air?. The Straight Dope. Retrieved on 2007-02-16.
^ G. J. Van Amerongen (1946). "The Permeability of Different Rubbers to Gases and Its Relation to Diffusivity and Solubility". Journal of Applied Physics 17 (11): 972–985. doi:10.1063/1.1707667.
^ http://recipes.howstuffworks.com/question446.htm
^ Jahn, GC, LP Almazan, and J Pacia (2005). "Effect of nitrogen fertilizer on the intrinsic rate of increase of the rusty plum aphid, Hysteroneura setariae (Thomas) (Homoptera: Aphididae) on rice (Oryza sativa L.)". Environmental Entomology 34 (4): 938–943.
^ ^a ^b RICHARD R. SCHROCK "Acc. Chem. Res. 2005, 38, 955-962" Acc. Chem. Res. 2005, 38, 955-962
^ Fryzuk, M. D. and Johnson, S. A. (2000). "The continuing story of dinitrogen activation". Coordination Chemistry Reviews 200–202: 379. doi:10.1016/S0010-8545(00)00264-2.
^ Biology Safety - Cryogenic materials. The risks posed by them. University of Bath. Retrieved on 2007-01-03.

Los Alamos National Laboratory – Nitrogen
Chemistry of the Elements, N. N. Greenwood and A. Earnshaw. ISBN 0-08-022057-6
Biochemistry, R.H. Garrett and C.M. Grisham. 2nd edition, 1999. ISBN 0-03-022318-0

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