NITROGEN

Descends from the Greek word azoos - lifeless, in Latin Nitrogenium. A chemical sign on an element - N. Nitrogen - a chemical element of V Mendeleyev's group, an order number 7, relative atomic weight 14,0067; the uncolored gas which does not have an odour and taste.

The historical inquiry

Nitrogen bonds - saltpeter, hydrogen nitrate, ammonia - were known long before nitrogen reception in a free state. In 1772 D.Rezerford, burning phosphorus and other materials in a glass bell, has shown, that the gas remaining after combustion named it “suffocating air”, does not sustain breath and burning. In 1787 A.Lavuaze has positioned, that the "vital" and "suffocating" gases which are a part of air, these are simple materials, and has offered the name "nitrogen". In 1784 G.Kavendish has shown, that nitrogen is a part some saltpeter; from here also there is a Latin name of nitrogen (from late latinпозднелатинского nitrum - saltpeter and Greek gennao - I bear, I effect), offered in 1790 Z.A.Shaptalem. To beginning ХIX century have been found out unreactiveness of nitrogen in a free state and its exclusive role in bonds with other elements as combined nitrogen.

Prevalence in the nature

Nitrogen - one of the most widespread elements on the Earth, and its basic mass (nearby 4*1015 permanently delete.) it is concentrated in a free state in atmosphere. In air free nitrogen (in the form of moleculas N2) compounds 78,09 % on volume basis (or 75,6 % on mass), not considering its dashes in the form of ammonia and oxides. The centre maintenance of nitrogen in to a lithosphere of 1,9*10-3 % on mass. Connatural bonds of nitrogen - ammonium muriate NH4CI and various nitrates. Large clumps of saltpeter are characteristic for a dry deserted climate (Chile, Central Asia). Long time of saltpeter were the main supplier of nitrogen for the industry (now the major importance for nitrogen fixation has industrial synthesis of ammonia from air and hydrogen nitrogen). Combined nitrogen Small amounts are in hard coal (1 - 2,5 %) and oil (0,02 - 1,5 %), and also in waters of the rivers, seas and oceans. Nitrogen collects in bedrocks (0,1 %) and in alive organisms (0,3 %).

Though the name "nitrogen" means “not bolstering life”, actually it is an element necessary for ability to live. In the squirrel of animals and the person contains 16 - 17 % of nitrogen. In organisms of carnivores of squirrels it is formed at the expense of the consumed albumens which are available in organisms of vegetarians and in plants. Plants synthesise squirrels, acquiring the nitrous materials containing in bedrock, mainly the inorganic. Nitrogen significant amounts enter in bedrock thanking nitrofixing to microorganisms, capable to translate free nitrogen of air in nitrogen bonds.

In the nature the nitrogen cycle is carried out, the leading role in which is played by microorganisms - nitroficated, denitroficated, nitrofixing, etc. However as a result of extraction from bedrock plants of a large quantity of combined nitrogen (especially at intensive agriculture) bedrocks appear impoverished. Deficiency of nitrogen is characteristic for agriculture almost all countries, deficiency of nitrogen and in animal industries (“albuminous starvation”) is observed. On bedrocks, poor accessible nitrogen, plants badly educe. Economic activities of the person break a nitrogen cycle. So, fuel burning concentrates with atmosphere nitrogen, and the factories effecting fertilizings, bind nitrogen from air. Transportation of fertilizings and agriculture products redistributes nitrogen on an earth surface.

Nitrogen - the fourth element on prevalence of Solar system (after hydrogen, helium and oxygen).

Atom, molecula

The choronomic electronic shell of atom of nitrogen consists of 5 electrons (one not divided pair and three not coupled - a configuration 2s22p3). More often nitrogen in bonds 3-kovalenten at the expense of not coupled electrons (as in ammonia NH3). Presence of not divided pair electrons can result in to formation of one more covalent linkage, and nitrogen becomes 4-covalent (as in an ion of ammonium NH4 +). Oxidation states of nitrogen vary from +5 (in N2O5) to-3 (in NH3). In usual conditions in a free state nitrogen forms molecula N2 where atoms of nitrogen are bound by three covalent linkages. The nitrogen molecula is very steady: its dissociation energy on atoms compounds 942,9 kdzh/MOLE, therefore even at temperature 33000С dissociation degree of nitrogen compounds only about 0,1 %.

Physical and chemical properties

Nitrogen is little bit easier than air; density of 1,2506 kg/m3 (at 00С and 101325 n/m2 or 760 mm Hg), tпл-209,860С, tкип-195,80С. Nitrogen is liquefied hardly: its critical temperature is low enough (-147,10S), and critical pressure is high 3,39 Мн/м2 (34,6 kgf/sm2); density of liquid nitrogen of 808 kg/m3. In water nitrogen less we will solve, than oxygen: at 00С in 1 м3 H2O 23,3 g of nitrogen solve. Better, than in water, nitrogen we will solve in some hydrocarbons.

Only with such awake metals as lithium, calcium, magnesium, nitrogen interreacts at heating to rather low temperatures. With the majority of other elements nitrogen reacts at a heat and in the presence of accelerators. Bonds of nitrogen with oxygen N2O, NO, N2O3, NO2 and N2O5 are well studied. Oxide NO which at refrigerating is easily oxidised further to dioxide NO2 is formed Of them at direct interaction of elements (40000С). In air nitric oxides are formed at atmospheric discharges. They can be received also action on an admixture of nitrogen with oxygen of ionising radiations. At dissolution in water of the nitrous N2O3 and nitrogenous N2O5 anhydrides nitrous acid НNO2 and hydrogen nitrate НNO3 forming salts - nitrites and nitrates are accordingly received. Nitrogen is bridged to hydrogen only at a heat and in the presence of accelerators, ammonia NH3 is thus formed. Except ammonia, other numerous bonds of nitrogen with hydrogen, for example hydrazine H2N-NH2, diimide HN-NH, azotisto-hydrogen acid HN3 (H-N=N=N), octnitrogen N8H14 are known also, etc.; the majority of bonds of nitrogen with hydrogen is secured only in the form of organic derivatives. With halogens nitrogen directly does not interreact, therefore all halogenides of nitrogen receive an indirect route, for example fluorine nitrogen NF3 - at interaction of fluorine with ammonia. As a rule, nitrogen halogenides - few-proof bonds (except for NF3); are steadier oxygalogenidуes nitrogen - NOF, NOCI, NOBr, NO2F and NO2CI. To sulphur also there is no nitrogen direct coupling; the nitrous sulphur N4S4 resulting reactions of liquid sulphur with ammonia. At interaction of the heated coke with nitrogen cyanogen (СN) 2 is formed. Heating of nitrogen with acetylene С2Н2 to 15000С hydrogen cyanide HCN can be received. Interaction of nitrogen with metals at heats result ins to formation of nitrides (for example, Mg3N2).

At action on usual nitrogen of electric discharges or at decomposing of white graphites, the titan, magnesium and calcium, and also at electric discharges in air the awake nitrogen representing an admixture of moleculas and atoms of nitrogen, possessing the raised margin of energy can be formed. Unlike molecular, awake nitrogen rather aggressively interreacts with oxygen, hydrogen, sulphur pairs, phosphorus and some metals.

Nitrogen is a part some very many major organic compounds (amines, amino acids, nitro compounds, etc.).

Reception and application

In laboratory nitrogen can be easily received at heating of concentrated nitrite of ammonium: NH4NO2 ® N2 + 2H2O. The technical mean of reception of nitrogen is based on division preliminarily liquid air which then is exposed to distillation.

The basic part of got free nitrogen is used for industrial production of ammonia which then in significant amounts is manufactured on hydrogen nitrate, fertilizings, explosives etc. Besides direct synthesis of ammonia from elements, industrial value for air nitrogen fixation has developed in 1905 cyanamide method, based that at 10000С calcium carbide (received by glowing of an admixture coal news in electrical board) reacts with free nitrogen: CaC2 + N2 ® CaCN2 + C. Formed calcium cyanamide at action of overheated steam cankers with ammonia separation: CaCN2 + 3H2O ® CaCO3 + 2NH3.

Free nitrogen apply in many industries: as inert medium at various chemical and metallurgical processes, for free space filling in mercurial thermometers, at pumping-over of combustible fluids etc. Liquid nitrogen finds application in a various refrigerating machinery. It store and transport in steel Dewar vacuum flasks, gaseous nitrogen in the cramped kind - in balloons. Widely apply many bonds of nitrogen. Combined nitrogen effecting began to educe strenuously after 1st world war and has now reached huge scales.