Nitrogen designation in the table. Nitrogen - Great Soviet Encyclopedia

Nitrogen is a chemical element with atomic number 7. It is an odorless, tasteless and colorless gas.


Thus, a person does not feel the presence of nitrogen in the earth’s atmosphere, while it consists of 78 percent of this substance. Nitrogen is one of the most common substances on our planet. You can often hear that without nitrogen there would be no food, and this is true. After all, the protein compounds that make up all living things necessarily contain nitrogen.

Nitrogen in nature

Nitrogen is found in the atmosphere in the form of molecules consisting of two atoms. In addition to the atmosphere, nitrogen is found in the Earth's mantle and in the humus layer of the soil. The main source of nitrogen for industrial production is minerals.

However, in recent decades, when mineral reserves began to deplete, an urgent need arose to separate nitrogen from the air on an industrial scale. This problem has now been solved, and huge volumes of nitrogen for industrial needs are extracted from the atmosphere.

The role of nitrogen in biology, the nitrogen cycle

On Earth, nitrogen undergoes a number of transformations in which both biotic (life-related) and abiotic factors are involved. Nitrogen enters plants from the atmosphere and soil, not directly, but through microorganisms. Nitrogen-fixing bacteria retain and process nitrogen, converting it into a form that can be easily absorbed by plants. In the plant body, nitrogen is converted into complex compounds, in particular proteins.

Through the food chain, these substances enter the bodies of herbivores and then predators. After the death of all living things, nitrogen returns to the soil, where it undergoes decomposition (ammonification and denitrification). Nitrogen is fixed in the soil, minerals, water, enters the atmosphere, and the circle repeats.

Application of nitrogen

After the discovery of nitrogen (this happened in the 18th century), the properties of the substance itself, its compounds, and the possibility of using it on the farm were well studied. Since the reserves of nitrogen on our planet are huge, this element has become extremely actively used.


Pure nitrogen is used in liquid or gaseous form. Liquid nitrogen has a temperature of minus 196 degrees Celsius and is used in the following areas:

— in medicine. Liquid nitrogen is a refrigerant in cryotherapy procedures, that is, cold treatment. Flash freezing is used to remove various tumors. Tissue samples and living cells (in particular, sperm and eggs) are stored in liquid nitrogen. Low temperature allows the biomaterial to be preserved for a long time, and then thawed and used.

The possibility of storing entire living organisms in liquid nitrogen, and, if necessary, defrosting them without any harm, was expressed by science fiction writers. However, in reality it has not yet been possible to master this technology;

— in the food industry Liquid nitrogen is used when bottling liquids to create an inert environment in the container.

In general, nitrogen is used in areas where a gaseous environment without oxygen is required, e.g.

— in fire fighting. Nitrogen displaces oxygen, without which combustion processes are not supported and the fire goes out.

Nitrogen gas has found application in the following industries:

— food production. Nitrogen is used as an inert gaseous medium to maintain the freshness of packaged products;

— in the oil industry and mining. Pipelines and tanks are purged with nitrogen, it is injected into mines to form an explosion-proof gas environment;

— in aircraft manufacturing The chassis tires are inflated with nitrogen.

All of the above applies to the use of pure nitrogen, but do not forget that this element is the starting material for the production of a mass of various compounds:

- ammonia. An extremely sought-after substance containing nitrogen. Ammonia is used in the production of fertilizers, polymers, soda, and nitric acid. It is itself used in medicine, in the manufacture of refrigeration equipment;

— nitrogen fertilizers;

- explosives;

- dyes, etc.


Nitrogen is not only one of the most common chemical elements, but also a very necessary component used in many branches of human activity.

Nitrogen is a well-known chemical element, which is denoted by the letter N. This element is perhaps the basis of inorganic chemistry; it begins to be studied in detail in the 8th grade. In this article we will look at this chemical element, as well as its properties and types.

History of the discovery of a chemical element

Nitrogen is an element that was first introduced by the famous French chemist Antoine Lavoisier. But many scientists are fighting for the title of discoverer of nitrogen, including Henry Cavendish, Karl Scheele, and Daniel Rutherford.

As a result of the experiment, he was the first to isolate a chemical element, but never realized that he had obtained a simple substance. He reported on his experience and also did a number of studies. Priestley probably also managed to isolate this element, but the scientist could not understand what exactly he got, so he did not deserve the title of discoverer. Karl Scheele carried out the same research at the same time as them, but did not come to the desired conclusion.

In the same year, Daniel Rutherford managed not only to obtain nitrogen, but also to describe it, publish a dissertation and indicate the basic chemical properties of the element. But even Rutherford never fully understood what he got. However, it is he who is considered the discoverer, because he was closest to the solution.

Origin of the name nitrogen

From Greek "nitrogen" is translated as "lifeless". It was Lavoisier who worked on the rules of nomenclature and decided to name the element that way. In the 18th century, all that was known about this element was that it did not support breathing. Therefore, this name was adopted.

In Latin, nitrogen is called “nitrogenium”, which means “giving birth to saltpeter”. The designation for nitrogen came from the Latin language - the letter N. But the name itself did not take root in many countries.

Element prevalence

Nitrogen is perhaps one of the most abundant elements on our planet, ranking fourth in abundance. The element is also found in the solar atmosphere, on the planets Uranus and Neptune. The atmospheres of Titan, Pluto and Triton are made of nitrogen. In addition, the Earth's atmosphere consists of 78-79 percent of this chemical element.

Nitrogen plays an important biological role, because it is necessary for the existence of plants and animals. Even the human body contains 2 to 3 percent of this chemical element. Part of chlorophyll, amino acids, proteins, nucleic acids.

A liquid nitrogen

Liquid nitrogen is a colorless transparent liquid, one of the aggregate states of the chemical nitrogen, widely used in industry, construction and medicine. It is used for freezing organic materials, cooling equipment, and in medicine for removing warts (aesthetic medicine).

Liquid nitrogen is non-toxic and non-explosive.

Molecular nitrogen

Molecular nitrogen is an element that is found in the atmosphere of our planet and forms most of it. The formula of molecular nitrogen is N 2. Such nitrogen reacts with other chemical elements or substances only at very high temperatures.

Physical properties

Under normal conditions, the chemical element nitrogen is odorless, colorless, and practically insoluble in water. Liquid nitrogen has a consistency similar to water, and is equally transparent and colorless. Nitrogen has another state of aggregation; at temperatures below -210 degrees, it turns into a solid and forms many large snow-white crystals. Absorbs oxygen from the air.

Chemical properties

Nitrogen belongs to the group of non-metals and takes on properties from other chemical elements from this group. In general, nonmetals are not good conductors of electricity. Nitrogen forms various oxides, such as NO (monoxide). NO or nitric oxide is a muscle relaxant (a substance that significantly relaxes muscles without causing any harm or other effects on the human body). Oxides containing more nitrogen atoms, for example N 2 O, is a laughing gas with a slightly sweet taste, which is used in medicine as an anesthetic. However, NO 2 oxide has nothing to do with the first two, because it is a rather harmful exhaust gas, which is contained in car exhaust and seriously pollutes the atmosphere.

Nitric acid, which is formed by hydrogen atoms, nitrogen atoms and three oxygen atoms, is a strong acid. It is widely used in the production of fertilizers, jewelry, organic synthesis, the military industry (production of explosives and the synthesis of toxic substances), production of dyes, medicines, etc. Nitric acid is very harmful to the human body; it leaves ulcers and chemical burns on the skin.

People mistakenly believe that carbon dioxide is nitrogen. In fact, due to its chemical properties, the element reacts with only a small number of elements under normal conditions. And carbon dioxide is carbon monoxide.

Application of a chemical element

Liquid nitrogen is used in medicine for cold treatment (cryotherapy), and also in cooking as a refrigerant.

This element has also found wide application in industry. Nitrogen is a gas that is explosion- and fireproof. In addition, it prevents rotting and oxidation. Now nitrogen is used in mines to create an explosion-proof environment. Nitrogen gas is used in petrochemicals.

In the chemical industry it is very difficult to do without nitrogen. It is used for the synthesis of various substances and compounds, for example, some fertilizers, ammonia, explosives, and dyes. Nowadays large amounts of nitrogen are used for the synthesis of ammonia.

In the food industry, this substance is registered as a food additive.

Mixture or pure substance?

Even scientists in the first half of the 18th century who managed to isolate the chemical element thought that nitrogen was a mixture. But there is a big difference between these concepts.

It has a whole range of permanent properties, such as composition, physical and chemical properties. A mixture is a compound that contains two or more chemical elements.

We now know that nitrogen is a pure substance because it is a chemical element.

When studying chemistry, it is very important to understand that nitrogen is the basis of all chemistry. It forms various compounds that we all encounter, including laughing gas, brown gas, ammonia, and nitric acid. It is not for nothing that chemistry at school begins with the study of such a chemical element as nitrogen.

1. nitrogen - (Alchem.) The creative principle in Nature, most of which is stored in the Astral Light. It is symbolized by a figure representing a cross (cf. Theosophical Dictionary
2. Azoth - Az'ot (fortified place) (Josh. 13:3; Joshua 15:47; 1 Kings 5:1, 3.5-7; 1 Kings 6:17; 2 Chronicles 26:6; Neh.4: 7; Neh.13:23; Is.20:1; Jer.25:20; Am.1:8; Am.3:9; Zeph.2:4; Zech.9:6; Acts 8:40) - one of the five main Philistine cities. Vikhlyantsev Bible Dictionary
3. nitrogen - nitrogen m. A chemical element, a colorless and odorless gas that makes up the bulk of the air and is one of the main elements of plant nutrition. Explanatory Dictionary by Efremova
4. NITROGEN - NITROGEN (lat. Nitrogenium) - N, chemical element of group V of the periodic table, atomic number 7, atomic mass 14.0067. The name comes from the Greek a - negative prefix and zoe - life (does not support respiration and combustion). Large encyclopedic dictionary
5. nitrogen - Nitrogen, pl. no, m. [from Greek. neg. a and zoe – life]. A colorless and odorless gas found in air. || Chemical element (chemical). Large dictionary of foreign words
6. nitrogen - Borrowed from French language in the 18th century Franz. azote is a new formation of the chemist Lavoisier (Greek a "not" and zōos "living"). Nitrogen literally means “not giving life.” See zoology with the same root. Shansky Etymological Dictionary
7. nitrogen - NITROGEN -a; m. [French] azote from Greek. an- - not-, without- and zōtikos - giving life]. Chemical element (N), a colorless and odorless gas that does not support respiration and combustion (it constitutes the main part of air by volume and mass... Kuznetsov's Explanatory Dictionary
8. nitrogen - AZ’OT, nitrogen, pl. no, husband (from Greek negative a and zoe - life). A colorless and odorless gas found in air. | Chemical element (chemical). Ushakov's Explanatory Dictionary
9. Nitrogen - I (chemical sign N, atomic weight - 14) - one of the chemical elements; a colorless gas that has neither odor nor taste; very slightly soluble in water. Its specific gravity is 0.972. Encyclopedic Dictionary of Brockhaus and Efron
10. nitrogen - NITROGEN, a, m. A chemical element, a colorless and odorless gas, the main component of air, which is also part of proteins and nucleic acids. | adj. nitrogenous, aya, oh and nitrogenous, aya, oh. Nitric, nitrous acids. Nitrogen fertilizers. Ozhegov's Explanatory Dictionary
11. Azoth - Ashdod (Ashdod), first mentioned in Joshua 11:22 as the city of the Anakim. It was later named among the five major Philistine city-states along with Gaza, Ashkelon, Gath, and Ekron (Joshua 13:3; 1 Sam. 6:17). acc. Joshua 15:47... Brockhaus Biblical Encyclopedia
12. Azoth - (fortified place; Joshua 11:22, 13:3, 15:47, Judges 1:18, Acts 8:40) - one of the five main cities of the Philistines, on the eastern shore of the Mediterranean Sea, between Ekron and Ascalon, in 15 -ti or 20 eng. miles to the village from Gaza. Archimandrite Biblical Encyclopedia. Nikephoros
13. nitrogen - NITROGEN (from the Greek a-prefix, here meaning absence, and life; lat. Nitrogenium, from nitrum - saltpeter and Greek gennao - I give birth, produce) N chemical. element V gr. periodic table, at. n. 7, at. m. 14.0067. Nature Chemical encyclopedia
14. nitrogen - -a, m. A chemical element, a colorless and odorless gas that does not support combustion (it constitutes the main part of the air by volume or mass, and is one of the main elements of plant nutrition). [French azote from Greek. ’α- - non-, without- and ζωή - life] Small academic dictionary
15. nitrogen - French – azote. Greek – azoos (non-living). The word “nitrogen” has become known and used in Russian since the 18th century. as a scientific term for a chemical element, a colorless gas. Etymological Dictionary of Semenov
16. Azoth - Azōtus, Ἄζωτος city in Palestine, near the sea. It was conquered by Psammetichus of Egypt (Hdt. 2.157), as well as Jonathan Maccabeus, who destroyed it. In 56 BC, it, together with other cities, was again built by the proconsul Gabinius. A. in the Old Testament, n. Esdud village. Dictionary of Classical Antiquities
17. nitrogen - NITROGEN (from the Greek a- - prefix, here meaning absence, and Joe - life; lat. Nitrogenium), N, chemical. element, colorless gas. Basic its mass is concentrated in a free state in the atmosphere. Agricultural Dictionary
18. nitrogen - Nitrogen/. Morphemic-spelling dictionary
19. NITROGEN - NITROGEN (symbol N), a colorless and odorless chemical element belonging to group V of the periodic table. Discovered in 1772, it is usually found in the form of gas. It is the main component of the Earth's atmosphere (78% of the volume). Scientific and technical dictionary
20. nitrogen - orf. nitrogen, -a Lopatin's spelling dictionary
21. nitrogen - This word was created artificially in 1787, when a scientific term was needed for the name of this gas. Since this gas does not support breathing and the name was coined accordingly... Krylov's etymological dictionary
22. Nitrogen - I Nitrogen (Nitrogenium, N) chemical element of group V of the periodic system D.I. Mendeleev, one of the most common chemical elements in nature. Composed of all living organisms... Medical encyclopedia
23. Nitrogen - N (lat. Nitrogenium * a. nitrogen; n. Stickstoff; f. azote, nitrogene; i. nitrogeno), - chemical. element of group V is periodic. Mendeleev system, at.sci. 7, at. m. 14.0067. Opened in 1772 researcher D. Rutherford. Under normal conditions A. Mountain encyclopedia
24. nitrogen - Nitrogen, nitrogen, nitrogen, nitrogen, nitrogen, nitrogen, nitrogen, nitrogen, nitrogen, nitrogen, nitrogen, nitrogen Zaliznyak's Grammar Dictionary
25. nitrogen - NITROGEN m. chemical. base, main element of saltpeter; saltpeter, saltpeter, saltpeter; It is also the main, in quantity, component of our air (nitrogen - 79 volumes, oxygen - 21). Nitrogenous, nitrogenous, nitrogen containing nitrogen. Dahl's Explanatory Dictionary
26. nitrogen - noun, number of synonyms: 8 gas 55 non-metal 17 nitrogen 1 organogen 6 saltpeter 3 saltpeter 3 saltpeter 3 element 159 Dictionary of Russian synonyms
27. nitrogen - NITROGEN -a m. azote m.<�араб. 1787. Лексис.1. алхим. Первая материя металлов - металлическая ртуть. Сл. 18. Пустился он <�парацельс>to the end of the world, offering everyone his Laudanum and his Azoth for a very reasonable price... Dictionary of Gallicisms of the Russian language

The content of the article

NITROGEN, N (nitrogenium), chemical element (at. number 7) VA subgroup of the periodic table of elements. The Earth's atmosphere contains 78% (vol.) nitrogen. To show how large these reserves of nitrogen are, we note that in the atmosphere above each square kilometer of the earth's surface there is so much nitrogen that up to 50 million tons of sodium nitrate or 10 million tons of ammonia (a compound of nitrogen with hydrogen) can be obtained from it, and yet this constitutes a small fraction of the nitrogen contained in the earth's crust. The existence of free nitrogen indicates its inertness and the difficulty of interacting with other elements at ordinary temperatures. Fixed nitrogen is part of both organic and inorganic matter. Plant and animal life contain nitrogen bound to carbon and oxygen in proteins. In addition, nitrogen-containing inorganic compounds such as nitrates (NO 3 –), nitrites (NO 2 –), cyanides (CN –), nitrides (N 3 –) and azides (N 3 –) are known and can be obtained in large quantities ).

Historical reference.

The experiments of A. Lavoisier, devoted to the study of the role of the atmosphere in maintaining life and combustion processes, confirmed the existence of a relatively inert substance in the atmosphere. Without establishing the elemental nature of the gas remaining after combustion, Lavoisier called it azote, which means “lifeless” in ancient Greek. In 1772, D. Rutherford from Edinburgh established that this gas is an element and called it “harmful air.” The Latin name for nitrogen comes from the Greek words nitron and gen, which means "saltpeter-forming".

Nitrogen fixation and the nitrogen cycle.

The term "nitrogen fixation" refers to the process of fixing atmospheric nitrogen N 2 . In nature, this can happen in two ways: either legumes, such as peas, clover and soybeans, accumulate nodules on their roots, in which nitrogen-fixing bacteria convert it into nitrates, or atmospheric nitrogen is oxidized by oxygen under lightning conditions. S. Arrhenius found that up to 400 million tons of nitrogen are fixed annually in this way. In the atmosphere, nitrogen oxides combine with rainwater to form nitric and nitrous acids. In addition, it has been established that with rain and snow, approx. 6700 g nitrogen; reaching the soil, they turn into nitrites and nitrates. Plants use nitrates to form plant proteins. Animals, feeding on these plants, assimilate the protein substances of the plants and convert them into animal proteins. After the death of animals and plants, they decompose and nitrogen compounds turn into ammonia. Ammonia is used in two ways: bacteria that do not form nitrates break it down to elements, releasing nitrogen and hydrogen, and other bacteria form nitrites from it, which are oxidized by other bacteria to nitrates. This is how the nitrogen cycle occurs in nature, or the nitrogen cycle.

Structure of the nucleus and electron shells.

There are two stable isotopes of nitrogen in nature: with a mass number of 14 (contains 7 protons and 7 neutrons) and with a mass number of 15 (contains 7 protons and 8 neutrons). Their ratio is 99.635:0.365, so the atomic mass of nitrogen is 14.008. Unstable nitrogen isotopes 12 N, 13 N, 16 N, 17 N were obtained artificially. Schematically, the electronic structure of the nitrogen atom is as follows: 1 s 2 2s 2 2p x 1 2p y 1 2p z 1 . Consequently, the outer (second) electron shell contains 5 electrons that can participate in the formation of chemical bonds; nitrogen orbitals can also accept electrons, i.e. the formation of compounds with oxidation states from (–III) to (V) is possible, and they are known.

Molecular nitrogen.

From determinations of gas density it has been established that the nitrogen molecule is diatomic, i.e. the molecular formula of nitrogen is Nє N (or N 2). Two nitrogen atoms have three outer 2 p-electrons of each atom form a triple bond:N:::N:, forming electron pairs. The measured N–N interatomic distance is 1.095 Å. As in the case of hydrogen ( cm. HYDROGEN), there are nitrogen molecules with different nuclear spins - symmetric and antisymmetric. At ordinary temperatures, the ratio of symmetric and antisymmetric forms is 2:1. In the solid state, two modifications of nitrogen are known: a– cubic and b– hexagonal with transition temperature a ® b–237.39° C. Modification b melts at –209.96° C and boils at –195.78° C at 1 atm ( cm. table 1).

The dissociation energy of a mole (28.016 g or 6.023 H 10 23 molecules) of molecular nitrogen into atoms (N 2 2N) is approximately –225 kcal. Therefore, atomic nitrogen can be formed during a quiet electrical discharge and is chemically more active than molecular nitrogen.

Receipt and application.

The method of obtaining elemental nitrogen depends on the required purity. Nitrogen is obtained in huge quantities for the synthesis of ammonia, while small admixtures of noble gases are acceptable.

Nitrogen from the atmosphere.

Economically, the release of nitrogen from the atmosphere is due to the low cost of the method of liquefying purified air (water vapor, CO 2, dust, and other impurities are removed). Successive cycles of compression, cooling and expansion of such air lead to its liquefaction. Liquid air is subjected to fractional distillation with a slow rise in temperature. The noble gases are released first, then nitrogen, and liquid oxygen remains. Purification is achieved by repeated fractionation processes. This method produces many millions of tons of nitrogen annually, mainly for the synthesis of ammonia, which is the feedstock in the production technology of various nitrogen-containing compounds for industry and agriculture. In addition, a purified nitrogen atmosphere is often used when the presence of oxygen is unacceptable.

Laboratory methods.

Nitrogen can be obtained in small quantities in the laboratory in various ways by oxidizing ammonia or ammonium ion, for example:

The process of oxidation of ammonium ion with nitrite ion is very convenient:

Other methods are also known - the decomposition of azides when heated, the decomposition of ammonia with copper(II) oxide, the interaction of nitrites with sulfamic acid or urea:

The catalytic decomposition of ammonia at high temperatures can also produce nitrogen:

Physical properties.

Some physical properties of nitrogen are given in table. 1.

Chemical properties.

As already noted, the predominant property of nitrogen under normal conditions of temperature and pressure is its inertness, or low chemical activity. The electronic structure of nitrogen contains an electron pair of 2 s-level and three half filled 2 R-orbitals, so one nitrogen atom can bind no more than four other atoms, i.e. its coordination number is four. The small size of an atom also limits the number of atoms or groups of atoms that can be associated with it. Therefore, many compounds of other members of the VA subgroup either have no analogues among nitrogen compounds at all, or similar nitrogen compounds turn out to be unstable. So, PCl 5 is a stable compound, but NCl 5 does not exist. A nitrogen atom is capable of bonding with another nitrogen atom, forming several fairly stable compounds, such as hydrazine N 2 H 4 and metal azides MN 3. This type of bond is unusual for chemical elements (with the exception of carbon and silicon). At elevated temperatures, nitrogen reacts with many metals, forming partially ionic nitrides M x N y. In these compounds, nitrogen is negatively charged. In table Table 2 shows the oxidation states and examples of corresponding compounds.

Nitrides.

Compounds of nitrogen with more electropositive elements, metals and non-metals - nitrides - are similar to carbides and hydrides. They can be divided depending on the nature of the M–N bond into ionic, covalent and with an intermediate type of bond. As a rule, these are crystalline substances.

Ionic nitrides.

The bonding in these compounds involves the transfer of electrons from the metal to nitrogen to form the N3– ion. Such nitrides include Li 3 N, Mg 3 N 2, Zn 3 N 2 and Cu 3 N 2. Apart from lithium, other alkali metals do not form IA subgroups of nitrides. Ionic nitrides have high melting points and react with water to form NH 3 and metal hydroxides.

Covalent nitrides.

When nitrogen electrons participate in the formation of a bond together with the electrons of another element without transferring them from nitrogen to another atom, nitrides with a covalent bond are formed. Hydrogen nitrides (such as ammonia and hydrazine) are completely covalent, as are nitrogen halides (NF 3 and NCl 3). Covalent nitrides include, for example, Si 3 N 4, P 3 N 5 and BN - highly stable white substances, and BN has two allotropic modifications: hexagonal and diamond-like. The latter is formed at high pressures and temperatures and has a hardness close to that of diamond.

Nitrides with an intermediate type of bond.

Transition elements react with NH 3 at high temperatures to form an unusual class of compounds in which the nitrogen atoms are distributed among regularly spaced metal atoms. There is no clear electron displacement in these compounds. Examples of such nitrides are Fe 4 N, W 2 N, Mo 2 N, Mn 3 N 2. These compounds are usually completely inert and have good electrical conductivity.

Hydrogen compounds of nitrogen.

Nitrogen and hydrogen react to form compounds vaguely resembling hydrocarbons. The stability of hydrogen nitrates decreases with increasing number of nitrogen atoms in the chain, in contrast to hydrocarbons, which are stable in long chains. The most important hydrogen nitrides are ammonia NH 3 and hydrazine N 2 H 4. These also include hydronitric acid HNNN (HN 3).

Ammonia NH3.

Ammonia is one of the most important industrial products of the modern economy. At the end of the 20th century. The USA produced approx. 13 million tons of ammonia annually (in terms of anhydrous ammonia).

Molecule structure.

The NH 3 molecule has an almost pyramidal structure. The H–N–H bond angle is 107°, which is close to the tetrahedral angle of 109°. The lone electron pair is equivalent to the attached group, resulting in the coordination number of nitrogen being 4 and nitrogen being located at the center of the tetrahedron.

Properties of ammonia.

Some physical properties of ammonia in comparison with water are given in table. 3.

The boiling and melting points of ammonia are much lower than those of water, despite the similarity of molecular weights and the similarity of molecular structure. This is explained by the relatively greater strength of intermolecular bonds in water than in ammonia (such intermolecular bonds are called hydrogen bonds).

Ammonia as a solvent.

The high dielectric constant and dipole moment of liquid ammonia make it possible to use it as a solvent for polar or ionic inorganic substances. Ammonia solvent occupies an intermediate position between water and organic solvents such as ethyl alcohol. Alkali and alkaline earth metals dissolve in ammonia, forming dark blue solutions. It can be assumed that solvation and ionization of valence electrons occurs in solution according to the scheme

The blue color is associated with solvation and the movement of electrons or the mobility of “holes” in a liquid. At a high concentration of sodium in liquid ammonia, the solution takes on a bronze color and is highly electrically conductive. Unbound alkali metal can be separated from such a solution by evaporation of ammonia or the addition of sodium chloride. Solutions of metals in ammonia are good reducing agents. Autoionization occurs in liquid ammonia

similar to the process occurring in water:

Some chemical properties of both systems are compared in Table. 4.

Liquid ammonia as a solvent has an advantage in some cases where it is not possible to carry out reactions in water due to the rapid interaction of components with water (for example, oxidation and reduction). For example, in liquid ammonia, calcium reacts with KCl to form CaCl 2 and K, since CaCl 2 is insoluble in liquid ammonia, and K is soluble, and the reaction proceeds completely. In water, such a reaction is impossible due to the rapid interaction of Ca with water.

Production of ammonia.

Gaseous NH 3 is released from ammonium salts under the action of a strong base, for example, NaOH:

The method is applicable in laboratory conditions. Small-scale ammonia production is also based on the hydrolysis of nitrides, such as Mg 3 N 2, with water. Calcium cyanamide CaCN 2 when interacting with water also forms ammonia. The main industrial method for producing ammonia is its catalytic synthesis from atmospheric nitrogen and hydrogen at high temperature and pressure:

Hydrogen for this synthesis is obtained by thermal cracking of hydrocarbons, the action of water vapor on coal or iron, the decomposition of alcohols with water vapor, or the electrolysis of water. Many patents have been obtained for the synthesis of ammonia, differing in the process conditions (temperature, pressure, catalyst). There is a method of industrial production through thermal distillation of coal. The names of F. Haber and K. Bosch are associated with the technological development of ammonia synthesis.

Chemical properties of ammonia.

In addition to the reactions mentioned in table. 4, ammonia reacts with water to form the compound NH 3 N H 2 O, which is often mistakenly considered ammonium hydroxide NH 4 OH; in fact, the existence of NH 4 OH in solution has not been proven. An aqueous solution of ammonia (“ammonia”) consists predominantly of NH 3, H 2 O and small concentrations of NH 4 + and OH – ions formed during dissociation

The basic nature of ammonia is explained by the presence of a lone electron pair of nitrogen:NH 3 . Therefore, NH 3 is a Lewis base, which has the highest nucleophilic activity, manifested in the form of association with a proton, or the nucleus of a hydrogen atom:

Any ion or molecule capable of accepting an electron pair (electrophilic compound) will react with NH 3 to form a coordination compound. For example:

Symbol M n+ represents a transition metal ion (B-subgroup of the periodic table, for example, Cu 2+, Mn 2+, etc.). Any protic (i.e. H-containing) acid reacts with ammonia in an aqueous solution to form ammonium salts, such as ammonium nitrate NH 4 NO 3, ammonium chloride NH 4 Cl, ammonium sulfate (NH 4) 2 SO 4, phosphate ammonium (NH 4) 3 PO 4. These salts are widely used in agriculture as fertilizers to introduce nitrogen into the soil. Ammonium nitrate is also used as an inexpensive explosive; it was first used with petroleum fuel (diesel oil). An aqueous solution of ammonia is used directly for introduction into the soil or with irrigation water. Urea NH 2 CONH 2, obtained by synthesis from ammonia and carbon dioxide, is also a fertilizer. Ammonia gas reacts with metals such as Na and K to form amides:

Ammonia also reacts with hydrides and nitrides to form amides:

Alkali metal amides (for example, NaNH 2) react with N 2 O when heated, forming azides:

Gaseous NH 3 reduces heavy metal oxides to metals at high temperatures, apparently due to hydrogen produced by the decomposition of ammonia into N 2 and H 2:

Hydrogen atoms in the NH 3 molecule can be replaced by halogen. Iodine reacts with a concentrated solution of NH 3, forming a mixture of substances containing NI 3. This substance is very unstable and explodes at the slightest mechanical impact. When NH 3 reacts with Cl 2, the chloramines NCl 3, NHCl 2 and NH 2 Cl are formed. When ammonia is exposed to sodium hypochlorite NaOCl (formed from NaOH and Cl 2), the final product is hydrazine:

Hydrazine.

The above reactions are a method for producing hydrazine monohydrate with the composition N 2 H 4 P H 2 O. Anhydrous hydrazine is formed by special distillation of the monohydrate with BaO or other water-removing substances. The properties of hydrazine are slightly similar to hydrogen peroxide H 2 O 2. Pure anhydrous hydrazine is a colorless, hygroscopic liquid, boiling at 113.5° C; dissolves well in water, forming a weak base

In an acidic environment (H +), hydrazine forms soluble hydrazonium salts of the + X – type. The ease with which hydrazine and some of its derivatives (such as methylhydrazine) react with oxygen allows it to be used as a component of liquid rocket fuel. Hydrazine and all its derivatives are highly toxic.

Nitrogen oxides.

In compounds with oxygen, nitrogen exhibits all oxidation states, forming oxides: N 2 O, NO, N 2 O 3, NO 2 (N 2 O 4), N 2 O 5. There is scant information on the formation of nitrogen peroxides (NO 3, NO 4). 2HNO2. Pure N 2 O 3 can be obtained as a blue liquid at low temperatures (-20

At room temperature, NO 2 is a dark brown gas that has magnetic properties due to the presence of an unpaired electron. At temperatures below 0° C, the NO 2 molecule dimerizes into dinitrogen tetroxide, and at –9.3° C, dimerization occurs completely: 2NO 2 N 2 O 4. In the liquid state, only 1% NO 2 is undimerized, and at 100° C 10% N 2 O 4 remains in the form of a dimer.

NO 2 (or N 2 O 4) reacts in warm water to form nitric acid: 3NO 2 + H 2 O = 2HNO 3 + NO. NO 2 technology is therefore very important as an intermediate stage in the production of an industrially important product - nitric acid.

Nitric oxide(V)

N2O5( outdated. nitric anhydride) is a white crystalline substance obtained by dehydrating nitric acid in the presence of phosphorus oxide P 4 O 10:

Nitrous acid

HNO 2 does not exist in pure form, however, aqueous solutions of its low concentration are formed by adding sulfuric acid to barium nitrite:

Nitrous acid is also formed when an equimolar mixture of NO and NO 2 (or N 2 O 3) is dissolved in water. Nitrous acid is slightly stronger than acetic acid. The oxidation state of nitrogen in it is +3 (its structure is H–O–N=O), i.e. it can be both an oxidizing agent and a reducing agent. Under the influence of reducing agents it is usually reduced to NO, and when interacting with oxidizing agents it is oxidized to nitric acid.

The rate of dissolution of some substances, such as metals or iodide ion, in nitric acid depends on the concentration of nitrous acid present as an impurity. Salts of nitrous acid - nitrites - dissolve well in water, except for silver nitrite. NaNO 2 is used in the production of dyes.

Nitric acid

HNO 3 is one of the most important inorganic products of the main chemical industry. It is used in the technologies of many other inorganic and organic substances, such as explosives, fertilizers, polymers and fibers, dyes, pharmaceuticals, etc.

Literature:

Nitrogenist's Directory. M., 1969
Nekrasov B.V. Basics of general chemistry. M., 1973
Nitrogen fixation problems. Inorganic and physical chemistry. M., 1982

Nitrogen is a chemical element of group V of the periodic system of Mendeleev, having atomic number 7 and atomic mass 14.00674. What properties does this element have?

Physical properties of nitrogen

Nitrogen is a diatomic gas, odorless, colorless and tasteless. The boiling point of nitrogen at atmospheric pressure is -195.8 degrees, the melting point is -209.9 degrees. Solubility in water at 20 degrees is very low - 15.4 ml/l.

Rice. 1. Nitrogen atom.

Atmospheric nitrogen consists of two isotopes: 14N (99.64%) and 15N (0.36%). Radioactive isotopes of nitrogen 13N and 16N are also known.

The translation of the name of the element “nitrogen” is lifeless. This name is true for nitrogen as a simple substance, but in a bound state it is one of the main elements of life, and is also part of proteins, nucleic acids, vitamins, etc.

Chemical properties of nitrogen

In the nitrogen molecule, the chemical bond is carried out due to three common pairs of p-electrons, the orbitals of which are directed along the x, y, z axes.

A covalent bond that is formed by overlapping orbitals along a line connecting the centers of the joining atoms is called a q-bond.

A covalent bond that occurs when the orbitals on either side of the line connecting the centers of the joining atoms overlap is called a n-bond. The nitrogen molecule has one q-bond and two p-bonds.

Rice. 2. Bonds in a nitrogen molecule.

Molecular nitrogen is a chemically inactive substance, this is explained by the triple bond between the nitrogen atoms and its short length

Under normal conditions, nitrogen can only react with lithium:

6Li+N 2 =2Li 3 N (lithium nitrite)

At high temperatures, the bonds between atoms weaken and nitrogen becomes more reactive. When heated, it can react with other metals, for example with magnesium, calcium, aluminum to form nitrides:

3Mg+N 2 =Mg 3 N 2

3Ca+N2 =Ca3N2

By passing nitrogen through hot coke, a compound of nitrogen and carbon is obtained - cyanogen.

Rice. 3. Dicyan formula.

With aluminum oxide and carbon, nitrogen also forms aluminum nitride at high temperatures:

Al 2 O 3 +3C+N 2 =2AlN+3CO,

and with soda and coal - sodium cyanide:

Na 2 CO 3 +4C+N 2 =2NaCN+3CO

When in contact with water, many nitrides completely hydrolyze to form ammonia and metal hydroxide:

Mg 3 N 2 +6H 2 O=3Mg(OH) 2 +2NH 3

At the temperature of the electric arc (3000-4000 degrees), nitrogen reacts with oxygen:. Total ratings received: 224.