Mendeleev's periodic table of elements is phosphorus. Mendeleev's periodic table of elements - phosphorus Mendeleev's phosphorus

	P	15			Phosphorus
					t o kip. (o C)	287.3 - white	Step oxide	-3 +3 +5
		30,97376			t o float(o C)	44.14(white) 593(red)	Density	1820(white) 2340(red)
	3s 2 3p 3				OEO	2,32	in the ground bark	0,118 %

"...Yes? It was a dog, huge, pitch black. But none of us mortals have ever seen such a dog. Flames erupted from her open mouth, her eyes threw sparks, and flickering fire shimmered across her muzzle and nape. In no one's fevered brain could a vision arise that was more terrible, more disgusting than this hellish creature that jumped out at us from the fog... A terrible dog, the size of a young lioness. Its huge mouth still glowed with a bluish flame, its deep-set wild eyes were surrounded by fiery circles.

I touched this luminous head and, taking my hand away, saw that my fingers also glowed in the dark. Phosphorus, I said.”

Learned? Arthur Conan Doyle. "The Hound of the Baskervilles." This is the nasty story Element No. 15 was involved in.

Another bad story

More than three hundred years separate us from the moment when the Hamburg alchemist Genning Brand discovered a new element - phosphorus. Like other alchemists, Brand tried to find the elixir of life or the philosopher's stone, with the help of which old people look younger, the sick recover, and base metals turn into gold. It was not concern for the welfare of people, but self-interest that guided Brand. This is evidenced by facts from the history of the only real discovery made by him.

During one of the experiments, he evaporated the urine, mixed the residue with coal and sand and continued evaporation. Soon a substance formed in the retort that glowed in the dark. True, Kaltes Feuer (cold fire), or “my fire,” as Brand called it, did not turn lead into gold and did not change the appearance of old people, but the fact that the resulting substance glowed without heating was unusual and new.

Brand was not slow to take advantage of this property of the new substance. He began to show phosphorus to various privileged persons, receiving gifts and money from them. It was not easy to keep the secret of obtaining phosphorus, and Brand soon sold it to the Dresden chemist I. Kraft. The number of phosphorus demonstrators increased when the recipe for its production became known to I. Kunkol and K. Kirchmeyer. In 1680, regardless of its predecessors, a new element was obtained by the famous English physicist and chemist Robert Boyle. But Boyle soon died, and his student A. Gankwitz betrayed the pure science and again revived “phosphorus speculation.” Only in 1743 A. Marggraf found a more advanced method for producing phosphorus and published his data for public information. This event put an end to Brand's business and served as the beginning of a serious study of phosphorus and its compounds.

At the first - fifty-year - stage of the history of phosphorus, besides Boyle's discovery, only one event was marked by the history of science: in 1715, Gensing established the presence of phosphorus in brain tissue. After Marggraf's experiments, the history of the element, which many years later became number 15, became the history of many great discoveries.

Chronology of these discoveries

In 1769, Yu. Gan proved that bones contain a lot of phosphorus. The same thing was confirmed two years later by the famous Swedish chemist K. Scheele, who proposed

a method of obtaining phosphorus from the ash formed during the firing of braids.

A few years later, J. L. Proust and M. Klaproth, studying various natural compounds, proved that phosphorus is widespread in earth's crust, mainly in the form of calcium phosphate.

The great French chemist Antoine Laurent Lavoisier achieved great success in studying the properties of phosphorus in the early seventies of the 18th century. By burning phosphorus with other substances in a closed volume of air, Lavoisier proved that phosphorus — an independent element, and air has a complex composition and is composed of at least two components - oxygen and nitrogen. “In this way, for the first time, he put on its feet all chemistry, which in its phlogistic form stood on its head.” This is how F. Engels wrote about Lavoisier’s works in the preface to the second volume of Capital.

In 1799, Dondonald proved that phosphorus compounds are necessary for normal development plants.

In 1839, another Englishman, Laws, was the first to obtain superphosphate - a phosphorus fertilizer that is easily absorbed by plants.

In 1847, the German chemist Schrötter, heating white phosphorus. without access to air, he received a new variety (allotropic modification) of element No. 15 - red phosphorus, and already in the 20th century, in 1934, the American physicist P. Bridgman, studying the effect of high pressures on various substances, isolated black phosphorus, similar to graphite. These are the main milestones in the history of element No. 15. Now let us trace what followed each of these discoveries.

“In 1715, Gensing established the presence of phosphorus in brain tissue... In 1769, Hahn proved that bones contain a lot of phosphorus”

Phosphorus is an analogue of nitrogen. Although physical and Chemical properties these elements are very strong; They differ, but they also have something in common, in particular, that both of these elements are absolutely necessary for animals and plants. Academician A.E. Fersman called phosphorus “the element of life and thought,” and this definition can hardly be classified as literary exaggeration. Phosphorus is found in literally all organs of green plants: stems, roots, leaves, but most of all in fruits and seeds. Plants accumulate phosphorus and supply it to animals.

In animals, phosphorus is concentrated mainly in the skeleton, muscles and nervous tissue.

Among human food products, the yolk of chicken eggs is especially rich in phosphorus.

The human body contains on average about one and a half kilograms of element No. 15. Of this amount, 1.4 kilograms are bones, about 130 grams are muscles and 12 grams are nerves and brain. Almost all the most important physiological processes occurring in our body are associated with the transformations of organophosphorus substances. Phosphorus is found in bones mainly in the form of calcium phosphate. Tooth enamel is also a phosphorus compound, which in composition and crystal structure corresponds to the most important phosphorus mineral apatite Ca 5 (PO 4) 3 (F, CI),

Naturally, like any vital element, phosphorus undergoes a cycle in nature. Plants take it from the soil, and from plants this element enters the bodies of humans and animals. Phosphorus returns to the soil with excrement and when corpses rot. Phosphorobacteria convert organic phosphorus into inorganic compounds.

However, per unit time, significantly more phosphorus is removed from the soil than is supplied back. The world's harvest now removes more than three million tons of phosphorus from fields every year.

Naturally, to obtain sustainable yields, this phosphorus must be returned to the soil, and therefore it is not surprising that world production of phosphates reached 58.5 million tons in 1964.

“...Proust and Klaproth proved that phosphorus is widely distributed in the earth’s crust, mainly in the form of calcium phosphate.”

In the earth's crust, phosphorus occurs exclusively in the form of compounds. These are mainly sparingly soluble

orthophosphoric acid salts; The cation most often is calcium ion.

Phosphorus accounts for 0.08% of the weight of the earth's crust. In terms of prevalence, it ranks 13th among everyone elements. Phosphorus is contained in at least 190 minerals, the most important of which are: fluorapatite - Ca 5 (PO 4) 3 F, hydroxyapatite - Ca 5 (PO 4) 3 OH, phosphorite - Ca 3 (PO 4) 2.

Less common are vivianite—Fe 3 (PO 4) 2 -8H20, monazite—(Ce, La) PO 4, amblygonite—LiAl(PO 4)F, triphylite—Li(Fe, Mn) PO 4, and even more rarely xenotmm—YPO 4 and torbernite - Cu(UO 2) 2 [PO 4 ] 2 12H 2 O.

Phosphorus minerals are divided into primary and secondary. Among the primary ones, apatites are especially common, often found among rocks of igneous origin. These minerals were formed during the formation of the earth's crust.

Unlike apatites, phosphorites occur among rocks sedimentary origin formed as a result of the death of living beings. These are secondary minerals.

Phosphorus is found in meteorites in the form of iron, cobalt, and nickel phosphides. Of course, this common element is also found in sea water (6-10-6%).

“Lavoisier proved that phosphorus is an independent chemical element...»

Phosphorus is a nonmetal (what was previously called a metalloid) of medium activity. The outer orbit of the phosphorus atom contains five electrons, three of which are unpaired. Therefore, it can exhibit valences of 3-, 3+ and 5+.

In order for phosphorus to exhibit a valence of 5+, some effect on the atom is necessary, which would turn the two paired electrons of the last orbit into unpaired ones.

Phosphorus is often called a multifaceted element. Indeed, under different conditions it behaves differently, exhibiting either oxidative or restorative properties. The versatility of phosphorus is its ability to exist in several allotropic modifications.

Perhaps the most famous modification of element No. 15 is soft, waxy, white or yellow phosphorus. It was Brand who discovered it, and thanks to its properties the element received its name: in Greek “phosphorus” means luminous, luminiferous. The white phosphorus molecule consists of four atoms arranged in the shape of a tetrahedron. Specific gravity 1.83, melting point 44.1° C. White phosphorus is poisonous and easily oxidizes. Soluble in carbon disulfide, liquid ammonia and SO2, benzene, ether. It is almost soluble in water.

When heated without access to air above 250 ° C, white phosphorus turns into red. This is already polymer, but not a very ordered structure. The reactivity of red phosphorus is significantly less than that of white phosphorus. It does not glow in the dark, does not dissolve in carbon disulfide, and is not poisonous. Its density is much higher, its structure is fine-crystalline.

Less known are other, even more high-molecular modifications of phosphorus - violet, brown and black, which differ from each other in molecular weight and degree of order of macromolecules. Black phosphorus, first obtained by P. Bridgman under high pressure conditions (200,000 atmospheres at a temperature of 200 ° C), is more reminiscent of graphite than white or red phosphorus. These modifications are laboratory exotic and, unlike white and red phosphorus practical application haven't found it yet.

By the way, about the applications of elemental phosphorus; Its main consumers are the production of matches, metallurgy, and chemical production. In the recent past, part of the resulting elemental phosphorus was spent at military enterprises; it was used to prepare smoke and incendiary compositions.

Metallurgists usually strive to get rid of phosphorus impurities in the metal—it worsens the mechanical properties, but sometimes phosphorus is deliberately introduced into the composition. This is done when it is necessary for the metal to expand slightly when solidifying and accurately take on the outline of the shape. Phosphorus is widely used in chemistry. Part of it is used for the preparation of phosphorus chlorides, needed in the synthesis of certain organic preparations; The stage of production of elemental phosphorus is also present in some technological schemes for the production of concentrated phosphorus fertilizers.

Now about its connections.

Phosphoric anhydride P 2 O 5 is an excellent desiccant that greedily absorbs water from the air and other substances. The P 2 O 5 content is the main criterion for the value of all phosphate fertilizers.

Phosphoric acids, primarily orthophosphoric acid H 3 PO 4, are used in the main chemical industry; Salts of phosphoric acids are primarily phosphorus fertilizers (a special discussion about them) and phosphates alkali metals necessary for the production of detergents.

Phosphorus halides (mainly PC1 3 and PCl 5 chlorides) are used in the organic synthesis industry.

Of the compounds of phosphorus with hydrogen, the most famous is phosphine PH 3 - a highly poisonous colorless gas with a garlicky odor.

Among phosphorus compounds, phosphorus has a special place organic compounds. Most of them have biological activity. Therefore, some organophosphorus compounds are used as medicines, others as pest control agents.

An independent class of substances consisted of phosphonitrile chlorides - compounds of phosphorus with nitrogen and chlorine. The phosphonitrile chloride monomer is capable of polymerization. With increasing molecular weight, the properties of substances of this class change, in particular, their solubility in organic liquids noticeably decreases. When the molecular weight of the polymer reaches several thousand, a rubber-like substance is obtained - the only rubber so far that contains no carbon at all. A further increase in molecular weight leads to the formation of solid plastic-eating substances. “Carbon-free rubber” has significant heat resistance: it begins to deteriorate only at 350°C.

“In 1839, the Englishman Laws was the first to obtain superphosphate, a phosphorus fertilizer easily absorbed by plants.”

In order for plants to absorb phosphorus, it must be in a soluble compound. To obtain these compounds, calcium phosphate and sulfuric acid mixed in such proportions that there are two gram molecules of acid per gram molecule of phosphate. As a result of the interaction, sulfate and soluble calcium dihydrogen phosphate are formed:

Ca 3 (PO 4) 2 + 2H 2 SO 4 = 2CaSO 4 + Ca(H 2 PO 4) 2. A mixture of these two salts is known as superphosphate. In this mixture, calcium sulfate from the point of view of agricultural chemistry is ballast, but it is not separated, since this operation is costly and greatly increases the cost of fertilizer. Simple superphosphate contains only 14-20% P 2 O 5 .

A more concentrated phosphorus fertilizer is double superphosphate. It is obtained by reacting calcium phosphate with phosphoric acid:

Ca 3 (PO 4) 2 + 4H 3 PO 4 = 3Ca (H 2 PO 4) 2.

Double superphosphate contains 40-50% P 2 O 5. In fact, it would be more correct to call it triple: it is three times richer in phosphorus than simple superphosphate.

Sometimes CaHPO 4 precipitate is used as a phosphorus fertilizer. H 2 O, which is obtained by reacting phosphoric acid with calcium hydroxide or calcium carbonate:

Ca(OH) 2 + H 3 PO 4 =CaHPO 4. 2H 2 O, 2CaCO 3 + 2H 3 PO 4 = 2CaHPO 4. 2H 2 O + 2CO 2.

This fertilizer contains 30-35% P 2 O 5.

Some combined fertilizers also contain phosphorus, for example diamophos (NH 4) 2 HPO 4, which also contains nitrogen.

With the explored reserves of phosphorus raw materials in our country, as well as throughout the world, the situation is not entirely favorable. Academician S. I. Volfkovich from the rostrum of the IX Mendeleev Congress on General and Applied Chemistry stated: “If the raw material base of the nitrogen industry - the air ocean, water and natural gas - does not limit the scale of new construction, and the deposits of potassium salts explored to date ensure the development of the production of potash fertilizers for more than a millennium, then the currently studied reserves of domestic phosphorus raw materials with the planned large volumes of fertilizer production will be enough for only a few decades.”

This does not mean at all that humanity is threatened with famine and harvests will decrease from year to year. There are reserves. A lot of additional phosphorus can be obtained through complex processing of mineral raw materials, bottom sea sediments and more detailed geological exploration. Consequently, we have no special grounds for pessimism, especially since Russia ranks one of the first places in the world in terms of recorded reserves of phosphorus ores. We have the largest deposits of apatite on the Kola Peninsula and phosphorites in Southern Kazakhstan and a number of other places.

But it is necessary to search for new deposits and develop methods for producing phosphate fertilizers from poorer ores now. This is necessary for the future, because phosphorus - “the element of life and thought” - will always be necessary for humanity.

Phosphorus(lat. phosphorus), P, chemical element of group V of the periodic system of Mendeleev, atomic number 15, atomic mass 30.97376, non-metal. Natural phosphorus consists of one stable isotope 31 p; six artificial radioactive isotopes were obtained: 28 p ( t 1/2 = 6,27 sec) , 29p ( t 1/2 = 4.45 sec); 30p ( t 1/2 = 2,55 min) , 31p ( t 1/2 = 14,22 days) , 32p ( t 1/2 = 25 days) , 33p ( t 1/2 = 12,5 sec) . Highest value has 32 p , possessing significant b-radiation energy and used in chemical and biochemical research as a labeled atom.

Historical reference . According to some literary data, the method of obtaining phosphorus was already known to the Arabs. alchemists of the 12th century. But the generally accepted date for the discovery of F. is considered to be 1669, when H. Brand (Germany), by calcining the dry residue from the evaporation of urine with sand and subsequent distillation without air access, obtained a substance that glows in the dark, first called “cold fire”, and later F. from the Greek . phosph o ros – luminiferous. Soon the method of obtaining F. became known to him. chemists - I. Kraft, I. Kunkel; in 1682 this method was published. In 1743 A.S. Marggraf developed the following method for obtaining phosphorus: a mixture of lead chloride and urine was evaporated to dryness and heated until the release of volatile products ceased; the residue was mixed with powdered charcoal and distilled in a clay retort; F. vapors condensed in a receiver with water. The simplest method of producing fermentation by calcining bone ash with coal was proposed only in 1771 K. Scheele. The elementary nature of F. was established by A. Lavoisier. In the 2nd half of the 19th century. industrial production of phosphorites from phosphorites in retort furnaces arose; at the beginning of the 20th century. they were replaced by electric ovens.

Distribution in nature . The average content of phosphorus in the earth's crust (clarke) is 9.3? 10 -2% by weight; in medium rocks 1.6 ? 10 -1, in basic rocks 1.4? 10 -1, less in granites and other acidic igneous rocks - 7? 10 -2 and even less in ultrabasic rocks (mantle) - 1.7? 10 -2%; in sedimentary rocks from 1.7? 10 -2 (sandstones) to 4 ? 10 -2% (carbonate rocks). F. takes part in magmatic processes and vigorously migrates in the biosphere. Both processes are associated with large accumulations of it, forming industrial deposits apatite And phosphorites. F. – extremely important biogenic element, it is accumulated by many organisms. Many processes of phosphorus concentration in the earth's crust are associated with biogenic migration. From waters, phosphorus easily precipitates in the form of insoluble minerals or is captured by living matter. Therefore, in sea water there are only 7? 10 -6% Ph. About 180 Ph minerals are known, mainly various phosphates, of which calcium phosphates are the most common .

Physical properties . Elementary phosphorus exists in the form of several allotropic modifications, the main of which are white, red and black. White F. is a waxy, transparent substance with a characteristic odor, formed by condensation of F. vapors. White F. in the presence of impurities - traces of red F., arsenic, iron, etc. – painted yellow, so commercial white F. is called yellow. There are two forms of white F.: a - and b -form. The a-modification represents crystals of the cubic system ( A= 18.5 å); density 1.828 g/cm 3, t pl 44.1 °C, t kip 280.5 °c, heat of fusion 2.5 kJ/mol p 4 (0.6 kcal/mol p 4), heat of evaporation 58.6 kJ/mol R 4 (14.0 kcal/mol p 4) , steam pressure at 25 °C 5.7 n/m 2 (0,043 mmHg Art.) . The coefficient of linear expansion in the temperature range from 0 to 44 °C is 12.4? 10 -4 , thermal conductivity 0.56 Tue/(m? K) at 25 °C. In terms of electrical properties, white phosphorus is close to dielectrics: the band gap is about 2.1 ev, electrical resistivity 1.54? 10 11 ohm? cm, diamagnetic, specific magnetic susceptibility – 0.86? 10 -6. Brinell hardness 6 Mn/m 2 (0,6 kgf/mm 2) . The a-form of white phosphorus dissolves well in carbon disulfide, less well in liquid ammonia, benzene, carbon tetrachloride, etc. At – 76.9 ° C and a pressure of 0.1 Mn/m 2(1 kgf/cm 2) a-form passes into the low-temperature b-form (density 1.88 g/cm 3) . With pressure increasing to 1200 Mn/m 2(12 thousand kgf/cm 2) the transition occurs at 64.5 °C. b-form – crystals with birefringence, their structure has not been definitively established. White F. is poisonous: it ignites spontaneously in air at a temperature of about 40 ° C, so it should be stored under water (solubility in water at 25 ° C 3.3 × 10 -4%) . By heating white phosphorus without air access at 250–300 °C for several hours, red phosphorus is obtained. The transition is exothermic, accelerated by ultraviolet rays, as well as by impurities (iodine, sodium, selenium). Ordinary commercial red F. is almost completely amorphous; has a color from dark brown to purple. With prolonged heating, it can irreversibly transform into one of the crystalline forms (triclinic, cubic, etc.) with different properties: density from 2.0 to 2.4 g/cm 3 ,t pl from 585 to 610 °C at a pressure of several tens of atmospheres, sublimation temperature from 416 to 423 °C, electrical resistivity from 10 9 to 10 14 ohm? cm. Red F. does not spontaneously ignite in air; up to a temperature of 240–250 ° C, but self-ignites upon friction or impact; insoluble in water, as well as in benzene, carbon disulfide, etc., soluble in tribromide F. At the sublimation temperature, red F. turns into steam, upon cooling of which mainly white F. is formed.

When white F. is heated to 200–220 °C under pressure (1.2–1.7) ? 10 3 Mn/m 2 [(12–17) ? 10 3 kgf/cm 2 ] black F is formed. This transformation can be carried out without pressure, but in the presence of mercury it is not large quantity black phosphorus crystals (seeds) at 370 °C for 8 days Black F. is a crystal of an orthorhombic structure ( A = 3.31 å, b= 4.38 å, With= 10.50 å), the lattice is built from fibrous layers with a pyramidal arrangement of atoms characteristic of phos- ge , density 2.69 g/cm 3 , t pl about 1000 °C under a pressure of 1.8? 10 3 Mn/m 2 (18 ? 10 3 kgf/cm 2) . By appearance black F. looks like graphite; semiconductor: bandgap 0.33 ev at 25 °C; has a specific electrical resistivity of 1.5 ohm? cm, temperature coefficient of electrical resistance 0.0077, diamagnetic, specific magnetic susceptibility – 0.27? 10 -6. When heated to 560–580 °C under the pressure of its own vapors, it turns into red phosphorus. Black phosphorus is low-active and difficult to ignite when ignited, so it can be safely subjected to mechanical processing in air.

Atomic radius F. 1.34 å, ionic radii: p 5 + 0.35 å, p 3 + 0.44 å, p 3 - 1.86 å.

F. atoms are combined into diatomic (p 2), tetraatomic (p 4), and polymer molecules. The most stable polymer molecules under normal conditions are those containing long chains of interconnected p4 tetrahedra. In liquid and solid form (white phosphorus) and in vapors below 800 °C, phosphorus consists of p 4 molecules. At temperatures above 800 °C p 4 molecules dissociate into p 2 , which, in turn, disintegrate into atoms at temperatures above 2000 °C. Only white F. consists of p 4 molecules, all other modifications are polymers.

Chemical properties. Configuration of the outer electrons of the atom F. 3 s 2 3 p 3, in compounds the most characteristic oxidation states are + 5, + 3, and – 3. Like nitrogen, phosphorus in compounds is mainly covalent. There are very few ionic compounds similar to phosphides na 3 p, ca 3 p 2. Unlike nitrogen, phosphorus has free 3 d-opbitals with rather low energies, which leads to the possibility of increasing the coordination number and the formation of donor-acceptor bonds.

F. is chemically active, white F. has the greatest activity; red and black F. in chemical reactions much more passive. Oxidation of white phosphorus occurs according to the mechanism chain reactions. F.'s oxidation is usually accompanied by chemiluminescence. When fermentation burns in an excess of oxygen, pentoxide p 4 o 10 (or p 2 o 5) is formed; when there is a deficiency, mainly trioxide p 4 o 6 (or p 2 o 3) is formed. Spectroscopically proven existence in pairs p 4 o 7, p 4 o 8 , p 2 o 6, po, etc. phosphorus oxides. Phosphorus pentoxide is produced on an industrial scale by burning elemental phosphorus in an excess of dry air. Subsequent hydration p 4 o 10 leads to the production of ortho- (H 3 PO 4) and poly- (H n+2 p n o 3 P+ 1) phosphoric acids. In addition, F. forms phosphorous acid h 3 po 3, phosphoric acid h 4 p 2 o 6 and hypophosphorous acid h 3 po 2, as well as peracids: perphosphoric h 4 p 2 o 8 and monoperphosphoric h 3 po 5 Salts of phosphoric acids are widely used ( phosphates) , less - phosphites and hypophosphites.

F. directly combines with all halogens, releasing a large amount of heat and forming trihalides (px 3, where X is a halogen), pentahalides (px 5) and oxyhalides (for example, pox 3) . When fusing phosphate with sulfur below 100°C, solid solutions based on phosphate and sulfur are formed, and above 100°C an exothermic reaction occurs, forming crystalline sulfides p 4 s 3 , p 4 s 5 , p 4 s 7 , p 4 s 10 , of which only p 4 s 5, when heated above 200 ° C, decomposes into p 4 s 3 and p 4 s 7, and the rest melt without decomposition. Phosphorus oxysulfides are known: p 2 o 3 s 2, p 2 o 3 s 3, p 4 o 4 s 3, p 6 o 10 s 5 and p 4 o 4 s 3. F. compared to nitrogen is less capable of forming compounds with hydrogen. Phosphorous hydrogen phosphine ph 3 and diphosphine p 2 h 4 can only be obtained indirectly. Among the compounds of phosphorus with nitrogen, the nitrides pn, p 2 n 3, and p 3 n 5 are known - solid, chemically stable substances obtained by passing nitrogen with phosphorus vapor through an electric arc; polymeric phosphonitrile halides – (pnx 2) n (for example, polyphosphonitrile chloride) , obtained by reacting pentahalides with ammonia under various conditions; amidoimidophosphates are compounds, usually polymeric, containing, along with P–O–P bonds, P–nh–P bonds.

At temperatures above 2000°c, phosphorus reacts with carbon to form carbide pc 3, a substance that is insoluble in ordinary solvents and does not react with either acids or alkalis. When heated with metals, f. forms phosphides.

F. forms numerous organophosphorus compounds.

Receipt. The production of elemental phosphorus is carried out by its electrothermal reduction from natural phosphates (apatites or phosphorites) at 1400–1600 °C with coke in the presence of silica (quartz sand):

2ca 3 (po 4) 2 + 10c + n sio 2 = p 4 + 10co + 6cao ? n sio 2

Pre-crushed and enriched phosphorus-containing ore is mixed in specified proportions with silica and coke and loaded into an electric furnace. Silica is necessary to reduce the temperature of the reaction, as well as increase its speed by binding the calcium oxide released during the reduction process into calcium silicate, which is continuously removed as molten slag. Silicates and oxides of aluminum, magnesium, iron and other impurities also pass into the slag, as well as ferrophosphorus (fe 2 p, fep, fe 3 p), formed by the interaction of part of the reduced iron with ferrophosphorus, as well as small amounts dissolved in it Manganese phosphides and other metals, as they accumulate, are removed from the electric furnace for subsequent use in the production of special steels.

F. vapors leave the electric furnace along with gaseous by-products and volatile impurities (co, sif 4, ph 3, water vapor, pyrolysis products of organic charge impurities, etc.) at a temperature of 250–350 °C. After cleaning from dust, phosphorus-containing gases are sent to condensation units, in which liquid technical white phosphorus is collected under water at a temperature not lower than 50 °C.

Methods are being developed for producing phosphorus using gaseous reducing agents and plasma reactors in order to intensify production by increasing temperatures to 2500–3000 °C, i.e., higher than the dissociation temperatures of natural phosphates and reducing gases (for example, methane) used as a transport agent. gas in low-temperature plasma.

Application. The bulk of produced phosphorus is processed into phosphoric acid and obtained on its basis phosphate fertilizers and technical salts ( phosphates) .

White F. is used in incendiary and smoke shells and bombs; red F. - in match production. F. is used in the production of non-ferrous metal alloys as a deoxidizing agent. The introduction of up to 1% F. increases the heat resistance of alloys such as fechral and chromal. F. is a component of some bronzes, because increases their fluidity and resistance to abrasion. Phosphides of metals, as well as some non-metals (B, si, as, etc.) are used in the preparation and alloying semiconductor materials. Phosphorus is partially used to produce chlorides and sulfides, which serve as starting materials for the production of phosphorus-containing minerals. plasticizers(for example, tricresyl phosphate, tributyl phosphate, etc.), medicines, organophosphorus pesticides, and are also used as additives in lubricants and fuels.

Safety precautions . White F. and its compounds are highly toxic. Working with F. requires careful sealing of the equipment; White F. should be stored under water or in a hermetically sealed metal container. When working with F., you should strictly follow safety rules.

L. V. Kubasova.

F. in the body. F. is one of the most important biogenic elements, necessary for the life of all organisms. Present in living cells in the form of ortho- and pyrophosphoric acids and their derivatives, and is also part of nucleotides, nucleic acids, phosphoproteins, phospholipids, phosphorus esters of carbohydrates, many coenzymes and other organic compounds. Thanks to the features chemical structure F. atoms, like sulfur atoms, are capable of forming energy-rich bonds in high-energy compounds; adenosine triphosphoric acid (ATP), creatine phosphate, etc. In the process biological evolution It is phosphorus compounds that have become the main, universal storers of genetic information and energy carriers in all living systems. Dr. The important role of phosphoryl compounds in the body lies in the fact that the enzymatic addition of a phosphoryl residue to various organic compounds ( phosphorylation) serves as a “pass” for their participation in metabolism, and, conversely, cleavage of the phosphoryl residue (dephosphorylation) excludes these compounds from active metabolism. Metabolic enzymes F. – kinases, phosphorylases And phosphatases. The liver plays the main role in the transformations of phosphorus compounds in the body of animals and humans. The metabolism of phosphorus compounds is regulated by hormones and vitamin D.

Contents F. (in mg by 100 G dry matter) in plant tissues – 230–350, marine animals – 400–1800, terrestrial animals – 1700–4400, bacteria – about 3000; in the human body there are especially many phosphorus in bone tissue (slightly more than 5000), in brain tissue (about 4000) and in muscles (220–270). Daily human need for F. 1–1.2 G(in children it is higher than in adults). Among the food products, the richest foods are cheese, meat, eggs, and legume grains (peas, beans, etc.). F.'s balance in the body depends on the general state of metabolism. Violation of phosphorus metabolism leads to profound biochemical changes, primarily in energy metabolism. With a lack of phosphorus in the body, animals and humans develop osteoporosis and other bone diseases, and plants develop phosphorus starvation. . The source of phosphorus in living nature is its inorganic compounds contained in the soil and dissolved in water. Phosphorus is extracted from the soil by plants in the form of soluble phosphates. Animals usually receive a sufficient amount of phosphorus with food. After the death of organisms, phosphorus again enters the soil and bottom sediments, thus participating in V circulation of substances. The important role of phosphorus in the regulation of metabolic processes determines the high sensitivity of many enzyme systems of living cells to the action of organophosphorus compounds. This circumstance is used in medicine in the development of therapeutic drugs, in agriculture in production phosphate fertilizers, as well as in creating effective insecticides. Many phosphorus compounds are extremely toxic, and some of the organophosphorus compounds can be classified as chemical warfare agents (sarin, soman, tabun). The radioactive isotope F. 32 p is widely used in biology and medicine as an indicator in the study of all types of metabolism and energy in living organisms .

N. N. Chernov.

Poisoning by phosphorus and its compounds is observed during their thermoelectric sublimation, working with white phosphorus, and the production and use of phosphorus compounds. Highly toxic organophosphorus compounds, having an anticholinesterase effect. F. penetrates the body through the respiratory system, gastrointestinal tract, and skin. Acute poisoning is manifested by a burning sensation in the mouth and stomach, headache, weakness, nausea, and vomiting. In 2–3 days pain occurs in the epigastric region, right hypochondrium, jaundice. Chronic poisoning is characterized by inflammation of the mucous membranes of the upper respiratory tract, signs of toxic hepatitis, and calcium metabolism disorders (development osteoporosis, fragility, sometimes necrosis of bone tissue, more often in the lower jaw), damage to the cardiovascular and nervous systems. First aid for acute poisoning by mouth (the most common) is gastric lavage, laxatives, cleansing enemas, intravenous solutions of glucose, calcium chloride, etc. For skin burns, treat the affected areas with solutions of copper sulfate or soda. The eyes are washed with a 2% solution of baking soda. Prevention: compliance with safety regulations, personal hygiene, oral care, every 6 months – medical examinations of those working with F.

Medicines containing phosphorus (adenosine triphosphoric acid, phytin, calcium glycerophosphate, phosphrene, etc.) affect mainly tissue metabolic processes and are used for muscle diseases, nervous system, with tuberculosis, loss of nutrition, anemia, etc. Radioactive isotopes of phosphorus are used as isotope tracers for studying metabolism, diagnosing diseases, as well as for radiation therapy of tumors .

A. A. Kasparov.

Lit.: Brief chemical encyclopedia, vol. 5, M., 1967; Cotton F., Wilkinson J., Modern Inorganic Chemistry, trans. from English, part 2, M., 1969; Weser Van-J.. Phosphorus and its compounds, trans. from English, vol. 1, M., 1962; Akhmetov N. S., Inorganic chemistry, 2nd ed., M., 1975; Nekrasov B.V., Fundamentals general chemistry, 3rd ed., vol. 1–2, M., 1973; Mosse A. L., Pechkovsky V. V., Application of low-temperature plasma in technology inorganic substances, Minsk, 1973; Horizons of Biochemistry, Sat. Art., trans. from English, M., 1964; Rapoport S. M., Medical biochemistry, trans., from German, M., 1966; Skulachev V.P., Energy accumulation in a cell, M., 1969; Origin of life and evolutionary biochemistry, M., 1975.

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The ideals that illuminated my path and gave me courage and courage were kindness, beauty and truth. Without a sense of solidarity with those who share my convictions, without the pursuit of the ever-elusive objective in art and science, life would seem absolutely empty to me.

Dmitry Ivanovich Mendeleev, reformer, teacher and scientist, was born into an intelligent and decent family in 1834. His father was the director of all district secondary schools educational institutions(gymnasiums and colleges) in the Tobolsk region, where the family lived. The boy’s mother, Maria Dmitrievna, belonged to an old merchant family, which is why she had a small factory in Siberia. (Later, seeing her son’s abilities, she will leave Siberia in order to give the boy a good education). Pavel Maksimovich, Mendeleev's grandfather, was a famous priest. Phosphorus in the periodic table A significant contribution to the education of the future scientist was made by his uncle, V.D. Korniliev, manager of the Trubetskoy princes.

At the age of thirteen, Mendeleev entered the gymnasium, having brilliantly graduated from which, Dmitry Ivanovich entered the institute for physics and mathematics in St. Petersburg. Since 1855, Mendeleev, having begun his work as a teacher, gave lectures at various gymnasiums and universities.

After 7 years Mendeleev will marry Leshchena F.N., who was several years older than Dmitry Ivanovich. In marriage they will have 3 children, but in 1869 Mendeleev falls in love with Popova Anna, which is why he files for divorce from Feozva Nikitichna. The new wife gave birth to Dmitry Ivanovich 4 more children.

From 1865 almost until his death (in January 1907), Mendeleev attended dozens of conferences and exhibitions and actively pursued his scientific developments.

It is difficult to find someone who has not heard of Dmitry Ivanovich Mendeleev. Most often this surname is associated with chemistry, although its field scientific activity It doesn’t just come down to chemistry. Dmitry Ivanovich was an excellent teacher, economist, geologist and instrument maker.

This extraordinary scientist was the first developer of a stratospheric balloon with a volume of more than 3600 m³. Dmitry Ivanovich made a significant contribution to shipbuilding, collaborating with Admiral S. O. Makarov in creating an experimental pool. The results of this work were very useful in the development of the Far North.

An interesting fact in Mendeleev’s scientific activity is his participation in a special commission. This commission consisted of a number of scientists who were engaged in exposing the popular at that time “mediumistic phenomena” (or simply spiritualism). Phosphorus in the periodic table The activities of this commission became widely known through the press, which caused a reaction from society. But the authority and scientific achievements of the scientists who participated in this commission prompted many people to move away from superstitions and traditions that contradict science.

Nature told the woman: be beautiful if you can, wise if you want, but you must certainly be prudent.