Yellow phosphorus properties. White phosphorus

Phosphorus is an important component of living and inanimate nature. It is found in the depths of the Earth, water and in our body, and Academician Fersman even nicknamed it “the element of life and thought.” Despite its usefulness, white phosphorus can be extremely dangerous and poisonous. Let's talk in more detail about its characteristics.

Opening an element

The history of the discovery of phosphorus began with alchemy. Since the 15th century, European scientists have been eager to find the philosopher's stone or the “great elixir” with which they can turn any metals into gold.

In the 17th century, alchemist Hennig Brand decided that the path to the “magic reagent” lay through urine. It is yellow, which means it contains gold or is somehow connected with it. The scientist carefully collected material, defended it, and then distilled it. Instead of gold, he received a white substance that glowed in the dark and burned well.

Brand called the discovery “cold fire.” Later, the Irish alchemist Robert Boyle and the German Andreas Maggraf came up with the idea of ​​obtaining phosphorus in a similar way. The latter also added coal, sand and the mineral phosgenite to the urine. Subsequently, the substance was named phosphorus mirabilis, which translated as “miraculous carrier of light.”

Luminiferous element

The discovery of phosphorus became a real sensation among alchemists. Some tried every now and then to buy the secret of obtaining the substance from Brand, others tried to get there on their own. In the 18th century, it was proven that the element was contained in the bone remains of organisms, and several factories for its production soon opened.

The French physicist Lavoisier proved that phosphorus is a simple substance. In the periodic table it is number 15. Together with nitrogen, antimony, arsenic and bismuth, it belongs to the group of pnictides and is characterized as a non-metal.

The element is quite common in nature. In percentage terms, it ranks 13th in the mass of the earth’s crust. Phosphorus actively interacts with oxygen and is not found in free form. It exists in numerous minerals (more than 190), such as phosphorites, apatites, etc.

White phosphorus

Phosphorus exists in several forms or allotropes. They differ from each other in density, color and chemical properties. There are usually four main forms: white, black, red and metallic phosphorus. Other modifications are only a mixture of the above.

White phosphorus is very unstable. Under normal light conditions it quickly turns red, but high pressure turns it black. Its atoms are arranged in the form of a tetrahedron. It has a crystalline molecular lattice, with the molecular formula P4.

I also highlight yellow phosphorus. This is not another modification of the substance, but the name of unrefined white phosphorus. It can have either a light or dark brown tint and is characterized by strong toxicity.

Properties of white phosphorus

The consistency and appearance of the substance resembles wax. It has a garlicky smell and is greasy to the touch. Phosphorus is soft (it can be cut with a knife without much effort) and is deformable. After cleansing it becomes colorless. Its transparent crystals shimmer iridescently in the sun and look like diamonds.

It melts at 44 degrees. The activity of the substance manifests itself even at room temperature. The main characteristic of phosphorus is its ability to chemiluminescent or glow. Oxidizing in air, it emits a white-green light, and over time it spontaneously ignites.

The substance is practically insoluble in water, but can burn in it with prolonged contact with oxygen. It dissolves well in organic solvents, such as carbon disulfide, liquid paraffin and benzene.

Application of phosphorus

Man has “tamed” phosphorus for both peaceful and military purposes. The substance is used to produce phosphoric acid, which is used for fertilizers. Previously, it was widely used for dyeing wool and making photosensitive emulsions.

White phosphorus is not widely used. Its main value is flammability. Thus, the substance is used for incendiary ammunition. This type of weapon was relevant during both World Wars. It was used in the Gaza war in 2009, as well as in Iraq in 2016.

Red phosphorus is used more widely. It is used to make fuel, lubricants, explosives and match heads. Various phosphorus compounds are used in industry in water softeners and added to passivation agents to protect metal from corrosion.

Content in the body and effect on humans

Phosphorus is one of the vital elements for us. In the form of compounds with calcium, it is present in the teeth and skeleton, giving bones hardness and strength. The element is present in ATP and DNA compounds. It is essential for brain function. Being in nerve cells, it promotes the transmission of nerve impulses.

Phosphorus is found in muscle tissue. It is involved in the process of converting energy from proteins, fats and carbohydrates entering the body. The element maintains the acid-base balance in cells, and their division occurs. It promotes metabolism and is essential during body growth and recovery.

However, phosphorus can be dangerous. White phosphorus itself is very toxic. Doses above 50 milligrams are fatal. Phosphorus poisoning is accompanied by vomiting, headache and stomach pain. Contact of the substance with the skin causes burns that heal very slowly and painfully.

Excess phosphorus in the body leads to brittle bones, cardiovascular diseases, bleeding, and anemia. The liver and digestive system also suffer from phosphorus oversaturation.

Among the biogenic elements, a special place should be given to phosphorus. After all, without it it is impossible to exist such vital compounds as, for example, ATP or phospholipids, as well as many others. At the same time, the inorganics of this element are very rich in various molecules. Phosphorus and its compounds are widely used in industry, are important participants in biological processes, and are used in a wide variety of human activities. Therefore, let us consider what this element is, what its simple substance is and the most important compounds.

Phosphorus: general characteristics of the element

The position in the periodic table can be described in several points.

1. Fifth group, main subgroup.
2. Third small period.
3. Serial number - 15.
4. Atomic mass - 30.974.
5. The electronic configuration of the atom is 1s 2 2s 2 2p 6 3s 2 3p 3.
6. Possible oxidation states are from -3 to +5.
7. Chemical symbol - P, pronunciation in formulas "pe". The name of the element is phosphorus. Latin name Phosphorus.

The history of the discovery of this atom goes back to the distant 12th century. Even in the records of alchemists, there was information that spoke of the production of an unknown “luminous” substance. However, the official date for the synthesis and discovery of phosphorus was 1669. The bankrupt merchant Brand, in search of the philosopher's stone, accidentally synthesized a substance capable of emitting a glow and burning with a bright, blinding flame. He did this by repeatedly calcining human urine.

After this, this element was obtained independently of each other using approximately the same methods:

• I. Kunkel;
• R. Boylem;
• A. Marggraf;
• K. Scheele;
• A. Lavoisier.

Today, one of the most popular methods of synthesizing this substance is reduction from the corresponding phosphorus-containing minerals at high temperatures under the influence of carbon monoxide and silica. The process is carried out in special ovens. Phosphorus and its compounds are very important substances both for living beings and for many syntheses in the chemical industry. Therefore, we should consider what this element is as a simple substance and where it is found in nature.

Simple substance phosphorus

It is difficult to name any specific compound when it comes to phosphorus. This is explained by the numerous allotropic modifications that this element has. There are four main types of the simple substance phosphorus.

1. White. This is a compound whose formula is P 4. It is a white volatile substance with a sharp, unpleasant odor of garlic. Spontaneously ignites in air at normal temperatures. Burns with a glowing pale green light. Very poisonous and life-threatening. The chemical activity is extremely high, so it is obtained and stored under a layer of purified water. This is possible due to poor solubility in polar solvents. Carbon disulfide and organic substances are best suited for this purpose for white phosphorus. When heated, it can transform into the next allotropic form - red phosphorus. When vapor condenses and cools, it can form layers. To the touch they are fatty, soft, easy to cut with a knife, white (slightly yellowish). Melting point 44 0 C. Due to its chemical activity it is used in syntheses. But due to its toxicity, it is not widely used industrially.
2. Yellow. It is a poorly purified form of white phosphorus. It is even more poisonous and also smells unpleasant of garlic. It ignites and burns with a bright glowing green flame. These yellow or brown crystals do not dissolve in water at all; upon complete oxidation, they emit clouds of white smoke with the composition P4O10.
3. Red phosphorus and its compounds are the most common and most commonly used modification of this substance in industry. The pasty red mass, which under elevated pressure can turn into the form of purple crystals, is chemically inactive. This is a polymer that can dissolve only in certain metals and nothing else. At a temperature of 250 0 C it sublimes, turning into a white modification. Not as poisonous as previous forms. However, with prolonged exposure to the body it is toxic. It is used in applying an ignition coating to matchboxes. This is explained by the fact that it cannot ignite spontaneously, but during denotation and friction it explodes (ignites).
4. Black. In appearance it is very reminiscent of graphite and is also greasy to the touch. It is a semiconductor of electric current. Dark crystals, shiny, which are not able to dissolve in any solvents at all. In order for it to ignite, very high temperatures and pre-heating are needed.

Also interesting is the recently discovered form of phosphorus - metallic. It is a conductor and has a cubic crystal lattice.

Chemical properties

The chemical properties of phosphorus depend on the form in which it is found. As mentioned above, the yellow and white modifications are the most active. In general, phosphorus is able to interact with:

• metals, forming phosphides and acting as an oxidizing agent;
• non-metals, acting as a reducing agent and forming volatile and non-volatile compounds of various kinds;
• strong oxidizing agents, turning into phosphoric acid;
• with concentrated caustic alkalis according to the type of disproportionation;
• with water at very high temperatures;
• with oxygen to form various oxides.

The chemical properties of phosphorus are similar to those of nitrogen. after all, it is part of the pnictogen group. However, the activity is several orders of magnitude higher, due to the diversity of allotropic modifications.

Being in nature

As a nutrient, phosphorus is very abundant. Its percentage in the earth's crust is 0.09%. This is quite a large figure. Where is this atom found in nature? There are several main places:

• the green part of plants, their seeds and fruits;
• animal tissues (muscles, bones, tooth enamel, many important organic compounds);
• earth's crust;
• soil;
• rocks and minerals;
• sea ​​water.

In this case, we can only talk about bound forms, but not about simple substance. After all, he is extremely active, and this does not allow him to be free. Among the minerals richest in phosphorus are:

• English;
• fluoropaptite;
• svanbergite;
• phosphorite and others.

The biological significance of this element cannot be overestimated. After all, it is part of such compounds as:

• proteins;
• phospholipids;
• phosphoproteins;
• enzymes.

That is, all those that are vital and from which the entire body is built. The daily requirement for an ordinary adult is about 2 grams.

Phosphorus and its compounds

As a very active element, this element forms many different substances. After all, it forms phosphides and itself acts as a reducing agent. Thanks to this, it is difficult to name an element that would be inert when reacting with it. Therefore, the formulas of phosphorus compounds are extremely diverse. Several classes of substances can be cited in the formation of which it is an active participant.

1. Binary compounds - oxides, phosphides, volatile hydrogen compounds, sulfides, nitrides and others. For example: P 2 O 5, PCL 3, P 2 S 3, PH 3 and others.
2. Complex substances: salts of all types (medium, acidic, basic, double, complex), acids. Example: H 3 PO 4, Na 3 PO 4, H 4 P 2 O 6, Ca(H 2 PO 4) 2, (NH 4) 2 HPO 4 and others.
3. Oxygen-containing organic compounds: proteins, phospholipids, ATP, DNA, RNA and others.

Most of the designated types of substances have important industrial and biological significance. The use of phosphorus and its compounds is possible both for medical purposes and for the manufacture of quite ordinary household items.

Connections to metals

Binary compounds of phosphorus with metals and less electronegative nonmetals are called phosphides. These are salt-like substances that are extremely unstable when exposed to various agents. Even ordinary water causes rapid decomposition (hydrolysis).

In addition, under the influence of non-concentrated acids, the substance also decomposes into the corresponding products. For example, if we talk about the hydrolysis of calcium phosphide, the products will be metal hydroxide and phosphine:

Ca 3 P 2 + 6H 2 O = 3Ca(OH) 2 + 2PH 3

And by subjecting phosphide to decomposition under the action of mineral acid, we obtain the corresponding salt and phosphine:

Ca 3 P 2 + 6HCL = 3CaCL 2 + 2PH 3

In general, the value of the compounds under consideration lies precisely in the fact that as a result a hydrogen compound of phosphorus is formed, the properties of which will be discussed below.

Phosphorus-based volatiles

There are two main ones:

• white phosphorus;
• phosphine

We have already mentioned the first above and given the characteristics. They said it was white thick smoke, highly poisonous, smelling unpleasant and self-igniting under normal conditions.

But what is phosphine? This is the most common and well-known volatile substance, which includes the element in question. It is binary, and the second participant is hydrogen. The formula of the hydrogen compound of phosphorus is PH 3, the name is phosphine.

The properties of this substance can be described as follows.

1. Volatile colorless gas.
2. Very poisonous.
3. Has the smell of rotten fish.
4. It does not interact with water and dissolves very poorly in it. Well soluble in organic matter.
5. Under normal conditions it is very chemically active.
6. Self-ignites in air.
7. Formed during the decomposition of metal phosphides.

Another name is phosphane. Stories from ancient times are associated with it. The whole thing is something that people sometimes saw and see now in cemeteries and swamps. Ball-shaped or candle-like lights that appear here and there, creating the impression of movement, were considered a bad omen and were greatly feared by superstitious people. The reason for this phenomenon, according to the modern views of some scientists, can be considered the spontaneous combustion of phosphine, which is formed naturally during the decomposition of organic residues, both plant and animal. The gas comes out and, coming into contact with oxygen in the air, ignites. Flame color and size may vary. Most often, these are greenish bright lights.

Obviously, all volatile phosphorus compounds are toxic substances that can be easily detected by their sharp, unpleasant odor. This sign helps to avoid poisoning and unpleasant consequences.

Compounds with non-metals

If phosphorus behaves as a reducing agent, then we should talk about binary compounds with non-metals. Most often, they turn out to be more electronegative. So, we can distinguish several types of substances of this kind:

• a compound of phosphorus and sulfur - phosphorus sulfide P 2 S 3;
• phosphorus chloride III, V;
• oxides and anhydride;
• bromide and iodide and others.

The chemistry of phosphorus and its compounds is varied, so it is difficult to identify the most important of them. If we talk specifically about the substances that are formed from phosphorus and nonmetals, then oxides and chlorides of different compositions are of greatest importance. They are used in chemical syntheses as water-removing agents, as catalysts, and so on.

So, one of the most powerful drying agents is the highest - P 2 O 5. It attracts water so strongly that upon direct contact with it, a violent reaction occurs with strong noise. The substance itself is a white snow-like mass, its state of aggregation is closer to amorphous.

It is known that organic chemistry far exceeds inorganic chemistry in terms of the number of compounds. This is explained by the phenomenon of isomerism and the ability of carbon atoms to form chains of atoms of different structures, closing with each other. Naturally, there is a certain order, that is, a classification to which all organic chemistry is subject. The classes of compounds are different, however, we are interested in one specific one, directly related to the element in question. It's with phosphorus. These include:

• coenzymes - NADP, ATP, FMN, pyridoxal phosphate and others;
• proteins;
• nucleic acids, since the phosphoric acid residue is part of the nucleotide;
• phospholipids and phosphoproteins;
• enzymes and catalysts.

The type of ion in which phosphorus participates in the formation of the molecule of these compounds is PO 4 3-, that is, it is the acidic residue of phosphoric acid. Some proteins contain it in the form of a free atom or simple ion.

For the normal functioning of every living organism, this element and the organic compounds it forms are extremely important and necessary. After all, without protein molecules it is impossible to build a single structural part of the body. And DNA and RNA are the main carriers and transmitters of hereditary information. In general, all connections must be present.

Application of phosphorus in industry

The use of phosphorus and its compounds in industry can be characterized in several points.

1. Used in the production of matches, explosive compounds, incendiary bombs, some types of fuel, and lubricants.
2. As a gas absorber, and also in the manufacture of incandescent lamps.
3. To protect metals from corrosion.
4. In agriculture as soil fertilizers.
5. As a water softener.
6. In chemical syntheses in the production of various substances.

Its role in living organisms is reduced to participation in the processes of formation of tooth enamel and bones. Participation in anabolic and catabolic reactions, as well as maintaining the buffering of the internal environment of the cell and biological fluids. It is the basis for the synthesis of DNA, RNA, and phospholipids.

General information and methods of obtaining

Phosphorus (P) is a non-metal. Discovered in 1669 by Brand (Germany), who obtained a substance that glows in the dark. The original name was “cold fire”, the later name was phosphorus, from the Greek “phosph6ros” - luminiferous.

Lavoisier established the elemental nature of phosphorus. In 1771, Schee-le proposed a method for obtaining phosphorus from bone ash by calcining it with coal.

In the second half of the 19th century. industrial production of phosphorus from phosphorites in retort furnaces was organized; at the beginning of the 20th century They were replaced by electric ovens.

The most important minerals containing phosphorus are apatite and phosphorite. The phosphorus content (in terms of P2O5) in apatites ranges from 20 to 41%.

Phosphorites are minerals of sedimentary origin, the main component of which is calcium phosphates; in addition, they contain numerous inclusions of quartz, calcite, glauconite, etc., as well as organic substances. The phosphorus content (in terms of P2O5) in phosphorites is 5-36%.

Currently, phosphorus is obtained by calcining phosphorites or apatites in electric furnaces with sand (Si0 2) and coal (C) without access to air. The released phosphorus vapors condense in a receiver under water.

Physical properties

Atomic characteristics. Atomic number 15, atomic mass 30.973 a. e.m. atomic volume 13.93-10_v m 3 /mol. Atomic radius 0.134 nm, ionic radii P 6 +, P 3 +, P 3 - 0.035; 0.044; 0.186 nm respectively. Electronegativity 2.1. The configuration of the outer electron shells is 3s 2 3p 3. Ionization potential values ​​/ (eV): 10.55; 19.65; 30.16.

Red phosphorus is an amorphous substance; color - from brown to purple; is formed when white phosphorus is heated without air access to 250-300 ° C for several hours. When red phosphorus is heated for a long time above 450 °C, its various crystalline forms exist: tricline, cubic, tetragonal, etc.

Black phosphorus is formed by heating white phosphorus to 200-220 °C and a pressure of 1.2-1.7 GPa. This transformation in the presence of mercury and a small amount of black phosphorus crystals is carried out at normal pressure and a temperature of 370°C for 8 days.

There are amorphous and crystalline forms of black phosphorus. Black phosphorus crystals have a rhombic lattice with parameters: l = 0.331 nm, 6 = 0.438 nm, c = 1.050 nm. There are 8 atoms in a unit cell.

The energy of the crystal lattice is 315 μJ/kmol. The electron affinity of atoms is 0.8-0.9 eV; molecular dissociation energy 5.0 eV. The effective cross section for thermal neutron capture is 19-10 -30 m g.

Density. White phosphorus: a-modification has a density p = = 1.828 Mg/m3, 6-modification 1.880 Mg/m3. The density of yellow is 2.223 Mg/m3, crystalline black is 2.702 Mg/m3, amorphous black is 2.250 Mg/m3, red is from 2.000 to 2.400 Mg/m3.

Chemical properties

Phosphorus exhibits oxidation states of +5, 4-3, -3. The electrochemical equivalent of phosphorus with oxidation state +5 is 0.06421 mg/C.

Various modifications of phosphorus differ sharply in chemical activity: white, red, black (in order of decreasing activity).

Finely ground white phosphorus ignites spontaneously in air and ignites in compact form when heated above 50 °C.

At normal temperature and humidity, red phosphorus reacts slowly with water vapor and oxygen, but large quantities of it ignite when stored in air.

Black phosphorus is more stable and can be safely processed in air.

Phosphorus does not interact with hydrogen under normal conditions, therefore compounds of these elements are obtained indirectly, namely: the action of acid or water on metal phosphides, boiling white phosphorus with a solution of potassium hydroxide, thermal decomposition of lower phosphorus acids, etc.

The following hydrogen compounds of phosphorus are known: phosphine РН3, diphosphine Р2Н4 and solid lower hydrides of phosphorus, corresponding to the general formula РгпН„. Phosphine is a strong reducing agent.

Solid lower phosphorus hydrides (PlnH) are polymers and in many respects resemble organic plastics and phosphate glasses.

Phosphorus forms a series of oxides with oxygen.

Phosphorus (V) oxide P 205, or phosphoric anhydride, is a white, hygroscopic powder that sublimes at 360 °C and atmospheric pressure. When exposed to light, P2O5 glows green.

Phosphoric anhydride reacts with metals to form a mixture of phosphates and phosphides; does not react with halides other than fluorine; dehydrates many organic substances; reacts with alcohols, phenols, ethers, alkylphosphates, etc.; when fused with basic oxides, it forms solid phosphates.

Phosphorus (III) oxide P 2 0 3, or phosphorous anhydride, is a volatile white crystal, toxic, soluble in organic solvents, and spontaneously decomposes during prolonged storage. It has strong reducing properties, reacts with chlorine and bromine, forming oxyhalides.

Phosphorus (IV) oxide, or phosphorus tetraoxide P0 2 (P20 4), is a polymer (P0 2)„, it is shiny transparent crystals that sublimate above 780 ° C, spread in air, absorbing moisture, and dissolve well in water.

Phosphorus reacts explosively with fluorine; in an atmosphere of chlorine and bromine, white phosphorus ignites in the cold; with red phosphorus the reaction proceeds calmly; White phosphorus interacts with iodine when cooled, red phosphorus interacts with iodine when heated. Phosphorus halides are extremely reactive; chemical activity decreases from fluorides to iodides, and strength similarly decreases.

When phosphorus fuses with sulfur below 100 °C, solid solutions are formed; above 100 °C - crystalline sulfides P 4 S 3, P 4 S 5, P4S7, P 4 S, 0.

When freshly distilled phosphorus (III) oxide P 4 0b is mixed with a calculated amount of sulfur in a nitrogen atmosphere, phosphorus oxysulfides are formed: P 2 0 3 S 2, P 2 0 2 S 3, P 4 0 4 S 3, P 6 O 10 S5 . Polymer sulfides are also known, the composition of which corresponds to the molar ratio 0< Я/5 < 0,4.

Phosphorus reacts with carbon in vapors at high temperatures (above 2000 °C).

When phosphorus (III) chloride PC1 3 interacts with acetylene magnesium iodine (C 2 Mg 2 l2), a yellowish-white amorphous precipitate of carbide (PC 3) is formed, which is not soluble in ordinary solvents and is not destroyed by acids and alkalis, but ignites at the slightest heating with carbon release

Phosphorus vapor reacts with nitrogen in an electrical discharge, forming solid nitrides. Pure nitrides are white, inert at room temperature, and do not interact with water, chlorine, hydrochloric acid and dilute sulfuric acid. Completely decomposes with boiling concentrated sulfuric acid. Above 500-700 °C, phosphorus nitrides dissociate to form nitrogen and elemental phosphorus.

With metals, as well as with more electropositive elements (B, Si, As, etc.), phosphorus forms phosphides, which react violently with water and mineral acids.

Phosphides of metals of the copper subgroup are thermally unstable, do not dissolve in nitric acid even when boiled, and are semiconductors.

Phosphides of metals of the zinc subgroup are easily decomposed by water and acids, they burn easily in a stream of oxygen, dry hydrogen does not affect them, fluorine acts already at room temperature, and chlorine, bromine and iodine only when heated.

Phosphides of transition metals, as well as lanthanides and actinides, are close in physical properties to either semiconductors (VP, NbP, TaP, CrP, MoP, WP, MnP) or metals (TiP, ZrP, HtP). Chemically, they are relatively stable; their chemical resistance decreases with decreasing phosphorus content. Phosphides of nonmetals and so-called semimetals are covalent compounds that are either dielectrics or semiconductors. Phosphides of elements of the boron subgroup reduce the chemical activity from BP to InP, and TeP is not formed at all under normal conditions.

Phosphides of elements of group IV (Si, Ge, Sn, Pb) and group V of the Periodic Table (As, Sb) are chemically unstable.

With silicon, phosphorus forms Si 2 P and SiP, with germanium GeP, with tin Sn 4 P 3 and SnP 4, with lead Pb 3 P 2, with arsenic AsP, with antimony SbP. Bismuth phosphides are not formed.

When heating phosphorus in HC vapor! phosphine PH 3 is formed, in the products of the interaction of phosphorus with HBr, phosphonium bromide PH 4 Br is isolated, with HI - phosphorus dinodnd P 2 1 4 and phosphonium iodide PH 4 1.

When phosphorus is heated with aqueous solutions of strong alkalis, phosphine PH 3 is formed.

Phosphorus does not interact with water, but at temperatures of 600-900 °C under pressure and in the presence of catalysts (Pt, Ti, Zr, Cu), phosphoric acid H 3 P0 4 and hydrogen are formed.

White phosphorus is easily oxidized by aqueous solutions of metal salts having a low redox potential (Cu, Ag, Au, Pb, etc.); red and black phosphorus do not oxidize.

According to their structure, organophosphorus compounds can be divided into phosphorus-containing carboxylic acids and their derivatives (esters, amides, etc.), as well as phosphines, their derivatives and related substances. In all of these compounds there is a direct connection between phosphorus and carbon.

Applications

Elemental phosphorus is used in military affairs, in the match industry, for the production of thermal phosphoric acid, polyphosphates, chlorides, sulfides, phosphides and other compounds.

In metallurgy, phosphorus is used for alloying steels (automatic steel up to 0.15% P, stainless steels up to 0.3% P, etc.),

cast iron (phosphorous cast iron up to 0.8% P). The alloy copper - magnesium phosphorus (up to 1.4% P) has high electrical conductivity and weakly softens when heated; an industrial alloy of copper with phosphorus (7% P) is characterized by superplasticity in the deformation temperature range (400-600 °C); many phosphorus-containing alloys are used as solders; sintered antifriction phosphorus-containing alloys (up to 2% P), which have high mechanical strength, wear resistance, and wearability, are used instead of ferrographite, bronze-graphite and bronze; sintered friction alloys (up to 1% P) are used to create soft magnetic materials, magnetic cores and other products; phosphorus-containing alloys are applied in the form of coatings to protect materials from wear and corrosion; films made from the alloys Co-P, Ni-P, Co-Fe-P, Co-W-P are ferromagnetic, they are used to create memory elements in computers.

Phosphorus is introduced into the composition of some bronzes (phosphor bronze - 0.5-1.2% P), increasing their fluidity and resistance to abrasion.

Surface treatment of steel products - phosphating - protects them from corrosion.

Phosphorus is used as a deoxidizing agent in the production of non-ferrous metal alloys (up to 1% P), which increases their heat resistance (fechral, ​​chromal, etc.).

Phosphorus is also used to produce semiconductors - gallium and indium phosphides; it is added to other semiconductors in small quantities as a necessary additive.

Phosphoric acid is used for the production of concentrated phosphorus fertilizers (double superphosphate, precipitate, nitrophoska, nitrophos, etc.). reagents.

Ammonium phosphates are used to impregnate fabrics, plastic, and wood to give them fire-resistant properties; Phosphates Fe, Na, K, Ca - components of drilling fluids, toothpastes; Foefash Ca and ammonium are used for the production of enamels and in the pharmaceutical industry.

Megaphosphates are used industrially to soften water and reduce its corrosiveness, to remove scale in steam boilers, and are included in some detergents.

Polyphosphates are used in the production of synthetic detergents.

Phosphides have the following areas of application: Boron phosphide - for e.g. sensors. etc. from Hall, semiconductor devices, IR radiation receivers, working fluids of quantum generators; copper phosphide - for soldering laauni: nickel phosphide - for creating wear-resistant coatings on machine parts.

Phosphorus (V) oxide P 2 O h is used as a drying agent for dehydration in the production of metallic acid resins.

Phosphorus chlorides have found widespread industrial use in the production of dyes, insecticides, drugs, surfactants and as an effective chlorinating agent.

The areas of application of phosphorus sulfides are the production of flotation reagents, anti-corrosion additives for oils and fuels, organophosphorus insecticides (thiophos, karbofos, etc.). Organophosphorus compounds - heat-resistant and fire-resistant varnishes, adhesives - for modifying polymers, for producing inorganic rubber.

The nuclear industry uses complex phosphorus compounds to extract rare and transuranium elements from ores.

Red phosphorus, also called violet phosphorus, is a more thermodynamically stable modification of elemental phosphorus. It was first obtained in 1847 in Sweden by the Austrian chemist A. Schrötter by heating white phosphorus at 500 °C in an atmosphere of carbon monoxide (CO) in a sealed glass ampoule.

Red phosphorus has the formula P n and is a polymer with a complex structure. Depending on the method of production and the degree of crushing of red phosphorus, it has shades from purple-red to violet, and in the cast state it has a dark purple metallic luster with a copper tint. The chemical activity of red phosphorus is significantly lower than that of white phosphorus; it is characterized by exceptionally low solubility. It is possible to dissolve red phosphorus only in certain molten metals (lead and bismuth), which is sometimes used to obtain large crystals. For example, the German physical chemist I.V. Hittorf in 1865 was the first to obtain perfectly constructed but small crystals (Hittorf phosphorus). Red Phosphorus does not spontaneously ignite in air, up to a temperature of 240-250 ° C (when it transforms into a white form during sublimation), but it spontaneously ignites upon friction or impact; it completely lacks the phenomenon of chemiluminescence. Insoluble in water, as well as in benzene, carbon disulfide and others, soluble in phosphorus tribromide. At the sublimation temperature, red phosphorus turns into vapor, upon cooling which produces mainly white phosphorus.

Its toxicity is thousands of times less than that of white, so it is used much more widely, for example, in the production of matches (the rubbing surface of boxes is coated with a composition based on red phosphorus). The density of red phosphorus is also higher, reaching 2400 kg/m³ in cast form. When stored in air, red phosphorus in the presence of moisture gradually oxidizes, forming a hygroscopic oxide, absorbs water and becomes damp (“soaked”), forming viscous phosphoric acid; therefore it is stored in an airtight container. When “soaking”, they are washed with water to remove residual phosphoric acids, dried and used for their intended purpose.

Black phosphorus

Black phosphorus is the most thermodynamically stable and chemically least active form of elemental phosphorus. Black phosphorus was first obtained in 1914 by the American physicist P. W. Bridgman from white phosphorus in the form of black shiny crystals with a high (2690 kg/m³) density. To carry out the synthesis of black phosphorus, Bridgman used a pressure of 2 × 10 9 Pa (20 thousand atmospheres) and a temperature of about 200 ° C. The beginning of the rapid transition lies in the region of 13,000 atmospheres and a temperature of about 230 °C.

Black phosphorus is a black substance with a metallic luster, greasy to the touch and very similar to graphite, and with absolutely no solubility in water or organic solvents. Black phosphorus can only be ignited by first heating it strongly in an atmosphere of pure oxygen to 400 °C. Black phosphorus conducts electricity and has semiconductor properties. The melting point of black phosphorus is 1000 °C under a pressure of 18 × 10 5 Pa.

The message on the topic “Using Phosphorus” will briefly tell you in which areas phosphorus is used and why.

Applications of phosphorus

Phosphorus is a chemical element that is located in group V in the periodic table of Mendeleev. Its chemical formula is R. The name of the element comes from the Greek word “phosphoros” and means “luminiferous”. There is quite a lot of it in the earth's crust - 0.08-0.09% of the total mass of the Earth's crust. There is also phosphorus in sea water. The element has high chemical activity, so you will not find it in a free state. It is capable of forming 190 minerals. It is also called the element of life, as it is found in animal tissues, green plants, proteins, and so on.

Use of phosphorus in medicine

Today, phosphorus is used to produce a class of potential therapeutic agents that treat diseases of soft tissues and bones accompanied by calcium metabolism disorders - biophosphonates.

Each element has its own spectrum of activity. They are resistant to enzymatic hydrolysis, have an affinity for metal ions, and form insoluble and soluble chelate aggregates and complexes.

The most common and used is etidronate. It is effective for disorders of calcium metabolism in the body. It is used for progressive myositis ossificans, Paget's disease, osteoporosis, heterogeneous ossification and tumor osteolysis.

Application of phosphorus in industry

Phosphoric acid is widely used. It is used for the production of combined and phosphate fertilizers, which increase the productivity of agricultural crops and give plants resistance to adverse climatic conditions and winter hardiness. In addition, fertilizers have an excellent effect on the soil, promoting structuring, changing the solubility of substances contained in the soil, the development of soil bacteria, and suppressing the formation of organic harmful substances.

Phosphoric acid is also used in the food industry. It tastes good and, when diluted, is added to marmalade, lemonade, and syrups to improve taste. Phosphoric acid salts have similar properties. For example, calcium hydrogen phosphates are a component of baking powders and enhance the taste of bread and rolls.

Phosphoric wood non-combustible boards, fire-retardant paints, and phosphate non-combustible foam are produced on the basis of orthophosphoric acid. Phosphoric acid salts protect against radiation, soften water, remove boiler scale and are included in detergents.

Organophosphorus compounds (plasticizers, extractants, lubricants, absorbents) are used in refrigeration units and as an additive to gunpowder. Alkyl phosphates act as surfactants, antifreeze, special fertilizers, and latex anticoagulants.

Matches are made from red phosphorus. Together with glue and crushed glass, it is applied to the sides of the matchbox. Zinc phosphide (Zn 3 P 2) is used to control rodents. White phosphorus is used to produce incendiary bombs, smoke-producing shells, checkers, grenades, and smoke screens.

Use of phosphorus in everyday life

In everyday life we ​​are also surrounded by things made of phosphorus. For example, dishes, figurines, vases and the like. In addition, it is an important element that is part of nucleic acids, proteins, and bone tissue. Phosphorus is an important element for muscle and mental activity. Has a beneficial effect on the kidneys and heart. It is found in bread, fish, meat, peas, beans, pearl barley, oatmeal and barley, cabbage, nuts, parsley, carrots, spinach and garlic.

We hope that the report on the topic “Use of Phosphorus” helped you prepare for the lesson. You can add your story about the use of phosphorus using the comment form below.