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Usually, the date of discovery of phosphorus is considered to be 1669, but there are some indications that it was known earlier. Gefer, for example, reports that in an alchemical manuscript from a collection stored in the Paris Library, it is said that around the 12th century. a certain Alkhid Bekhil obtained a substance by distillation of urine with clay and lime, which he called "escarbucle". Perhaps this was phosphorus, which is the great secret of the alchemists. In any case, it is known that in search of the philosopher's stone, alchemists subjected all kinds of materials to distillation and other operations, including urine, feces, bones, etc. Since ancient times, substances capable of glowing in the dark have been called phosphorus. In the 17th century Bolognese phosphorus was known - a stone found in the mountains near Bologna; after burning on coals, the stone acquired the ability to glow. It also describes "Baldwin's phosphorus", prepared by the volost foreman Alduin from a calcined mixture of chalk and nitric acid. The glow of such substances caused extreme surprise and was considered a miracle. In 1669, the Hamburg amateur alchemist Brand, a bankrupt merchant who dreamed of improving his affairs with the help of alchemy, processed a wide variety of products. Assuming that physiological products might contain the "primordial matter" thought to be the basis of the Philosopher's Stone, Brand became interested in human urine.

He collected about a ton of urine from the soldiers' barracks and evaporated it to a syrupy liquid. This liquid he again distilled and obtained a heavy red "urinary oil". Distilling this oil again, he found at the bottom of the retort the remains of a "dead head" (Caput mortuum), seemingly unusable. However, calcining this residue for a long time, he noticed that white dust appeared in the retort, which slowly settled to the bottom of the retort and clearly glowed. Brand decided that he managed to extract elemental fire from the "oily dead head", and he continued the experiments with even greater zeal. Of course, he failed to turn this "fire" into gold, but he still kept his discovery of phosphorus (from the Greek - light and "I carry", that is, the light-bearer) in strict confidence. However, a certain Kunkel, who at that time served as an alchemist and secret valet for the Saxon Elector, found out about Brand's secret. Kunkel asked his colleague Kraft, who was leaving for Hamburg, to find out from Brand any information about phosphorus. Kraft, however, decided to use Brand's secret himself. He bought a secret from him for 200 thalers and, having made a sufficient amount of phosphorus, went on a trip to Europe, where he demonstrated the glow of phosphorus to noble people with great success. In particular, in England, he showed phosphorus to King Charles II and the scientist Boyle. In the meantime, Kunkel managed to prepare phosphorus himself in a way close to Brand's, and unlike the latter, he widely advertised phosphorus, but kept silent about the secret of its manufacture. This happened in the 70s of the XVII century. For the third time, phosphorus was discovered by Boyle in 1680, who, like Kunkel, published data on the properties of phosphorus, but reported on the method of obtaining it in a closed package only to the Royal Society of London; this message was not published until 12 years later, after Boyle's death. Phosphorus didn't make Brand and Boyle rich, it made Kraft and Kunkel rich. Boyle's assistant Hankwitz developed a particularly wide industrial activity in the manufacture of this substance: for 50 years he widely traded in phosphorus at a very high price. In Holland, for example, an ounce (31.1 g) of phosphorus cost 16 ducats at that time. The most fantastic assumptions have been made about the nature of phosphorus. In the XVIII century. Many prominent scientists were engaged in phosphorus, among them Marggraf, who improved the method for obtaining phosphorus from urine by adding lead chloride to the latter (1743). In 1777, Scheele established the presence of phosphorus in the bones and horns of animals in the form of phosphoric acid associated with lime. Some authors, however, attribute this discovery to another Swedish chemist Hahn, but it was Scheele who developed a method for obtaining phosphorus from bones. Phosphorus was recognized as an elementary substance by Lavoisier on the basis of his well-known experiments on the combustion of phosphorus in oxygen. In the table of simple bodies, Lavoisier placed phosphorus in the second group of simple bodies, non-metallic, oxidizing and producing acids. Since the 19th century Phosphorus is widely used mainly in the form of salts used for soil fertilization.

Since ancient times, phosphors have been called substances that can glow in the dark. In the 17th century Bolognese phosphorus was known - a stone found in the mountains near Bologna; after burning on coals, the stone acquired the ability to glow. It also describes "Baldwin's phosphorus", prepared by the volost foreman Alduin from a calcined mixture of chalk and nitric acid. The glow of such substances caused extreme surprise and was considered a miracle.

In 1669, the Hamburg amateur alchemist Brand, a bankrupt merchant who dreamed of improving his affairs with the help of alchemy, processed a wide variety of products. Assuming that physiological products might contain the "primordial matter" thought to be the basis of the Philosopher's Stone, Brand became interested in human urine.

Oh, how he was carried away by the idea, what efforts he made to implement it! Believing that the products of the vital activity of a person, the “king of nature”, can contain the so-called primary energy, the tireless experimenter began distilling human urine, one might say, on an industrial scale: in the soldiers’ barracks, he collected a whole ton of it in total! And he evaporated to a syrupy state (not in one go, of course!), And after distillation, he again distilled the resulting “urine oil” and calcined it for a long time. As a result, white dust appeared in the retort, which settled to the bottom and glowed, which is why it was called “cold fire” (kaltes Feuer) by Brand. Brand's contemporaries called this substance phosphorus because of its ability to glow in the dark (another Greek jwsjoroV).

In 1682, Brand published the results of his research, and he is now rightly considered the discoverer of element No. 15. Phosphorus was the first element whose discovery was documented, and its discoverer is known.

Interest in the new substance was enormous, and Brand took advantage of this - he demonstrated phosphorus only for money or exchanged small amounts of it for gold. Despite numerous efforts, the Hamburg merchant could not fulfill his cherished dream - to obtain gold from lead using "cold fire", and therefore he soon sold the recipe for obtaining a new substance to a certain Kraft from Dresden for two hundred thalers. The new owner managed to make a much larger fortune on phosphorus - with "cold fire" he traveled all over Europe and demonstrated it to scientists, high-ranking and even royal people, for example, Robert Boyle, Gottfried Leibniz, Charles II. Although the method of preparing phosphorus was kept in the strictest confidence, in 1682 Robert Boyle managed to obtain it, but he also disclosed his method only at a closed meeting of the Royal Society of London. Boyle's method was made public after his death, in 1692.

In the spring of 1676, Kraft arranged a session of experiments with phosphorus at the court of Elector Friedrich Wilhelm of Brandenburg. At 9 pm on April 24, all the candles in the room were extinguished, and Kraft showed those present experiments with "eternal fire", without revealing, however, the method by which this magical substance was prepared.

In the spring of the following year, Kraft came to the court of Duke Johann Friedrich in Hannover3, where at that time the German philosopher and mathematician G.W. Leibniz (1646-1716) served as a librarian. Kraft also arranged a session of experiments with phosphorus here, showing, in particular, two flasks that glowed like fireflies. Leibniz, like Kunkel, was extremely interested in the new substance. At the first session, he asked Kraft if a large piece of this substance would not be able to light up the whole room. Kraft agreed that it was quite possible, but would be impractical, since the process of preparing the substance is very complicated.

Who had this? I had.

Leibniz's attempts to persuade Kraft to sell the secret to the duke failed. Then Leibniz went to Hamburg to Brand himself. Here he managed to conclude a contract between Duke Johann Friedrich and Brand, according to which the former was obliged to pay Brand 60 thalers for revealing the secret. From that time on, Leibniz entered into regular correspondence with Brand.

At about the same time, I.I. Becher (1635-1682) arrived in Hamburg with the aim of luring Brand to the Duke of Mecklenburg. However, Brand was again intercepted by Leibniz and taken to Hanover to Duke Johann Friedrich. Leibniz was fully convinced that Brand was very close to discovering the "philosopher's stone", and therefore advised the duke not to let him go until he had completed this task. Brand, however, stayed in Hanover for five weeks, prepared fresh supplies of phosphorus outside the city, showed, according to the contract, the secret of production and left.

Then Brand prepared a significant amount of phosphorus for the physicist Christian Huygens, who studied the nature of light, and sent a supply of phosphorus to Paris.

Brand, however, was very dissatisfied with the price Leibniz and Duke Johann Friedrich gave him for revealing the secret of phosphorus production. He sent an angry letter to Leibniz, complaining that the amount received was not enough even to support his family in Hamburg and pay travel expenses. Similar letters were sent to Leibniz and Brand's wife, Margarita.

Brand was also dissatisfied with Kraft, to whom he expressed resentment in letters, reproaching him for having resold the secret for 1000 thalers to England. Kraft forwarded this letter to Leibniz, who advised Duke Johann Friedrich not to irritate Brand, to pay him more generously for revealing the secret, fearing that the author of the discovery, in the form of an act of revenge, would share the recipe for making phosphorus with someone else. Leibniz sent a reassuring letter to Brand himself.

Apparently, Brand received a reward, tk. in 1679 he again came to Hanover and worked there for two months, receiving a weekly salary of 10 thalers with additional payment for the table and travel expenses. Correspondence between Leibniz and Brand, judging by the letters kept in the Hanover Library, continued until 1684.

Let us now return to Kunkel. According to Leibniz, Kunkel learned through Kraft the recipe for making phosphorus and set to work. But his first experiments were unsuccessful. He wrote letter after letter to Brand, complaining that he had been sent a recipe that was very incomprehensible to another person. In a letter written in 1676 from Wittenberg, where Kunkel was then living, he asked Brand about the details of the process.

In the end, Kunkel achieved success in his experiments, somewhat modifying Brand's method. By adding a little sand to dry urine before distilling it, he received phosphorus and ... made a claim to the independence of the discovery. In the same year, in July, Kunkel told about his successes to his friend, Professor of Wittenberg University Kaspar Kirchmeyer, who published a work on this issue under the title "Permanent night lamp, sometimes sparkling, which was long sought, now found." In this article, Kirchmeyer speaks of phosphorus as a long-known luminous stone, but does not use the term "phosphorus" itself, obviously not yet accustomed to that time.

In England, independently of Brand, Kunkel and Kirchmeyer in 1680, phosphorus was obtained by R. Boyle (1627-1691). Boyle knew about phosphorus from the same Kraft. As early as May 1677, phosphorus was demonstrated at the Royal Society of London. In the summer of the same year, Kraft himself came with phosphorus to England. Boyle, according to his own account, visited Kraft and saw phosphorus in his solid and liquid form. In gratitude for the warm welcome, Kraft, saying goodbye to Boyle, hinted to him that the main substance of his phosphorus was something inherent in the human body. Obviously, this hint was enough to give an impetus to Boyle's work. After Kraft's departure, he began to test blood, bones, hair, urine, and in 1680 his efforts to obtain a luminous element were crowned with success.

Boyle began to exploit his discovery in the company of an assistant, the German Gaukwitz. After Boyle's death in 1691, Gaukwitz launched the production of phosphorus, improving it on a commercial scale. By selling phosphorus at three pounds sterling an ounce and supplying the scientific institutions and individual scientists of Europe with it, Gaukwitz amassed a huge fortune. To establish commercial connections, he traveled to Holland, France, Italy and Germany. In London itself, Gaukwitz founded a pharmaceutical company that became famous during his lifetime. It is curious that, despite all his experiments with phosphorus, sometimes very dangerous, Gaukwitz lived to be 80 years old, outliving his three sons and all the people who participated in the work related to the early history of phosphorus.

Since the discovery of phosphorus by Kunkel and Boyle, it has rapidly fallen in price as a result of the competition of inventors. In the end, the heirs of the inventors began to acquaint everyone with the secret of its production for 10 thalers, all the while lowering the price. In 1743, A.S. Marggraf found an even better way to produce phosphorus from urine and immediately published it, because. fishing is no longer profitable.

Currently, phosphorus is not produced anywhere by the Brand-Kunkel-Boyle method, since it is completely unprofitable. For the sake of historical interest, we will nevertheless give a description of their method.

Rotting urine is evaporated to a syrupy state. The resulting thick mass is mixed with three times the amount of white sand, placed in a retort equipped with a receiver, and heated for 8 hours on an even fire until the volatile substances are removed, after which the heating is increased. The receiver is filled with white vapor, which then turns into bluish solid and luminous phosphorus.

Phosphorus got its name due to the property to glow in the dark (from Greek - luminiferous). Among some Russian chemists there was a desire to give the element a purely Russian name: "gem", "lighter", but these names did not take root.

Lavoisier, as a result of a detailed study of the combustion of phosphorus, was the first to recognize it as a chemical element.

The presence of phosphorus in the urine gave chemists a reason to look for it in other parts of the body of animals. In 1715, phosphorus was found in the brain. The significant presence of phosphorus in it served as the basis for the assertion that "without phosphorus there is no thought." In 1769, Yu.G. Gan found phosphorus in the bones, and two years later, K.V. Scheele proved that the bones consist mainly of calcium phosphate, and proposed a method for obtaining phosphorus from the ash remaining after bones were burned. Finally, in 1788, M.G. Klaproth and J.L. Proust showed that calcium phosphate is an extremely widespread mineral in nature.

The allotropic modification of phosphorus - red phosphorus - was discovered in 1847 by A. Schretter. In a work entitled "A New Allotropic State of Phosphorus", Schretter writes that sunlight changes white phosphorus to red, and factors such as dampness, atmospheric air, have no effect. Schretter separated the red phosphorus by treatment with carbon disulfide. He also prepared red phosphorus by heating white phosphorus to a temperature of about 250 ° C in an inert gas. At the same time, it was found that a further increase in temperature again leads to the formation of a white modification.

It is very interesting that Schroetter was the first to predict the use of red phosphorus in the match industry. At the World Exhibition in Paris in 1855, red phosphorus, already obtained by the factory, was demonstrated.

The Russian scientist A.A. Musin-Pushkin in 1797 received a new modification of phosphorus - violet phosphorus. This discovery is erroneously attributed to I.V. Gittorf, who, having almost completely repeated the Musin-Pushkin method, received violet phosphorus only in 1853.

In 1934, Professor P.W. Bridgman, subjecting white phosphorus to a pressure of up to 1100 atm, turned it into black and thus obtained a new allotropic modification of the element. Along with the color, the physical and chemical properties of phosphorus have changed: white phosphorus, for example, ignites spontaneously in air, and black, like red, does not have this property.

sources

Phosphorus (from Greek phosphoros - luminiferous; lat. Phosphorus) - an element of the periodic table of chemical elements of the periodic table, one of the most common elements of the earth's crust, its content is 0.08-0.09% of its mass. The concentration in sea water is 0.07 mg/l. It is not found in the free state due to its high chemical activity. It forms about 190 minerals, the most important of which are apatite Ca 5 (PO 4) 3 (F,Cl,OH), phosphorite Ca 3 (PO 4) 2 and others. Phosphorus is found in all parts of green plants, and even more in fruits and seeds (see phospholipids). Contained in animal tissues, is part of proteins and other essential organic compounds (ATP, DNA), is an element of life.

Story

Phosphorus was discovered by the Hamburg alchemist Hennig Brand in 1669. Like other alchemists, Brand tried to find the philosopher's stone, but received a luminous substance. Brand focused on experiments with human urine, because he believed that it, having a golden color, may contain gold or something necessary for mining. Initially, his method consisted in the fact that at first the urine was settled for several days until the unpleasant odor disappeared, and then boiled to a sticky state. By heating this paste to high temperatures and bringing it up to the appearance of bubbles, he hoped that, when condensed, they would contain gold. After several hours of intense boiling, grains of a white wax-like substance were obtained, which burned very brightly and, moreover, flickered in the dark. Brand named this substance phosphorus mirabilis (lat. "miraculous light carrier"). Brand's discovery of phosphorus was the first discovery of a new element since antiquity.
Somewhat later, phosphorus was obtained by another German chemist, Johann Kunkel.
Regardless of Brand and Kunkel, phosphorus was obtained by R. Boyle, who described it in the article “Method of preparing phosphorus from human urine”, dated October 14, 1680 and published in 1693.
An improved method for obtaining phosphorus was published in 1743 by Andreas Marggraf.
There is evidence that Arab alchemists were able to obtain phosphorus in the 12th century.
The fact that phosphorus is a simple substance was proved by Lavoisier.

origin of name

In 1669, Henning Brand, by heating a mixture of white sand and evaporated urine, obtained a substance glowing in the dark, first called "cold fire". The secondary name "phosphorus" comes from the Greek words "φῶς" - light and "φέρω" - I carry. In ancient Greek mythology, the name Phosphorus (or Eosphorus, other Greek Φωσφόρος) was worn by the guardian of the Morning Star.

Receipt

Phosphorus is obtained from apatites or phosphorites as a result of interaction with coke and silica at a temperature of 1600 ° C:
2Ca 3 (PO 4) 2 + 10C + 6SiO 2 → P4 + 10CO + 6CaSiO 3 .

The resulting white phosphorus vapor condenses in the receiver under water. Instead of phosphorites, other compounds can be reduced, for example, metaphosphoric acid:
4HPO 3 + 12C → 4P + 2H 2 + 12CO.

Physical Properties

Elemental phosphorus under normal conditions represents several stable allotropic modifications; The problem of phosphorus allotropy is complex and not fully resolved. Usually there are four modifications of a simple substance - white, red, black and metallic phosphorus. Sometimes they are also called the main allotropic modifications, implying that all the others are a variety of these four. Under normal conditions, there are only three allotropic modifications of phosphorus, and under conditions of ultrahigh pressures, there is also a metallic form. All modifications differ in color, density and other physical characteristics; there is a noticeable tendency to a sharp decrease in chemical activity during the transition from white to metallic phosphorus and an increase in metallic properties.

Chemical properties

The chemical activity of phosphorus is much higher than that of nitrogen. The chemical properties of phosphorus are largely determined by its allotropic modification. White phosphorus is very active; in the process of transition to red and black phosphorus, the chemical activity decreases sharply. White phosphorus glows in the dark in air, the glow is due to the oxidation of phosphorus vapor to lower oxides.
In the liquid and dissolved state, as well as in vapors up to 800 ° C, phosphorus consists of P 4 molecules. When heated above 800 ° C, the molecules dissociate: P 4 \u003d 2P 2. At temperatures above 2000 °C, molecules break up into atoms.

"...Yes! It was a dog, huge, pitch black. But none of us mortals have ever seen such a dog. Flames shot out of her open mouth, sparks flew from her eyes, flickering fire poured over her muzzle and nape. In no one's inflamed brain could a vision more terrible, more disgusting than this hellish creature that jumped out of the fog at us ... A terrible dog, the size of a young lioness. Its huge maw still glowed with bluish flames, its deep-seated wild eyes circled in flames.

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

Learned? Arthur Conan Doyle. "The Hound of the Baskervilles".

This is the bad story that element #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 become younger, the sick recover, and base metals turn into gold. Not concern for the welfare of the people, but self-interest led Brand. This is evidenced by facts from the history of the only real discovery made by him.

During one of the experiments, he evaporated urine, mixed the residue with coal, 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 soon Brand sold it to the Dresden chemist I. Kraf. The number of phosphorus demonstrators increased when the recipe for its manufacture became known to I. Kunkel and K. Kirchmeyer. In 1680, regardless of the predecessors, a new element was obtained by the famous English physicist and chemist Robert Boyle. But Boyle soon died, and his student A. Hankwitz betrayed pure science and revived the "phosphorus speculation" again. Only in 1743, A. Markgraf found a more perfect way to obtain phosphorus and published his data for general information. This event put an end to the brand business and was the beginning of a serious study of phosphorus and its compounds.

At the first, fifty-year stage in 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 the brain tissue. After the experiments of Markgraf, the history of the element, which many years later acquired the 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 was confirmed two years later by the famous Swedish chemist K. Scheele, who proposed a method for obtaining phosphorus from the ash formed during the roasting of bones.

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

Great success in the study of the properties of phosphorus was achieved in the early 70s of the 18th century. the great French chemist Antoine Laurent Lavoisier. By burning phosphorus with other substances in a closed volume of air, Lavoisier proved that phosphorus is 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.” So F. Engels wrote about the works of Lavoisier in the preface to the second volume of Capital.

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

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

In 1847, the German chemist Schretter, by heating white phosphorus without access to air, obtained 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 pressure on various substances, isolated black phosphorus similar to graphite. These are the milestones in the history of element #15. Now let's look at what followed each of these discoveries.

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

Phosphorus is an analogue of nitrogen. Although the physical and chemical properties of these elements are very different, they also have in common, in particular, that both 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 literally in all organs of green plants: in 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.

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

The human body contains an average of about 1.5 kg of element No. 15. Of this amount, 1.4 kg is in the bones, about 130 g is in the muscles, and 12 g is in the nerves and brain. Almost all the most important physiological processes occurring in our body are associated with the transformation of organophosphorus substances. Phosphorus is present 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, Cl).

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

However, much more phosphorus is removed from the soil per unit time than it enters the soil. The world harvest now carries away more than 3 million tons of phosphorus from the fields every year.

Naturally, in order to obtain sustainable yields, this phosphorus must be returned to the soil, and therefore there is nothing surprising in the fact that the world production of phosphorite ore is now more than 100 million tons per year.

"... 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 salts of orthophosphoric acid; the most common cation is calcium non.

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

Less common are vivianite Fe 3 (РO 4) 2 8Н 2 O, monazite (Се, La) PO 4 , amblygonite LaAl (PO 4) F, triphylite Li (Fe, Mn) PO 4 and even less often xenotime YPO 4 and torbernite Сu (UO 2) 2 [PO 4] 2 12H 2 O.

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

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

In the form of phosphides of iron, cobalt, nickel, phosphorus is found in meteorites. 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 non-metal (what used to be called a metalloid) of medium activity. There are five electrons in the outer orbit of the phosphorus atom, and three of them are not paired. Therefore, it can exhibit valencies 3–, 3+, and 5+.

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

Phosphorus is often referred to as a multifaceted element. Indeed, under different conditions, it behaves differently, showing either oxidizing or reducing properties. The diversity of phosphorus is also its ability to be in several allotropic modifications.

Perhaps the most famous modification of element No. 15 is soft, like wax, white or yellow phosphorus. It was Brand who discovered it, and thanks to its properties, the element got its name: in Greek, “phosphorus” means luminous, luminiferous. The white phosphorus molecule consists of four atoms arranged in the form of a tetrahedron. Density 1.83, melting point 44.1°C. White phosphorus is poisonous and easily oxidized. Soluble in carbon disulfide, liquid ammonia and SO 2, benzene, ether. Almost insoluble in water.

When heated in the absence of air above 250°C, white phosphorus turns red. This is already a polymer, but not a very ordered structure. The reactivity of red phosphorus is much less than that of white. It does not glow in the dark, does not dissolve in carbon disulfide, is not poisonous (Always contains small amounts of white phosphorus, as a result of which it may be poisonous.). Its density is much greater, the structure is fine-grained.

Less well known are other, even more high-molecular modifications of phosphorus - violet, brown and black, which differ from one another in molecular weight and the degree of ordering of macromolecules. Black phosphorus, first obtained by P. Bridgman under conditions of high pressure (200 thousand atm. 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, have not yet found practical application.

By the way, about the applications of elemental phosphorus; its main consumers are the production of matches, metallurgy, and chemical industries. 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 alloys. This is done when it is necessary that, when solidified, the metal expands a little and accurately perceives the outlines of the form. Phosphorus is also widely used in chemistry. Part of it goes to the preparation of phosphorus chlorides, which are needed in the synthesis of certain organic preparations; the stage of production of elemental phosphorus is also 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, greedily absorbing water from the air and other substances. The content of P 2 O 5 is the main criterion for the value of all phosphate fertilizers.

Phosphoric acids, primarily orthophosphoric H 3 PO 4 , are used in the mainstream chemical industry. Salts of phosphoric acids are primarily phosphate fertilizers (there is a special discussion about them) and alkali metal phosphates necessary for the production of detergents.

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

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

Among phosphorus compounds, a special place belongs to organophosphorus compounds. Most of them are biologically active. Therefore, some organophosphorus compounds are used as medicines, others - as pest control agents.

An independent class of substances was phosphonitrile chlorides - compounds of phosphorus with nitrogen and chlorine. Phosphonitrile chloride monomer is capable of polymerization. With an increase in 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, which does not contain carbon at all. Further growth in molecular weight leads to the formation of solid plastic-like substances. "Carbon-free rubber" has significant heat resistance: it begins to break down only at 350°C.

"In 1839, the Englishman Lause first received superphosphate - a phosphorus fertilizer that is easily absorbed by plants."

In order for plants to absorb phosphorus, it must be in the composition of a soluble compound. To obtain these compounds, calcium phosphate and sulfuric acid are 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. The mixture of these two salts is known as superphosphate. In this mixture, calcium sulfate from the point of view of agrochemistry is ballast, but it is usually 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 phosphate 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% Р 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 2H 2 O precipitate is used as a phosphorus fertilizer, which is obtained by reacting phosphoric acid with hydroxide or calcium carbonate:

Ca (OH) 2 + H 3 PO 4 → CaHPO 4 2H 2 O.

2CaCO 3 + 2H 3 RO 4 → 2CaHPO 4 2H 2 O + 2CO 2.

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

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 potash salts explored to date ensure the development of potash fertilizer production for more than a millennium, then the reserves of domestic phosphorus raw materials studied to date, with the planned large volumes of fertilizer production will only last a few decades.”

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

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

Isotopes of phosphorus

Natural phosphorus, unlike the overwhelming majority of elements, consists of only one isotope 31 P. Several short-lived radioactive isotopes of element No. 15 have been synthesized in nuclear reactions. One of them, phosphorus-30, was generally the first isotope obtained artificially. This was obtained in 1934 by Frederic and Irene Joliot-Curie by irradiating aluminum with alpha particles. Phosphorus-30 has a half-life of 2.55 minutes and decays to emit positrons ("positive electrons"). Six radioactive isotopes of phosphorus are now known. The longest-lived of them, 33 P, has a half-life of 25 days. Isotopes of phosphorus are mainly used in biological research.

Start of the superphosphate industry

The world's first industrial production of superphosphate was organized in 1842 in England. In Russia, similar enterprises appeared in 1868 and 1871. Before the revolution, only six superphosphate plants were built in our country, their total productivity did not exceed 50 thousand tons per year. During the years of the First World War, foreign intervention and civil war, four out of six plants went out of order, and in 1918 only 2.8 thousand tons of superphosphate were produced in our country. And just 20 years later, in 1938, in the production of phosphate fertilizers, the Soviet Union took first place in Europe and second place in the world. Now the share of our country in the world production of phosphate rock and phosphate fertilizers is about a quarter.

Testifies D.N. Pryanishnikov

“... No matter how correctly manure is stored and applied, it cannot return to the soil what it does not contain itself, i.e. a large share of phosphorus alienated from the economy in sold grain, animal bones, milk, etc.; thus, the soil gradually but steadily loses its phosphorus (or at least its assimilable part), and beyond a certain limit, phosphorus falls into the position of that “minimum factor” that is most lacking for a good harvest, as was quite rightly noted Liebig." (From the article "On the importance of phosphates for our agriculture and on the expansion of the possibility of the direct use of phosphorites", 1924).

Apatity of the Arctic

In 1926 A.E. Fersman and his collaborators discovered huge reserves of apatite on the Kola Peninsula. Many years later, Academician A.E. Fersman wrote about this deposit: “... decrees sparkling apatite with gray nepheline forms a solid wall of 100 m. This wonderful belt of the Khibiny tundra stretches for 25 km, bending around them in a ring. Studies have shown that apatite ore goes deep even below the surface of the ocean, and about two billion tons of these most valuable minerals have been accumulated here in the Khibiny, having no equal anywhere in the world.” ("Entertaining mineralogy", 1937.) On the basis of this deposit, the mining and chemical plant "Apatit" was built. CM. Kirov. Shortly before the war, another very large deposit of phosphorus raw materials was discovered - Kara-Tau phosphorites in Kazakhstan. There are also phosphorites in other regions of our country, in particular in the Moscow region. But the best raw material for the production of phosphate fertilizers is still provided by the apatite "belt of the Khibiny tundra".

What does apatite look like?

Let us turn again to Entertaining Mineralogy. “Apatite is calcium phosphate, but its appearance is so varied and strange that it was not for nothing that the old mineralogists called it apatite, which means “deceiver” in Greek: either these are transparent crystals, to the smallest detail resembling beryl or even quartz, or these are dense masses , indistinguishable from simple limestone, then these are radially radiant balls, then the rock is granular and shiny, like coarse-grained marble.

Who is the first?

The French historian F. Gefer argues that the generally accepted opinion that phosphorus was first obtained by the alchemist G. Brand in 1669 is incorrect. According to him, phosphorus was obtained as early as the 12th century. Arab alchemists, and their technology for obtaining phosphorus was the same as that of Brand: evaporating urine and heating the dry residue with coal and sand. If so, then humanity has been familiar with element #15 for almost 800 years.

Red and purple

The most famous modifications of phosphorus are white and red, both of which are used in industry. Other varieties of element No. 15 - purple, brown, black phosphorus - can only be found in laboratories. But purple phosphorus became known to people much earlier than red. Russian scientist A.A. Musin-Pushkin first received it back in 1797. In some books you can find the statement that red and purple phosphorus are one and the same. But these varieties differ not only in color. Violet phosphorus crystals are larger. Red phosphorus is obtained by heating white in a closed volume already at 250°C, and violet - only at 500°C.

"The Luminous Monk"

From the memoirs of Academician S.I. Volfkovich: “Phosphorus was obtained in an electric furnace installed at Moscow University on Mokhovaya Street. Since these experiments were then carried out in our country for the first time, I did not take the precautions that are necessary when working with gaseous phosphorus - a poisonous, self-igniting and luminous bluish element. During many hours of work at the electric furnace, part of the liberated gaseous phosphorus soaked my clothes and even shoes so much that when I walked from the university at night along the dark, then unlit streets of Moscow, my clothes emitted a bluish glow, and from under my shoes (when rubbing them on the pavement) sparks were fired.

Each time a crowd gathered behind me, among which, despite my explanations, there were quite a few people who saw in me a “newly appeared” representative of the other world. Soon, among the inhabitants of the Mokhovaya district and throughout Moscow, fantastic stories about the “luminous monk” began to be passed from mouth to mouth ...

Miracles without miracles

The church has repeatedly used white phosphorus to fool the faithful. There are at least two types of "miracles" that this substance is involved in. The first miracle: a candle that lights up by itself. This is done as follows: a solution of phosphorus in carbon disulfide is applied to the wick, the solvent evaporates rather quickly, and the phosphorus grains remaining on the wick are oxidized by atmospheric oxygen and ignite spontaneously. The second miracle: "divine" inscriptions flashing on the walls. Same solution, same reactions. If the solution is sufficiently saturated, then the inscriptions first glow, and then flash and disappear.

Organophosphorus and life

Many volumes have been written about the role of organophosphorus compounds in the most important biochemical reactions of the body. In any biochemistry textbook, these substances are not only mentioned many times, but also described in detail. Without organophosphorus compounds, the process of carbohydrate metabolism in the brain tissue could not go on. The phosphorus-containing enzyme phosphorylase contributes not only to the breakdown, but also to the synthesis of polysaccharides in the brain. Diphosphopyridine nucleotide and inorganic phosphate play an important role in the process of carbohydrate oxidation in the brain tissue. Another important process - muscle contraction is supported by the energy released during reactions involving adenosine phosphates. When the muscle contracts, the adenosine triphosphate (ATP) molecule breaks down into adenosine diphosphate and inorganic phosphoric acid. In this case, a lot of energy is released (8 ... 11 kcal / mol). The important role of these substances is also evidenced by the fact that a constant level of ATP is always maintained in muscle tissue.

By the middle of 1677, rumors of a remarkable discovery made in Germany had reached the British: "Someone Daniel Kraft from Hamburg obtained a substance that spontaneously ignites and glows with a steady light in the dark." One of the first in England to know about this was Robert Boyle (1627-1691). His book "The Skeptic Chemist" unambiguously showed that Boyle decisively prefers their strict quantitative characteristics to the qualitative description of processes. In 1662, in a treatise entitled "In Defense of the Doctrine of the Elasticity and Weight of Air," Boyle published a law relating pressure to the volume of a gas, now familiar to all schoolchildren. However, with all this, Boyle was irrevocably fascinated by alchemy. He was one of many who were fascinated by the dream of the "philosopher's stone" - a mysterious substance supposedly capable of turning base metals into gold. In addition, Boyle and other scientists were seriously fascinated by the idea of "phosphorus" - objects glowing in the dark. This and "wandering lights" ( ignis fatuus) that treacherously lure travelers into swamps, and many living creatures - fireflies, luminous plankton, and light-emitting saprophytic bacteria that feed on decaying plant and animal tissues.

In the autumn of 1677, the English king Charles II, himself an amateur alchemist, invited Kraft to London to demonstrate the amazing properties of the new phosphorus. On the evening of September 15, Kraft, with his alchemical paraphernalia, arrived at Ranelah House on Pall Mall in London, where Robert Boyle had assembled the members of the Royal Society. Boyle's own account of what they saw has been preserved: "... The windows were closed with wooden shutters, and the candles were taken to the next room before; remaining in the dark, we were able to enjoy the following phenomenon. First, Kraft took out a glass ball filled with a suspension of what something solid in the water - the substance was no more than two or three teaspoons - and yet it lit up the whole sphere, so that it looked like a cannonball, which, having been red-hot, was removed from the furnace. When Kraft shook his ball, the luminosity still increased, and individual flashes could be seen, but when the other vessel and the nectar contained in it were shaken, smoke arose, which almost completely filled the vessel, and something like a flash of lightning, very rarefied, was clearly visible, which pleasantly surprised me. then Kraft brought out a solid lump of phosphorus, which, as he declared, has been glowing for two years without interruption! Kraft took the smallest amount of solid substance and broke it into pieces so small that I counted them twenty or thirty I then scattered them in disorder over the carpet, and there, to our admiration, they sparkled very brightly and, moreover, twinkled like stars, but, fortunately, did not harm the expensive Turkish carpet. Then Kraft rubbed the surface of the phosphor with his finger, drew luminous letters on a sheet of paper so that they shimmered ominously in the dark, then smeared his face with phosphorus. A smell rose from the paper, which reminded me of sulfur and cucumbers at the same time ... ".

A few days later, Kraft demonstrated the ignition of phosphorus. A small piece of it, taken from a bottle of water, he wrapped in paper, which soon caught fire. Another piece of phosphorus immediately set fire to a pile of gunpowder. Boyle was deeply impressed by this, and he wished to immediately make his own experiments with a mysterious substance. When asked to leave a sample of phosphorus, Kraft refused, and when asked about its origin, he only said that it was made "from some derivative of the human body."

Boyle decided that phosphorus was most likely derived from urine: the yellow liquid always fired the imagination of alchemists, who assumed that it contained the primordial matter of gold. His assistant, Daniel Bilger, he ordered to collect incredible volumes of urine and evaporate the water from it. Unfortunately, there was no luminous substance in the solid residue. Then it was decided to conduct experiments with another "derivative of the human body" - the contents of cesspools. However, in this case, the desired result was not obtained. Boyle worked on the secret of obtaining phosphorus from urine for two years and, in the end, he still managed to get a luminous substance. In one of the many experiments, another assistant, the German Ambrose Godfrey Hankwitz (1660-1741), calcined a mixture of solid urine residue with sand, causing the retort to burst. Boyle, having come to look at the fragments, discovered their glow.

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