Carbon: the history of the discovery of the element. Why did Antoine Lavoisier burn the diamond? Lavoisier's diamond burning experience

And two types of diamond deposits are known, primary - bedrock or igneous and secondary - sedimentary or placer. It was mentioned above that India is considered the “discoverer” of diamonds.

Its legendary mines of Golconda gave the world almost all the diamonds famous since ancient times, for example, the legendary “Kohinoor”... Few of them have survived to this day.

TO XVII century the mines were depleted, India lost its leadership in the supply of diamonds to the world market, supplanted first by Brazil and later by South Africa. Currently, two fields are being developed in India. In South India, in the Golconda region - traditional, alluvial; the second is in Central India, in Panna, in a recently discovered diatreme.

The mined stones are cut in Bombay and exported. Currently, the annual production of Indian diamonds is 8,000-10,000 carats.

This is where, indeed, diamonds were discovered by “his majesty by chance”, it was in Brazil! Since 1695, gold miner Antonio Rodrigo Arado used funny stones instead of chips when playing cards or dice. Arado came across them quite often at the Tejuco mine, where he mined for gold and quartz...
For thirty years, players chased stones across the green cloth of the tables, until one of the gold miners, Bernado da Fanesca-Labo, determined the noble origin of the “chips” in 1725. A stream of happiness seekers poured into Brazil. By 1727, the volume of Brazilian diamond production had sharply reduced prices on the world diamond market. And people kept finding new placers.

By 1729, eleven diamond-bearing rivers had already been discovered. Prices fell catastrophically, and the destructive process was stopped only by tough administrative measures. They established a Portuguese royal monopoly on diamond mining, huge duties on their export, and enslaving conditions for leasing diamond-bearing areas.

In 1822, Brazil gained sovereignty and took leadership in the world diamond market. Brazilian diamonds are small in size. Only six of them are most famous in the world: “Star of the South”, “Star of Egypt”, “Star of Minas”, “Minas Gerais”, “English Diamond of Dresden” and “President Vargas”. The vast majority of Brazilian diamonds are premium crystals of the highest quality. But the leadership did not last long...

A strange white pebble found by the son of Boer farmer Daniel Jacobs in 1867 on the banks of the Orange River changed the course of development South Africa. After much ordeal, the “pebble” was examined by mineralogist William Guilbon Atherston, who identified it as a beautiful diamond. The crystal was cut, the diamond weighing 10.75 carats was given name“Eureka” took its place in history as the first-born of South African diamond mining.

One autumn day in 1772, Parisians walking near the Louvre, in the Infanta's garden, along the Seine embankment, could see a strange structure resembling a flat cart in the form of a wooden platform on six wheels. Huge glass was installed on it. The two largest lenses, which had a radius of eight feet, were fastened together to form a magnifying glass that collected the sun's rays and directed them onto a second, smaller lens, and then onto the surface of the table. On the platform stood the scientists in wigs and black glasses engaged in the experiment, and their assistants scurried about like sailors on the deck, adjusting this entire complex structure to the sun, constantly holding the luminary floating across the sky “at gunpoint.”

Among the people who used this facility, an 18th-century “particle accelerator,” was Antoine Laurent Lavoisier. He was then interested in what happens when a diamond is burned.

It had long been known that diamonds burned, and local jewelers asked the French Academy of Sciences to investigate whether there was any risk in this. Lavoisier himself was interested in a slightly different question: the chemical essence of combustion. The beauty of the “fire glass” was that, by focusing the sun’s rays at a point inside the container, it heated everything that could be placed at that point. The smoke from the vessel could be directed through a tube into a vessel containing water, the particles contained in it could be precipitated, then the water could be evaporated and the residue analyzed.

Unfortunately, the experiment was unsuccessful: the intense heating caused the glass to constantly burst. However, Lavoisier did not despair - he had other ideas. He proposed a program to the Academy of Sciences to study “the air contained in matter” and how it, this air, is related to combustion processes.

Newton managed to direct the development of physics along the right way, but in chemistry in those days things were very bad - it was still a captive of alchemy. “Henna, dissolved in a well refluxed spirit of saltpeter, will give a colorless solution,” wrote Newton. “But if you put it in good oil of vitriol and shake it until it dissolves, the mixture will first turn yellow and then dark red.” On the pages of this " cookbook"nothing was said about measurements or quantities. “If the spirit of salt is placed in fresh urine, then both solutions will mix easily and calmly,” he noted, “but if the same solution is dropped onto evaporated urine, then hissing and boiling will follow and the volatile and acidic salts will coagulate into a third after some time.” a substance resembling ammonia in nature. And if you dilute a decoction of violets, dissolving it in a small amount of fresh urine, then a few drops of fermented urine will take on a bright green color.”

Quite far from modern science. There is much in alchemy, even in Newton's own writings, that resembles magic. In one of his diaries, he conscientiously copied several paragraphs from the book of the alchemist George Starkey, who called himself Philalethes.

The passage begins: “In [Saturn] is hidden the immortal soul.” Saturn usually meant lead, since each element was associated with a planet. But in in this case the reference was to the silvery metal known as antimony. "Immortal Spirit" is a gas that the ore emits when heated to extreme temperatures. “Mars is tied to Saturn by bonds of love (this meant that iron was added to antimony), which in itself devours great power, whose spirit divides the body of Saturn, and from both together flows wonderful bright water, into which the Sun sets, releasing its light.” . The sun is gold, which in this case is immersed in mercury, often called amalgam. "Venus, the brightest star, is in the embrace of [Mars]." Venus was the name given to the copper that was added to the mixture at this stage. This metallurgical recipe is most likely a description of the early stages of obtaining the “philosopher’s stone”, which all alchemists strove for, since it was believed that with its help it was possible to turn base elements into gold.

Lavoisier and his contemporaries were able to go beyond these mystical spells, but chemists even at that time still believed in alchemical ideas that the behavior of substances is determined by three principles: mercury (which liquefies), salt (which thickens) and sulfur (which makes the substance flammable ). The "sulphurous spirit", also called terra pingua ("greasy" or "oily" earth), occupied the minds of many. At the beginning of the 18th century, the German chemist Georg Ernst Stahl began to call it phlogiston (from the Greek phlog - related to fire).

It was believed that objects burn because they contain a lot of phlogiston. As objects are consumed by fire, they release this flammable substance into the air. If you set fire to a piece of wood, it will stop burning, leaving behind just a pile of ash, only when it has used up all its phlogiston. Therefore, it was believed that the tree consists of ash and phlogiston. Similarly, after calcination, i.e. When exposed to extreme heat, the metal is left with a white, brittle substance known as scale. Therefore, the metal consists of phlogiston and scale. The rusting process is a slow burning process, like breathing, i.e. reactions that occur when phlogiston is released into the air.

The reverse process was also considered. It was believed that the scale resembled ore mined from the earth, which was then refined, undergoing reduction, or “regeneration,” by heating next to charcoal. The charcoal emitted phlogiston, which combined with the scale to restore the shiny metal.

In itself, the use of a hypothetical substance that cannot be measured, but can be assumed, does not contain anything wrong. Nowadays, cosmologists also operate with the concept of “dark matter”, which must exist so that galaxies do not fly apart when rotating under the influence of centrifugal force, and that anti-gravitational “dark energy” is behind the expansion of the Universe.

With the help of phlogiston, scientists could logically explain combustion, calcination, reduction, and even respiration. Chemistry suddenly became meaningful.

However, this did not solve all the problems: the scale remaining after calcination weighed more than the original metal. How could it happen that after phlogiston left the substance, it became heavier? Like “dark energy” a quarter of a millennium later, phlogiston, in the words of the French philosopher Condorcet, “was driven by forces opposite in direction to gravity.” To make this idea seem more poetic, one chemist declared that phlogiston “gives wings to the molecules of the earth.”

Lavoisier, like scientists of that time, I was sure that phlogiston is one of the main components of matter. But by the time he began experimenting with diamonds, he began to wonder: could something weigh less than zero?

His mother died when he was still a boy, leaving him an inheritance that was enough to enter into a lucrative enterprise called "Main Farming". The French government entered into an agreement with this consortium of private individuals to collect taxes, of which farmers such as Lavoisier had a certain share. This activity constantly distracted him from research, but provided income that allowed him after some time to become the owner of one of the best laboratories in Europe. Among the first experiments in 1769 was an experiment with which Lavoisier decided to test the then prevailing idea that water could be turned into earth.

The evidence was quite convincing: water evaporating in a frying pan leaves a solid residue. But Lavoisier decided to get to the bottom of it, using a sublimation vessel known as a pelican. Having a large round container at the base and a small upper chamber, the vessel was equipped with two curved tubes (a bit like a pelican's beak) through which the steam returned back down. For alchemists, the pelican symbolized the sacrificial blood of Christ, so the pelican vessel was believed to have the power of transformation. Moreover, the water that boiled in the pelican would continuously evaporate and condense, so that no substance - solid, liquid or gaseous - could leave the system.

After distilling pure water for a hundred days, Lavoisier discovered that sediment actually existed. But he guessed where it came from. Having weighed the empty Pelican, he noticed that the vessel had become lighter. Having dried and weighed the sediment, Lavoisier saw that the weight of the sediment quite accurately corresponded to the decrease in the weight of the vessel, and this fact led him to the idea that the source of the sediment was the glass of the vessel.

Two years later, in 1771, Lavoisier turned twenty-eight years old. That same year he got married. His chosen one was Marie-Anne Pierrette Polze, the thirteen-year-old daughter of another tax farmer. (This rather pretty girl was engaged by that time, and her second potential groom was fifty.) Maria Anna liked her so much scientific studies husband that she quickly mastered chemistry and helped in any way she could: she took notes, translated English scientific literature into French and completed the most complex drawings of an experiment that turned out to be so elegant that it, like the philosopher's stone, was destined to transform alchemy into chemistry.

The chemists of the generation to which Lavoisier belonged already knew that, as the Englishman Joseph Priestley was able to formulate it, “there are several types of air.” Mephitic (“fetid” or “stale”) air causes the flame to go out, and the mouse in it dies from suffocation. Such air makes lime water (calcium hydroxide) cloudy, forming a white precipitate (calcium carbonate). However, the plants felt good in this air and after a while made it breathable again.

Another asphyxiating gas was produced when a candle burned for some time in a closed container. This gas did not precipitate limewater, and since it was clearly associated with the combustion process, it came to be called phlogiston air, or nitrogen (from the Greek “lifeless”). The most mysterious was the volatile gas released when iron filings were dissolved in dilute sulfuric acid. It was so flammable that it was called “flammable air.” If you inflate a balloon with this air, it will rise high above the ground.

The question arose whether new types of air chemical elements or, as Priestley suggested, modifications of "ordinary" air obtained by the addition or extraction of phlogiston?

With difficulty containing his skepticism, Lavoisier repeated some of the experiments of his colleagues. He confirmed that burning phosphorus to produce phosphoric acid or burning sulfur to produce sulfuric acid produces substances that weigh more than the substances used, i.e. as in the calcination of metals. But why does this change occur? It seemed to him that he had found the answer to this question. Using a magnifying glass to heat tin enclosed in a sealed glass vessel, he discovered that the entire installation weighed the same before and after the experiment. Slowly opening the vessel, he heard the air rush inside with a noise, after which the weight increased again. Maybe objects burn not because they emit phlogiston, but because they absorb some part of the air?

If this is so, then restoration, i.e. smelting ore into pure metal releases air. He measured out a certain amount of lead scale, called litharge, and placed it on a small raised surface in a vessel of water next to a piece of charcoal. Covering it all with a glass bell, he began to heat the scale using a magnifying glass. From the water being displaced, he could guess that gas was being released. Carefully collecting the released gas, he discovered that this gas extinguished the flame and precipitated limewater. It appears that the "stale" air was a product of recovery, but was that all there was to it?

It turned out that the answer lay in a reddish substance called mercurius calcinatus, or scale of mercury, which was sold by Parisian apothecaries as a cure for syphilis at a price of 18 livres or more per ounce, i.e. $1,000 in today's prices. Any experiments with this substance were no less extravagant than experiments with burning diamonds. Like any other scale, it could be obtained by calcining pure metal over a high flame. However, with further heating, the resulting substance again turned into mercury. In other words, mercurius calcinatus could be restored even without the use of charcoal. But what then was the source of phlogiston? In 1774, Lavoisier and several of his colleagues at the French Academy of Sciences confirmed that mercury scale could indeed be reduced "without additional substances" with a loss of about one-twelfth of its weight.

Priestley also experimented with this substance, heating it with a magnifying glass and collecting the gases released. “What struck me so much that there are not even enough words to express the feelings that overwhelmed me,” he later wrote, “is that the candle burned in this air with a rather strong flame... I could not find an explanation for this phenomenon.” Having found out that the laboratory mouse felt good in the magic gas, he decided to breathe it himself. “It seemed to me that after some time I felt extraordinary lightness and freedom in my chest. Who would have imagined that this clean air would eventually become a fashionable luxury item. In the meantime, only two mice and I myself have had the pleasure of inhaling it.”

Priestley decided to call the gas, in which one can breathe well and burn easily, “dephlogisticated”, i.e. air in its purest form. He was not alone in such reasoning. In Sweden, a pharmacist named Karl Wilhelm Scheele also studied the properties of “fire air”.

By this time, Lavoisier had already called the gas released during the reduction of mercurius calcinatus “extremely beneficial for breathing,” or “living” air. Like Priestley, he believed that this gas represented air in its primordial form. However, here Lavoisier encountered one difficulty. When he tried to reduce mercury scale using charcoal, i.e. in the old, proven way, the same gas was released as when restoring litharge - it extinguished the candle flame and precipitated limewater. Why did the reduction of mercury scale without charcoal produce “living” air, and when using charcoal, a suffocating “stale” air appeared?

There was only one way to clarify everything. Lavoisier took a vessel from the shelf, which was called a flat flask. Its lower part was round, and Lavoisier heated the high neck and bent it so that it first curved down and then up again.

If in his 1769 experiment the vessel resembled a pelican, then the current one looked like a flamingo. Lavoisier poured four ounces of pure mercury into the round lower chamber of the vessel (labeled A in the figure). The vessel was installed on the furnace so that its neck was in an open container, also filled with mercury, and then raised into a glass bell. This part of the setup was used to determine the amount of air that would be consumed during the experiment. Having marked the level (LL) with a paper strip, he lit the furnace and brought the mercury in chamber A almost to a boil.

We can assume that nothing special happened on the first day. A small amount of mercury evaporated and settled on the walls of the flat flask. The resulting balls were heavy enough to flow down again. But on the second day, red dots began to form on the surface of the mercury - scale. Over the next few days, the red crust increased in size until it reached its maximum size. On the twelfth day, Lavoisier stopped the experiment and made some measurements.

At that time, the mercury in the glass bell exceeded the initial level by the amount of air that was consumed to form scale. Taking into account changes in temperature and pressure inside the laboratory, Lavoisier calculated that the amount of air had decreased by about one-sixth of its original volume, i.e. from 820 to 700 cubic centimeters. In addition, the nature of the gas has changed. When a mouse was placed inside the container containing the remaining air, it immediately began to choke, and “the candle placed in this air immediately went out, as if it had been put into water.” But since the gas did not cause sedimentation in the limewater, it could more likely be attributed to nitrogen rather than “stale air.”

But what did mercury get from the air during combustion? Having removed the red coating that had formed on the metal, Lavoisier began to heat it in a retort until it again became mercury, releasing from 100 to 150 cubic centimeters of gas - about the same amount as mercury absorbed during calcination. The candle inserted into this gas “burned beautifully,” and the charcoal did not smolder, but “glowed with such a bright light that the eyes could hardly bear it.”

This was a turning point. Burning, mercury absorbed “living” air from the atmosphere, leaving nitrogen. The reduction of mercury again led to the release of “living” air. So Lavoisier managed to separate the two main components of atmospheric air.

To be sure, he mixed eight parts of “living” air and forty-two parts of nitrogen and showed that the resulting gas had all the characteristics of ordinary air. Analysis and synthesis: “Herein lies the most convincing proof available in chemistry: air, when decomposed, recombines.”

In 1777, Lavoisier reported the results of his research to members of the Academy of Sciences. Phlogiston turned out to be a fiction. Combustion and calcination occurred when the substance absorbed “living” air, which he called oxygen because of its role in the formation of acids. (Oxy means “spicy” in Greek.) Absorbing oxygen from the air results in only unbreathable nitrogen remaining in the air.

As for the gas, which was called "stale" air, it was formed when the oxygen released during reduction combined with something in the charcoal, creating what we today call carbon dioxide.

Year after year, Lavoisier's colleagues, especially Priestley, grumbled about the fact that he allegedly arrogated to himself primacy in experiments that they also carried out. Priestley once dined at the Lavoisier couple's house and told them about his phlogiston-deprived air, and the Swedish pharmacist Scheele sent Lavoisier a letter telling about your experiences. But despite all this, they continued to think that oxygen is air devoid of phlogiston.

In the play Oxygen, which premiered in 2001, two chemists, Carl Djerassi and Roald Hoffman, created a plot in which the Swedish king invited the three scientists to Stockholm to decide which of them should be considered the discoverer of oxygen. Scheele was the first to isolate the gas, and Priestley was the first to publish a paper suggesting its existence, but only Lavoisier understood what they had discovered.

He looked much deeper and formulated the law of conservation of mass. As a result chemical reaction the substance—in this case, burning mercury and air—changes shape. But mass is neither created nor destroyed. As many substances enter into the reaction, the same amount should come out. As a tax collector might say, the balance has to balance anyway.

In 1794, during the revolutionary terror, Lavoisier and Marie-Anne's father, along with other tax farmers, were recognized as “enemies of the people.” They were brought on a cart to Revolution Square, where wooden stages had already been built, the appearance of which even in detail resembled the platform on which Lavoisier burned diamonds. Only instead of huge lenses there was another achievement of French technology - the guillotine.

A message recently appeared on the Internet that during the execution Lavoisier managed to carry out his last experiment. The fact is that they began to use the guillotine in France because they thought it was the most humane form of execution - it brings instant and painless death. And now Lavoisier had the opportunity to find out if this was so. The moment the guillotine blade touched his neck, he began to blink his eyes and did so as much as he could. There was an assistant in the crowd who had to count how many times he could blink. It is possible that this story is a fiction, but it is quite in the spirit of Lavoisier.

(c) George Johnson "Ten Most Beautiful Experiments in Science."

Why did Antoine Lavoisier burn the diamond?

Eighteenth century, France, Paris. Antoine Laurent Lavoisier, one of the future creators of chemical science, after many years of experiments with various substances in the quiet of his laboratory, is convinced again and again that he has made a genuine revolution in science. His essentially simple chemical experiments on the combustion of substances in hermetically sealed volumes completely refuted the generally accepted theory of phlogiston at that time. But strong, strictly quantitative evidence in favor of the new “oxygen” theory of combustion is not accepted in the scientific world. The visual and convenient phlogiston model has become very firmly ingrained in our heads.

What to do? Having spent two or three years in fruitless efforts to defend his idea, Lavoisier comes to the conclusion that his scientific environment has not yet matured to purely theoretical arguments and that he should take a completely different path. In 1772, the great chemist decided to undertake an unusual experiment for this purpose. He invites everyone to take part in the spectacle of burning... a weighty piece of diamond in a sealed cauldron. How can one resist curiosity? After all, we are not talking about anything, but about a diamond!

It is quite understandable that following the sensational message, the scientist’s ardent opponents, who had previously not wanted to delve into his experiments with all sorts of sulfur, phosphorus and coal, poured into the laboratory along with ordinary people. The room was polished to a shine and shone no less than a precious stone sentenced to public burning. It must be said that Lavoisier’s laboratory at that time belonged to one of the best in the world and was fully consistent with an expensive experiment in which the owner’s ideological opponents were now simply eager to take part.

The diamond did not disappoint: it burned without a visible trace, according to the same laws that applied to other despicable substances. Nothing significantly new with scientific point no vision occurred. But the “oxygen” theory, the mechanism of formation of “bound air” (carbon dioxide) have finally reached the consciousness of even the most inveterate skeptics. They realized that the diamond had not disappeared without a trace, but that under the influence of fire and oxygen it had undergone qualitative changes and turned into something else. After all, at the end of the experiment, the flask weighed exactly as much as at the beginning. So, with the false disappearance of the diamond before everyone’s eyes, the word “phlogiston”, meaning a hypothetical component substances allegedly lost during its combustion.

But a holy place is never empty. One went, another came. The phlogiston theory was supplanted by a new fundamental law of nature - the law of conservation of matter. Lavoisier was recognized by historians of science as the discoverer of this law. Diamond helped convince humanity of its existence. At the same time, these same historians have created such clouds of fog around the sensational event that it still seems quite difficult to understand the reliability of the facts. A priority important discovery For many years now, and without any reason, it has been disputed by the “patriotic” circles of the most different countries: Russia, Italy, England...

What arguments support the claims? The most ridiculous ones. In Russia, for example, the law of conservation of matter is attributed to Mikhail Vasilyevich Lomonosov, who did not actually discover it. Moreover, as evidence, the scribblers of chemical science shamelessly use excerpts from his personal correspondence, where the scientist, sharing with colleagues his reasoning about the properties of matter, allegedly personally testifies in favor of this point of view.

Italian historiographers explain their claims to the priority of a world discovery in chemical science by the fact that... Lavoisier was not the first to have the idea to use diamond in experiments. It turns out that back in 1649, prominent European scientists became acquainted with letters reporting similar experiments. They were provided by the Florentine Academy of Sciences, and from their contents it followed that local alchemists had already exposed diamonds and rubies to strong fire, placing them in hermetically sealed vessels. At the same time, the diamonds disappeared, but the rubies were preserved in their original form, from which the conclusion was drawn about the diamond as “a truly magical stone, the nature of which defies explanation.” So what? We are all, in one way or another, following in the footsteps of our predecessors. And the fact that the alchemists of the Italian Middle Ages did not recognize the nature of diamond only suggests that many other things were inaccessible to their consciousness, including the question of where the mass of a substance goes when it is heated in a vessel that excludes access to air.

The authorial ambitions of the British also look very shaky, as they generally deny Lavoisier’s involvement in the sensational experiment. In their opinion, the great French aristocrat was unfairly credited with credit that actually belonged to their compatriot Smithson Tennant, who is known to mankind as the discoverer of the two most expensive metals in the world - osmium and iridium. It was he, as the British claim, who performed such demonstration stunts. In particular, he burned diamond in a golden vessel (previously graphite and charcoal). And it was he who came up with the important conclusion for the development of chemistry that all these substances are of the same nature and, upon combustion, form carbon dioxide in strict accordance with the weight of the substances being burned.

But no matter how hard some historians of science try, even in Russia, even in England, to belittle outstanding achievements Lavoisier and assign him a secondary role in unique research, they still fail. The brilliant Frenchman continues to remain in the eyes of the world community as a man of a comprehensive and original mind. Suffice it to recall his famous experiment with distilled water, which once and for all shook the view held at that time among many scientists on the ability of water to turn into a solid substance when heated.

This incorrect view was formed on the basis of the following observations. When the water was evaporated “to dryness,” a solid residue was invariably found at the bottom of the vessel, which for simplicity was called “earth.” This is where there was talk about turning water into land.

In 1770, Lavoisier put this conventional wisdom to the test. To begin with, he did everything to get the purest water possible. This could be achieved then only in one way - distillation. Taking the best rainwater in nature, the scientist distilled it eight times. Then he filled a pre-weighed glass container with water purified from impurities, sealed it hermetically and recorded the weight again. Then, for three months, he heated this vessel on a burner, bringing its contents almost to a boil. As a result, there really was “ground” at the bottom of the container.

But from where? To answer this question, Lavoisier again weighed the dry vessel, the mass of which had decreased. Having established that the weight of the vessel had changed as much as “earth” had appeared in it, the experimenter realized that the solid residue that had confused his colleagues was simply leaching out of the glass, and there could be no question of any miraculous transformations of water into earth. This is where a curious chemical process occurs. And under the influence of high temperatures it proceeds much faster.

Carbon (English Carbon, French Carbone, German Kohlenstoff) in the form of coal, soot and soot has been known to mankind since time immemorial; about 100 thousand years ago, when our ancestors mastered fire, they dealt with coal and soot every day. Probably, very early people became acquainted with allotropic modifications of carbon - diamond and graphite, as well as fossil coal. It is not surprising that the combustion of carbon-containing substances was one of the first chemical processes to interest man. Since the burning substance disappeared when consumed by fire, combustion was considered a process of decomposition of the substance, and therefore coal (or carbon) was not considered an element. The element was fire - a phenomenon accompanying combustion; In ancient teachings about the elements, fire usually appears as one of the elements. At the turn of the XVII - XVIII centuries. The phlogiston theory arose, put forward by Becher and Stahl. This theory recognized the presence in each combustible body of a special elementary substance - a weightless fluid - phlogiston, which evaporates during the combustion process. Since when a large amount of coal is burned, only a little ash remains, phlogistics believed that coal was almost pure phlogiston. This is what explained, in particular, the “phlogisticating” effect of coal - its ability to restore metals from “limes” and ores. Later phlogistics, Reaumur, Bergman and others, already began to understand that coal is an elementary substance. However, “clean coal” was first recognized as such by Lavoisier, who studied the process of combustion of coal and other substances in air and oxygen. In the book "Method of Chemical Nomenclature" (1787) by Guiton de Morveau, Lavoisier, Berthollet and Fourcroix, the name "carbon" (carbone) appeared instead of the French "pure coal" (charbone pur). Under the same name, carbon appears in the “Table of Simple Bodies” in Lavoisier’s “Elementary Textbook of Chemistry.” In 1791, the English chemist Tennant was the first to obtain free carbon; he passed phosphorus vapor over calcined chalk, resulting in the formation of calcium phosphate and carbon. It has long been known that diamond burns without leaving a residue when heated strongly. Back in 1751, the French king Francis I agreed to give diamond and ruby ​​for combustion experiments, after which these experiments even became fashionable. It turned out that only diamond burns, and ruby ​​(aluminum oxide with an admixture of chromium) can withstand prolonged heating at the focus of the ignition lens without damage. Lavoisier carried out a new experiment on burning diamonds using a large incendiary machine and came to the conclusion that diamond is crystalline carbon. The second allotrope of carbon - graphite in the alchemical period was considered a modified lead luster and was called plumbago; It was only in 1740 that Pott discovered the absence of any lead impurity in graphite. Scheele studied graphite (1779) and, being a phlogistician, considered it a special kind of sulfur body, a special mineral coal containing bound “aerial acid” (CO 2) and a large amount of phlogiston.

Twenty years later, Guiton de Morveau turned diamond into graphite and then into carbonic acid by careful heating.

The international name Carboneum comes from the Latin. carbo (coal). This word is of very ancient origin. It is compared with cremare - to burn; root sag, cal, Russian gar, gal, gol, Sanskrit sta means to boil, cook. The word "carbo" is associated with the names of carbon in other European languages ​​(carbon, charbone, etc.). The German Kohlenstoff comes from Kohle - coal (Old German kolo, Swedish kylla - to heat). Old Russian ugorati, or ugarati (to burn, scorch) has the root gar, or mountains, with a possible transition to gol; coal in Old Russian yugal, or coal, of the same origin. The word diamond (Diamante) comes from the ancient Greek - indestructible, unyielding, hard, and graphite from the Greek - I write.

IN early XIX V. the old word coal in Russian chemical literature was sometimes replaced by the word “carbonate” (Scherer, 1807; Severgin, 1815); Since 1824, Soloviev introduced the name carbon.

The word "diamond" comes from Greek language. It is translated into Russian as "". Indeed, to damage this stone, superhuman efforts must be made. It cuts and scratches all the minerals known to us, while itself remaining unharmed. Acid does not harm him. One day, out of curiosity, an experiment was carried out in a forge: a diamond was placed on an anvil and hit with a hammer. The iron one almost split in two, but the stone remained intact.

Diamond burns with a beautiful bluish color.

Of all solids Diamond has the highest thermal conductivity. It is resistant to friction, even against metal. This is the most elastic mineral with the lowest compression ratio. An interesting property of diamond is to luminesce even under the influence of artificial rays. It glows with all the colors of the rainbow and refracts color in an interesting way. This stone seems to be saturated with the color of the sun and then radiates it. As you know, a natural diamond is not beautiful, but it is the cutting that gives it true beauty. A gemstone made from a cut diamond is called a diamond.

History of experiments

In the 17th century in England, Boyle managed to burn a diamond by shining a sunbeam on it through a lens. However, in France, experience with calcination of diamonds in a melting vessel did not produce any results. The French jeweler who conducted the experiment found only a thin layer of dark plaque on the stones. At the end of the 17th century, Italian scientists Averani and Tardgioni, while trying to fuse two diamonds together, were able to establish the temperature at which a diamond burns - from 720 to 1000 ° C.

Diamond does not melt due to its strong structure crystal lattice. All attempts to melt the mineral ended with it burning.

The great French physicist Antoine Lavoisier went further, deciding to place diamonds in a sealed glass vessel and filling it with oxygen. Using a large lens, he heated the stones and they completely burned. Having studied the composition of the air, they found that in addition to oxygen, it contains carbon dioxide, which is a compound of oxygen and carbon. Thus, the answer was received: diamonds burn, but only with access to oxygen, i.e. on open air. When burned, diamond turns into carbon dioxide. That is why, unlike coal, after burning a diamond, not even ash remains. Experiments by scientists have confirmed another property of diamond: in the absence of oxygen, diamond does not burn, but its molecular structure changes. At a temperature of 2000°C, graphite can be obtained in just 15-30 minutes.