α-carbyne and β-carbyne. Carbyne is a new form of carbon, superior in strength to graphene and carbon nanotubes

“Carbyne” is a material created from carbon atoms that are assembled into a chain in a certain way. Created in the laboratory new form carbon - “Carbin”, which could be touched with your hands, was not recognized by scientists for a long time. It has not yet been discovered in nature.

Carbyne - a nanomaterial of the future

Scientists first discovered Carbin in pieces of some meteorites before it was recognized as an existing material.

After lengthy experiments, Carbin was synthesized in the laboratory, but it was such a tiny amount that the main properties had to be determined mathematically.

They calculated that the strength of “Carbin” is almost 2 times higher than the strength of “Graphene” and found that the molecules of “Carbin” do not stretch, but do not lose flexibility. This is a chemically inactive material. By adding molecules of certain substances to Carbin, you can obtain materials with completely different properties.

IN given time physical and chemical properties"Carbina" has already been well studied. The creation of materials using “Carbin” in industrial quantities begins, the strength of which is twice as strong as “Graphene”. These materials have good adhesion and are chemically inactive.

“Carbin”, like “Graphene”, has a thickness of 1 atom. This means that the surface area relative to the mass is very large. This means that it can be used in the manufacture batteries and supercapacitors.

In addition, Carbin has a number of other properties that allow it to be used in electronics and medicine.

Based on electronic properties, scientists build sensors for gas, light and the presence of life. Samsung's Advanced Technology Institute is working to develop flexible displays, transistors and storage devices.

"Carbin" has high biological compatibility, so it is widely used in medicine. Using Karbin, vascular prostheses, suture threads, and coatings for rubbing joints were created. It is already used in ophthalmology, urology and dentistry.

Physical properties

Carbon exists in many allotropic modifications with very diverse physical properties. The variety of modifications is due to the ability of carbon to form chemical bonds of different types.

Carbon isotopes

Natural carbon consists of two stable isotopes - 12 C (98.93%) and 13 C (1.07%) and one radioactive isotope 14 C (β-emitter, T ½ = 5730 years), concentrated in the atmosphere and upper part earth's crust. It is constantly formed in the lower layers of the stratosphere as a result of the impact of neutrons from cosmic radiation on nitrogen nuclei according to the reaction: 14 N (n, p) 14 C, and also, since the mid-1950s, as a man-made product of nuclear power plants and as a result of testing hydrogen bombs .

The radiocarbon dating method, widely used in Quaternary geology and archeology, is based on the formation and decay of 14 C.

Allotropic modifications of carbon

Schemes of the structure of various modifications of carbon
a: diamond, b: graphite, c: lonsdaleite, d: fullerene - buckyball C 60, e: fullerene C 540, f: fullerene C 70, g: amorphous carbon, h: carbon nanotube

Crystalline carbon

· Diamond, Graphene, Graphite, Carbyne, Lonsdaleite, Nanodiamond, Fullerenes, Fullerite, Carbon fiber, Carbon nanofibers, Carbon nanotubes

Amorphous carbon

· Activated carbon, Charcoal, Fossil coal: anthracite, Coal coke, petroleum, Glassy carbon, Carbon black, Soot, Carbon nanofoam

In practice, as a rule, the amorphous forms listed above are chemical compounds high in carbon rather than the pure allotropic form of carbon.

Cluster forms

· Astralens

Dicarbon

Structure

The electron orbitals of a carbon atom can have different geometries, depending on the degree of hybridization of its electron orbitals. There are three basic geometries of the carbon atom.

· tetrahedral, formed by mixing one s- and three p-electrons (sp 3 hybridization). The carbon atom is located at the center of the tetrahedron, connected by four equivalent σ-bonds to carbon or other atoms at the vertices of the tetrahedron. The carbon allotropic modifications diamond and lonsdaleite correspond to this geometry of the carbon atom. Carbon exhibits such hybridization, for example, in methane and other hydrocarbons.

· trigonal, formed by mixing one s- and two p-electron orbitals (sp 2 hybridization). The carbon atom has three equivalent σ bonds located in the same plane at an angle of 120° to each other. The p-orbital not involved in hybridization, located perpendicular to the plane of σ-bonds, is used to form a π-bond with other atoms. This carbon geometry is characteristic of graphite, phenol, etc.

Digonal, formed by mixing one s- and one p-electrons (sp-hybridization). In this case, two electron clouds are elongated along one direction and look like asymmetrical dumbbells. The other two p electrons make a π bond. Carbon with such an atomic geometry forms a special allotropic modification - carbyne.

Graphite and diamond

The main and well-studied allotropic modifications of carbon are diamond and graphite. Under normal conditions, only graphite is thermodynamically stable, while diamond and other forms are metastable. At atmospheric pressure and temperatures above 1200 K, diamond begins to transform into graphite; above 2100 K, the transformation takes place in seconds. ΔН 0 transition - 1.898 kJ/mol. At normal pressure carbon sublimates at 3,780 K. Liquid carbon exists only at a certain external pressure. Triple points: graphite-liquid-vapor T = 4130 K, p = 10.7 MPa. The direct transition of graphite to diamond occurs at 3000 K and a pressure of 11-12 GPa.

Carbin

The crystalline modification of carbon of the hexagonal system with a chain structure of molecules is called carbyne. The chains have either a polyene structure (-C≡C-) or a polycumulene structure (=C=C=). Several forms of carbyne are known, differing in the number of atoms in the unit cell, cell sizes and density (2.68-3.30 g/cm³). Carbyne occurs in nature in the form of the mineral chaoite (white veins and inclusions in graphite) and is obtained artificially - by oxidative dehydropolycondensation of acetylene, by the action of laser radiation on graphite, from hydrocarbons or CCl 4 in low-temperature plasma.

Carbyne is a fine-crystalline black powder (density 1.9-2 g/cm³) and has semiconductor properties. Received in artificial conditions made up of long chains of carbon atoms arranged parallel to each other.

Carbyne is a linear polymer of carbon. In the carbyne molecule, the carbon atoms are connected in chains alternately either by triple and single bonds (polyene structure) or permanently by double bonds (polycumulene structure). This substance was first obtained by Soviet chemists V.V. Korshak, A.M. Sladkov, V.I. Kasatochkin and Yu.P. Kudryavtsev in the early 60s. at the Institute of Organoelement Compounds of the USSR Academy of Sciences. Carbyne has semiconducting properties, and its conductivity increases greatly when exposed to light. The first is based on this property practical application- in photocells.

Properties

Carbyne is a fine-crystalline black powder (density 1.9÷2 g/cm³) and has semiconductor properties. Obtained under artificial conditions from long chains of carbon atoms laid parallel to each other. Carbyne is a linear polymer of carbon. In the carbyne molecule, the carbon atoms are connected in chains alternately either by triple and single bonds (polyine structure) or permanently by double bonds (polycumulene structure). This substance was first obtained by Soviet chemists V.V. Korshak, A.M. Sladkov, V.I. Kasatochkin and Yu.P. Kudryavtsev in the early 60s. at the USSR Academy of Sciences (INEOS). Carbyne has semiconducting properties, and its conductivity increases greatly when exposed to light. The first practical application is based on this property - in photovoltaic cells.

Background of the opening

The question of the possibility of the existence of forms of carbon with sp-hybridization of atoms has been repeatedly considered theoretically. Back in 1885, the German chemist Adolf Bayer tried to synthesize chain carbon from acetylene derivatives using a stepwise method. However, Bayer's attempt to get polyine(a compound containing at least three isolated or conjugated C≡C bonds in a molecule) was unsuccessful; he obtained a hydrocarbon consisting of four acetylene molecules connected in a chain, which turned out to be extremely unstable. The instability of lower polyines served as the basis for Bayer to create the stress theory, in which he postulated the impossibility of obtaining chain carbon. The scientist's authority cooled the interest of researchers in the synthesis of polyines, and work in this direction ceased for a long time.

The one-dimensional (linear) form of carbon has long remained the missing link in carbon allotropy. An important stimulus for the resumption of work in this area was the discovery of representatives of the polyacetylene series in nature in the 1930s. In some plants and lower fungi, polyine compounds containing up to five conjugated acetylene groups were discovered. One of the first who decided to challenge the authority of their predecessors were the head of the laboratory of macromolecular compounds at INEOS, Vasily Vladimirovich Korshak and Alexey Mikhailovich Sladkov. Their work led to the discovery of a new linear allotropic form of carbon.

In 1959–1960, systematic studies of the oxidative coupling reaction of diacetylene compounds were carried out in the laboratory of macromolecular compounds of INEOS, headed by Academician Korshak. It was found that in the presence of divalent copper salts, this reaction can be carried out with any diacetylene compounds to form polymers, the elementary unit of which retains the carbon skeleton of the original diacetylene. In this case, polymeric Cu(I) polyacetylenides are first formed. This variant of the oxidative coupling reaction was called oxidative dehydropolycondensation. Scientists have suggested that acetylene can be used as a monomer for such polycondensation. Indeed, when acetylene was passed into an aqueous ammonia solution of Cu(II) salt, a black precipitate quickly formed. It was this path that led A.M. Sladkov, V.V. Korshak, V.I. Kasatochkin and Yu.P. Kudryavtsev to the discovery of the linear form of carbon, which they, at Sladkov’s suggestion, called “ carbine».

According to the discoverers of carbyne, the most difficult thing for them was to determine by what bonds the carbon atoms were connected in a chain. These could be alternating single and triple bonds (–С≡С–С≡С–), only double bonds (=С=С=С=С=), or both simultaneously. Only a few years later it was possible to prove that there were no double bonds in the resulting carbyne. The polyyne structure of the chains was confirmed by the formation of oxalic acid during the ozonation of carbyne.

However, the theory allowed the existence of a linear carbon polymer with only double bonds, which was obtained in 1968 by Sladkov’s graduate student V.P. Nepochatykh: counter synthesis (by reduction of polymer glycol) led to the formation of a linear carbon polymer with cumulene bonds, which was called polycumulene. Evidence of the presence of double bonds in the resulting substance was the fact that when polycumulene is ozonized, only carbon dioxide is obtained.

So, two forms of linear carbon were obtained: polyine (–C≡C–) n, or α-carbine, and polycumulene (=C=C=) n, or β-carbine. The authors of the discovery conducted a detailed study of the structure of carbyne various methods, its thermodynamic and electrophysical properties have been studied.

Structure on carbine

According to some researchers, unambiguous and rigorous evidence of the individuality of carbyne and its structure has not yet been obtained, while other authors, on the contrary, believe that such evidence exists. The discussion about the existence of carbyne is largely due to the fact that its diagnosis has a number of technical difficulties, since when using high-energy methods, the transition of carbyne into other forms of carbon is possible. In addition, ideas about the structure of carbyne have long been imperfect. The authors of the discovery of carbyne proposed a model of its crystal structure in the form of a set of chains of the cumulene or polyyne type, packed into crystals due to van der Waals forces. The chains were assumed to be straight, since each carbon atom is in a state of sp-hybridization.

Indeed, it has now been established that the structure of carbyne is formed by carbon atoms assembled in chains with double bonds (β-carbyne) or alternating single and triple bonds (α-carbyne). Polymer chains have reactive ends (that is, they carry a localized negative charge) and bends with chain vacancies, in places where the chains are connected to each other due to the overlapping π-orbitals of carbon atoms. The presence of metal impurities such as iron and potassium is important for the formation of crosslinks. Convincing evidence for the presence of zigzags in a linear carbon chain was obtained in the theoretical work of Korshak: the results of his calculation are in good agreement with the IR spectrum of carbyne.

Based on the results of further studies of the structure of crystalline carbyne, a model of its unit cell was proposed. According to this model, the unit cell of carbyne is composed of parallel carbon chains with zigzags, due to which the cell turns out to be two-layer. The thickness of one layer is a chain of six carbon atoms. In the lower layer, the chains are tightly packed and located in the center and corners of the hexagon, while in top layer there is no central chain, and the resulting vacancy may contain impurity atoms. It is possible that they are catalysts for the crystallization of carbyne. This model provides the key to uncovering the carbyne phenomenon and explains in what configuration a generally unstable set of linear carbon chains can be stabilized.

Notes

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Synonyms:

Carbyne will take away the title of the most durable material from graphene if and as soon as they learn to produce it in significant quantities. This is stated in an article by theoretical physicist Boris Yakobson and his colleagues published this week.

Not long ago, graphene made all the news, becoming the most durable material. The Nobel Prize was awarded for experiments with graphene in 2010. But scientists may have synthesized a new, strongest material known as carbyne.

The properties of carbyne became known back in the summer. This material is a chain of carbon atoms connected either by double bonds in series or by alternating triple and single bonds. This, in some ways, makes carbyne a one-dimensional material - as opposed to two-dimensional graphene or three-dimensional hollow carbon nanotubes.

The new paper says that if produced in sufficient quantities, it will be possible to take advantage of some of the unique properties of carbyne. In particular, calculations have shown that the tensile strength of the new material can be twice as high as that for graphene. In addition, it is two times harder than graphene and three times harder than diamond. In addition, carbyne has pronounced semiconducting properties and can act as a material for energy storage devices.

But few people already remember that carbyne is also called ALEXEY SLADKOV’S CARBON.

In 1960, carbine was synthesized by the Soviet chemist A.M. Sladkov 1922–1982 within the walls of the Institute of Organoelement Compounds in Moscow and named by him carbine. He did not know that, having unique properties, this artificially created substance attracted the interest of the whole world and its practical use began in various areas of human activity, for example, in medicine and electronics. ‎In 1968, American scientists, A. El Goresi and G. Donnay, examining samples meteorite crater(Germany, Bavaria), demineralized them by treating them with various acids. In the insoluble concentrate it was graphite. Scientists discovered inclusions of an unknown substance of silvery-white color - carbon. The optical properties of the substance were absolutely not similar to the properties of natural diamond or its artificially obtained crystalline modification - lonsdaleite. The discovered substance turned out to be a new allotropic form of carbon (“white carbon”), which was confirmed by studying it using X-ray diffraction. Scientists have come to the conclusion that this form of ugred was formed from graphite as a result of a meteorite falling under the influence of high temperature and pressure.

The most paradoxical thing in this story is that the existence of carbine, which in the laboratory of A.M. Sladkov could be seen, touched, and experiments were conducted with him; until his discovery in nature, it was not officially recognized. More precisely, they were cautious with its recognition, thereby once again confirming how strong conservative manifestations are in science, how difficult it is to prove the fallacy of the statements of recognized authorities. One of the first who decided to challenge the authority of his predecessors was the talented Russian scientist Alexei Mikhailovich Sladkov. The work he carried out at the Institute of Organoelement Compounds, which was distinguished, according to the employees of his laboratory I. Golding and N. Vasneva, by “astonishing subtlety and clarity of design” - the oxidative polycondensation of acetylene - led to the discovery of a new linear allotropic form of carbon.

Being the son of a famous Russian chemist repressed in the thirties, a professor at the Moscow Institute of Chemical Technology. DI. Mendeleev, scientific director of the largest Institute food products and dyes (NIOPIK), A.M. Sladkov did not find recognition at that time. He avoided public affairs in every possible way and was not in the ranks of the CPSU because of his repressed father.

The author's certificate for the method of producing carbyne by the Committee for Inventions and Discoveries under the Council of Ministers of the USSR was registered as a discovery with priority of 1960 only on December 7, 1971. Those. eleven years after the series successful experiences. It took eleven years of waiting to break the mistrust of a discovery that refutes world authorities. Having received carbyne, A.M. Sladkov came to the idea of the multiplicity of carbyne forms of carbon, the existence large quantity basic carbon polymers. Subsequent research by scientists confirmed this guess. Often in the scientific literature there are publications claiming the synthesis of a new crystalline form or allotropic modification of carbon.

In support of this, in 1985, for example, there was the discovery of a large family of spherical carbon molecules called fullerenes. This discovery gave new impetus to research around the world in the field of carbon and its allotropes. The authors of the next discovery - a group of American scientists - brought Nobel Prize. Doesn’t all this mean that, being the discoverer of these new forms of carbon molecules, the Russian scientist has every reason to claim, and, moreover, receive a Nobel Prize for his outstanding discovery of CARBINE!?

On at the moment obtaining carbyne remains extremely challenging task, so scientists are not yet conducting experiments with real matter, but resorting to quantum mechanical modeling on supercomputers. "IN previous works... attention was focused on some of its individual characteristics, but we set out to characterize it from all sides at once, that is, to create a complete mechanical model of the material,” says Artyukhov.

The results of such modeling showed that carbyne has a uniquely high rigidity - its specific strength per kilogram of mass is 1 million kilonewtons per meter. This is twice the strength of nanotubes and graphene (0.45 million kilonewtons) and almost three times stronger than diamond - 0.35 million kilonewtons). “We discovered several other interesting phenomena, for example, that the torsional rigidity of carbyne can be “turned on” by attaching certain functional groups to the ends,” the agency’s interlocutor said.

In addition, Jacobson and his colleagues were able to prove that when stretching a carbyne thread, its electrical properties radically change - it “transforms” from the form of cumulene (which is a conductor) to the form of polyine (a dielectric), that is, by stretching the carbyne thread, you can turn off and turn on conductivity.

Not a space elevator, but electronics

Currently, the technologies for producing carbyne are extremely complex. The longest carbyne thread - 6 nanometers - was obtained in 2010 by scientists from Canada. Therefore, according to Artyukhov, carbyne can be used as a component of various complex nanosystems. "It could serve as a 'nanocable' or 'nanorod' (depending on the length), as well as a conductive or semiconductor 'cable,'" says the scientist.

Despite its unique mechanical strength, carbyne is unlikely to be used to create ultra-strong macroscopic cables, for example, for “space elevators.”

“The fact is that the strength of a material is always determined not by the strongest, but, on the contrary, by the weakest “link” in it. In carbon fibers, these are connections between graphite sheets; in composites with nanotubes, these are contacts between the nanotube and the matrix. And no matter how much you improve the properties of the reinforcing elements in the system, its strength will remain constant if they are poorly connected to each other,” says Artyukhov.

But carbyne can be useful in electronics - depending on the tension, its conductivity and optical absorption spectrum change dramatically. “By tension you can control what wavelength of light the material is most sensitive to. This is very useful property for optoelectronic applications, in particular in telecommunications,” the scientist noted.

Carbin

But few people already remember that Carbin is also called CARBON BY ALEXEY SLADKOV.

In 1960, carbine was synthesized by the Soviet chemist A.M. Sladkov 1922-1982 within the walls of the Institute of Organoelement Compounds in Moscow and named by him carbine. He did not know that, having unique properties, this artificially created substance attracted the interest of the whole world and its practical use began in various areas of human activity, for example, in medicine and electronics. In 1968, American scientists A. El Goresi and G. Donnay, studying samples from a meteorite crater (Germany, Bavaria), demineralized them by treating them with various acids. In the insoluble concentrate it was graphite. Scientists discovered in it inclusions of an unknown substance of a silvery-white color - carbon. The optical properties of the substance were absolutely not similar to the properties of natural diamond or its artificially obtained crystalline modification - lonsdaleite. The discovered substance turned out to be a new allotropic form of carbon (“white carbon”), which was confirmed by studying it using X-ray diffraction. Scientists have concluded that this form of ugreda was formed from graphite as a result of a meteorite falling under the influence of high temperature and pressure.

The most paradoxical thing in this story is that the existence of carbine, which in the laboratory of A.M. Sladkov could be seen, touched, and experiments were conducted with him; until his discovery in nature, it was not officially recognized. More precisely, they were cautious with its recognition, thereby once again confirming how strong conservative manifestations are in science, how difficult it is to prove the fallacy of the statements of recognized authorities. One of the first who decided to challenge the authority of his predecessors was the talented Russian scientist Alexei Mikhailovich Sladkov. The work he carried out at the Institute of Organoelement Compounds, which was distinguished, according to the employees of his laboratory I. Golding and N. Vasneva, by “amazing subtlety and clarity of design” - the oxidative polycondensation of acetylene - led to the discovery of a new linear allotropic form of carbon.

Being the son of a famous Russian chemist repressed in the thirties, a professor at the Moscow Institute of Chemical Technology. DI. Mendeleev, scientific director of the largest Institute of Food Products and Dyes (NIOPIK), A.M. Sladkov did not find recognition at that time. He avoided public affairs in every possible way and was not in the ranks of the CPSU because of his repressed father.

The author's certificate for the method of producing carbyne by the Committee for Inventions and Discoveries under the Council of Ministers of the USSR was registered as a discovery with priority of 1960 only on December 7, 1971. Those. eleven years after a series of successful experiments. It took eleven years of waiting to break the mistrust of a discovery that refutes world authorities. Having obtained carbyne, A.M. Sladkov came to the idea of the multiplicity of carbyne forms of carbon, the existence of a large number of basic carbon polymers. Subsequent research by scientists confirmed this guess. Often in the scientific literature there are publications claiming the synthesis of a new crystalline form or allotropic modification of carbon.

In support of this, in 1985, for example, the discovery of a large family of spherical carbon molecules called fullerenes was made. This discovery gave new impetus to research around the world in the field of carbon and its allotropes. The authors of the next discovery, a group of American scientists, received the Nobel Prize in 1996. Doesn’t all this mean that, being the discoverer of these new forms of carbon molecules, the Russian scientist has every reason to claim, and, moreover, receive a Nobel Prize for his outstanding discovery of CARBINE!?

At the moment, obtaining carbyne remains an extremely difficult task, so scientists are not yet conducting experiments with the real substance, but resorting to quantum mechanical modeling on supercomputers. “In previous works... attention was focused on some of its individual characteristics, but we set out to characterize it from all sides at once, that is, to create a complete mechanical model of the material,” says Artyukhov.

The results of such modeling showed that carbyne has a uniquely high rigidity - its specific strength per kilogram of mass is 1 million kilonewtons per meter. This is twice the strength of nanotubes and graphene (0.45 million kilonewtons) and almost three times stronger than diamond (0.35 million kilonewtons). “We discovered several other interesting phenomena, for example, that the torsional rigidity of carbyne can be “turned on” by attaching certain functional groups at the ends,” the agency’s interlocutor said.

In addition, Jacobson and his colleagues were able to prove that when a carbyne thread is stretched, its electrical properties radically change - it “transforms” from the form of cumulene (which is a conductor) to the form of polyine (a dielectric), that is, by stretching the carbyne thread, you can turn off and turn on conductivity.