The chemical element helium was first discovered on the Sun and only then on Earth.

A key role in the history of the discovery of helium was played by Norman Lockyer, the founder of one of the world's leading scientific publications - the journal Nature. In preparation for the publication of the magazine, he became acquainted with the London scientific establishment and became interested in astronomy. This was a time when, inspired by the Kirchhoff-Bunsen discovery, astronomers were just beginning to study the spectrum of light emitted by stars. Lockyer himself managed to make a series important discoveries- in particular, he was the first to show that sunspots are colder than the rest solar surface, and was also the first to point out the presence of an outer shell of the Sun, calling it chromosphere. In 1868, while studying the light emitted by atoms in prominences—huge ejections of plasma from the surface of the Sun—Lockyer noticed a number of previously unknown spectral lines ( cm. Spectroscopy). Attempts to obtain the same lines in the laboratory failed, from which Lockyer concluded that he had discovered a new chemical element. Lockyer called it helium, from the Greek helios- "Sun".

Scientists were perplexed as to how to react to the appearance of helium. Some suggested that a mistake was made in interpreting the spectra of prominences, but this point of view received fewer and fewer supporters, since all more Astronomers were able to observe the Lockyer lines. Others argued that the Sun contains elements that do not exist on Earth - which, as already mentioned, contradicts the main point about the laws of nature. Still others (there was a minority) believed that someday helium would be found on Earth.

In the late 1890s, Lord Rayleigh and Sir William Ramsay conducted a series of experiments that led to the discovery of argon. Ramsay modified his setup to use it to study the gases released by uranium-containing minerals. Ramsay discovered unknown lines in the spectrum of these gases and sent samples to several colleagues for analysis. Upon receiving the sample, Lockyer immediately recognized the lines that he had observed in sunlight more than a quarter of a century earlier. The helium mystery has been solved: the gas is undoubtedly found on the Sun, but it also exists here on Earth. Nowadays, this gas is best known in everyday life as a gas for inflating airships and balloons (cm. Graham's Law), and in science - thanks to its application in cryogenics, technologies for achieving ultra-low temperatures.

Coronium and nebulium

The question of whether there are chemical elements somewhere in the Universe that are not found on Earth has not lost its relevance in the 20th century. When studying the outer solar atmosphere - solar crowns, consisting of hot, highly rarefied plasma, astronomers discovered spectral lines that they could not identify with any of the known terrestrial elements. Scientists have suggested that these lines belong to a new element, which is called coronium. And when studying the spectra of some nebulae- distant accumulations of gases and dust in the Galaxy - another mysterious lines were discovered. They were attributed to another “new” element - nebulia. In the 1930s, the American astrophysicist Ira Sprague Bowen (1898-1973) came to the conclusion that the nebulium lines actually belong to oxygen, but acquired this appearance due to extreme conditions existing on the Sun and in nebulae, and these conditions cannot be reproduced in earthly laboratories. Coronium turned out to be highly ionized iron. And these lines got the name prohibited lines.

Joseph Norman LOCKYER
Joseph Norman Lockyer, 1836-1920

English scientist. Born in the town of Rugby in the family of a military doctor. Lockyer came to science in an unusual way, starting his career as an official in the War Department. To earn extra money, he took advantage of public interest to science, began to publish a popular science magazine. The first issue of the magazine was published in 1869 Nature, and for 50 years Lockyer remained its editor. He participated in many expeditions observing total solar eclipses. One of these expeditions led him to the discovery of helium. Lockyer is also known as the founder of archaeoastronomy - the science that studies the astronomical meaning of ancient structures such as Stonehenge - and the author of many popular science books.

HELIUM, He (Latin Helium, from Greek helios - Sun, since it was first discovered in the solar spectrum * a. helium; n. Helium; f. helium; i. helio), - element VIII group periodic table Mendeleev, refers to inert gases, atomic number 2, atomic mass 4.0026. Natural helium consists of two stable isotopes 3 He and 4 He. Discovered in 1868 by the French astronomer J. Jansen and the English astronomer J. N. Lockyer during a spectroscopic study of solar prominences. Helium was first isolated in 1895 by the English physicist W. Ramsay from the radioactive mineral kleveite.

Properties of helium

Under normal conditions, helium is a colorless and odorless gas. 0.178 kg/m 3, boiling point - 268.93° C. Helium is the only element that liquid state does not harden under normal pressure, no matter how deeply it is cooled. In 1938 Soviet physicist P. L. Kapitsa discovered superfluidity in 4 He - the ability to flow without viscosity. The minimum pressure required to convert liquid helium into solid is 2.5 MPa, while the melting point is 272.1 ° C. (at 0°C) 2.1.10 -2 W/m.K. The helium molecule consists of one atom, its radius is from 0.085 (netin) to 0.133 nm (van der Waals) (0.85-1.33 E). About 8.8 ml of helium dissolves in 1 liter of water at 20°C Stable chemical compounds of helium have not been obtained.

Helium in nature

In terms of prevalence in the Universe, helium ranks second after. There is little helium on Earth: 1 m 3 of air contains 5.24 cm 3 of helium, the average content is 3.10 -7%. In the strata lithosphere, there are 3 genetic components of helium - radiogenic, primordial and atmospheric helium. Radiogenic helium is formed everywhere during radioactive transformations of heavy elements and various nuclear reactions, primordial helium enters the lithosphere both from deep rocks that occluded primordial helium and preserved it since the formation of the planet, and from space along with cosmic dust, meteorites, etc. Atmospheric helium enters precipitation from the air, during sedimentogenesis processes, and also with infiltrating surface waters.

The value of the 3 He/4 He ratio in radiogenic helium is 10 -8, in mantle helium (a mixture of primordial and radiogenic) (3±1).10 -5, in cosmic helium 10 -3 -10 -4, in atmospheric air 1.4.10 -6. The 4 He isotope absolutely predominates in terrestrial helium. The main amount of 4 He was formed during the a-decay of natural radioactive elements (radioisotopes, actinouranium and). Minor sources of formation of 4 He and 3 He in the lithosphere - nuclear reactions(neutron fission of lithium, etc.), decay of tritium, etc. In ancient stable areas of the earth's crust, radiogenic 4 He 3 He/ 4 He = = (2±1).10 -8 predominates. Tectonically disturbed earth's crust (rift zones, deep faults, eruptive devices, with tectonomagmatic or seismic activity, etc.) is characterized by an increased amount of 3 He 3 He/ 4 He = n.10 -5. For other geological structures, the 3 He/4 He ratio in reservoir gases and fluids varies within 10 -8 -10 -7. The difference in the helium isotope ratios 3 He/4 He in mantle and crustal helium is an indicator of the modern connection of deep fluids with the mantle. Due to the lightness, inertness and high permeability of helium, most rock-forming materials do not retain it, and helium migrates through the fractured pore spaces of rocks, dissolving in the fluids that fill them, sometimes being separated far from the main zones of formation.

Helium is an obligatory impurity in all gases that form independent accumulations in earth's crust or coming out in the form of natural gas jets. Usually helium is an insignificant admixture of other gases; in rare cases, its amount reaches several% (by volume); maximum concentrations of helium were found in underground gas accumulations (8-10%), uranium gases (10-13%) and water-dissolved gases (18-20%).

Helium production

In industry, helium is obtained from helium-containing gases by deep cooling (down to -190°C), and a small amount is obtained during the operation of air separation plants. The main gas components are condensed (frozen out), and the remaining helium concentrate is cleared of hydrogen and. Diffuse methods for helium extraction are also being developed.

Transportation and storage of helium is in highly sealed containers. Helium of grades 1-2 is usually transported in steel cylinders of various capacities, usually up to 40 liters, under pressure up to 15 MPa. Helium storage facilities are also installed in underground salt chambers, and raw helium (about 60% He and 40% N2) is stored in exhausted underground gas structures. Helium is supplied over long distances in compressed and liquid form using specially equipped transport, as well as by gas pipeline (for example, in the USA).

Helium use

The use of helium is based on its unique properties such as complete inertness (welding in a helium atmosphere, production of ultrapure and semiconductor materials, additive to breathing mixtures, etc.), high permeability (leak detectors in high and low pressure apparatus). helium is the only chemical element that allows one to obtain ultra-low temperatures necessary for all types of superconducting systems and installations (cryoenergetics). Liquid helium is a coolant for scientific research.

Helium is the second order element of the periodic system of chemical elements of D. I. Mendeleev, with atomic number 2. Located in main subgroup eighth group, first period of the periodic table. Leads the group inert gases V periodic table. Denoted by the symbol He (lat. Helium). The simple substance helium (CAS number: 7440-59-7) is an inert monatomic gas without color, taste or smell. Helium is one of the most common elements in the Universe, second only to hydrogen. Helium is also the second lightest chemical element (after hydrogen). Helium is extracted from natural gas process of low-temperature separation - the so-called fractional distillation

On August 18, 1868, the French scientist Pierre Jansen, while in full solar eclipse in the Indian city of Guntur, for the first time explored the chromosphere of the Sun. Jansen managed to configure the spectroscope in such a way that the spectrum of the solar corona could be observed not only during an eclipse, but also on ordinary days. The very next day, spectroscopy of solar prominences, along with the hydrogen lines - blue, blue-green and red - revealed a very bright yellow line, initially taken by Jansen and other astronomers who observed it to be the sodium D line. Jansen immediately wrote about this to the French Academy of Sciences. It was subsequently found that the bright yellow line in the solar spectrum does not coincide with the sodium line and does not belong to any of the previously known chemical elements.

Two months later, on October 20, English astronomer Norman Lockyer, not knowing about the developments of his French colleague, also conducted research on the solar spectrum. Having discovered an unknown yellow line with a wavelength of 588 nm (more precisely 587.56 nm), he designated it D3, since it was very close to the Fraunhofer lines D 1 (589.59 nm) and D 2 (588.99 nm) sodium Two years later, Lockyer, together with the English chemist Edward Frankland, with whom he worked, proposed giving the new element the name “helium” (from the ancient Greek ἥλιος - “sun”).

It is interesting that the letters from Jansen and Lockyer arrived at the French Academy of Sciences on the same day - October 24, 1868, but Lockyer's letter, written four days earlier, arrived several hours earlier. The next day, both letters were read out at a meeting of the Academy. In honor of the new method of studying prominences, the French Academy decided to mint a medal. On one side of the medal there were portraits of Jansen and Lockyer over crossed laurel branches, and on the other there was an image of the mythical Sun god Apollo, driving a chariot with four horses galloping at full speed.

In 1881, the Italian Luigi Palmieri published a report on his discovery of helium in volcanic gases (fumaroles). He examined a light yellow oily substance that settled from gas jets on the edges of the crater of Vesuvius. Palmieri calcined this volcanic product in the flame of a Bunsen burner and observed the spectrum of gases released. Scientific circles greeted this message with disbelief, since Palmieri described his experience unclearly. Many years later, small amounts of helium and argon were actually found in fumaroles.

Only 27 years after its initial discovery, helium was discovered on Earth - in 1895, Scottish chemist William Ramsay, examining a sample of the gas obtained from the decomposition of the mineral kleveite, discovered in its spectrum the same bright yellow line previously found in the solar spectrum. The sample was sent for additional research to the famous English spectroscopist William Crookes, who confirmed that the yellow line observed in the spectrum of the sample coincided with the D3 line of helium. On March 23, 1895, Ramsay sent a message about his discovery of helium on Earth to the Royal Society of London, as well as to the French Academy through the famous chemist Marcelin Berthelot.

In 1896, Heinrich Kaiser, Siegbert Friedländer, and two years later Edward Bely finally proved the presence of helium in the atmosphere.

Even before Ramsay, helium was also isolated by the American chemist Francis Hillebrand, but he mistakenly believed that he had obtained nitrogen and in a letter to Ramsay recognized its priority of discovery.
Exploring various substances and minerals, Ramsay discovered that helium in them accompanies uranium and thorium. But it was only much later, in 1906, that Rutherford and Royds discovered that the alpha particles of radioactive elements were helium nuclei. These studies laid the foundation modern theory structure of the atom.

Only in 1908, the Dutch physicist Heike Kamerlingh Onnes managed to obtain liquid helium by throttling (see Joule-Thomson effect), after the gas was pre-cooled in liquid hydrogen boiling under vacuum. Attempts to obtain solid helium remained unsuccessful for a long time, even at a temperature of 0.71 K, which was achieved by Kamerlingh Onnes's student, the German physicist Willem Hendrik Keesom. Only in 1926, having applied pressure above 35 atm and cooled the compressed helium in liquid helium boiling under rarefaction, he managed to isolate the crystals.

In 1932, Keesom studied the nature of the change in the heat capacity of liquid helium with temperature. He found that around 2.19 K, a slow and smooth rise in heat capacity gives way to a sharp drop and the heat capacity curve takes the form greek letterλ (lambda). Hence, the temperature at which a jump in heat capacity occurs is given the conventional name “λ-point.” A more accurate temperature value at this point, established later, is 2.172 K. At the λ-point, deep and abrupt changes in the fundamental properties of liquid helium occur - one phase of liquid helium is replaced at this point by another, without releasing latent heat; a phase transition of the second order takes place. Above the temperature of the λ-point there is so-called helium-I, and below it - helium-II.

In 1938, Soviet physicist Pyotr Leonidovich Kapitsa discovered the phenomenon of superfluidity of liquid helium-II, which consists of a sharp decrease in the viscosity coefficient, as a result of which helium flows practically without friction. This is what he wrote in one of his reports about the discovery of this phenomenon.

Origin of the name

From Greek ἥλιος - “Sun” (see Helios). It is curious that the name of the element used the ending “-i”, characteristic of metals (in Latin “-um” - “Helium”), since Lockyer assumed that the element he discovered was a metal. By analogy with other noble gases, it would be logical to give it the name “Helion”. IN modern science The name “helion” was assigned to the nucleus of a light isotope of helium - helium-3.

Prevalence

In the Universe
Helium is second in abundance in the Universe after hydrogen - about 23% by mass. However, helium is rare on Earth. Almost all the helium in the Universe was formed in the first few minutes after Big Bang, during primary nucleosynthesis. In the modern Universe, almost all new helium is formed as a result of thermonuclear fusion from hydrogen in the interior of stars (see proton-proton cycle, carbon-nitrogen cycle). On Earth, it is formed as a result of the alpha decay of heavy elements (the alpha particles emitted during alpha decay are helium-4 nuclei). Part of the helium that appears during alpha decay and seeps through the rocks of the earth’s crust is captured by natural gas, the concentration of helium in which can reach 7% of the volume and higher.

Earth's crust
Within the eighth group, helium ranks second in content in the earth's crust (after argon). The helium content in the atmosphere (formed as a result of the decay of Ac, Th, U) is 5.27×10−4% by volume, 7.24×10−5% by mass. Helium reserves in the atmosphere, lithosphere and hydrosphere are estimated at 5×1014 m³. Helium-bearing natural gases usually contain up to 2% helium by volume. It is extremely rare to find accumulations of gases, the helium content of which reaches 8 - 16%. The average helium content in terrestrial matter is 3 g/t. The highest concentration of helium is observed in minerals containing uranium, thorium and samarium: kleveite, fergusonite, samarskite, gadolinite, monazite (monazite sands in India and Brazil), thorianite. The helium content in these minerals is 0.8 - 3.5 l/kg, and in thorianite it reaches 10.5 l/kg

Definition

Helium is determined qualitatively by analyzing emission spectra (characteristic lines 587.56 nm and 388.86 nm), quantitatively by mass spectrometric and chromatographic analysis methods, as well as by methods based on measurement physical properties(density, thermal conductivity, etc.

Chemical properties

Helium is the least chemically active element of the eighth group of the periodic table (inert gases). Many helium compounds exist only in the gas phase in the form of so-called excimer molecules, in which the excited electronic states are stable and the ground state is unstable. Helium forms diatomic molecules He 2 +, HeF fluoride, HeCl chloride (excimer molecules are formed by the action of an electric discharge or ultraviolet radiation on a mixture of helium with fluorine or chlorine). Known chemical compound helium LiHe (possibly meant the compound LiHe 7

Receipt

In industry, helium is obtained from helium-containing natural gases (currently, mainly deposits containing > 0.1% helium are exploited). Helium is separated from other gases by deep cooling, taking advantage of the fact that it liquefies more difficult than all other gases. Cooling is carried out by throttling in several stages, purifying it from CO 2 and hydrocarbons. The result is a mixture of helium, neon and hydrogen. This mixture, the so-called. crude helium (He - 70-90% vol.) is purified from hydrogen (4-5%) using CuO at 650-800 K. Final purification is achieved by cooling the remaining mixture with N2 boiling under vacuum and adsorption of impurities on active carbon in adsorbers, also cooled with liquid N2. They produce helium of technical purity (99.80% helium by volume) and high purity (99.985%). In Russia, helium gas is obtained from natural and petroleum gas. Currently, helium is extracted at the helium plant of Gazprom Dobycha Orenburg LLC in Orenburg from gas with a low helium content (up to 0.055% vol.), so Russian helium has a high cost. Current problem is the development and comprehensive processing of natural gases large deposits Eastern Siberia with a high helium content (0.15-1% vol.), which will significantly reduce its cost. The USA leads in helium production (140 million m³ per year), followed by Algeria (16 million m³). Russia ranks third in the world - 6 million m³ per year. World helium reserves amount to 45.6 billion m³.

Does not obey the laws of classical mechanics. Scientists are trying to unravel the mystery of helium-4. It's easy, no radioactive isotope element. In fact, it accounts for 99.9% of the helium on Earth.

So, if the 4th isotope is cooled to -271 degrees Celsius, a liquid will be obtained. Only its properties are not typical for a liquid. For example, superfluidity is observed.

If you place helium into a vessel and place it vertically, the liquid will violate the laws of gravity. After a few minutes, the contents of the container will flow out of it. From this it follows that helium – element curious, and curiosity must be satisfied. Let's start getting acquainted with the properties of matter.

Properties of helium

Not. This is not a particle of negation, but a designation of the 2nd element of the periodic table, that is, helium. Gas in its normal state, it thickens only at sub-zero temperatures. Moreover, this minus should be a couple of hundred degrees Celsius.

At the same time, in properties of helium gas insolubility in water is included. That is, if it itself is not, then its molecules are in one phase, without moving into others. Meanwhile, it is the change of phases of a substance that determines the formation of a solution.

Helium is an inert gas. Its inertia is manifested not only in the lack of “desire” to dissolve in water. The substance is in no hurry to enter into other reactions. Reason: - stable outer shell of the atom.

It contains 2 electrons. It is difficult to break a strong pair, that is, to remove one of the particles from the shell of an atom. Therefore, helium was not discovered during chemical experiments, and in the spectroscopic study of prominences.

This happened in the second half of the 19th century. Other inert gases, and there are 6 of them, were discovered even later. Around the same time, that is, at the beginning of the 20th century, it was possible to convert helium into liquid form.

Helium - monatomic gas without taste or smell. This is also an expression of the inertia of the element. He communicates only with three “colleagues” on the periodic table, -, and. The reaction itself will not start.

You need ultraviolet light or electric shocks. But for helium to “escape” from a test tube or other volumetric body, no effort is needed. The 2nd element has the lowest adsorption, that is, the ability to concentrate on a plane or in volume.

Store helium gas in cylinders. They must be absolutely airtight. Otherwise, adsorption will play a cruel joke on suppliers. The substance will seep through the slightest cracks. And if the cylinders were made of porous material, helium would escape through it.

Helium gas density 7 times inferior to oxygen. The latter indicator is 1.3 kilograms per cubic meter. Helium has a density of only 0.2 kilograms. Accordingly, the hero is easy. Molar mass helium equal to 4 grams per mole.

For comparison, air as a whole has an indicator of 29 grams. It becomes clear why it is popular helium for balloons. The difference in the masses of the 2nd element and air is spent on lifting loads. Remember that a mole is equal to 22 liters. It turns out that 22 liters of helium are capable of lifting a 25-gram load. A cubic meter of gas will already carry more than a kilogram.

Finally, we note that helium has excellent electrical conductivity. At least this applies to gases. Among them, the 2nd is no longer in second, but in first place. But in terms of content on Earth, helium is not a leader. In the atmosphere of the planet of the hero of the article there are millionths of a percent. So where does gas come from then? Fishing it out of the atmosphere is impractical.

Helium extraction

Helium formula is a component not only of the atmosphere, but also of the natural environment. The content of the 2nd element also varies in different deposits. In, for example, the deposits are richest in helium Far East and eastern Siberia.

However, gas fields in these regions are poorly developed. The 0.2-0.8 percent helium content encourages their development. For now, it is mined only at one deposit in the country. It is located in Orenburg and is recognized as poor in helium. Nevertheless, 5,000,000 cubic meters of gas are produced per year.

Global helium production per year is 175,000,000 cubic meters. At the same time, gas reserves are 41 billion cubic meters. Most of them are hidden in the depths of Algeria, Qatar and the USA. also included in the list.

Helium is obtained from natural gas by low-temperature condensation. The result is a concentrate of the 2nd element with its content of at least 80%. Another 20% comes from argon, neon, methane, and nitrogen. What gas is helium? interferes? No. But impurities bother people. Therefore, the concentrate is purified, turning 80% of the 2nd element into 100%.

The problem is that there is also 100% certainty that the planet will face a helium shortage. By 2030, global gas consumption should reach 300,000,000 cubic meters.

Helium production in 10 years will not be able to cross the 240,000,000 mark due to a shortage of raw materials. It is a non-renewable resource. The second is released bit by bit during the decay of radioactive rocks.

The speed of natural production cannot keep up with the needs of people. Therefore, experts predict a sharp jump in helium. For now, the low value is being depreciated by the sale of the US reserve fund, which has become unprofitable for the country to maintain.

The national reserve was created at the beginning of the last century in order to fill military airships and commercial aircraft. The storage facility is located in Texas.

Application of helium

Helium can be found in rocket fuel tanks. There the 2nd is adjacent to liquid hydrogen. Only helium, at the same time, is able to remain gaseous, and therefore create the required pressure in the engine tanks.

Filling balloons is another task in which it comes in handy helium gas. Carbonic, for example, it won’t fit because it’s heavy. Lighter than helium only one gas, this is hydrogen. Except it's explosive.

At the beginning of the last century, the Hindenburg airship was filled with hydrogen and watched as it ignited during the flight. Since then, it has been made in favor of inert, albeit slightly heavier, helium.

Helium is also popular as a cooling agent. The application is related to the gas’s ability to generate ultra-low temperatures. Helium is purchased for hadron colliders and nuclear magnetic resonance spectrometers. The second element is used in the same way in MRI machines. There, helium is pumped into superconductors.

Many people have undergone MRI. Scanners at checkout counters that read barcodes are also close to the mass consumer. So, helium and neon are pumped into store lasers. Separately, helium is placed in ion microscopes. They give a better picture than electronic ones; one might say, they also read data.

In air conditioning systems, the 2nd is needed to diagnose leaks. The super-permeability of the hero of the article comes in handy. If it finds somewhere to leak, it means that other components may also “leak”.

We are talking about car air conditioning systems. By the way, airbags are also filled with helium. It seeps into life-saving containers faster than other gases.

Helium price

Bye, on helium gas price equal to approximately 1,300 rubles per one and a half cubic meters. They hold 10 liters of the 2nd element. There are cylinders of 40 liters. That's almost 6 cubic meters of helium. The price tag for 40-liter packages is approximately 4,500.

By the way, for greater tightness, protective covers are put on gas cylinders. They also usually cost about 300 rubles for a 40-liter container and 150 rubles for 10-liter cylinders.

Helium, typically produced by the radioactive decay of uranium-238 and uranium-235, was found in the solar atmosphere 13 years earlier than on Earth. This gas has the lowest critical values, the lowest boiling point, and the lowest heat of evaporation and melting. As for the melting temperature of helium, at normal pressure it does not exist at all. No other substance like this can be found in nature...

Helium is an unusual element, and its history is somewhat mysterious and incomprehensible. It was found in the solar atmosphere 13 years earlier than on Earth. More precisely, in the spectrum solar corona The bright yellow D line was discovered, and what was hidden behind it became known for certain only after helium was extracted from earthly minerals containing radioactive elements.

How is helium formed?

Terrestrial helium is mainly formed during the radioactive decay of uranium-238, uranium-235, thorium and unstable products of their decay. Helium accumulates slowly in the earth's crust. One ton of granite containing 2 g of uranium and 10 g of thorium produces only 0.09 mg of helium over a million years - half a cubic centimeter. The very few minerals rich in uranium and thorium have quite high helium contents - several cubic centimeters helium per gram.

Over time, most minerals undergo processes of weathering, recrystallization, etc., and helium leaves them. Helium bubbles released from crystalline structures partially dissolve in groundwater. Another part of the helium escapes into the atmosphere through the pores and cracks of minerals. The remaining gas molecules fall into underground traps, where they accumulate for tens or hundreds of millions of years. The traps here are layers of loose rocks, the voids of which are filled with gas. The bed for such gas reservoirs is usually water or oil, and on top they are covered by gas-impermeable strata of dense rocks.

Helium synthesis - the beginning of life

The interior and atmosphere of our planet are poor in helium. But this does not mean that there is little of it everywhere in the Universe. According to modern estimates, 76% of cosmic mass is hydrogen and 23% helium; only one percent remains for all other elements. Thus, the world's matter can be called hydrogen-helium. These two elements dominate stars, planetary nebulae and interstellar gas. The helium synthesis reaction is the basis for the energetic activity of stars and their glow. Consequently, the synthesis of helium can be considered the forefather of all reactions in nature, the root cause of life, light, heat and meteorological phenomena on Earth.

Natural gases are practically the only source of raw materials for the industrial production of helium. Helium is present in natural gases as a minor impurity. Its content does not exceed thousandths, hundredths, rarely tenths of a percent. Large (1.5–10%) helium content of methane-nitrogen deposits is an extremely rare phenomenon. For separation from other gases, the exceptional volatility of helium, associated with its low liquefaction temperature, is used. After all other components of the natural gas have condensed during deep cooling, the helium gas is pumped out. It is then cleaned of impurities. The purity of factory helium reaches 99.995%. Liquid helium is produced by liquefying helium gas.

Properties of helium

Helium gas– an inert gas without color, odor or taste. Liquid helium– a colorless, odorless liquid with a boiling point at normal atmospheric pressure of 101.3 kPa (760 mm Hg) 4.215 K (minus 268.9 ° C) and a density of 124.9 kg/m 3.

Helium is not toxic, not flammable, not explosive, but at high concentrations in the air it causes oxygen deficiency and suffocation. Liquid helium is a low-boiling liquid that can cause frostbite to the skin and damage to the mucous membrane of the eyes.

Helium atom(aka molecule) is the strongest of molecular structures. The orbits of its two electrons are exactly the same and pass extremely close to the nucleus. To expose the helium nucleus, it is necessary to expend a record amount of energy (78.61 eV). This implies the phenomenal chemical passivity of helium.

Helium molecules are non-polar. The forces of intermolecular interaction between them are extremely small - less than in any other substance. For this reason, helium has the lowest critical values, the lowest boiling point, and the lowest heat of evaporation and melting. As for the melting temperature of helium, at normal pressure it does not exist at all. Liquid helium at arbitrarily close to absolute zero temperature does not harden unless, in addition to temperature, it is subjected to pressure of 25 atmospheres or more. There is no other substance like this in nature. It is the best conductor of electricity among gases and the second best conductor of heat, after hydrogen. Its heat capacity is very high, and its viscosity, on the contrary, is small.

Helium, airships, divers and nuclear energy...

Helium was first used in Germany. In 1915, the Germans began filling their airships that bombed London with it. Soon, lightweight but non-flammable helium became an indispensable filler for aeronautical vehicles. The decline in airship construction that began in the mid-30s led to some decline in helium production, but only for a short time. This gas increasingly attracted the attention of chemists, metallurgists and mechanical engineers.

Another area of ​​application of helium is due to the fact that many technological processes and operations cannot be carried out in air environment. To avoid interaction of the resulting substance (or feedstock) with air gases, special protective environments are created, and there is no gas more suitable for these purposes than helium.

In helium protective environment undergo separate stages of obtaining nuclear fuel. Fuel elements are stored and transported in containers filled with helium. nuclear reactors. With the help of special leak detectors, the action of which is based on the exceptional diffusion ability of helium, they identify the slightest possibility of leakage in nuclear reactors and other systems under pressure or vacuum.

IN scientific research and in technology widely used liquid helium. Ultra-low temperatures favor in-depth knowledge of matter and its structure - with more high temperatures fine details energy spectra masked by the thermal movement of atoms.

There already exist superconducting solenoids made from special alloys that create strong magnetic fields(up to 300 thousand oersted) with negligible energy consumption. At the temperature of liquid helium, many metals and alloys become superconductors. Superconducting cryotron relays are increasingly used in the designs of electronic computers. They are simple, reliable, and very compact. Superconductors, and with them liquid helium, are becoming necessary for electronics. They are included in the designs of infrared radiation detectors, molecular amplifiers (masers), optical quantum generators (lasers), and instruments for measuring ultrahigh frequencies.

Helium-oxygen mixtures became a reliable means of preventing decompression sickness and gave a big gain in time when lifting divers. As is known, the solubility of gases in liquids, other things being equal, is directly proportional to pressure. Divers working under high pressure have much more nitrogen dissolved in their blood compared to normal conditions existing on the surface of the water. When rising from depth, when the pressure approaches normal, the solubility of nitrogen decreases and its excess begins to be released. If the rise is rapid, the release of excess dissolved gases occurs so violently that the blood and water-rich tissues of the body, saturated with gas, foam with a mass of nitrogen bubbles - like champagne when opening a bottle.

The formation of nitrogen bubbles in the blood vessels disrupts the functioning of the heart, their appearance in the brain disrupts its functions, and all this together leads to severe disorders of the body’s functioning and ultimately to death. In order to prevent the development of the described phenomena, known as “decompression sickness,” the rise of divers, i.e., the transition from high pressure to normal, is carried out very slowly.

In this case, excess dissolved gases are released gradually and no painful disorders occur. With the use of artificial air, in which nitrogen is replaced by less soluble helium, it is possible harmful disorders is eliminated almost completely. This makes it possible to increase the depth of divers’ descent (up to 100 meters or more) and lengthen the time spent under water.

“Helium” air has a density three times less than that of ordinary air. Therefore, it is easier to breathe such air than normal air (the work of the respiratory muscles decreases). This circumstance is important for respiratory diseases. That's why "helium" air also used in medicine in the treatment of asthma, suffocation and other diseases.

Not yet eternal, but already harmless

Developed at Los Alamos Fermi National Laboratory (New Mexico) new engine, which can seriously change the perception of the car as one of the main sources of pollution. With an efficiency comparable to that of an internal combustion engine (30–40%), it is devoid of its main disadvantages: moving parts that require lubrication to reduce friction and wear, and are harmful to environment emissions of products of incomplete combustion of fuel.

Essentially we're talking about about the improvement of the well-known external combustion engine, proposed by the Scottish priest R. Stirling back in 1816. This engine was not widely used in vehicles due to its more complex design compared to the internal combustion engine, higher material consumption and cost. But the thermoacoustic energy converter proposed by American scientists, in which compressed helium serves as the working fluid, differs favorably from its predecessor in the absence of bulky heat exchangers that prevented its use in passenger cars, and in the near future is capable of becoming an environmentally acceptable alternative not only to the internal combustion engine, but also solar energy converter, refrigerator, air conditioner. The scale of its application is still difficult to imagine.