In 1861, a newly invented physical method for studying substances - spectral analysis - once again demonstrated its power and reliability as the key to a great future in science and technology. With its help, a second previously unknown chemical element was discovered - rubidium. Then, with the discovery of the periodic law in 1869 by D.I. Mendeleev, rubidium, along with other elements, took its place in the table, which brought order to chemical science.

Further study of rubidium showed that this element has a number of interesting and valuable properties. We will consider here the most characteristic and important of them.

General characteristics of the chemical element

Rubidium has atomic number 37, that is, its atoms contain exactly the same number of positively charged particles - protons - in their nuclei. Accordingly, a neutral atom has 37 electrons.

The element symbol is Rb. Rubidium is classified as an element of group I, period - fifth (in the short-period version of the table it belongs to the main subgroup of group I and is located in the sixth row). It is an alkali metal and is a soft, very fusible crystalline substance of silvery-white color.

Discovery history

The honor of discovering the chemical element rubidium belongs to two German scientists - chemist Robert Bunsen and physicist Gustav Kirchhoff, the authors of the spectroscopic method for studying the composition of matter. After the use of spectral analysis led to the discovery of cesium in 1860, scientists continued their research, and the very next year, when studying the spectrum of the mineral lepidolite, they discovered two unidentified dark red lines. It was thanks to the characteristic shade of the strongest spectral lines, by which it was possible to establish the existence of a previously unknown element, that it received its name: the word rubidus is translated from Latin as “crimson, dark red.”

In 1863, Bunsen first isolated rubidium metal from mineral spring water by evaporating a large amount of solution, separating potassium, cesium and rubidium salts, and finally reducing the metal using soot. Later, N. Beketov managed to restore rubidium from its hydroxide using aluminum powder.

Physical characteristics of the element

Rubidium is a light metal; it has a density of 1.53 g/cm 3 (at zero temperature). Forms crystals with a cubic body-centered lattice. Rubidium melts at only 39 °C, that is, at room temperature its consistency is already close to pasty. The metal boils at 687 °C, its vapors have a greenish-blue tint.

Rubidium is paramagnetic. Its conductivity is more than 8 times higher than that of mercury at 0 °C and almost the same number of times lower than that of silver. Like other alkali metals, rubidium has a very low photoelectric effect threshold. To excite a photocurrent, long-wave (that is, low-frequency and carrying less energy) red light rays are sufficient. In this respect, only cesium surpasses it in sensitivity.

Isotopes

Rubidium has an atomic weight of 85.468. It occurs in nature as two isotopes, differing in the number of neutrons in the nucleus: rubidium-85 makes up the largest proportion (72.2%), and rubidium-87 in a much smaller amount - 27.8%. The nuclei of their atoms, in addition to 37 protons, contain 48 and 50 neutrons, respectively. The lighter isotope is stable, and rubidium-87 has a huge half-life - 49 billion years.

Currently, several dozen radioactive isotopes of this chemical element have been obtained artificially: from ultra-light rubidium-71 to rubidium-102, which is overloaded with neutrons. Half-lives of artificial isotopes vary from several months to 30 nanoseconds.

Basic chemical properties

As noted above, among the chemical elements rubidium (like sodium, potassium, lithium, cesium and francium) belongs to the alkali metals. The peculiarity of the electronic configuration of their atoms, which determines the chemical properties, is the presence of only one electron at the outer energy level. This electron easily leaves the atom, and the metal ion acquires an energetically favorable electronic configuration of the inert element in front of it in the periodic table. For rubidium, this is the configuration of krypton.

Thus, rubidium, like other alkali metals, has pronounced reducing properties and an oxidation state of +1. Alkaline properties are more pronounced with increasing atomic weight, since the radius of the atom also increases, and, accordingly, the connection between the outer electron and the nucleus is weakened, which causes an increase in chemical activity. Therefore, rubidium is more active than lithium, sodium and potassium, and cesium, in turn, is more active than rubidium.

Summarizing all of the above about rubidium, the element can be analyzed as in the illustration below.

Compounds formed by rubidium

In air, this metal, due to its exceptional reactive activity, oxidizes violently, with ignition (the flame has a violet-pinkish color); During the reaction, rubidium superoxide and peroxide are formed, which exhibit the properties of strong oxidizing agents:

• Rb + O 2 → RbO 2 .
• 2Rb + O 2 → Rb 2 O 2.

An oxide is formed if oxygen access to the reaction is limited:

• 4Rb + O 2 → 2Rb 2 O.

It is a yellow substance that reacts with water, acids and acid oxides. In the first case, one of the strongest alkalis is formed - rubidium hydroxide, in the rest - salts, for example, rubidium sulfate Rb 2 SO 4, most of which are soluble.

Even more violently, accompanied by an explosion (since both rubidium and the liberated hydrogen instantly ignite), the reaction of the metal with water occurs, in which rubidium hydroxide is formed, an extremely aggressive compound:

• 2Rb + 2H 2 O → 2RbOH +H 2.

Rubidium is a chemical element that can also react directly with many non-metals - phosphorus, hydrogen, carbon, silicon, and halogens. Rubidium halides - RbF, RbCl, RbBr, RbI - are highly soluble in water and in some organic solvents, for example, ethanol or formic acid. The interaction of metal with sulfur (grinding with sulfur powder) occurs explosively and leads to the formation of sulfide.

There are also poorly soluble rubidium compounds, such as perchlorate RbClO 4, they are used in analytics for the determination of this chemical element.

Being in nature

Rubidium is not a rare element. It is found almost everywhere, is part of many minerals and rocks, and is also found in the ocean, groundwater and river waters. In the earth's crust, the content of rubidium reaches the total content of copper, zinc and nickel. However, unlike many much rarer metals, rubidium is an extremely trace element, its concentration in rock is very low, and it does not form its own minerals.

In the composition of minerals, rubidium everywhere accompanies potassium. The highest concentration of rubidium is found in lepidolites, minerals that also serve as a source of lithium and cesium. So rubidium is always present in small quantities where other alkali metals are found.

A little about the use of rubidium

Brief description of the chem. The element of rubidium can be supplemented with a few words about the areas in which this metal and its compounds are used.

Rubidium is used in the production of photocells, in laser technology, and is part of some special alloys for rocketry. In the chemical industry, rubidium salts are used due to their high catalytic activity. One of the artificial isotopes, rubidium-86, is used in gamma flaw detection and, in addition, in the pharmaceutical industry for the sterilization of drugs.

Another isotope, rubidium-87, is used in geochronology, where it is used to determine the age of ancient rocks due to its very long half-life (rubidium-strontium method).

If several decades ago it was believed that rubidium was a chemical element whose scope of application was unlikely to expand, now new prospects are emerging for this metal, for example, in catalysis, in high-temperature turbine units, in special optics and in other areas. So rubidium plays and will continue to play an important role in modern technologies.

Rubidium element is a white alkali metal with a metallic luster (see photo). It is easy to melt; this process occurs at a temperature of only 39°C. In all its characteristics, the element is similar to potassium and sodium. The name Rubidium is lat. dark red was not assigned to him for his natural coloring. German scientists Bunsen and Kirchhoff examined the new substance in a spectrograph and noticed red lines.

Rubidium is a very active element, but its characteristic feature is that most reactions occur explosively, and combustion is accompanied by a bright violet flame. In a similar way, interaction occurs with all known elements, regardless of their nature (metal-non-metal). Store it in vessels with dry kerosene or in a vacuum. In addition to being active, rubidium is also a radioactive element that gradually turns into strontium.

This substance is, by its nature, very unique. When exposed to light, it becomes a source of electric current. This phenomenon is called the photoelectric effect, and allows the element to be used for the manufacture of photocells used in cinema, television, and remote control of automation. Rubidium is valued very highly, and therefore consumption is quite small (several tens of kilograms per year).

It is also used in the manufacture of measuring instruments, as components of lubricants for rocket and space technology operating in vacuum conditions, and in X-ray equipment. It is thanks to the content of rubidium and strontium in rocks that geologists are able to determine their age.

In nature, rubidium is quite common, but only in the form of impurities. Its salts are often found in mineral springs and volcanic rocks.

Effect of rubidium and its biological role

The effect of a macroelement on a biological organism is associated with its concentration in certain organs: bone tissue, lungs, brain, ovaries. Its absorption from food occurs in the gastrointestinal tract, and it is excreted through natural secretions.

Scientists have not yet sufficiently studied the effect of the element on humans, but without a doubt, it plays a significant role in the body and has the following effect:

• can to some extent replace potassium and play its role in enzyme activation;
• has an antihistamine effect (fights the effects of allergens);
• weakens inflammatory processes in cells and the body as a whole;
• restores the balance of the central nervous system and has a calming effect.

Today, scientists are studying the effect of the element on stimulating blood circulation and using these properties to treat hypotension. Another famous doctor S. Botkin noticed in 1898 that rubidium chloride can increase pressure in the arteries and associated this with the process of vasoconstriction and activation of the cardiovascular system.

It has also been noted that microdoses of the element can cause red blood cells to resist harmful effects and increase the mass of hemoglobin in them. This in turn leads to increased immunity.

Most often, rubidium is studied in combination with cesium. The salts of these elements help to endure hypoxia - lack of oxygen.

We hope that this element will reveal many more of its unique abilities to the medical and scientific world.

Daily norm

The daily macronutrient requirement for an adult is approximately 1-2 mg. It is absorbed by the body quite quickly - after 1-1.5 hours you can find its content in the blood. In total, human tissues and organs contain about 1 gram of rubidium.

Deficiency of a chemical element in the body

Macronutrient deficiency and its effects on the human body have been practically unexplored. The experiments were carried out only on animals and their reaction was as follows:

• loss of appetite, and even complete refusal to eat;
• growth retardation, slow development, shortened life expectancy;
• premature birth, miscarriages;
• abnormalities in fetal development and decreased fertility.

Excess rubidium

An excess of a macroelement can cause dangerous complications due to the fact that rubidium belongs to the same category of poisonous and toxic elements as arsenic and sulfuric acid. Overdoses can cause great harm to health and even death.

The reason for such large doses may be work in enterprises where substance compounds are used that penetrate the body with vapors and dust. Theoretically, one of the reasons could be excessive intake of the element from food and water.

A slight increase in the level of a macronutrient can lead to migraines, insomnia, diseases and inflammation of the lungs and respiratory organs, rapid heartbeat (arrhythmias), skin allergies and increased levels of proteins in the urine. If poisoning is caused by the accumulation of critical masses of an element, then the consequences are similar to those caused by a deficiency of the element: slower growth and development, shortened life span.

Uniqueness again? The upside is that you need to be taking more than 1000 mg daily for these symptoms to occur, which is already very difficult.

Treatment of poisoning is carried out with substances that, when reacting with toxins, form compounds that easily dissolve in water and are excreted by the kidneys. Basically it is a complexing agent based on potassium or sodium. Drugs are also used to relieve characteristic symptoms.

What are the sources of the element?

The list of foods containing rubidium mainly consists of plant foods. Here are the most basic of them: eggplants, ginger, potatoes, beets, tomatoes, garlic, onions, mushrooms (champignons and porcini mushrooms), many fruits and dried fruits, nuts (almonds, walnuts and pine, hazelnuts, pistachios), sunflower seeds, cereals , legumes. Our body receives the largest amount from tea and coffee (about 40% of the total amount) and mineral water, depending on the origin.

This element is capable of accumulating in living tissues, especially in marine organisms. Therefore, eating seafood will help you get the required amount of rubidium.

Indications for use

Indications for prescribing a macronutrient are based on the nature of the effect on the human body. Its main medicinal purpose is the treatment of nervous system disorders. Even 100 years ago, it was actively used to get rid of epilepsy. Today it is used as a neurotropic drug to strengthen the nervous system.

It may also be necessary in the treatment of allergic diseases, muscle weakness, and anemia.

The content of the article

RUBIDIUM(Rubidium) Rb, a chemical element of the 1st (Ia) group of the Periodic table. Alkaline element. Atomic number 37, relative atomic mass 85.4678. It occurs in nature as a mixture of the stable isotope 85 Rb (72.15%) and the radioactive isotope 87 Rb (27.86%) with a half-life of 4.8. 10 10 years. Another 26 radioactive isotopes of rubidium with mass numbers from 75 to 102 and half-lives from 37 ms (rubidium-102) to 86 days (rubidium-83) have been artificially obtained.

Oxidation state +1.

Rubidium was discovered in 1861 by German scientists Robert Bunsen and Gustav Kirchhoff and was one of the first elements discovered by spectroscopy, which was invented by Bunsen and Kirchhoff in 1859. The name of the element reflects the color of the brightest line in its spectrum (from the Latin rubidus deep red) .

While studying various minerals with a spectroscope, Bunsen and Kirchhoff noticed that one of the lepidolite samples sent from Rosen (Saxony) produced lines in the red region of the spectrum. (Lepidolite is a mineral of potassium and lithium, which has the approximate composition K 2 Li 3 Al 4 Si 7 O 21 (OH,F) 3.) These lines were not found in the spectra of any known substance. Soon, similar dark red lines were discovered in the spectrum of sediment obtained after the evaporation of water from samples taken from mineral springs in the Black Forest. However, the content of the new element in the tested samples was negligible, and in order to extract more or less noticeable quantities, Bunsen had to evaporate over 40 m 3 of mineral waters. From the evaporated solution he precipitated a mixture of potassium, rubidium and cesium chloroplatinates. To separate rubidium from its closest relatives (and especially from a large excess of potassium), Bunsen subjected the precipitate to repeated fractional crystallization and obtained rubidium and cesium chlorides from the least soluble fraction and then converted them into carbonates and tartrates (tartaric acid salts), which allowed for even better purification rubidium and free it from the bulk of cesium. Bunsen managed to obtain not only individual rubidium salts, but also the metal itself. Metallic rubidium was first obtained by reducing the acid salt of rubidium hydrogen tartrate with soot.

A quarter of a century later, Russian chemist Nikolai Nikolaevich Beketov proposed another method for obtaining metal rubidium - by reducing it from hydroxide with aluminum powder. He carried out this process in an iron cylinder with a gas outlet tube, which was connected to a glass refrigerator tank. The cylinder was heated on a gas burner, and a violent reaction began in it, accompanied by the release of hydrogen and the sublimation of rubidium in the refrigerator. As Beketov himself wrote, “rubidium is driven gradually, flowing down like mercury, and even retaining its metallic luster due to the fact that the projectile is filled with hydrogen during the operation.”

Distribution of rubidium in nature and its industrial extraction. The content of rubidium in the earth's crust is 7.8·10 3%. This is approximately the same as for nickel, copper and zinc. In terms of abundance in the earth's crust, rubidium is approximately in 20th place, but in nature it is in a dispersed state, rubidium is a typical trace element. The intrinsic minerals of rubidium are unknown. Rubidium is found together with other alkaline elements and always accompanies potassium. It is found in many rocks and minerals, particularly in North America, South Africa and Russia, but its concentration there is extremely low. Only lepidolites contain slightly more rubidium, sometimes 0.2%, and occasionally up to 13% (in terms of Rb 2 O).

Rubidium salts are dissolved in the water of seas, oceans and lakes. Their concentration here is very low, on average about 100 µg/l. In some cases, the content of rubidium in water is higher: in the Odessa estuaries it turned out to be 670 µg/l, and in the Caspian Sea 5700 µg/l. Increased rubidium content has also been found in some mineral springs in Brazil.

From seawater, rubidium passed into potassium salt deposits, mainly into carnallites. In the Strassfurt and Solikamsk carnallites, the rubidium content ranges from 0.037 to 0.15%. The mineral carnallite is a complex chemical compound formed by potassium and magnesium chlorides with water; its formula is KCl MgCl 2 6H 2 O. Rubidium gives a salt of similar composition RbCl MgCl 2 6H 2 O, and both salts potassium and rubidium have the same structure and form a continuous series of solid solutions, crystallizing together. Carnallite is highly soluble in water, so opening the mineral is not difficult. Rational and economical methods for extracting rubidium from carnallite, along with other elements, have now been developed and described in the literature.

However, most mined rubidium is obtained as a by-product in the production of lithium from lepidolite. After lithium is isolated in the form of carbonate or hydroxide, rubidium is precipitated from mother liquors in the form of a mixture of aluminum rubidium, aluminum potassium and aluminum cesium alum MAl(SO 4) 2 12H 2 O (M = Rb, K, Cs). The mixture is separated by repeated recrystallization. Rubidium is also isolated from the waste electrolyte obtained when producing magnesium from carnallite. Rubidium is isolated from it by sorption on precipitates of iron or nickel ferrocyanides. Then the ferrocyanides are calcined and rubidium carbonate with impurities of potassium and cesium is obtained. When obtaining cesium from pollucite, rubidium is extracted from the mother liquors after the precipitation of Cs 3 . Rubidium can also be extracted from technological solutions formed during the production of alumina from nepheline.

To extract rubidium, extraction and ion exchange chromatography methods are used. High purity rubidium compounds are prepared using polyhalides.

Much of the rubidium produced is recovered during the production of lithium, so the emergence of great interest in lithium for use in fusion processes in the 1950s led to an increase in the production of lithium, and therefore rubidium, and therefore rubidium compounds became more accessible.

Rubidium is one of the few chemical elements whose resources and production capabilities are greater than the current needs for it. There are no official statistics on the production and use of rubidium and its compounds. It is believed that the annual production of rubidium is about 5 tons.

The market for rubidium is very small. There is no active trade in the metal, and there is no market price for it. Prices set by companies selling rubidium and its compounds vary tenfold.

Characteristics of a simple substance, industrial production and use of metallic rubidium. Rubidium is a soft, silvery-white metal. At normal temperatures it has an almost paste-like consistency. Rubidium melts at 39.32° C, boils at 687.2° C. Rubidium vapor is colored greenish-blue.

Rubidium is highly reactive. In air, it instantly oxidizes and ignites, forming superoxide RbO 2 (with an admixture of peroxide Rb 2 O 2):

Rb + O 2 = RbO 2, 2Rb + O 2 = Rb 2 O 2

Rubidium reacts explosively with water to form hydroxide RbOH and release hydrogen: 2Rb + 2H 2 O = 2RbOH + H 2.

Rubidium combines directly with most nonmetals. However, it does not interact with nitrogen under normal conditions. Rubidium nitride Rb 3 N is formed by passing an electric discharge in liquid nitrogen between electrodes made of rubidium.

Rubidium reduces oxides to simple substances. It reacts with all acids to form the corresponding salts, and with alcohols it gives alcoholates:

2Rb + 2C 2 H 5 OH = 2C 2 H 5 ORb + H 2

Rubidium dissolves in liquid ammonia, producing blue solutions containing solvated electrons and exhibiting electronic conductivity.

Rubidium forms alloys and intermetallic compounds with many metals. The RbAu compound, in which the bond between metals is partially ionic in nature, is a semiconductor.

Metallic rubidium is obtained mainly by the reduction of rubidium compounds (usually halides) with calcium or magnesium:

2RbCl + 2Ca = 2Rb + CaCl 2

Rb 2 CO 3 + 3Mg = 2Rb + 3MgO + C

The reaction of rubidium halide with magnesium or calcium is carried out at 600-800 ° C and 0.1 Pa. The product is purified from impurities by rectification and vacuum distillation.

Rubidium can be obtained electrochemically from a melt of rubidium halide on a liquid lead cathode. From the resulting lead-rubidium alloy, rubidium is isolated by distillation in a vacuum.

In small quantities, rubidium is obtained by reducing rubidium chromate Rb 2 CrO 4 with zirconium or silicon powder, and high-purity rubidium is obtained by slow thermal decomposition of rubidium azide RbN 3 in a vacuum at 390-395 ° C.

Metallic rubidium is a component of the cathode material for photocells and photoelectric multipliers, although rubidium photocathodes are inferior to some others, in particular cesium, in sensitivity and range of action. It is part of lubricant compositions used in jet and space technology. Rubidium vapor is used in electric discharge tubes.

Metallic rubidium is a component of catalysts (it is applied to active aluminum oxide, silica gel, metallurgical slag) for the oxidation of organic impurities during the production of phthalic anhydride, as well as the process of producing cyclohexane from benzene. In its presence, the reaction occurs at lower temperatures and pressures than when catalysts are activated by sodium or potassium, and it is almost uninterrupted by poisons that are “deadly” for conventional catalysts—substances containing sulfur.

Rubidium is dangerous to handle. It is stored in special glass ampoules in an argon atmosphere or in sealed steel vessels under a layer of dehydrated mineral oil.

Rubidium compounds. Rubidium forms compounds with all common anions. Almost all rubidium salts are highly soluble in water. Like potassium, the salts Rb 2 SiF 6 and Rb 2 PtCl 6 are slightly soluble.

Compounds of rubidium with oxygen.

Rubidium forms numerous oxygen compounds, including Rb 2 O oxide, Rb 2 O 2 peroxide, RbO 2 superoxide, and RbO 3 ozonide. All of them are colored, for example, Rb 2 O is bright yellow, and RbO 2 is dark brown. Rubidium superoxide is formed when rubidium is burned in air. Rubidium peroxide is obtained by oxidizing rubidium dissolved in anhydrous ammonia with anhydrous hydrogen peroxide, and rubidium oxide by heating a mixture of rubidium metal and its peroxide. Oxide, peroxide and superoxide are thermally stable, they melt at a temperature of about 500 ° C.

Using X-ray diffraction analysis, it was shown that the compound of composition Rb 4 O 6, obtained in the solid state by the reaction of Rb 2 O 2 with RbO 2 in a ratio of 1:2, has the composition. At the same time, diatomic oxygen anions of different types (peroxide and superoxide) in a cubic unit cell are indistinguishable even at 60° C. This compound melts at 461° C.

Rubidium ozonide RbO 3 is formed by the action of ozone on anhydrous RbOH powder at low temperature:

4RbOH + 4O 3 = 4RbO 3 + 2H 2 O + O 2

Partial oxidation of rubidium at low temperatures produces a compound with the composition Rb 6 O, which decomposes above 7.3 ° C to form shiny copper-colored crystals with the composition Rb 9 O 2. When exposed to water, the Rb 9 O 2 compound ignites. At 40.2°C it melts with decomposition and the formation of Rb 2 O and Rb in a ratio of 2:5.

Rubidium carbonate Rb 2 CO 3 melts at 873° C, is highly soluble in water: at 20° C, 450 g of rubidium carbonate dissolves in 100 g of water.

In 1921, German chemists Fischer Franz (1877–1947) and Hans Tropsch (1889–1935) found that rubidium carbonate was an excellent catalyst component for the production of synthetic petroleum synthol (a mixture of alcohols, aldehydes and ketones, formed from water gas at 410° C and a pressure of 140150 atm in the presence of a special catalyst).

Rubidium carbonate has a positive effect on the polymerization of amino acids; with its help, synthetic polypeptides with a molecular weight of up to 40,000 are obtained, and the reaction proceeds very quickly.

Rubidium hydride RbH is obtained by the interaction of simple substances when heated under a pressure of 510 MPa in the presence of a catalyst:

2Rb + H 2 = 2RbH

This compound melts at 585° C; decomposes when exposed to water.

Rubidium halides RbF, RbCl, RbBr, RbI are prepared by reacting rubidium hydroxide or carbonate with the corresponding hydrohalic acids, by reacting rubidium sulfate with soluble barium halides, and by passing rubidium sulfate or nitrate through an ion exchange resin.

Rubidium halides are highly soluble in water, but less soluble in organic solvents. They dissolve in aqueous solutions of hydrohalic acids, forming hydrohalides in solution, the stability of which decreases from hydrodifluoride RbHF 2 to hydrodiiodide RbHI 2.

Rubidium fluoride is included in special glasses and compositions for heat accumulation. It is an optical material, transparent in the range of 916 microns. Rubidium chloride serves as an electrolyte in fuel cells. It is added to special iron castings to improve their mechanical properties, and is a component of the cathode material of cathode ray tubes.

For mixtures of rubidium chlorides with copper, silver or lithium chlorides, the electrical resistance drops so sharply with increasing temperature that they can become very convenient thermistors in various electrical installations operating at temperatures of 150-290 ° C.

Rubidium iodide is used as a component of luminescent materials for fluorescent screens, solid electrolytes in chemical current sources. The compound RbAg 4 I 5 has the highest electrical conductivity of all known ionic crystals. It can be used in thin film batteries.

Complex connections. Rubidium is not characterized by the formation of covalent bonds. Its most stable complexes are with polydentate ligands, such as crown ethers, where it usually exhibits a coordination number of 6.

Another group of very effective ligands that have recently been used to coordinate alkali element cations are macrocyclic polydentate ligands, which the French organic chemist Jean Marie Lehn called cryptands (Fig. 1).

Rubidium forms the CNS complex. H 2 O, in which the cryptand N((CH 2 CH 2 O) 2 CH 2 CH 2 ) 3 N (crypt) encloses the cation in a coordination polyhedron shaped like a double-capped trigonal prism (Fig. 2).

Rubidium ozonide forms stable solutions in organic solvents (such as CH 2 Cl 2, tetrahydrofuran or CH 3 CN) if the cation is coordinated by crown ethers or cryptands. Slow evaporation of ammonia solutions of such complexes leads to the formation of red crystals. X-ray diffraction analysis of the compound showed that the coordination number of the rubidium atom is 9. It forms six bonds with the crown ether, two with the O 3 ion and one with the ammonia molecule.

Application of rubidium isotopes.

Rubidium-87 spontaneously emits electrons (b-radiation) and turns into an isotope of strontium. About 1% of strontium was formed on Earth in this very way, and if you determine the ratio of strontium and rubidium isotopes with a mass number of 87 in any rock, you can calculate its age with great accuracy. This method is suitable for the most ancient rocks and minerals. With its help, it was established, for example, that the oldest rocks of the American continent arose 2100 million years ago.

The radionuclide rubidium-82, with a half-life of 76 s, is used in diagnostics. With its help, in particular, the condition of the myocardium is assessed. The isotope is injected into the patient's bloodstream and the blood flow is analyzed using positron emission tomography (PET).

Elena Savinkina

Rubidium was discovered in 1861 by R. Bunsen and G. Kirgoff based on special lines in the dark red region of the spectrum.

Receipt:

Rubidium does not form its own minerals; it is found in apatite-nepheline rocks, mica, and carnallite. It is obtained by metallothermic methods (reduction of rubidium chloride with calcium metal) and thermal decomposition of compounds, followed by purification from impurities by vacuum distillation.
World production (1979) is about 450 kg/year (without the USSR).

Physical properties:

Shiny, silvery-white metal. The density of rubidium is low d=1.5 g/cm 3 ; t pl =39°, t kip =689°. Very soft, easy to cut with a knife.

Chemical properties:

Rubidium ignites instantly in air, as well as in an atmosphere of fluorine and chlorine, and interaction with liquid bromine is accompanied by a strong explosion.
Reacts explosively with water and dilute acids.

The most important connections:

Oxide, Rb 2 O- yellow, reacts vigorously with water, forming a hydroxide, chemically active.
Hydroxide, RbOH- colorless, very hygroscopic substance, strong base.
Peroxides When rubidium is burned, superoxide RbO 2 is formed. Indirectly, you can also obtain Rb 2 O 2, which is less stable than Na 2 O 2. Rb 2 O 2 and RbO 2 are strong oxidizing agents. They easily decompose with water, and even more so with dilute acids.
2RbO 2 + 2H + = 2Rb + + H 2 O 2 + O 2
An even stronger oxidizing agent is the ozonide RbO 3:
4RbOH + 4O 3 =4RbO 3 +O 2 +2H 2 O
Salts. Almost all rubidium salts are easily soluble in water, form crystalline hydrates, and are colorless.
Rubidium persulfides (polysulfides) are obtained by boiling sulfides with excess sulfur. They are resilient.

Application:

Due to the high activity of rubidium, its atoms easily lose electrons under the influence of light (photoelectric effect), therefore rubidium is widely used for the manufacture of photocathodes used in measuring circuits, sound reproduction devices for optical phonograms, in transmitting television tubes, etc.
Rubidium is used to remove traces of air from vacuum tubes.
Rubidium compounds are used in medicine and in analytical chemistry, as a catalyst in organic synthesis. Salts are used as electrolytes in fuel cells.

Rubidium- a metal whose name resembles the name of a precious stone. The mineral is red. This justifies his name, translated as “scarlet”.

Rubidium is silver-gray. What's the catch? In the history of metal discovery. It was isolated from the mineral.

Having decomposed the stone into its components, chemists “lost” 2.5% of the mass. At first, they attributed it to water evaporating during the reactions.

Then, we decided to conduct a spectral analysis. A dark red line was revealed.

The elements known to science did not have this. So, in 1863 it was opened metal rubidium. What humanity has managed to learn about him over the past century and a half, we will tell below.

Chemical and physical properties of rubidium

Rubidium metal forms crystals. They resemble cubes. Characteristic of metals is visible only on a cross-section of aggregates.

Cutting them is not a problem - the material is soft, like cheese. This is a feature of most alkali metals, which include rubidium. Formula it is characterized by one electron in the outer level.

There are 5 of them in total. It is not surprising that the element is a powerful reducing agent and is chemically active. An electron removed from the nucleus is easily replaced.

This is how all types of salts are formed, for example, rubidium chloride. Like other compounds, it is easily soluble in water.

Two isotopes of element 37 have been identified in nature. 85th rubidium atom is stable, but 87 is radioactive, albeit weakly.

After complete decay, the 87th isotope is converted into a stable species. In artificial conditions rubidium element gave 20 isotopes.

All are radioactive. Isotopic numbers are equal to their atomic mass. If it is less than 85, beta + rays are emitted.

Such rubidium often disintegrates in a few minutes, and sometimes even seconds. The 81st isotope is the most stable.

Its half-life is 4 hours. Afterwards, krypton is released. This is a gas, also radioactive.

If a metal enters into compounds with others, it is always monovalent, that is, it forms only one chemical bond with another atom.

The oxidation state is +1. Rubidium oxide is formed only under conditions of lack of oxygen.

If there is enough of it, a violent reaction occurs, the result of which is the peroxide and superoxide of the 37th element.

In an oxygen environment alkali metal rubidium lights up. This is where the violence of the reaction lies.

The combination with water is even more dangerous. An explosion occurs. You also have to be careful with carbide. rubidium

Chemical element in the substance is capable of spontaneous combustion in a carbon dioxide environment. In water, the compound, like pure metal, explodes.

Rubidium, in this case, burns. All that remains is carbon. It is released in the form of coal. So, this is one of the ways to extract fuel.

Applications of rubidium

The element was first used by nature. She put 1 milligram of metal into the body of each person.

Rubidium is found in bones, lungs, brain, female ovaries,. The 37th element acts as an antiallergen, has an anti-inflammatory effect, slightly inhibits, and soothes.

In blood rubidium, color whose spectral feature merges with the tone of red blood cells, fights free radicals.

Metal also reduces the effect of oxidizing agents. Thanks to this, blood cells live longer and function better. Immunity and hemoglobin levels increase.

Doctors prescribe rubidium preparations as painkillers and sleeping pills.

In addition, the 37th element is received by epileptics. Doctors rely on the drug's inhibitory effect on nerve impulses.

Rubidium is excreted from the body through urine. Therefore, replenishment is required. The daily intake of the element is 1-2 milligrams.

You can get them by eating legumes, cereals, nuts, porcini mushrooms, almost all fruits and berries, especially black currants.

Outside the body, rubidium is present in television tubes, devices that reproduce optical phonograms, and in photocathodes.

The reason is the photoelectric effect. Element 37 is capable of this thanks to the rapid loss of electrons under the influence of light.

Similar behavior cesium. Rubidium competes with it for a place in the solar cell market.

Rubidium fluoride, like other salts of the element, are placed in fuel cells. The 37th metal compound serves as an electrolyte in them.

An electrolyte is also rubidium hydroxide. It is recommended for low-temperature chemical power sources.

The 37th element can speed up its flow as an additive to the hydroxide solution.

Already acts as a catalyst rubidium carbonate. It is purchased for the production of synthetic oil. It is called synthol.

Special rubidium catalysts have been patented for the synthesis of higher alcohols, styrene and butadeine.

Rubidium nitrate recognized as a means for calibrating calorimeters. These are devices that measure the amount of heat.

The technology detects both its release and absorption during various chemical, physical, and biological processes.

Can't get by without rubidium and nuclear industry. The 37th element is listed in the composition of metal coolants.

They are imprisoned in nuclear reactors. Rubidium is also found in vacuum radio tubes. The metal forms positive ions on their filaments.

In the space industry rubidium metal included in lubricant mixtures. Element 37 can even be found in thermometers.

We are not talking about mercury samples, but about models for measuring elevated temperatures up to 400 degrees Celsius. These thermometers contain a mixture of chlorides and rubidium

Electronic the industry uses alkali metal vapor. In particular, they are associated with the production of highly sensitive magnetometers. They are used in space exploration and geophysical surveys.

Rubidium mining

Rubidium is a trace element. This makes it difficult to develop substantial reserves. The metal ranks 20th in abundance in the earth's crust.

However, it does not have its own minerals and ores, that is, rocks in which rubidium is the basis.

In the same lepidolite from which the element was once isolated, it is present only as an impurity.

Rubidium has to be searched for along with other alkali metals. You can also use sea water. Salts of the 37th element are dissolved in it. But, for now, this resource is not being developed.

Industrial obtaining rubidium- This is a release from the electrolyte remaining after the production of magnesium. It is mined from carnallite.

A precipitate of ferrocyanides, iron and... remains. Rubidium is hidden in the former. Ferrocyanides are calcined to produce carbonate of the 37th metal. It is contaminated with cesium and potassium. All that remains is to clean up.

A lot of rubidium is extracted in lithium production. After its isolation, the 37th element is precipitated from the mother liquors.

The result of the operation is aluminum rubidium alum. After their repeated recrystallization, it is possible to separate the components.

As production has increased dramatically since the 1950s, so has the supply of rubidium.

It is no longer a costly deficit. Let's find out how much metal is valued by contemporaries.

Rubidium price

In Russia, rubidium is produced at the Rare Metals Plant. The company is located in the Novosibirsk region and sells packages of 30 grams and 1 kilogram.

For the last volume you will have to pay about 400,000 rubles. Private sellers offer rubidium divided by gram.

For one they usually ask for 5-6 US dollars. So do the math. At the same time, previously prices for the 37th element were even higher.

But rubidium, nevertheless, was not a record holder. The leader is Californian. This is the rarest and most expensive metal.

The cost of a gram exceeds $6,000,000. Compared to this price tag, suppliers' demands for rubidium seem insignificant.

By the way, in addition to the Novosibirsk plant, Servermed from the Murmansk region also sells the 37th element.