Rubidium
RUBIDIUM-I; m.[from lat. rubidus - reddish] Chemical element (Rb), a soft metal of silvery-white color, similar in properties to potassium and sodium.
◁ Rubidium, oh, oh.
rubidium(lat. Rubidium), chemical element of group I of the periodic table; refers to alkali metals. Name from lat. rubidus - dark red (open along lines in the red part of the spectrum). Silvery-white metal with a paste-like consistency. Density 1.532 g/cm 3 t pl 39.32°C, t kip 687°C. In air it ignites instantly and reacts explosively with water. Disseminated in nature, it accompanies potassium and lithium and is extracted from their minerals. Used to a limited extent (cathodes for photocells, additive in gas-discharge tubes, catalyst in organic synthesis).
RUBIDIUMRUBIDIUM (lat. rubidium, from lat. rubidus - red), Rb (read “rubidium”), chemical element with atomic number 37, atomic mass 85.4678. Natural rubidium consists of a mixture of the stable nuclide 85 Rb (72.15% by mass) and weakly radioactive 87 Rb (half-life T 1/2 = 4.8·10 10 years). Located in group IA (alkali metals), in the 5th period. Electronic configuration of outer layer 5 s 1, Oxidation state +1 (valency I).
The radius of the neutral rubidium atom is 0.248 nm, the radius of the Rb + ion is 0.166 nm (coordination number 6). The sequential ionization energies of the Rb atom are 4.177, 27.5, 40.0, 52.6 and 71 eV. Electron affinity 0.49 eV. The electron work function is 2.16 eV. Electronegativity according to Pauling (cm. PAULING Linus) 0,8.
History of discovery
German researchers R.W. Bunsen (cm. BUNSEN Robert Wilhelm) and G.R. Kirchhoff performed spectral studies of the mineral lepidolite in 1861 (cm. LEPIDOLITE) and sediment formed after the evaporation of mineral waters from the Black Forest springs. The spectra contained a dark red line belonging to the new element.
After evaporation of mineral waters, a mixture of potassium, rubidium and cesium chloroplatinates was precipitated from the resulting residue using ammonium chloroplatinate (NH 4) 2 PtCl 6. Then, chloroplatinates were converted into carbonates and tartaric acid salts - tartrates. By repeated fractional recrystallization of acid tartrates, Bunsen managed to purify rubidium from potassium and cesium and obtain the first rubidium salt preparation. In 1863, Bunsen prepared the first sample of metallic rubidium by reducing rubidium acid tartrate with soot.
Being in nature
The content of rubidium in the earth's crust is 1.5·10 -2% by mass. Does not form its own minerals; as a rule, it is accompanied by K or Li. Found in mineral springs, lake, sea and underground waters.
Receipt
Rubidium is mainly obtained by processing either lepidolite into Li compounds, or carnallite, which serves as a raw material in the production of Mg. The residue formed after separation of the main amounts of Li, K and Mg and containing salts K, Rb and Cs is separated into fractions by methods of fractional crystallization, sorption, extraction and ion exchange.
Rubidium metal is usually prepared by reducing Rb halides with calcium (cm. CALCIUM) or magnesium. (cm. MAGNESIUM)
Physical and chemical properties
Rubidium is a soft, silvery-white metal.
At normal temperatures it has a paste-like consistency, melting point +39.32°C. The boiling point of rubidium is 687.2°C. Crystal lattice of metal cubic body-centered, cell parameter A= 0.570 nm. Rubidium is a light metal, its density is 1.532 kg/dm 3.
The reactivity of rubidium is very high. Its standard electrode potential is -2.925 V. In air and in an oxygen atmosphere, rubidium metal ignites, forming a mixture of rubidium peroxide Rb 2 O 2 and rubidium superoxide RbO 2. If the oxygen content in the gas with which Rb reacts is insignificant, the formation of Rb 2 O oxide is also possible. Rubidium reacts explosively with water:
2Rb + 2H 2 O = 2RbOH + H 2
When heated under elevated pressure, Rb reacts with H to form the hydride RbH. Rb reacts directly with halogens, S to form sulfide Rb 2 S. Rubidium does not react with nitrogen under normal conditions, and rubidium nitride Rb 3 N is formed by passing an electric discharge between rubidium electrodes placed in liquid nitrogen. When heated, rubidium reacts with red phosphorus to form rubidium phosphide Rb 2 P 5 . Also, when heated, rubidium reacts with graphite, and depending on the reaction conditions, carbides of the compositions C 8 Rb and C 24 Rb appear.
Rubidium is characterized by interaction with ammonia to form the amide RbNH 2. When rubidium reacts with acetylene, acetylenide Rb 2 C 2 appears. Metallic rubidium is capable of reducing silicon from glass and SiO 2 .
Rubidium forms intermetallic compounds with many metals.
Rubidium hydroxide RbOH is a strong base, highly soluble in water, and behaves similarly to KOH and NaOH.
Rubidium salts such as RbCl chloride, Rb 2 SO 4 sulfate, RbNO 3 nitrate, Rb 2 CO 3 carbonate are highly soluble in water, rubidium perchloride RbClO 4 and rubidium chloroplatinate Rb 2 PtCl 6 are poorly soluble in water
Application
Metallic rubidium is part of lubricating compositions used in jet and space technology. It is used as a component of the cathode material of photocells and photovoltaic multipliers. Rubidium vapor is used in discharge tubes and low-pressure lamps. Some rubidium compounds are used in the manufacture of special glasses.
Features of treatment
Store in Pyrex glass ampoules in an argon atmosphere or in sealed steel vessels under a layer of anhydrous petroleum jelly or paraffin.
encyclopedic Dictionary. 2009 .
Synonyms:See what “rubidium” is in other dictionaries:
A silver-colored alkali metal, an analogue of potassium. Dictionary of foreign words included in the Russian language. Chudinov A.N., 1910. RUBIDIA is a silver-colored metal with a yellowish tint. A complete dictionary of foreign words that came into use in... ... Dictionary of foreign words of the Russian language
Rb (a. rubidium; n. Rubidium; f. rubidium; i. rubidio), chemical. element of group I periodic. Mendeleev system, at. n. 37, at. m. 85.4678; refers to alkali metals. It occurs in nature as a mixture of two stable isotopes: 85Rb... ... Geological encyclopedia
- (chemical; Rubidium; Rb = 85.44 at 0 = 16, average of the definitions of Bunsen, Picard and Godefroy) the second metallic element discovered (in 1861) by Bunsen and Kirchhoff using spectral analysis; it got its name from two dark red (rubidus)… … Encyclopedia of Brockhaus and Efron
RUBIDIUM- chem. element, symbol Rb (lat. Rubidium), at. n. 37, at. m. 85.47, refers to alkali metals; very dispersed and has no minerals of its own. It is found as an impurity in the minerals potassium, cesium and lithium from which it is extracted. Rubidium is soft,... ... Big Polytechnic Encyclopedia
- (Rubidium), Rb, chemical element of group I of the periodic table, atomic number 37, atomic mass 85.4678; refers to alkali metals. Discovered by German scientists R. Bunsen and G. Kirchhoff in 1861... Modern encyclopedia
- (lat. Rubidium) Rb, chemical element of group I of the periodic system of Mendeleev, atomic number 37, atomic mass 85.4678. Refers to alkali metals. Name from lat. rubidus is dark red (discovered along lines in the red part of the spectrum).… … Big Encyclopedic Dictionary
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
DEFINITION
Rubidium located in the fifth period of group I of the main (A) subgroup of the Periodic Table. Designation – Rb. Rubidium in the form of a simple substance is a silvery-white metal with a body-centered crystal lattice.
Density - 1.5 g/cm3. Melting point 39.5 o C, boiling point - 750 o C. Soft, easy to cut with a knife. Self-ignites in air.
Oxidation state of rubidium in compounds
Rubidium is an element of group IA of the Periodic Table of D.I. Mendeleev. It belongs to the group of alkali metals, which in their compounds exhibit a constant and positive only possible oxidation state equal to (+1) , for example Rb +1 Cl -1, Rb +1 H -1, Rb +1 2 O -2, Rb +1 O -2 H +1, Rb +1 N +5 O -2 3, etc.
Rubidium also exists in the form of a simple substance - a metal, and the oxidation state of metals in the elemental state is equal to zero, since the distribution of electron density in them is uniform.
Examples of problem solving
EXAMPLE 1
| Exercise | In which series can all elements exhibit oxidation states (-1) and (+5):
|
| Solution | In order to find the correct answer to the question posed, we will check each of the proposed options one by one. a) All these chemical elements have only one oxidation state, which is equal to the group number of the Periodic Table D.I. Mendeleev, in which they are located, with a “+” sign. Those. The oxidation state of rubidium and lithium is (+1), and calcium is (+2). The answer is incorrect. b) Fluorine has only one oxidation state value, equal to (-1), so this answer option is incorrect and it makes no sense to check the remaining chemical elements. c) All of these elements belong to the group of halogens, and they are characterized by oxidation states (-1), 0, (+1), (+3), (+5) and (+7), i.e. this is the correct answer. |
| Answer | Option 3. |
Rubidium– an alkali metal, light and soft, silvery-white, although its name speaks of a completely different color: in Latin “rubidus” means “red”, or even “dark red” - that’s what scientists Gustav Robert Kirchhoff and Robert Wilhelm Bunsen called it in 1861. The first scientist was a great physicist, and the second was an experimental chemist; They examined minerals using a spectroscope, an instrument invented by Kirgoff, and noticed special red lines in one of the samples of concentration minerals, and decided that it was an unknown element. And so it turned out, but it turned out to be difficult to isolate the new mineral: Bunsen had to do a lot of work - the chemist worked tirelessly for 2 years - before rubidium was purified and separated from other elements - potassium salts, cesium, etc.
Today, chemists call rubidium a typical trace element, since there is a lot of it in the earth's crust, but it is almost always an admixture of other minerals; it is often found in volcanic rocks; Rubidium salts are often found in mineral water from various sources, in the water of seas and lakes (including groundwater), and in mineral concentrates - they contain tens of times more various chemical elements than in ordinary ore.
Pure rubidium is a unique element in many ways. It can only be stored in a vacuum, in special sealed glass ampoules - in the open air it immediately ignites, reacting instantly with oxygen. The chemical activity of rubidium is generally very high: it quickly reacts with almost all known chemical elements - with metals and non-metals, and sometimes even explodes.
The uniqueness of rubidium can also be judged by its melting point - it melts already at a temperature of 39°C, so, as soon as you hold an ampoule with this metal in your hands for a while, it will become semi-liquid right before your eyes - other metals are no different from this , except for mercury - everyone knows that it is precisely because of this property that it is successfully used in medical thermometers.
Of course, we are more interested in the role of rubidium in living organisms, including the human body, however, even here this element can be considered unusual - its role in this regard has not been clarified, and it is usually considered together with cesium, while simultaneously studying their effect on the body .
Sources of rubidium
There is rubidium in the tissues of plants and animals, but there is very little of it: for example, in the leaves of tobacco, a plant considered one of its sources, there is 1000 times less rubidium than potassium. In marine plants - algae, it is even less, but it can accumulate in living tissue: in particular, it is found in sea anemones, sea worms, crustaceans, mollusks, echinoderms and some fish. Rubidium also accumulates in some land plants - for example, in certain varieties of beets and grapes.
The metabolism of rubidium in the body is also poorly studied, but we get up to 1.5-4 mg of it every day with food, and mainly with black tea and coffee, as well as with drinking water. The human body should normally contain about 1 g of rubidium.
The role of rubidium in the body
Rubidium enters the blood very quickly, 1-1.5 hours after it enters the stomach; Rubidium accumulates in the brain and skeletal muscles, bones, lungs, and soft tissues.
Rubidium has antihistamine properties, and in earlier times, in the 19th century, it was used to treat some diseases of the nervous system - in particular, epilepsy. Otherwise, the physiological role of rubidium has also been little studied.
Rubidium belongs to the toxic elements of the 2nd hazard class - substances of this class are defined as highly dangerous to humans: for example, sulfuric acid and arsenic belong to the same class.
Doctors also know little about the symptoms of rubidium deficiency, as well as their causes - experiments were carried out on some animals. If they lacked rubidium in their food, this affected their ability to reproduce: embryos developed poorly, miscarriages and premature births were observed. Also, the animals’ growth and development in general slowed down, their appetite decreased, and their life expectancy decreased.
With an increased content of rubidium, the same symptoms are observed - slower growth and development and a shortened lifespan, but for this you need to take a lot of it - about 1000 mg per day. The radioactive isotope of rubidium is considered dangerous to health, but from the point of view of special sciences - radiobiology, radiation chemistry, etc. - this element can be considered weakly radioactive or even stable, since its half-life compared to the time of human life is unimaginably huge - it is 4.923 × 1010 years. If we try to translate this into a language we understand, it will be about 50-60 billion years - even our planet has not yet existed for that long.
However, it is considered risky to health to constantly work in certain industries: in the glass, chemical and electronics industries, and rubidium can also be ingested in large quantities through food and water - this depends on the geological features of the area. An excess of rubidium can cause headaches and sleep disturbances, arrhythmia, chronic inflammatory diseases of the respiratory tract, local irritation of the mucous membranes and skin, as well as proteinuria - increased protein content in the urine.
In case of rubidium poisoning, symptomatic treatment is usually prescribed, which involves eliminating individual symptoms, as well as treatment with complexing agents (usually sodium and potassium preparations), which form water-soluble compounds with toxic and radioactive substances, which are then excreted through the kidneys.
However, it is worth saying that both modern medicine and biology continue to study the possibilities of using rubidium in the treatment of many diseases.
As a rule, rubidium is studied in parallel with cesium: today it has been found that they can stimulate blood circulation and have a vasoconstrictor and hypertensive effect. For these purposes, they were used in the 19th century by the famous Russian scientist and doctor S.S. Botkin: he proved that cesium and rubidium salts increase blood pressure and maintain it for a long time.
These elements are also active in relation to the immune system: they increase the body’s resistance to diseases, as they increase the activity of leukocytes and lysozyme, an antibacterial agent that destroys the cell walls of pathogenic bacteria and thereby causes their rapid death.
Salts of rubidium and cesium also help the body more easily tolerate hypoxia - oxygen deficiency, and in modern medicine rubidium is also used: its iodide, bromide and chloride salts have a calming and analgesic effect.
Applications of rubidium
Rubidium is used in various fields, but it cannot be said that it is actively used: little of it is produced in the world - it amounts to tens, not hundreds of kg per year, and it is quite expensive. Rubidium compounds are used in analytical chemistry, in the manufacture of special optics, measuring instruments, and in the electronic and nuclear industries.
Rubidium is part of special effective lubricants used in rocket and space technology when working in vacuum conditions.
In electrical engineering, luminous tubes are used, in the manufacture of which rubidium is used; Rubidium compounds are used in the manufacture of special glasses and in X-ray technology, as well as in thermoelectric generators and ion engines.
In geochronology, when determining the geological age of rocks and minerals, the so-called strontium method is used, which makes it possible to establish this age very accurately - specialists determine the content of rubidium and 87Sr in these rocks. It was with the help of this method that scientists were able to determine the age of the oldest rocks of the American continent - they are 2 billion 100 million years old.
Gataulina Galina
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Rubidium was discovered in 1861 by German scientists Robert Bunsen and Gustav Kirchhoff and became one of the first elements discovered by spectroscopy, which was invented by Bunsen and Kirchhoff in 1859. Robert Bunsen and Gustav Kirchhoff mined 150 kg of lepidolite and obtained several grams of rubidium salts for analysis, so Thus, they discovered a new element. The name of an element reflects the color of the brightest line in its spectrum.
World Rubidium Resources
The content of rubidium in the earth's crust is 7.8·10−3%, which is approximately equal to the total content of 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 1-3% (in terms of Rb2O).
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 MgCl2 6H2O. Rubidium gives a salt of similar composition RbCl MgCl2 6H2O, 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.
Obtaining rubidium
Most mined rubidium is obtained as a by-product of lithium production from lepidolite. After lithium is isolated in the form of carbonate or hydroxide, rubidium is precipitated from the mother liquors in the form of a mixture of aluminum rubidium, potassium aluminum and cesium alum RbAl(SO4)2 12H2O, KAl(SO4)2 12H2O, CsAl(SO4)2 12H2O. 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 Cs3. 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 comes from lithium production, 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. This is why rubidium compounds have become more accessible.
Applications of rubidium
Although rubidium is inferior to cesium in some applications, this rare alkali metal plays an important role in modern technology. The following main areas of application of rubidium can be noted: catalysis, electronics industry, special optics, nuclear industry, medicine (its compounds have normothymic properties).
Rubidium is used not only in its pure form, but also in the form of a number of alloys and chemical compounds. Rubidium has a good raw material base, more favorable than for cesium. The scope of rubidium is expanding due to its increasing availability.
The isotope rubidium-86 is widely used in gamma flaw detection, measurement technology, as well as in the sterilization of drugs and food products. Rubidium and its alloys with cesium are a very promising coolant and working medium for high-temperature turbine units (in this regard, rubidium and cesium have become important in recent years, and the extreme high cost of metals is taking a backseat to the possibilities of dramatically increasing the efficiency of turbine units, and therefore and reduce fuel consumption and environmental pollution). The most widely used rubidium-based systems as coolants are ternary alloys: sodium-potassium-rubidium, and sodium-rubidium-cesium.
In catalysis, rubidium is used in both organic and inorganic synthesis. The catalytic activity of rubidium is used mainly for the refining of petroleum into a number of important products. Rubidium acetate, for example, is used for the synthesis of methanol and a number of higher alcohols from water gas, which is important in connection with the underground gasification of coal and in the production of artificial liquid fuels for cars and jet fuel. A number of alloys of rubidium with tellurium have higher sensitivity in the ultraviolet region of the spectrum than cesium compounds, and therefore, in this case, it is able to compete with cesium as a material for photoconverters. As part of special lubricating compositions (alloys), rubidium is used as a highly effective lubricant in vacuum (rocket and space technology).
Rubidium hydroxide is used to prepare an electrolyte for low-temperature chemical current sources [source not specified 560 days], and also as an additive to a solution of potassium hydroxide to improve its performance at low temperatures and increase the electrical conductivity of the electrolyte. Rubidium metal is used in hydride fuel cells.
Rubidium chloride alloyed with copper chloride is used for measuring high temperatures (up to 400 °C).
Rubidium vapor is used as a working fluid in lasers, in particular, in rubidium atomic clocks.
Rubidium chloride is used in fuel cells as an electrolyte, and the same can be said for rubidium hydroxide, which is very effective as an electrolyte in fuel cells using direct oxidation of coal.