It melts in your hands, but not snow - a riddle from the “chemistry” section. Guess – cesium. The melting point of this metal is 24.5 degrees Celsius. The substance, which literally flows through your fingers, was discovered in 1860. Cesium was the first element discovered by spectral analysis.
It was conducted by Robert Bunsen and Gustav Kirgoff. Chemists studied the waters of mineral springs in Durkheim. Found magnesium, lithium, calcium,... Finally, we placed a drop of water in the spectroscope and saw two blue lines - evidence of the presence of an unknown substance.
First, its chloroplatinate was isolated. For the sake of 50 grams, 300 tons of mineral water were processed. There was no trickery with the name of the new metal. From Latin “cesium” is translated as “blue”.
Chemical and physical properties of cesium
In a spectroscope, the metal glows bright blue. In reality, the element is similar to, but slightly lighter. In the liquid state, the yellowness of cesium disappears, and the melt becomes silvery. It is not easy to obtain raw materials for experiments.
Of the metals, the element is the rarest and most dispersed in the earth's crust. Only one isotope occurs in nature - cesium 133. It is completely stable, that is, it is not subject to radioactive decay.
Radioactive isotopes of the metal are obtained artificially. Cesium 135 is long-lived. Its half-life is approaching 3,000,000 years. Cesium 137 half disintegrates in 33.5 years. The isotope is recognized as one of the main sources of pollution of the biosphere.
The nuclide enters it from the discharges of factories, nuclear power plants. Half-life of cesium allows it to penetrate into water, soil, plants, accumulate in them. The 137th isotope is especially abundant in freshwater algae and lichens.
Being the rarest of the metals, cesium is also the most active. The alkaline element is located in the main subgroup of the 1st group of the periodic table, which already obliges the substance to easily enter into chemical reactions. Their flow is enhanced by the presence of water. Yes, in the air cesium atom explodes due to the presence of its vapor in the atmosphere.
Interaction with water is accompanied by an explosion, even if it is frozen. Reaction with ice is possible at -120 degrees Celsius. Dry ice is no exception. An explosion is also inevitable when cesium comes into contact with acids, simple alcohols, heavy metal halides, and organic halogens.
Interactions are easy to launch for 2 reasons. The first is a strong negative electrochemical potential. That is, the atom is negatively charged, tends to attract other particles to itself.
The second reason is the surface area of cesium during reactions with other substances. Melting in room conditions, the element spreads. It turns out that a greater number of atoms are open for interaction.
The activity of the element has led to the absence of its pure form in nature. There are only connections, for example, . Among them: cesium chloride, fluoride, iodite, azite, cyanite, bromide and cesium carbonate. All salts of the 55th element are easily soluble in water.
If work is carried out with cesium hydroxide, you need to be afraid not of its dissolution, but of the fact that it itself is capable of destroying, for example, glass. Its structure is disrupted by the reagent already at room temperature. As soon as you increase the degree, the hydroxide will not spare cobalt, corundum, and iron.
Reactions occur especially quickly in an oxygen environment. Only cesium hydroxide can resist. Nitrogen does not interact with element 55 either. Cesium asite is obtained only indirectly.
Applications of cesium
Cesium, formula which provides a low electron work function, is useful in the manufacture of solar cells. In devices based on the 55th substance, the cost of generating current is minimal. Sensitivity to radiation, on the contrary, is maximum.
To prevent photovoltaic equipment from being prohibitively expensive due to the rarity of cesium, it is alloyed with , , , . Cesium is used as a current source in fuel cells. Solid electrolyte based on 55 metal - part of cars and high-energy batteries.
The 55th metal is also used in charged particle counters. Cesium iodide is purchased for them. Activated with thallium, it detects almost any radiation. Cesium detectors are purchased for nuclear enterprises, geological exploration, and medical clinics.
They also use devices from the space industry. In particular, Mars-5 studied the elemental composition of the surface of the red planet thanks to a cesium-based gamma spectrometer.
The ability to capture infrared rays is the reason for its use in optics. They add to it cesium bromide And cesium oxide. It is found in binoculars, night vision goggles, and weapon sights. The latter are triggered even from space.
The 137th isotope of the element also found worthy use. The radioactive nuclide not only pollutes the atmosphere, but also sterilizes products, or rather, containers for them. Half-life of cesium long Millions of canned foods can be processed. Sometimes meat is also sterilized - bird carcasses and...
Medical instruments and medicines can also be processed with the 137th isotope. The nuclide is also needed in the treatment itself when it comes to tumors. The method is called radiotherapy. Preparations with cesium are also given for schizophrenia, diphtheria, peptic ulcers, and some types of shock.
Metallurgists need a pure element. It is mixed with alloys and. The additive increases their heat resistance. In , for example, it triples with cesium at only 0.3%.
Tensile strength and corrosion resistance also increase. True, industrialists are looking for an alternative to the 55th element. It is too scarce and not competitive in price.
Cesium mining
The metal is isolated from pollucite. It is a hydrous aluminosilicate and cesium. Minerals containing the 55th element of the unit. In pollucite, the percentage of cesium makes mining economically feasible. There is also a lot of metal in avogardite. However, this stone itself is as rare as cesium.
Industrialists open pollucite with chlorides or sulfates. Cesium extracted from the stone by immersing it in heated hydrochloric acid. Antimony chloride is also poured there. A precipitate forms.
It is washed with hot water. The result of the operations is cesium chloride. When working with sulfate, pollucite is immersed in sulfuric acid. The output is cesium alum.
Laboratories use other methods for obtaining the 55th element. There are 3 of them, all labor intensive. You can heat cesium dichromate and zirconium chromate. But this requires a vacuum. It is also needed for the decomposition of cesium azide. Vacuum is avoided only by heating specially prepared calcium and chloride of the 55th metal.
Cesium price
In Russia, the Rare Metals Plant in Novosibirsk is engaged in the mining and processing of pollucite. The Lovozersk Mining and Processing Plant also offers products. The latter offers cesium in ampoules 10 and 15 milligrams.
They come in packs of 1000 pieces. Minimum price – 6000 rubles. Sevredmet also sells ampoules, but is ready to supply smaller volumes - from 250 grams.
If the purity of the metal is 99.9%, for one gram, as a rule, they ask for around 15-20 US dollars. We are talking about the stable 133rd isotope of the 55th element of the periodic table.
(Caesium; from Latin caesius - blue), Cs - chemical. element of group I of the periodic system of elements; at, n. 55, at. m. 132.9054. Silver-white metal. In compounds it exhibits an oxidation state of +1. Natural carbon consists of the stable isotope 133Cs. 22 radioactive isotopes have been obtained, of which the most practical use is the 137Cs isotope with a half-life of 27 years. Cesium was discovered (1860) by the German chemist R. W. Bunsen and the German physicist G. P. Kirchhoff while studying the spectrum of alkali metal salts obtained from the water of the Durkheim mineral spring.
Cesium metal was first obtained (1882) by K. Setterberg by electrolysis of a melted mixture of cesium and barium cyanides. Cesium is a rare element. Its content in the earth's crust is 3.7 10-4% and is not found in nature in the free state due to its high activity. C. was found in 78 minerals; the largest amount of it is contained in cesium minerals: pollucite (up to 36% Cs20), sparrowite and avogadrite (up to 7.5% Cs20). Contains in small quantities (from 0.004 to 0.001% or less). rocks: basalts, granites, diabases, syenites, nephelines, micas, feldspars, limestones, shales, etc. The main sources of C. are pollucite, carnallite, brine of salt lakes, brines and marine mud. Crystal lattice C. body-centered cubic with period a = 6.05 A (temperature - 175 ° C).
Atomic radius 2.65 A, ionic radius of Cs+ is 165 A. Density 1.9039 (temperature 0°C) and 1.880 g/cm3 (temperature 26.85°C); melting point 28.60° C; boiling point 685.85°C; Wed coefficient linear expansion (in the temperature range 0-26° C) 9.7-10-5 deg-1; coefficient thermal conductivity (temperature 28.5° C) 0.04 - 0.065 cal/cm -sec-deg; heat capacity average 7.24 (temperature 0° C) and 7.69 cal/g-atom deg (temperature 25° C); specific electrical resistance is 18.30 (temperature 0° C) and 21.25 μΩ cm (temperature 26.85° C). Metallic vapor is amagnetic. Cesium is a soft, ductile metal. Hardness on the Mohs scale 0.2; HB - = 0.015; modulus of normal elasticity 175 kgf/mm2; compressibility at room temperature 7.0-10-5 kgf/cm2. Cesium metal has the highest reactivity among the alkaline elements. In air it instantly oxidizes with inflammation, forming peroxide and superoxide.
With hydrogen at a temperature of 200-350 ° C and a pressure of 50-100 at. forms the hydride CsH - a white crystalline substance that ignites in a humid environment, in an environment of chlorine and fluorine. With oxygen, depending on the conditions, it gives: Cs2O oxide - red-brown crystals, spreading in air; Cs2O2 peroxide - hygroscopic yellow crystals; CsO2 superoxide - yellow crystals, at temperatures above 180 ° C they change color to orange; ozonide CsO3 - fine crystalline orange - red powder; CsOH hydroxide is a white crystalline substance that quickly dissolves in air. C. directly combines with halogens (with ignition), forming halides CsF, CsCl, CsBr in Csl - colorless crystals, highly soluble in water and many others. organic solvents.
In liquid nitrogen, during an electric discharge between electrodes, cesium nitride is obtained from cesium - a hygroscopic, unstable powder of a grayish-green or blue color. Azide CsN3 - yellow-white crystals. There are known compounds of calcium with sulfur, selenium, and tellurium—chalcogenides. With sulfur, cesium forms sulfide Cs2S, a dark red crystalline powder soluble in water. In addition, di-, tri- and pentasulfides have been obtained. C. with selenium and tellurium forms crystalline compounds: white powder of Cs2Se selenide and light yellow powder of Cs2Te telluride, which decompose in air. With silicon it forms silicide CsSi, a yellow crystalline substance that ignites in air; when interacting with water, it ignites explosively. There are known compounds of C. with phosphorus - . When replacing hydrogen in an inorganic substance with carbon, the corresponding salts are obtained: sulfate, nitrate, carbonate, etc.
With many metals, including alkali metals, Cesium also forms intermetallic compounds, of which the most important are compounds with bismuth, antimony, gold and mercury. In reactions with inorganic compounds, cesium behaves as a strong reducing agent. Reacts explosively with carbon dioxide and carbon tetrachloride. Metallic zinc is obtained mainly by reacting with zinc salts, for example. on, magnesium or calcium at high
t-rah in a vacuum. To obtain carbon, an electrochemical method is also used, in which during electrolysis, for example, CsCl on a liquid lead cathode, a lead-cesium alloy is obtained, from which the color is removed by vacuum distillation. Small amounts of zirconium are obtained by reducing its chromate (Cs2Cr04) with powdered zirconium at a temperature of 650°C or by decomposing CsN3 at a temperature of 390-395°C in a vacuum.
Applications of Cesium
It is used in photocells; in photomultipliers intended for scintillation counters, celestial navigation instruments, spectroscopes, for radiation detectors in laser systems; in electro-optical converters used in night vision devices; in transmitting cathode ray tubes. Cesium is used as a getter to absorb residual traces of air in the production of vacuum radio tubes. It finds application in glow discharge thyratrons and in atomic standards - the most accurate standards of time intervals. The error of an atomic clock with a cesium source is 1 second in 4000 years. Cesium vapor is used in optical quantum generators - gas lasers. Additions of carbon to an inert gas in magnetohydrodynamic generators make it possible to ionize the gas at temperatures approximately two times lower than without these additives. C. is used in thermionic converters designed to directly convert heat into electricity. energy; in ion rocket engines for spacecraft. Cesium has found application in a new branch of electronics - microwave plasma electronics, as well as in cesium lamps, which are superior in intensity to other light sources.
Element characteristics
The discovery of cesium, like rubidium, is associated with spectral analysis. In 1860, R. Bunsen discovered two bright blue lines in the spectrum that did not belong to any element known at that time. This is where the name “caesius” comes from, which means sky blue. It is the last element of the alkali metal subgroup that still occurs in measurable quantities. The largest atomic radius and the smallest first ionization potentials determine the character and behavior of this element. It has pronounced electropositivity and pronounced metallic qualities. The desire to donate the outer 6s electron leads to the fact that all its reactions proceed extremely violently. Small difference in atomic 5 energiesd- and 6 s -orbitals causes easy excitability of atoms. Electron emission from cesium is observed under the influence of invisible infrared rays (heat). This feature of the atomic structure determines good electrical conductivity of current. All this makes cesium indispensable in electronic devices. Recently, more and more attention has been paid to cesium plasma as a fuel of the future and in connection with solving the problem of thermonuclear fusion.
Properties of simple matter and compounds
Cesium under normal room conditions is a semi-liquid metal (t pl = 28.5°C, t boil = 688°C). Its shiny surface has a pale golden color. Cesium is a light metal with sq. 1.9 g/cm³ , for example, with approximately the same atomic mass weighs more than 6 times more.
The reason that cesium is many times lighter than its neighbors on the periodic table is the large size of its atoms. The atomic and ion radii of the metal are very large:R at = 2.62 A, R and he =1.6 A. Cesium is unusually chemically active. It reacts so greedily with oxygen that it is able to purify the gas mixture from the slightest traces of oxygen even in deep vacuum conditions. It reacts with water when frozen to -116° C. Most reactions with other substances occur with explosions: with halogens, sulfur, phosphorus, graphite, silicon (in the last three cases, slight heating is required). Difficult people also react violently with it: CO 2 , tetrachloride, silica (at 300°C). In a hydrogen atmosphere, CsH hydride is formed, which ignites in insufficiently dry air. It displaces all inorganic and organic acids, forming salts.
The reactions of cesium with nitrogen proceed more calmly in the field of a quiet electric charge, and with coal when heated. Reacts with hydrogen at 300-350°C or under a pressure of 5 -10⋅ 10 ⁶ Pa. Therefore, it can be safely stored in a vessel filled with hydrogen.
2Сs + 2SiO 2 = Сs 2 O 4 + 2Si
2Rb + 2SiO 2 = Rb 2 O 4 + 2Si
Of the cesium compounds, the most important are c silver and antimony. Cesium bromide and iodide crystals are transparent to infrared rays, therefore they are used in optics and electrical engineering.
Sulfate СsSO 4 - a refractory and thermally stable compound that begins to evaporate noticeably only at temperatures above 1400°C. At the same time, all cesium salts are high.
Production and use of cesium
Cesium, like , does not form independent minerals and usually accompanies the more common elements of group I. Cesium occurs in nature as an impurity in the minerals Na and K. Pollucite CsNa ⋅ nH 2 is richest in cesium O. It is found in nature in a very dispersed state in the form of compounds accompanying other ores. For example, pollucite contains cesium along with sodium. The most labor-intensive part of their production is the enrichment and separation of fractions with rubidium and cesium from potassium, sodium, and lithium. Pure (Rb and Cs) are obtained from halogens by reduction with calcium metal at 700-800°C. They are obtained by the exchange reaction of molten chlorides with calcium metal:
The characteristics of cesium, its structural features and qualities characteristic of this element must be covered in a chemistry course. Not only schoolchildren, but also students of chemical specialties should know the specific features of this compound. The use of cesium is currently quite widespread - but in a specific area. This is largely due to the fact that at room temperature the element acquires a liquid state and is practically never found in its pure form. Currently, only five metals have similar qualities. The properties of cesium determine the interest of scientists in it and the possibilities for using the compound.
What is it about?
The soft metal cesium is designated in the periodic table by the symbol Cs. Its serial number is 55. The soft metal has a silvery, golden hue. Melting point - 28 degrees Celsius.
Cesium is an alkali metal whose qualities and characteristics are similar to potassium and rubidium. The structure of cesium causes increased reactivity. The metal can react with water at a temperature on the Celsius scale of 116 degrees below zero. The chemical element cesium has high pyrophoricity. It is mined from pollucite. Many radioactive isotopes of cesium (including the widely used cesium 137) are produced during the processing of waste generated during the operation of a nuclear reactor. Cesium 137 is the result of a fission reaction.
Historical background
The credit for the discovery of the electronic formula of cesium belongs to chemists from Germany, outstanding minds in their field, Kirchhoff and Bunsen. This event happened back in 1860. During that period, they began to actively change the newly invented flame spectroscopy technique, and in the course of their experiments, German scientists discovered a chemical element previously unknown to the public - cesium. At that moment, cesium was presented as a recipient, which is relevant for photocells and electron tubes.
Noticeable changes in the history of the definition and isolation of the element occurred in 1967. Taking into account Einstein's statement that the speed of light can be considered the most constant measuring factor inherent in our universe, it was decided to isolate cesium 133. This became an important point in expanding the range of applications of the chemical element cesium - in particular, it is used to make atomic clocks.
Cesium in the nineties
It was in the last decade of the last century that the chemical element cesium began to be used especially actively by humanity. It turned out that it is applicable in drilling fluids. It was also possible to find a fairly wide area of application in the chemical industries. It turned out that cesium chloride and its other derivatives can be used in the construction of complex electronics.
Then, in the nineties, special attention of the scientific community was focused on everything that could become a new word in atomic and nuclear energy. It was then that radioactive cesium was studied most thoroughly. It was revealed that the half-life of this component requires about three decades. Currently, radioactive isotopes of cesium are widely used in hydrology. Medicine and industry cannot do without them. The most widely used radioactive isotope is cesium 137. Cesium has a low level of toxic properties, while at the same time radioactive derivatives in high concentrations can harm nature and humans.
Physical parameters
The specificity of cesium (as well as cesium chloride and other derivatives of this metal) makes it possible to widely use the product. Among other elements, cesium has the lowest hardness index - only 0.2 units. In addition to softness, the metal is characterized by pliability. In its normal state, the correct electronic formula of cesium allows the formation of a pale-colored material that can change color to a darker one at the slightest contact with oxygen compounds.
The melting point of the metal is only 28 degrees Celsius, which means that the compound is one of the five metals that are in the liquid phase at or near room temperature. An even lower melting point than that of cesium has been recorded only for mercury. The boiling point of cesium is also low - only mercury has a lower boiling point. The characteristics of the electrochemical potential regulate the combustion of the metal - it creates violet shades or a blue color.
Compatibility and features
Cesium has the ability to react with the element. The element also forms cesium oxides. In addition, reactions with mercury mixtures and gold are observed. Features of interaction with other compounds, as well as temperature conditions at which reactions are possible, indicate possible intermetallic compositions. In particular, cesium is the starting component for the formation of photosensitive compounds. To do this, a metal reaction is carried out with the participation of thorium, antimony, gallium, and indium.
In addition to cesium oxide, chemists are also interested in the results of interaction with a number of alkaline elements. At the same time, it must be taken into account that the metal cannot react with lithium. Each of the cesium alloys has its own shade. Some mixtures are black-violet compounds, others have a golden hue, and others are almost colorless but have a distinct metallic luster.
Chemical features
The most pronounced feature of cesium is its pyrophoricity. In addition, the attention of scientists is attracted by the electrochemical potential of the metal. Cesium can spontaneously combust right in the air. When interacting with water, an explosion occurs, even if the reaction conditions assumed low temperatures. Cesium differs noticeably in this regard from the first group of the periodic chemical table. When cesium and water interact in solid form, a reaction also occurs.
It was found that the half-life of cesium lasts about three decades. The material was recognized as dangerous due to its characteristics. To work with cesium, it is necessary to create an atmosphere of an inert gas. At the same time, an explosion upon contact with water with equal amounts of sodium and cesium in the second case will be noticeably weaker. Chemists explain this by the following feature: when cesium comes into contact with water, an instant explosive reaction occurs, that is, there is not a sufficiently long time period left for the accumulation of hydrogen. The optimal method for storing cesium is in sealed containers made of borosilicate compounds.
Cesium: in compounds
Cesium in compounds acts as a cation. There are many different anions with which the reaction to form a compound is possible. Most cesium salts are colorless unless the coloration is due to an anion. Simple salts are hygroscopic, although to a lesser extent than other light alkali metals. Many are soluble in water.
They have a relatively low degree of solubility. It has found quite a wide application in industry. For example, aluminum-cesium sulfate is actively used in ore purification plants due to its low solubility with water.
Cesium: unique and useful
Visually, this metal is similar to gold, but is slightly lighter than the most popular noble metal. If you take a piece of cesium in your hand, it will quickly melt, and the resulting substance will be mobile and slightly change color - closer to silver. In the molten state, cesium perfectly reflects light rays. Of the alkali metals, cesium is considered the heaviest, but at the same time it has the lowest density.
The history of the discovery of cesium contains references to the Durchheim source. It was from here that a water sample was sent for laboratory testing. During the analysis of the constituent components, special attention was paid to solving the question: which element provides the healing qualities of the liquid? The German scientist Bunsen decided to use the method of spectral analysis. It was then that two unexpected blue lines appeared, not typical of compounds known at that time. It was the color of these stripes that helped scientists choose a name for the new component - sky blue in Latin sounds like “cesium”.
Where can I find you?
As was revealed during long-term testing, cesium is a trace element that is extremely rare in natural conditions. Thus, conducting a comparative analysis of the content of rubidium and cesium in the planet’s crust, scientists discovered that the latter is hundreds of times less. An approximate estimate of the concentration gave an indicator of 7*10(-4)%. No other less sensitive method than spectroscopy could simply detect such a rare compound. This explains the fact that previously scientists did not even suspect the existence of cesium.
It has now been found that cesium is more common in rocks extracted from mountains. Its concentration in this material does not exceed thousandths of a percent. Categorically small quantities were recorded in sea waters. The concentration level in lithium and potassium mineral compounds reaches tenths of a percent. Most often it can be detected in lepidolite.
When comparing the distinctive features of cesium and rubidium, as well as other elements that are extremely rare, it was possible to reveal that cesium is characterized by the formation of unique minerals, which other compounds are not capable of. This is how pollucite, rodicite, and avogadrite are obtained.
Rodicite, as scientists have found, is extremely rare. Likewise, avogadrite is very difficult to find. Pollucite is somewhat more common, with small deposits found in a number of cases. They have very low power, but contain cesium in an amount of 20-35 percent of the total mass. The most important, from the public's point of view, pollucites were discovered in the American subsoil and in Russia. There are also Swedish and Kazakh developments. It is known that pollucite was found in the southwest of the African continent.
Work continues
It is no secret that discovering an element and obtaining it in its pure form are two completely different tasks, although they are interconnected. When it became clear that cesium was very rare, scientists began to develop techniques for synthesizing the metal in the laboratory. At first it seemed that this was a completely impossible task if we used the means and technology available at that time. Over the years, Bunsen was unable to isolate cesium metal in its pure form. It was only two decades later that advanced chemists were finally able to solve this problem.
The breakthrough occurred in 1882, when Setterberg from Sweden electrolyzed a mixture consisting of four parts cesium cyanide, to which one part barium was mixed. The latter component was used to make the melting point lower. Cyanide, as scientists already knew at this point, was a very dangerous component. At the same time, contamination was formed due to barium, which did not make it possible to obtain a more or less satisfactory amount of cesium. It was clear that the technique required significant improvements. A good proposal in this area was submitted for discussion to the scientific community by Beketov. It was then that cesium hydroxide attracted attention. If this compound is restored by using metallic magnesium, increasing the heat and using a hydrogen current, a slightly better result can be achieved than that proven by the Swedish chemist. However, real experiments have shown that the yield is half that calculated in theory.
What's next?
Cesium continued to be the focus of attention of the international chemical scientific community. In particular, the French scientist Axpil devoted a lot of effort and time to him in his research. In 1911, he proposed a radically new approach to the issue of extracting pure cesium. It was necessary to carry out the reaction in a vacuum, metal chloride was taken as the starting material, and calcium metal was used to restore it.
Such a reaction, as experiments have shown, occurs almost to completion. To achieve a sufficient effect, you must use a special device. In laboratories, they usually resort to refractory glass or use quartz containers. The device must have an extension. The pressure inside is maintained at about 0.001 mmHg. Art. For a successful reaction, it is necessary to ensure that the container is heated to 675 degrees Celsius. This releases cesium, which evaporates almost immediately. The pairs move into the process intended for this purpose. But potassium chloride mainly settles directly in the reactor. Under given conditions, the volatility of this salt is so low that it can be ignored altogether, since this compound has a characteristic melting point of 773 degrees (on the same Celsius scale). This means that the sediment can melt if the container is overheated by one hundred degrees relative to what was intended. To achieve the most effective results, it is necessary to repeat the distillation process. To do this, create a vacuum. The output will be ideal cesium metal. Currently, the described method is most widely used and is considered optimal for obtaining the compound.
Activity and reactions
In the course of numerous studies, scientists were able to determine that cesium has amazing activity that is not normally characteristic of metals. Upon contact with air, combustion occurs, which leads to the release of superoxide. Oxide can be achieved by limiting the access of oxygen to the reagents. There is a possibility of formation of suboxides.
If cesium comes into contact with phosphorus, sulfur, or halogen, this provokes an explosive reaction. The explosion is also accompanied by a reaction with water. Using a crystallizer or glass, you may encounter the container literally falling into pieces. A reaction with ice is also possible if the temperature on the Celsius scale is not lower than 116 degrees. As a result of this reaction, hydrogen and hydroxide are produced.
Hydroxide: features
While studying the reaction products produced by cesium, chemists discovered that the resulting hydroxide is a very strong base. When interacting with it, you must remember that at high concentrations this compound can easily destroy glass even without additional heating. But when the temperature rises, the hydroxide easily melts nickel, iron, and cobalt. The effect on corundum and platinum will be similar. If oxygen takes part in the reaction, cesium hydroxide extremely quickly destroys silver and gold. If you limit the supply of oxygen, the process proceeds relatively slowly, but still does not stop. Rhodium and several alloys of this compound are resistant to cesium hydroxide.
Use wisely
Not only cesium, but also compounds known based on this metal are currently used very widely. Without them it is impossible to imagine the design of radio engineering; they are also indispensable in electronics. Cesium compounds and variations are actively used in chemistry, industry, ophthalmology, and medicine. Cesium has not been ignored in the development of technologies applicable in space, as well as nuclear energy.
It is now common to use cesium in the construction of solar cells. Bromide and iodide of this metal are necessary to create infrared vision systems. Industrially produced single crystals can be used as detector elements that allow recording ionizing radiation. Some cesium-based compounds are actively used as catalysts in industrial processes. This is necessary when creating ammonia, forming and producing butadiene.
Radiation and cesium
The isotope cesium 137 attracts the greatest attention of scientists. It belongs to the category of beta emitters. Currently, this element is indispensable in the process of sterilization of food and medicinal compounds. It is customary to resort to it in the treatment of malignant neoplasms. Modern approaches have made it possible to use the element in gamma flaw detection. Level sensors and also current sources are designed on its basis. The 137th isotope was released into the environment in very large quantities after the accident at the Chernobyl nuclear power plant. It is this that is one of the most important factors of pollution after this disaster.
However, 137 is not the only radioactive isotope of cesium that has found application in modern industry. Thus, atomic clocks are created using the cesium 133 isotope. Currently, this is the most accurate device that allows you to control the passage of time. One second, as modern scientists have found out through high-precision research, is 9192631770 periods of radiation. This allows the atom of the cesium 133 isotope to be used as a standard for determining frequency and time.
DEFINITION
Cesium located in the sixth period of group I of the main (A) subgroup of the Periodic table.
Belongs to the family s-elements. Metal. Designation - Cs. Serial number - 55. Relative atomic mass - 132.95 amu.
Electronic structure of the cesium atom
A cesium atom consists of a positively charged nucleus (+55), inside of which there are 55 protons and 78 neutrons, and 55 electrons move around in six orbits.
Fig.1. Schematic structure of the cesium atom.
The distribution of electrons among orbitals is as follows:
55Cs) 2) 8) 18) 18) 8) 1 ;
1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 2 4p 6 4d 10 5s 2 5p 6 6s 1 .
The outer energy level of the cesium atom contains 1 electron, which is a valence electron. There is no excited state. The energy diagram of the ground state takes the following form:
The valence electron of a cesium atom can be characterized by a set of four quantum numbers: n(main quantum), l(orbital), m l(magnetic) and s(spin):
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Sublevel |
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Examples of problem solving
EXAMPLE 1
| Exercise | The atom of the element manganese corresponds to the abbreviated electronic formula:
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| Solution | We will take turns deciphering the abbreviated electronic formulas to discover the one that corresponds to the manganese atom in the ground state. The serial number of this element is 25. Let's write down the electronic configuration of argon: 18 Ar1 s 2 2s 2 2p 6 3s 2 3p 6 . Then, the complete ionic formula will look like: 1s 2 2s 2 2p 6 3s 2 3p 6 3d 5 4s 2 . The total number of electrons in the electron shell coincides with the element's atomic number in the Periodic Table. It is equal to 25. Manganese has this serial number. |
| Answer | Option 1 |
