Reactor named “LB” and tellurium The reactor was named “AD” by its scientific supervisor A.P. Aleksandrov. The reactor was designed at the famous artillery plant No. 92 in Gorky. It was here that during the Great Patriotic War the best guns were fired, more than 100 thousand in total. well and

Tellus, Tellurium

Tellus, Tellura (Roman) - “mother earth” - the ancient Roman goddess of the earth and its productive forces (Mother Earth, Terra Mater). T. was identified with Gaia and was considered the goddess of life and the underworld, since the earth receives the dead. As a fertility goddess and patroness

Oxides

Tellurium – chemical element belonging to the 16th group, located in the periodic table, atomic number 52 and designated by the Latin Te - special identification. The element belongs to the metalloids. Tellurium formula — 4d10 5s2 5p4.

Tellurium - element having a white-silver tint and a metallic luster and fragile structure. At high temperatures, like many metals, tellurium becomes ductile.

Origin of tellurium

The element was discovered in gold mines in the mountains of Transylvania. Humanity knows at least one hundred minerals containing tellurium. In particular, these are silver, gold, copper and zinc. There are various tellurium compounds, for example, these are some types of ocher. In its pure form, in one deposit you can find selenium, tellurium and sulfur, which indicates the possibility of the element being native.

All of the minerals mentioned are more often found in the same deposit with silver, lead and bismuth. In industrial settings, for the most part tellurium is isolated chemically from other metals, despite the fact that its main minerals are quite common. In particular, it is contained in sufficient quantities in chalcopyrite, which is part of nickel-copper and copper pyrite ores.

Additionally, it can be found in, molybdenite and galena, it is also found in copper ores, polymetallic deposits and lead-zinc deposits. These minerals also contain sulfide and antimony rocks containing cobalt and mercury.

Mostly in industry, tellurium is extracted from sludge, which is formed by the electrolytic refining of copper and lead. During processing, the sludge is burned, and the burnt residues contain a certain tellurium content. To isolate the required element, the cinders are washed with hydrochloric acid.

To separate the metal from the resulting acid solution, sulfur dioxide must be passed through it. Obtained in this way tellurium oxide, is processed with coal to obtain a pure element from it. For its further purification, a chlorination procedure is used.

This produces tetrachloride, which must be purified by distillation or rectification. Next, it is hydrolyzed, and the resulting tellurium hydroxide is reduced by hydrogen.

Applications of tellurium

This metal is used in the manufacture of many different materials (copper, lead, iron), so the metallurgy industry is its main consumer. Tellurium makes stainless steel and copper more workable. Also, adding this element to malleable cast iron gives it the positive properties of gray cast iron.

Its casting qualities and machinability are improved. It is able to significantly improve the physical properties of lead, reducing negative corrosion from sulfuric acid during its processing.

Tellurium is widely used in semiconductor devices and electronics. In particular, it is used to produce solar cells. The use of tellurium opens up broad prospects in the application of these advanced technologies. The percentage of production of such equipment has increased significantly in recent years. This led to a noticeable increase in the turnover of tellurium on the world market.

The metal is used, including in space technological developments, in particular, these are alloys with the addition of tellurium, which have unique properties. They are used in technologies for detecting radiation left by spacecraft.

For this reason, the expensive alloy is largely in demand in the military industry, for tracking the enemy in outer space. In addition to this mixture selenium – tellurium is part of the delay powder in detonator caps for explosive devices produced by military factories.

Various tellurium compounds are used in the production of semiconductor compounds with a multilayer structure. Many compounds that include tellurium exhibit remarkable superconductivity.

Tellurium also works for the benefit of ordinary people. In particular, metal oxide is used in the production of compact discs to create a rewritable thin layer on them. It is also present in some microcircuits, for example, those produced by Intel. Bismuth telluride is included in many thermoelectric devices and infrared sensors.

This metal is also used when painting ceramic products. In the manufacture of fiberglass for information communications (television, Internet, etc.), the participation of tellurium in cable production is based on the positive property of tellurides and selenides to increase optical refraction when added to glass.

Vulcanization of rubber also involves the use of substances close to metal - selenium or sulfur, which can be replaced, if possible, by tellurium. Rubber with its addition will demonstrate much better qualities. Tellurium has also found its niche in medicine - it is used in the diagnosis of diphtheria.

Tellurium price

In terms of consumption of this rare earth metal in the world, China is in first place, Russia is in second, and the USA is in third. Total consumption is 400 tons of metal per year. Tellurium is usually sold in the form of powder, rods or.

Due to the small volumes of production, due to its relatively small content in rocks, the price of tellurium is quite high. Approximately, if you do not take into account the constant price hikes for tellurium, buy It can be sold on the world market for $200-300 per kilogram of metal. The price also depends on the degree of purification of the metal from unwanted impurities.

But, despite the inaccessibility of this unique element, there is always considerable demand for it, with constant growth trends. Every year the range of areas requiring the use of tellurium and its compounds is expanding.

It is easy to follow the trend of rising prices for tellurium by comparing prices at the beginning of 2000, when it was $30 per 1 kg, and ten years later, when it reached $350. And despite the fact that a year later it still fell, there is a serious tendency for prices to rise, due to a fall in tellurium production volumes.

The fact is that the tellurium market directly depends on the volume of production, since tellurium is one of the by-products during its extraction. At the moment, the copper market has significantly reduced its turnover, and new technologies for its production have appeared, the features of which will significantly affect the volume of additional tellurium produced.

This will certainly affect its supplies, and naturally prices. According to estimates, a new price hike is expected in a couple of years. Despite the fact that tellurium has certain analogues in industry, they do not have such valuable properties.

This situation on the world market is not at all beneficial for many manufacturers whose production involves tellurium. In particular, these are manufacturers of solar panels, whose products have been gaining increasing popularity in recent years.

The oxygen subgroup, or chalcogens, is the 6th group of the periodic table D.I. Mendelian, including the following elements: O;S;Se;Te;Po. The group number indicates the maximum valency of the elements in this group. The general electronic formula of chalcogens is: ns2np4– on the outer valence level, all elements have 6 electrons, which rarely give up and more often accept the 2 missing ones until the electron level is completed. The presence of the same valence level determines the chemical similarity of chalcogens. Characteristic oxidation states: -1; -2; 0; +1; +2; +4; +6. Oxygen exhibits only -1 – in peroxides; -2 – in oxides; 0 – in a free state; +1 and +2 – in fluorides – O2F2, ОF2 because it does not have a d-sub-level and electrons cannot be separated, and the valence is always 2; S – everything except +1 and -1. In sulfur, a d-sublevel appears and electrons from 3p and 3s in the excited state can be separated and go to the d-sublevel. In the unexcited state, the valency of sulfur is 2 in SO, 4 in SO2, 6 in SO3. Se +2; +4; +6, Te +4; +6, Po +2; -2. The valencies of selenium, tellurium and polonium are also 2, 4, 6. The values ​​of oxidation states are reflected in the electronic structure of the elements: O – 2s22p4; S – 3s23p4; Se – 4s24p4; Te – 5s25p4; Po – 6s26p4. From top to bottom, with an increase in the external energy level, the physical and chemical properties of chalcogens naturally change: the atomic radius of the elements increases, the ionization energy and electron affinity, as well as electronegativity decrease; Non-metallic properties decrease, metallic properties increase (oxygen, sulfur, selenium, tellurium are non-metals), polonium has a metallic luster and electrical conductivity. Hydrogen compounds of chalcogens correspond to the formula: H2R: H2О, H2S, H2Sе, H2Те – chalc hydrogens. Hydrogen in these compounds can be replaced by metal ions. The oxidation state of all chalcogens in combination with hydrogen is -2 and the valency is also 2. When hydrogen chalcogens are dissolved in water, the corresponding acids are formed. These acids are reducing agents. The strength of these acids increases from top to bottom, as the binding energy decreases and promotes active dissociation. Oxygen compounds of chalcogens correspond to the formula: RO2 and RO3 – acid oxides. When these oxides are dissolved in water, they form the corresponding acids: H2RO3 and H2RO4. In the direction from top to bottom, the strength of these acids decreases. Н2RO3 – reducing acids, Н2RO4 – oxidizing agents.

Oxygen - the most common element on Earth. It makes up 47.0% of the mass of the earth's crust. Its content in the air is 20.95% by volume or 23.10% by mass. Oxygen is part of water, rocks, many minerals, salts, and is found in proteins, fats and carbohydrates that make up living organisms. In laboratory conditions, oxygen is obtained: - decomposition when heating berthollet salt (potassium chlorate) in the presence of a catalyst MnO2: 2KClO3 = 2KCl + 3O2 - decomposition when heating potassium permanganate: 2KMnO4 = K2MnO4 + MnO2 + O2 This produces very pure oxygen. You can also obtain oxygen by electrolysis of an aqueous solution of sodium hydroxide (nickel electrodes); The main source of industrial oxygen production is air, which is liquefied and then fractionated. First, nitrogen is released (boiling point = -195°C), and almost pure oxygen remains in the liquid state, since its boiling point is higher (-183°C). A widely used method for producing oxygen is based on the electrolysis of water. Under normal conditions, oxygen is a colorless, tasteless and odorless gas, slightly heavier than air. It is slightly soluble in water (31 ml of oxygen dissolves in 1 liter of water at 20°C). At a temperature of -183°C and a pressure of 101.325 kPa, oxygen turns into a liquid state. Liquid oxygen is bluish in color and is drawn into a magnetic field. Natural oxygen contains three stable isotopes 168O (99.76%), 178O (0.04%) and 188O (0.20%). Three unstable isotopes were obtained artificially - 148O, 158O, 198O. To complete the outer electron level, the oxygen atom lacks two electrons. By vigorously taking them, oxygen exhibits an oxidation state of -2. However, in compounds with fluorine (OF2 and O2F2), the common electron pairs are shifted towards fluorine, as a more electronegative element. In this case, the oxidation states of oxygen are respectively +2 and +1, and fluorine is -1. The oxygen molecule consists of two O2 atoms. The chemical bond is covalent nonpolar. Oxygen forms compounds with all chemical elements except helium, neon and argon. It reacts directly with most elements, except halogens, gold and platinum. The rate of oxygen reaction with both simple and complex substances depends on the nature of the substances, temperature and other conditions. An active metal such as cesium ignites spontaneously in atmospheric oxygen already at room temperature. Oxygen reacts actively with phosphorus when heated to 60°C, with sulfur - up to 250°C, with hydrogen - more than 300°C, with carbon (in the form of coal and graphite) - at 700-800°C.4P+5O2=2P2O52H2+O2=2H2O S+O2=SO2 C+O2=CO2 When complex substances burn in excess oxygen, oxides of the corresponding elements are formed: 2H2S+3O2=2S02+2H2OC2H5OH+3O2 =2CO2+3H2OCH4+2O2=CO2+2H20 4FeS2+11O2=2Fe2O3+8SO2 The reactions considered are accompanied by the release of both heat and light. Such processes involving oxygen are called combustion. In terms of relative electronegativity, oxygen is the second element. Therefore, in chemical reactions with both simple and complex substances, it is an oxidizing agent, because accepts electrons. Combustion, rusting, rotting and respiration occur with the participation of oxygen. These are redox processes. To accelerate oxidation processes, instead of ordinary air, oxygen or air enriched with oxygen is used. Oxygen is used to intensify oxidative processes in the chemical industry (production of nitric and sulfuric acids, artificial liquid fuels, lubricating oils and other substances). The metallurgical industry consumes quite a lot of oxygen. Oxygen is used to obtain high temperatures. The temperature of the oxygen-acetylene flame reaches 3500°C, the oxygen-hydrogen flame reaches 3000°C. In medicine, oxygen is used to facilitate breathing. It is used in oxygen devices when performing work in difficult-to-breathe atmospheres.

Sulfur- one of the few chemical elements that have been used by humans for several millennia. It is widespread in nature and is found both in the free state (native sulfur) and in compounds. Minerals containing sulfur can be divided into two groups - sulfides (pyrites, sparkles, blende) and sulfates. Native sulfur is found in large quantities in Italy (the island of Sicily) and the USA. In the CIS, there are deposits of native sulfur in the Volga region, in the states of Central Asia, in the Crimea and other areas. Minerals of the first group include lead luster PbS, copper luster Cu2S, silver luster - Ag2S, zinc blende - ZnS, cadmium blende - CdS, pyrite or iron pyrite - FeS2, chalcopyrite - CuFeS2, cinnabar - HgS. Minerals of the second group include gypsum CaSO4 2H2O, mirabilite (Glauber's salt) - Na2SO4 10H2O, kieserite - MgSO4 H2O. Sulfur is found in the bodies of animals and plants, as it is part of protein molecules. Organic sulfur compounds are found in oil. Receipt 1. When obtaining sulfur from natural compounds, for example from sulfur pyrites, it is heated to high temperatures. Sulfur pyrite decomposes to form iron (II) sulfide and sulfur: FeS2=FeS+S 2. Sulfur can be obtained by oxidation of hydrogen sulfide with a lack of oxygen according to the reaction: 2H2S+O2=2S+2H2O3. Currently, it is common to obtain sulfur by reducing sulfur dioxide SO2 with carbon, a by-product during the smelting of metals from sulfur ores: SO2 + C = CO2 + S4. Exhaust gases from metallurgical and coke ovens contain a mixture of sulfur dioxide and hydrogen sulfide. This mixture is passed at high temperature over a catalyst: H2S+SO2=2H2O+3S Sulfur is a lemon-yellow, hard, brittle substance. It is practically insoluble in water, but is highly soluble in carbon disulfide CS2 aniline and some other solvents. It conducts heat and electric current poorly. Sulfur forms several allotropic modifications: Natural sulfur consists of a mixture of four stable isotopes: 3216S, 3316S, 3416S, 3616S. Chemical properties The sulfur atom, having an incomplete external energy level, can attach two electrons and exhibit an oxidation state of -2. Sulfur exhibits this oxidation state in compounds with metals and hydrogen (Na2S, H2S). When electrons are given away or withdrawn to an atom of a more electronegative element, the oxidation state of sulfur can be +2, +4, +6. In the cold, sulfur is relatively inert, but with increasing temperature its reactivity increases. 1. With metals, sulfur exhibits oxidizing properties. These reactions produce sulfides (does not react with gold, platinum and iridium): Fe+S=FeS
2. Under normal conditions, sulfur does not interact with hydrogen, and at 150-200°C a reversible reaction occurs: H2 + S«H2S 3. In reactions with metals and hydrogen, sulfur behaves as a typical oxidizing agent, and in the presence of strong oxidizing agents it exhibits reducing reactions properties.S+3F2=SF6 (does not react with iodine)4. The combustion of sulfur in oxygen occurs at 280°C, and in air at 360°C. In this case, a mixture of SO2 and SO3 is formed: S+O2=SO2 2S+3O2=2SO35. When heated without air access, sulfur directly combines with phosphorus and carbon, exhibiting oxidizing properties: 2P+3S=P2S3 2S + C = CS26. When interacting with complex substances, sulfur behaves mainly as a reducing agent:

7. Sulfur is capable of disproportionation reactions. Thus, when sulfur powder is boiled with alkalis, sulfites and sulfides are formed: Sulfur is widely apply in industry and agriculture. About half of its production is used to produce sulfuric acid. Sulfur is used to vulcanize rubber: in this case, rubber turns into rubber. In the form of sulfur color (fine powder), sulfur is used to combat diseases of vineyards and cotton. It is used to produce gunpowder, matches, and luminous compounds. In medicine, sulfur ointments are prepared to treat skin diseases.

31 Elements of IV A subgroup.

Carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb) are elements of group 4 of the main subgroup of PSE. On the outer electron layer, the atoms of these elements have 4 electrons: ns2np2. In a subgroup, as the atomic number of an element increases, the atomic radius increases, non-metallic properties weaken, and metallic properties increase: carbon and silicon are non-metals, germanium, tin, lead are metals. Elements of this subgroup exhibit both positive and negative oxidation states: -4; +2; +4.

--------------------->(metallic properties increase)

Discovered by F. Müller in 1782. The name of the element comes from the Latin tellus, genitive telluris, Earth (the name was proposed by M. G. Klaproth, who isolated the element as a simple substance and determined its most important properties).

Receipt:

In nature, it exists as a mixture of 8 stable isotopes (120, 122-126, 128, 130). The content in the earth's crust is 10 -7%. The main minerals are altaite (PbTe), tellurobismuthite (Bi 2 Te 3), tetradymite (Bi 2 Te 2 S), found in many sulfide ores.
It is obtained from copper production sludge by leaching with a NaOH solution in the form of Na 2 TeO 3 , from which tellurium is separated electrolytically. Further purification is by sublimation and zone melting.

Physical properties:

Compact tellurium is a silvery-gray substance with a metallic luster, having a hexagonal crystal lattice (density 6.24 g/cm 3, melting point - 450°C, boiling point - 990°C). From solutions it precipitates in the form of a brown powder; in vapor it consists of Te 2 molecules.

Chemical properties:

Tellurium is stable in air at room temperature; when heated, it reacts with oxygen. Interacts with halogens and reacts with many metals when heated.
When heated, tellurium is oxidized by water vapor to form tellurium(II) oxide and reacts with concentrated sulfuric and nitric acids. When boiled in aqueous solutions of alkalis, it disproportions similarly to sulfur:
8 Te + 6NaOH = Na 2 TeO 3 + 2Na 2 Te + 3H 2 O
In compounds it exhibits oxidation states -2, +4, +6, less often +2.

The most important connections:

Tellurium(IV) oxide Tellurium dioxide, TeO 2, is poorly soluble in water, an acidic oxide, reacts with alkalis to form telluric acid salts. Used in laser technology, a component of optical glasses.
Tellurium(VI) oxide, tellurium trioxide, TeO 3, yellow or gray substance, practically insoluble in water, decomposes when heated to form dioxide, reacts with alkalis. Obtained by the decomposition of telluric acid.
Telluric acid, H 2 TeO 3 , slightly soluble, prone to polymerization, therefore it usually represents a precipitate with variable water content TeO 2 *nH 2 O. Salts - tellurites(M 2 TeO 3) and polytellurites (M 2 Te 2 O 5, etc.), usually obtained by sintering carbonates with TeO 2, are used as components of optical glasses.
Telluric acid, H 6 TeO 6 , white crystals, highly soluble in hot water. A very weak acid, in solution it forms salts of the composition MH 5 TeO 6 and M 2 H 4 TeO 6. When heated in a sealed ampoule, metatelluric acid H 2 TeO 4 was also obtained, which in solution gradually turns into telluric acid. Salts - tellurates. It is also obtained by fusing tellurium(IV) oxide with alkalis in the presence of oxidizing agents, or by fusing telluric acid with carbonate or metal oxide. Alkali metal tellurates are soluble. They are used as ferroelectrics, ion exchangers, and components of luminescent compositions.
Hydrogen telluride, H 2 Te is a poisonous gas with an unpleasant odor, obtained by hydrolysis of aluminum telluride. A strong reducing agent, in solution it is quickly oxidized by oxygen to tellurium. In an aqueous solution, the acid is stronger than sulfur and hydrogen selenide. Salts - tellurides, usually obtained by the interaction of simple substances, alkali metal tellurides are soluble. Many p- and d-element tellurides are semiconductors.
Halides. Tellurium(II) halides, for example TeCl 2 , are known to be salt-like and, when heated and in solution, disproportionate into Te and Te(IV) compounds. Tellurium tetrahalides are solid substances that hydrolyze in solution to form telluric acid and easily form complex halides (for example, K2). TeF 6 hexafluoride, a colorless gas, unlike sulfur hexafluoride, is easily hydrolyzed, forming telluric acid.

Application:

Component of semiconductor materials; alloying additive for cast iron, steel, lead alloys.
World production (without the USSR) is about 216 tons/year (1976).
Tellurium and its compounds are toxic. MPC is about 0.01 mg/m3.

See also:
Tellurium // Wikipedia. . Update date: 12/20/2017. URL: http://ru.wikipedia.org/?oldid=89757888 (access date: 12/25/2017).
Discovery of elements and origin of their names. Tellurium //
URL: http://www.chem.msu.su/rus/history/element/Te.html