Tin element name. What is tin? Properties and uses of tin. Description of tin. Tin sulfide compounds

Tin or Stannum (lat.) is a low-melting, ductile metal with a silver-white color (see photo). The Latin name means “durable, resistant” and was originally the name given to the alloy with lead and silver. And the Slavic name, which has Baltic roots, simply means the color of the metal - white.

This element belongs to the seven most ancient metals. Already 6000 years ago, humanity was familiar with it. It was most widespread as part of bronze and was strategically important during the “Bronze Age” about 4,000 years ago. Money was printed from this composition until the 16th century, dishes and jewelry were made, and it was used as an anti-corrosion coating. Mentions of metal were found even on the pages of the Bible.

Occurs in nature in the form of minerals. The most common are cassiterite (river tin) and stanine (tin pyrite). Tin is extracted from them for industrial purposes: electronics, batteries, glass processing (it becomes impenetrable to the rays of an X-ray machine). Also, compounds of this element are used to make cans and substances that repel insects.

Tin has another remarkable ability - its presence in the composition of the materials of a musical instrument, which will distinguish this instrument with excellent purity of sound and melody.

The element was discovered in living organisms in 1923. When studying the remains of ancient people, it turned out that the tin content in the bones was 1000 times less than that of modern humans. This may be due to the fact that we can absorb it from the air. And the development of industry has led to the fact that about a quarter of a million tons end up in the atmosphere in the form of exhaust gases.

Action of tin

The effect of a macroelement on a living organism can hardly be called toxic; it is often used in the food industry. Its role is not fully understood. The element is found mainly in bones, and some of it is also found in the lungs, heart, kidneys, and intestines. And with age, the content in the lungs may increase, this is due to environmental influences.

To date, the following facts of biological effects are known:

participation in growth processes;
is part of the stomach enzyme gastrin;
actively participates in redox reactions;
Due to its concentration in bone tissue, it promotes their proper development and the development of the musculoskeletal system.

It can have a beneficial effect on the body only when it is contained in fatty acids. Mineral compounds can have a toxic effect.

Relatively recently, tin was used by doctors to treat many diseases - epilepsy, neuroses, helminthiasis, eczema, clouding of the cornea. The external use of tin chloride was mainly practiced. Fortunately, today progress has brought more effective and less toxic drugs without metal content.

Tin is a fairly chemically inactive element, so from this point of view it will not bring any particular benefit or harm. The only interactions observed are with copper and zinc. They mutually neutralize each other's action.

Daily norm

The daily macronutrient requirement ranges from 2 to 10 mg, depending on age and gender. Although our body enters about 50 mg per day only with food (and a dosage of 20 mg is considered toxic), poisoning will not occur. This is explained by the fact that our gastrointestinal tract is able to absorb only 3-5% of the total incoming amount. All other metal is simply excreted naturally through urine.

Lack of tin in the human body

A deficiency of a macroelement in the body occurs with a chronic intake of less than 1 mg per day. This process may be accompanied by hearing loss, weight loss due to loss of appetite, slowed growth, mineral imbalance, and hair loss (partial or complete pathology).

Such processes are quite rare, because Usually, the macronutrient intake from food is sufficient and is most often caused by digestive problems and difficulties with absorption.

Harm from excess tin intake

Employees of enterprises that use tin salts are mainly at risk of getting an excess of macronutrients: the production of plastics, pesticides, linoleum, etc. Due to the regular absorption of vapors and dust, lung diseases develop. Also at risk are people living dangerously close to highways (within half a kilometer) - they receive a high dose from exhaust gases. Tin in large quantities suppresses the content of magnesium, which can protect cells from tumors.

There is another source of high doses of the element - cans. During long-term storage, they begin to deteriorate, especially if the contents are rich in nitrates. Therefore, after opening such a jar, it is recommended to immediately transfer the products into glass. It is strictly prohibited to store canned food in open form.

The bodies of older people and children cannot quickly remove tin from the body, so it begins to accumulate. A very tiny dose is enough to cause poisoning.

There is an interesting theory from the story of the fall of the Roman Empire. Tin got into the wine, abundantly consumed by the ancient Romans, from dishes and caused health problems. Only in the seventh century were doctors able to determine the cause of the disease, but it was too late - the empire fell.

The complications that arise from excess tin are quite unpleasant. A dose of 2 grams of a macroelement is considered dangerous, but it is not lethal (this norm has not yet been determined). It can cause anemia, liver disease, respiratory tract disease, and nervous system disorders. A disease such as stannosis may develop - a severe cough accompanied by sputum production and shortness of breath.

But that’s not all – there are a lot of main symptoms of poisoning:

If tin is consumed in large doses over a long period of time, there is a risk of structural changes in chromosomes, which can lead to serious consequences at the genetic level.

When exposed to the central nervous system, this macroelement can cause depression. And children can be aggressive, lack interest in studying, playing, and reading.

Treatment is usually prescribed based on symptoms - diets, hepatoprotectors (liver protection), drugs containing copper and zinc. In case of critical poisoning, medications are administered that can bind and remove toxins - chelating substances.

What foods does it contain?

Products containing tin can be found of both animal and plant origin. The bulk comes from pig meat, beef, poultry, milk and its derivatives. Peas, sunflower seeds, potatoes, and beets can also provide some amount of the element. Other vegetables contain very small doses of tin.

In addition, we receive macronutrients from water and air every day. And don’t forget that frequent consumption of canned food can also supply the body with excess amounts of tin.

Some plants are capable of absorbing large amounts of the element from the environment. Therefore, you should be careful about products grown near highways and industrial zones.

Indications for use

Indications for prescribing a macronutrient are mainly used by homeopaths. They treat diseases such as:

bronchitis, lung diseases;
migraine;
pancreatitis;
small height and weight;
and also used as an anthelmintic.

It has been noticed that when taking small doses of medications containing tin, the patient’s mental state often changes - a good mood is replaced by irritability, melancholicity, and tearfulness. Therefore, such appointments are used in extremely rare cases.

Tin (lat. Stannum; designated by the symbol Sn) is an element of the main subgroup of the fourth group, the fifth period of the periodic table of chemical elements of D.I. Mendeleev, with atomic number 50. Belongs to the group of light metals. Under normal conditions, the simple substance tin is a ductile, malleable and fusible shiny metal of a silvery-white color. Tin forms two allotropic modifications: below 13.2 °C, α-tin (gray tin) with a cubic diamond-type lattice is stable; above 13.2 °C, β-tin (white tin) with a tetragonal crystal lattice is stable.

Story

Tin was known to man already in the 4th millennium BC. e. This metal was inaccessible and expensive, since products made from it are rarely found among Roman and Greek antiquities. There are mentions of tin in the Bible, the Fourth Book of Moses. Tin is (along with copper) one of the components of bronze (see History of copper and bronze), invented at the end or middle of the 3rd millennium BC. BC. Since bronze was the most durable metal and alloy known at that time, tin was a “strategic metal” during the entire “Bronze Age”, more than 2000 years (very approximately: 35-11 centuries BC).

origin of name
The Latin name stannum, related to the Sanskrit word meaning “steady, durable,” originally referred to an alloy of lead and silver, and later to another alloy imitating it, containing about 67% tin; by the 4th century, this word began to be used to refer to tin itself.
The word tin is common Slavic, having correspondences in the Baltic languages (cf. Lit. alavas, alvas - “tin”, Prussian alwis - “lead”). It is a suffix from the root ol- (cf. Old High German elo - “yellow”, Latin albus - “white”, etc.), so the metal is named by color.

Production

Application

1. Tin is used primarily as a safe, non-toxic, corrosion-resistant coating in its pure form or in alloys with other metals. The main industrial uses of tin are in tinplate (tinned iron) for food containers, in solders for electronics, in household piping, in bearing alloys, and in coatings of tin and its alloys. The most important alloy of tin is bronze (with copper). Another well-known alloy, pewter, is used to make tableware. Recently, there has been a revival of interest in the use of metal, since it is the most “ecologically friendly” among heavy non-ferrous metals. Used to create superconducting wires based on the intermetallic compound Nb 3 Sn.
2. Intermetallic compounds of tin and zirconium have high melting points (up to 2000 °C) and resistance to oxidation when heated in air and have a number of applications.
3. Tin is the most important alloying component in the production of structural titanium alloys.
4. Tin dioxide is a very effective abrasive material used to “finish” the surface of optical glass.
5. A mixture of tin salts - “yellow composition” - was previously used as a dye for wool.
6. Tin is also used in chemical current sources as an anode material, for example: manganese-tin element, mercury-tin oxide element. The use of tin in a lead-tin battery is promising; for example, at the same voltage, compared to a lead battery, a lead-tin battery has 2.5 times greater capacity and 5 times greater energy density per unit volume, its internal resistance is much lower.

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1 . Isthorium tin discovery

Tin (English Tin, French Etain, German Zinn) is one of the seven metals of antiquity. In Egypt, Mesopotamia and other countries of the ancient world, bronze was made from tin already in the 3rd millennium BC; tin was also used for making various household items, especially dishes. Most countries of the ancient world did not have rich tin ores. Tin was imported by sea from Spain, as well as from the Caucasus and Persia, and it often could not be distinguished from lead. The ancient Greek name for tin "kassiteros" is of eastern origin and is undoubtedly related to the Akkadian name for tin "ik-kasduru", the Assyrian "kazazatira" and the late Babylonian "kastera". The Latin name for tin (Stannum or Stagnum) came into use in Rome during the imperial period. It is believed that this word is related to the Sanskrit stha (to stand, to hold firm) or sthavan (firmly, steadfastly). However, the word Stagnum in Latin means “still water”, “pond”, “lake” and figuratively “sea”. In the Middle Ages, tin was sometimes considered a modification of lead and was called white (Plumbum album) or shiny (Plumbum candidum) lead in contrast to ordinary black lead (Plumbum nigrum). German Zinn (English Tin, French Etain) comes from the Old German zein - stick or plate. As for the Russian “tin” and the consonant Lithuanian “alwas” and Prussian “alwis”, representatives of the Indo-Germanic theory of the origin of languages believe that these names came from the Latin album, which appears in the name of the tin Plumbum album, just as the word Cuprum came from Aes cyprium. This word formation is very unreliable. In our opinion, the word tin or tin (Polish olow - lead) has a functional origin. The ancient Slavs had an intoxicating drink made from barley and ghee, called olovina or ol. Since even among the Romans, vessels for storing and maturing wine were made of lead, it can be assumed that tin was the name given to the material (lead) for making vessels intended for storing tin; the word tin also stands in connection with the name of another liquid body - oil (oleum).

2 . Radistribution in nature

Tin is a rare trace element; tin ranks 47th in terms of abundance in the earth's crust. The Clark content of tin in the earth's crust is, according to various sources, from 2·10?4 to 8·10?3% by mass. The main mineral of tin is cassiterite (tin stone) SnO 2, containing up to 78.8% tin. Much less common in nature is stannin (tin pyrite) - Cu 2 FeSnS 4 (27.5% Sn).

Place of Birth

The world's tin deposits are found in Southeast Asia, mainly in China, Indonesia, Malaysia and Thailand. There are also large deposits in South America (Bolivia, Peru, Brazil) and Australia.

In Russia, tin ore reserves are located in the Chukotka Autonomous Okrug (mine / village Valkumey, Iultin - mining was closed in the early 1990s), in the Primorsky Territory (Kavalerovsky district), in the Khabarovsk Territory (Solnechny district, Verkhnebureinsky district (Pravourmiyskoye deposit) ), in Yakutia (Deputatskoye deposit) and other areas.

3 . Fiphysical properties

Density: solid at 20°C - 7.3 g/cm; in the liquid state at the melting point - 6.98 g/cm;

Temperature: melting - 231.9°C; boiling point - 2600°C;

Linear expansion coefficient at a temperature of 20?100°C - 22.4*10?6 K?1;

Specific heat capacity: in the solid state at 20°C - 226 J/(kg*K); in the liquid state at the melting point - 268 J/(kg*K);

Thermal conductivity at 20°C - 65.8 W/(m*K);

Electrical resistivity at 20°C - 0.115 μOhm*m;

Specific electrical conductivity at 20°C - 8.69 MS/m;

Mechanical and technological properties of tin:

Elastic modulus 55 GPa at 0°C and 48 GPa at 100°C

Temporary tensile strength - 20 MPa;

Relative elongation - 80%;

Brinell hardness - 50 MPa;

Casting temperature - 260?300°C;

The simple substance tin is polymorphic. Under normal conditions, it exists in the form of a b-modification (white tin), stable above 13.2°C. White tin is a silvery-white, soft, ductile metal with a tetragonal unit cell, parameters a = 0.5831, c = 0.3181 nm. The coordination environment of each tin atom in it is an octahedron. The density of β-Sn is 7.228 g/cm 3 .

When cooled, for example, during frost outside, white tin turns into the b-modification (gray tin). Gray tin has the structure of diamond (cubic crystal lattice with parameter a = 0.6491 nm). In gray tin, the coordination polyhedron of each atom is a tetrahedron, coordination number 4. The phase transition of b-Sn to b-Sn is accompanied by an increase in specific volume by 25.6% (the density of b-Sn is 5.75 g/cm 3), which leads to to disintegrate tin into powder. In the old days, the scattering of tin products observed during severe cold weather was called the “tin plague.” As a result of this “plague,” the buttons on the soldiers’ uniforms, their buckles, mugs, and spoons fell apart, and the army could lose its combat effectiveness. (For more information about the “tin plague” see interesting facts about tin, link at the bottom of this page). White tin also turns into gray under the influence of ionizing radiation.

Due to the strong difference in the structures of the two modifications of tin, their electrical properties also differ. Thus, c-Sn is a metal, and b-Sn is a semiconductor. Below 3.72 K -Sn goes into a superconducting state. The standard electrode potential E°Sn 2+ /Sn is equal to?0.136 V, and E of the°Sn 4+ /Sn 2+ pair is 0.151 V.

4 . Heemic properties

At room temperature, tin, like its group neighbor germanium, is resistant to air or water. This inertness is explained by the formation of a surface film of oxides. Noticeable oxidation of tin in air begins at temperatures above 150°C:

tin chemical metal

When heated, tin reacts with most non-metals. In this case, compounds are formed in the oxidation state +4, which is more characteristic of tin than +2. For example:

Tin reacts slowly with concentrated hydrochloric acid:

Tin does not dissolve in dilute sulfuric acid, but reacts very slowly with concentrated sulfuric acid.

The composition of the reaction product of tin with nitric acid depends on the concentration of the acid. In concentrated nitric acid, tin acid is formed -SnO 2 ·nH 2 O (sometimes its formula is written as H 2 SnO 3). In this case, tin behaves like a non-metal:

When interacting with dilute nitric acid, tin exhibits the properties of a metal. As a result of the reaction, the salt tin(II) nitrate is formed:

When heated, tin, like lead, can react with aqueous solutions of alkalis. In this case, hydrogen is released and a hydroxo complex Sn (II) is formed, for example:

Tin hydride - stannan SnH 4 - can be obtained by the reaction:

This hydride is very unstable and slowly decomposes even at a temperature of 0°C.

The two oxides responsible for tin are SnO 2 (formed during the dehydration of tin acids) and SnO. The latter can be obtained by weakly heating tin (II) hydroxide Sn(OH) 2 in a vacuum:

When heated strongly, tin(II) oxide disproportionates:

When stored in air, SnO monoxide gradually oxidizes:

When hydrolyzing solutions of tin (IV) salts, a white precipitate is formed - the so-called -stannous acid:

Freshly obtained stannous acid dissolves in acids and alkalis:

During storage, stannous acid ages, loses water and turns into stannous acid, which is more chemically inert. This change in properties is associated with a decrease in the number of active HO-Sn groups when standing and their replacement with more inert bridging - Sn-O-Sn - bonds.

When a solution of Sn(II) salt is exposed to sulfide solutions, a precipitate of tin(II) sulfide precipitates:

This sulfide can be easily oxidized to SnS 2 with ammonium polysulfide solution:

The resulting disulfide SnS 2 dissolves in a solution of ammonium sulfide (NH 4) 2 S:

Tin tetravalent forms a large class of organotin compounds used in organic synthesis, as pesticides, and others.

5 . Byraying

During the production process, the ore-bearing rock (cassiterite) is crushed to particle sizes of an average of ~ 10 mm in industrial mills, after which cassiterite, due to its relatively high density and mass, is separated from the waste rock using the vibration-gravity method on dressing tables. In addition, the flotation method of ore enrichment/purification is used. In this way, it is possible to increase the tin content in the ore to 40-70%. Next, the concentrate is roasted in oxygen to remove impurities of sulfur and arsenic. The resulting tin ore concentrate is smelted in furnaces. During the smelting process, it is restored to a free state through the use of charcoal in the reduction, the layers of which are laid alternately with layers of ore, or aluminum (zinc) in electric furnaces: SnO 2 + C = Sn + CO 2. Particularly pure tin of semiconductor purity is prepared by electrochemical refining or the zone melting method.

6 . Cotin unity

Native elements, alloys and intermetallic compounds

Although the concentrations of these minerals in rocks are very low, they are distributed in a wide range of genetic formations. Among the native forms, along with Sn, Fe, Al, Cu, Ti, Cd, etc. were identified, not counting the already known native platinoids, gold and silver. These same elements also form various alloys with each other: (Cu + Sn + Sb), (Pb + Sn + Sb), etc., as well as solid solutions. Among the intermetallic compounds, stistaite SnSb, atakite (Pd, Pt) 3 Sn, shtumyrlite Pt (Sn, Bi), zvyagintsevite (Pd, Pt) 3 (Pb, Sn), taymyrite (Pd, Cu, Pt) 3 Sn and others were identified.

The following forms of occurrence of tin and other elements are found in various geological formations:

1. Group of intrusive and effusive igneous rocks: traps, picrites of the Siberian platform, hyperbasites and gabbroids of Kamchatka, kimberlites of Yakutia, lamproites of Aldan, etc.; granitoids of Primorye, Far East, Tien Shan.

2. A group of metasomatically and hydrothermally altered rocks: copper-nickel ores of the Siberian platform, gold deposits of the Urals, the Caucasus, Uzbekistan, etc.

3. Group of modern ore formation: pelagic sediments of the Pacific Ocean, products of the Great Fissure Tolbachik eruption, Uzon hydrothermal system in Kamchatka, etc.

4. A group of sedimentary rocks of various origins.

Tin oxide compounds

The best known form is the main mineral tin - cassiterite SnO 2, which is a compound of tin and oxygen. According to nuclear gamma resonance spectroscopy, the mineral contains Sn +4.

Cassiterite

Cassiterite (from the Greek kassiteros - tin) is the main ore mineral for the production of tin. Theoretically contains 78.62% Sn. It forms separate secretions, grains, continuous massive aggregates, in which the grains of the mineral reach a size of 3 - 4 mm and even more.

Density 6040-7120 kg/m³ (lowest for light-colored cassiterites).

· Hardness 6S.

· Gloss - matte, on the edges - diamond.

· Cleavage is imperfect.

· Conchoidal fracture.

The main forms of cassiterite isolation:

1. microinclusions in other minerals;

2. accessory mineral deposits in rocks and ores;

3. solid or disseminated ores: needle-shaped radial aggregates (Primorye), colomorphic and cryptocrystalline segregations and accumulations (Primorye); The crystalline form is the main form of cassiterite isolation. In Russia, cassiterite deposits are found in the Northeast, Primorye, Yakutia, and Transbaikalia; abroad - in Malaysia, Thailand, Indonesia, China, Bolivia, Nigeria, etc.

Hydroxide compounds

A secondary place is occupied by tin hydroxide compounds, which can be considered as salts of polytin acids. These include the mineral succulite Ta 2 Sn 2 +2 O; solid solution of tin in magnetite of the type Fe 2 SnO 4 or Fe 3 SnO 3 (Brettstein Yu.S., 1974; Voronina L.B. 1979); “varlamovit” is a product of stannine oxidation; it is believed to be a mixture of amorphous and semi-amorphous Sn compounds, metatinic acid, a polycondensed phase and a hydrocassiterite phase. Hydrated oxidation products are also known - hydromartite 3SnOxH 2 O; mushistonite (Cu, Zn, Fe) Sn(OH) 6 ; copper hydrostannate CuSn(OH) 6, etc.

Silicates

A large group is known tin silicates, represented by malayaite CaSn; pabstite Ba (Sn, Ti) Si 3 O 9 , stocazite Ca 2 Sn 2 Si 6 O 18 x4H 2O, etc. Malayaite even forms industrial accumulations.

Spinelids

Other oxide compounds are also known spinels, for example, the mineral nigerite Sn 2 Fe 4 Al 16 O 32 (Peterson E.U., 1986).

Tin sulfide compounds

Includes various tin and sulfur compounds. This is the second most industrially important group of mineral forms of tin. The most important of these is stannine, the second most important mineral. In addition, frankeite Pb 5 Sn 3 Sb 2 S 14, herzenbergite SnS, berndtite SnS 2, tillite PbSnS 2 and kesterite Cu 2 ZnSnS 4 are noted. More complex sulfide compounds of tin with lead, silver, and copper, which are mainly of mineralogical significance, have also been identified. The close connection of tin with copper determines the frequent presence of chalcopyrite CuFeS 2 deposits in tin ore deposits with the formation of the cassiterite - chalcopyrite paragenesis.

Stannine (from Latin stannum - tin), tin pyrite, a mineral from the class of sulfides with the general formula of the form Cu 2 FeSnS 4. It follows from the chalcopyrite formula by replacing one Fe atom with Sn. Contains 29.58% Cu, 12.99% Fe, 27.5% Sn and 29.8 S, as well as impurities of Zn, Sb, Cd, Pb and Ag. A widespread mineral in tin ore deposits in Russia. In a number of deposits in Russia (Primorye, Yakutia) and Central Asia (Tajikistan), it is an essential element of sulfide minerals and often, together with varlamovite, makes up 10-40% of total tin. Often forms impregnations in ZnS sphalerite and chalcopyrite. In many cases, stannine decomposition phenomena with the release of cassiterite are observed.

7 . Mehmethods of analysis

Determination of tin by back titration with a copper salt solution in the presence of PAN

Reagents

EDTA, 0.1 M solution. Copper nitrate, 0.1 M solution. Acetate buffer solution, pH = 5. Hexamine, 20% aqueous solution.

Thymol blue.

Progress of determination. 30 ml of EDTA solution and a little thymol blue indicator are added to the test solution, strongly acidified with hydrochloric acid, and heated to a boil. Slowly add a 20% solution of hexamine drop by drop with stirring and constant boiling until the solution turns yellow. Then add 20 ml of buffer solution with

pH = 5, dilute to 200 ml and cool to room temperature. After adding a small amount of indicator, PAN is titrated with a solution of copper nitrate until the color of the solution turns purple and finally titrated with a solution of EDTA until the color changes from violet to green-yellow.

Determination of tin with pyrocatechol violet back titration with zinc acetate solution

Reagents

EDTA, 0.05 M solution. Zinc acetate, 0.05 M solution. Acetic acid. Ammonia, solution 1: 1. Sodium acetate, 3 M solution. Pyrocatechol violet. Thymol blue.

Progress of determination. To a strongly acidic test solution containing up to 150 mg of tin, add 30.00 ml of EDTA and 2 ml of acetic acid and, with strong stirring, slowly neutralize with an ammonia solution (1:1) until the color of the thymol blue indicator changes. After adding 10 ml of sodium acetate solution, the pH of the solution is about 5. Then the solution is diluted to 150-200 ml, heated to 70-80 ° C, pyrocatechol violet is added and titrated with a solution of zinc acetate until the color turns blue.

Notes. Neutralization should be done slowly. The addition of acetic acid should prevent overneutralization by creating a buffer solution, but despite this, local oversaturation with alkali should be avoided by neutralizing slowly and stirring vigorously. If turbidity forms, then, according to the author’s own experiences, it is best to strongly acidify the solution again and begin neutralization with great precautions.

The equivalence point is determined by the reaction between tin ions and pyrocatechol violet. In practice, this reaction occurs instantly, but the substitution reaction SnY + Zn2+ = ZnY2- + Sn4+ occurs slowly in the cold and therefore the titration is carried out at elevated temperatures.

Sbv, alkaline earth metals and magnesium do not interfere with the determination. Bi, As111, AsV, SbIII, W, Mo, Ti, Al, Mn, Cr, Zr interfere with complexing anions such as tartrate, citrate and oxalate; Ag interferes by oxidizing the indicator, but titration in the presence of silver is possible if the indicator is added shortly before the equivalence point or renewed and the determination is carried out quickly to completion. Together with Sn, Pb, Cu, Cd, Zn and Ni are titrated. However, using the differential titration method, it is possible to determine Sn in the presence of moderate amounts of these metals. In an aliquot portion of the analyzed solution, according to the above method, the total content of these metals, including tin, is determined. In the second aliquot, the tin is masked with triethanolamine and the excess EDTA is back-titrated with a solution of zinc acetate with eriochrome black T at pH = 10; Sn is determined by the difference.

Difficulties arising during the neutralization process can be avoided if neutralization is carried out in a homogeneous solution. This is provided in the method described below, which is based on unpublished research by Flaschka and Wolfram and is designed for the analysis of analytically pure tin salts.

8 . Etcestate

Tin is used primarily as a safe, non-toxic, corrosion-resistant coating in its pure form or in alloys with other metals. The main industrial uses of tin are in tinplate (tinned iron) for food containers, in solders for electronics, in household piping, in bearing alloys, and in coatings of tin and its alloys. The most important alloy of tin is bronze (with copper). Another well-known alloy, pewter, is used to make tableware. About 33% of all mined tin is consumed for these purposes. Up to 60% of tin produced is used in the form of alloys with copper, copper and zinc, copper and antimony (bearing alloy, or babbitt), with zinc (packaging foil) and in the form of tin-lead and tin-zinc solders. Recently, there has been a revival of interest in the use of metal, since it is the most “ecologically friendly” among heavy non-ferrous metals. Used to create superconducting wires based on the intermetallic compound Nb 3 Sn.

Tin disulfide SnS 2 is used in paints that imitate gilding (“potal”). Artificial tin radionuclide 119m Sn - a source of gamma radiation in Mössbauer spectroscopy.

Intermetallic compounds of tin and zirconium have high melting points (up to 2000°C) and resistance to oxidation when heated in air and have a number of applications.

Tin is the most important alloying component in the production of structural titanium alloys.

Tin dioxide is a very effective abrasive material used to “finish” the surface of optical glass.

A mixture of tin salts - the "yellow composition" - was previously used as a dye for wool.

Tin is also used in chemical current sources as an anode material, for example: manganese-tin element, mercury-tin oxide element. The use of tin in a lead-tin battery is promising; for example, at the same voltage, compared to a lead battery, a lead-tin battery has 2.5 times greater capacity and 5 times greater energy density per unit volume, its internal resistance is much lower.

Prices for metallic tin in 2006 averaged $12-18/kg, high-purity tin dioxide about $25/kg, single-crystalline high-purity tin about $210/kg.

Isolated two-dimensional layers of tin (stanene), created by analogy with graphene, are studied.

9 . Ininteresting facts about the element

At temperatures below 13.2°C, the specific volume of pure tin increases by 25.6%, and it spontaneously transforms into another phase state - gray tin (6-Sn), in the crystal lattice of which the atoms are arranged less densely. One modification changes to another the faster the lower the ambient temperature. At?33°C the transformation rate becomes maximum. The tin cracks and turns to powder. Moreover, the contact of gray tin and white leads to “infection” of the latter. The combination of these phenomena is called the “tin plague.” The current name for this process was given by G. Cohen in 1911. The scientific study of this phase transition began in 1870 with the work of the St. Petersburg scientist, academician J. Fritzsche. It has been established that this is a process of allotropic transformation of white tin into gray tin with a diamond-type structure. Many valuable observations and thoughts about this process were expressed by D.I. Mendeleev in his “Fundamentals of Chemistry”.

White tin is a silvery-white, shiny metal with a specific tetragonal structure and an s 2 p 2 electronic state - the b-phase. Gray tin is a covalent crystal with a diamond structure and an electronic sp 3 state - b phase. Phase transitions of tin from white to gray and back are accompanied by a restructuring of the electronic structure and a strong (25.6%) volume effect. White tin can be supercooled to helium temperatures (phase b-c-equilibrium temperature is about +13.2°C).

One way to prevent the "tin plague" is to add a stabilizer, such as bismuth, to the tin. On the other hand, the catalyst accelerating the transition of white tin to gray at not very low temperatures is ammonium chlorostannate (NH 4) 2 SnCl 6.

Interesting facts:

· “Tin Plague” - one of the reasons for the death of Scott’s expedition to the South Pole in 1912. It was left without fuel due to the fact that fuel leaked from tanks sealed with tin, affected by the “tin plague”.

· Some historians point to the “tin plague” as one of the circumstances of the defeat of Napoleon’s army in Russia in 1812 - severe frosts led to the transformation of tin buttons on soldiers’ uniforms into powder.

· The “Tin Plague” destroyed many valuable collections of tin soldiers. For example, in the storerooms of the St. Petersburg Museum of Alexander Suvorov, dozens of figurines turned into dust - in the basement where they were stored, the heating radiators burst in winter.

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Characteristics

Physical

Tin is a soft, malleable, ductile and highly crystalline silvery-white metal. When a tin plate is bent, a cracking sound known as "tin crack" can be heard from the twinning of the crystals. Tin melts at a low temperature, around 232 °C, the lowest in group 14. The melting point drops further to 177.3 °C for 11 nm particles. β-tin (metallic form, or white tin, BCT structure), which is stabilized at room temperature and above, is malleable. In contrast, α-tin (the non-metallic form, or gray tin), which is stabilized at temperatures up to 13.2 °C, is brittle. α-tin has a cubic crystal structure similar to diamond, silicon or germanium. α-tin has no metallic properties at all because its atoms form a covalent structure in which electrons cannot move freely. It is a dull gray powdery material that does not have any widespread use beyond a few specialized semiconductor applications. These two allotropes, α-tin and β-tin, are better known as gray tin and white tin, respectively. Two more allotropes, γ and σ, exist at temperatures above 161 °C and pressures above several gigapascals. Under cold conditions, β-tin spontaneously transforms into α-tin. This phenomenon is known as the "tin plague". Although the α-β transformation temperature is nominally 13.2 °C and impurities (eg Al, Zn, etc.) below the transition temperature are below 0 °C and, with the addition of Sb or Bi, the transformation may not occur at all, increasing the durability of tin. Commercial grades of tin (99.8%) resist transformation due to the inhibitory effect of small amounts of bismuth, antimony, lead and silver present as impurities. Alloying elements such as copper, antimony, bismuth, cadmium, silver increase the hardness of the substance. Tin quite easily forms hard, brittle intermetallic phases, which are often undesirable. Tin does not form many solid solutions in other metals in general, and several elements have appreciable solid solubility in tin. Simple eutectic systems, however, are observed with bismuth, gallium, lead, thallium and zinc. Tin becomes a superconductor below 3.72 K and is one of the first superconductors to be studied; The Meissner effect, one of the characteristic features of superconductors, was first discovered in superconducting tin crystals.

Chemical properties

Tin resists corrosion from water, but can be attacked by acids and alkalis. Tin can be highly polished and is used as a protective coating for other metals. A protective oxide (passive) layer prevents further oxidation, the same as that formed on tin-lead and other tin alloys. Tin acts as a catalyst when oxygen is in solution and helps accelerate chemical corrosion.

Isotopes

Tin has ten stable isotopes with atomic masses 112, 114, 120, 122 and 124, the largest number of any element. The most common of these are 120Sn (almost a third of all tin), 118Sn and 116Sn, while the least common are 115Sn. Isotopes with even mass numbers have no nuclear spin, while isotopes with odd numbers have a spin of +1/2. Tin, with three common isotopes 116Sn, 118Sn and 120Sn, is one of the easiest elements to detect and analyze using NMR spectroscopy. This large number of stable isotopes is believed to be a direct result of atomic number 50, the "magic number" in nuclear physics. Tin also occurs in 29 unstable isotopes, covering all other atomic masses from 99 to 137. Apart from 126Sn, with a half-life of 230,000 years, all radioisotopes have half-lives of less than a year. Radioactive 100Sn, discovered in 1994, and 132Sn are among the few nuclides with a “double magic” nucleus: although unstable, having a very uneven proton-neutron ratio, they represent endpoints beyond which stability declines rapidly. Another 30 metastable isomers were characteristic of isotopes between 111 and 131, the most stable being 121mCH with a half-life of 43.9 years. Relative differences in the abundance of stable tin isotopes can be explained by their different modes of formation in stellar nucleosynthesis. 116Sn through 120Sn inclusive are formed by the s-process (slow neutrons) in most stars and are therefore the most common isotopes, while 122Sn and 124Sn are not only formed by the R-process (fast neutrons) in supernovae and less commonly. (The isotopes 117Sn through 120Sn also benefit from the r-process.) Finally, the rarest proton-rich isotopes, 112Sn, 114Sn, and 115Sn, cannot be produced in significant quantities in the s- and r-processes and are considered to be among the p-processes. nuclei, the origin of which is not fully understood. Some proposed mechanisms for their formation include proton capture as well as photodisintegration, although 115Sn can also be partially produced in the s-process, both at once, and as a “daughter” of long-lived 115In.

Etymology

The English word tin (tin) is common to the Germanic languages and can be traced to reconstructed Proto-Germanic *tin-om; cognates include German Zinn, Swedish tenn and Dutch tin. The word is not found in other branches of Indo-European languages, except as a borrowing from Germanic (for example, the Irish word tinne came from English tin). The Latin name stannum originally meant an alloy of silver and lead, and in the 4th century BC. e. it came to mean "tin" - the earlier Latin word for it was plumbum quandum, or "white lead". The word stannum appears to have been derived from the earlier stāgnum (same substance), the origin of the Romanesque and Celtic designation for tin. The origin of stannum/stāgnum is unknown; it may be pre-Indo-European. According to Meyer's Encyclopedic Dictionary, on the contrary, stannum is considered to be a derivative of Cornish stean and is evidence that Cornwall was the main source of tin in the first centuries AD.

Story

The extraction and use of tin began in the Bronze Age, around 3000 BC. BC, when it was noted that copper objects formed from polymetallic ores with different metal contents have different physical properties. The earliest bronze objects contained less than 2% tin or arsenic and are therefore believed to be the result of unintentional alloying by tracing the metal content of the copper ore. Adding a second metal to copper increases its strength, lowers its melting point, and improves the casting process by creating a thinner melt that is denser and less spongy when cooled. This made it possible to create much more complex forms of closed bronze objects. Bronze objects with arsenic appeared primarily in the Middle East, where arsenic is often found in association with copper ore, however, the health risks associated with the use of such objects soon became clear, and the search for sources of much less dangerous tin ores began early Bronze Age. This created a demand for the rare metal tin and formed a trade network linking distant sources of tin to the markets of Bronze Age cultures. Cassiterite, or tin ore (SnO2), an oxide of tin, was most likely the original source of tin in ancient times. Other forms of tin ores are less common sulfides such as stannite, which require a more active smelting process. Cassiterite often accumulates in alluvial channels as placer deposits because it is heavier, tougher, and more chemically resistant than granite. Cassiterite is usually black or generally dark in color, and its deposits are easily visible in river banks. Alluvial (placer) deposits can be easily collected and separated by methods similar to gold panning.

Compounds and chemistry

In the vast majority, tin has an oxidation state of II or IV.

Inorganic compounds

Halide compounds are known for both oxidation states. For SN(IV), all four halides are well known: SnF4, SnCl4, SnBr4, and SnI4. The three heaviest elements are volatile molecular compounds, while tetrafluoride is polymeric. All four halides for Sn(II) are also known: SnF2, SnCl2, SnBr2 and SnI2. These are all polymeric solids. Of these eight compounds, only iodides are colored. Tin(II) chloride (also known as stannous chloride) is the most important tin halide commercially. Chlorine reacts with tin metal to create SnCl4 while the reaction of hydrochloric acid and tin produces SnCl2 and hydrogen gas. In addition, SnCl4 and Sn combine with tin chloride through a process called co-proportionation: SnCl4 + CH → 2 Sncl2 Tin can form many oxides, sulfides and other chalcogenide derivatives. SnO2 dioxide (cassiterite) is formed when tin is heated in the presence of air. SnO2 is amphoteric in nature, which means it dissolves in acidic and basic solutions. Stannates with the structure Sn(OH)6]2, like K2, are also known, although free stannous acid H2[CH(on)6] is unknown. Tin sulfides exist in both +2 and +4 oxidation states: tin(II) sulfide and tin(IV) sulfide (mosaic gold).

Hydrides

Stannan (SnH4), with tin in the +4 oxidation state, is unstable. Organotin hydrides, however, are well known, for example tributyline hydride (Sn(C4H9)3H). These compounds release transient tributyltin tin radicals, which are rare examples of tin(III) compounds.

Organotin compounds

Organotin compounds, sometimes called stannanes, are chemical compounds with tin-carbon bonds. Of the tin compounds, the organic derivatives are the most commercially useful. Some organotin compounds are very toxic and are used as biocides. The first known organotin compound was diethyltin diodide (C2H5)2SnI2), which was discovered by Edward Frankland in 1849. Most organic tin compounds are colorless liquids or solids that are resistant to air and water. They adopt tetrahedral geometry. Tetraalkyl and tetraaryltine compounds can be prepared using Grignard's reagents:

4 + 4 RMgBr → R

Mixed alkyl halides, which are more common and have greater commercial value than tetraorganic derivatives, are prepared by rearrangement reactions:

4Sn → 2 SnCl2R2

Divalent organotin compounds are rare, although more common than divalent organogermanium and organosilicon compounds. The greater stabilization that Sn(II) has is attributed to the “inert pair effect.” Organotin(II) compounds include both stannylenes (formula: R2Sn, as seen for singlet carbenes) and distannylenes (R4Sn2), which are roughly equivalent to alkenes. Both classes exhibit unusual reactions.

Emergence

Tin is formed in the long-term s-process in low- and medium-mass stars (with masses from 0.6 to 10 times the mass of the Sun) and, finally, during the beta decay of heavy indium isotopes. Tin is the most abundant 49th element in the earth's crust, at 2 ppm compared to 75 mg/L for zinc, 50 ppm for copper, and 14 ppm for lead. Tin does not occur as a native element, but must be extracted from various ores. Cassiterite (SnO2) is the only commercially important source of tin, although small quantities of tin are recovered from complex sulfides such as stannite, cypindrite, frankeite, canfieldite and tillite. Tin minerals are almost always associated with granite rock, usually at the 1% tin oxide level. Due to the high specific gravity of tin dioxide, about 80% of mined tin comes from secondary deposits recovered from primary deposits. Tin is often recovered from granules washed downstream in the past and deposited in valleys or the sea. The most economical methods of mining tin are scooping, hydraulics or open pits. Most of the world's tin is produced from placer deposits, which may contain as little as 0.015% tin. World tin mine reserves (tons, 2011)

China 1500000

Malaysia 250000

Indonesia 800000

Brazil 590000

Bolivia 400000

Russia 350000

Australia 180000

Thailand 170000

Others 180000

Total 4800000

Approximately 253,000 tonnes of tin were mined in 2011, mainly from China (110,000 tonnes), Indonesia (51,000 tonnes), Peru (34,600 tonnes), Bolivia (20,700 tonnes) and Brazil (12,000 tonnes). Estimates of tin production have historically varied depending on economic viability dynamics and developments in mining technology, but at current rates of consumption and technology, it is estimated that the Earth will run out of tin mining within 40 years. Lester Brown suggested that tin could run out within 20 years based on an extremely conservative extrapolation of 2% growth per year. Economically recoverable tin reserves: Million. tons per year

Recycled or scrap tin is also an important source of this metal. Tin recovery through secondary production or recycling of scrap tin is growing at a rapid pace. While the United States has not mined tin since 1993 nor smelted tin since 1989, it has been the largest secondary producer of tin, processing nearly 14,000 tons in 2006. New deposits are found in southern Mongolia, and in 2009 new tin deposits were discovered in Colombia by Seminole Group Colombia CI, SAS.

Production

Tin is produced by carbothermic reduction of oxide ore using carbon or coke. Reverberatory furnaces and electric furnaces can be used.

Price and exchange

Tin is unique among other mineral commodities due to complex agreements between producing and consuming countries dating back to 1921. Earlier agreements tended to be somewhat informal and sporadic and led to the "First International Tin Agreement" in 1956, the first of a permanent series of agreements that effectively ceased to exist in 1985. Through this series of agreements, the International Tin Council (ITC) had a significant influence on tin prices. MCO supported the price of tin during periods of low prices by purchasing tin for its buffer stock and was able to contain the price during periods of high prices by selling tin from this stock. This was an anti-market approach designed to ensure a sufficient flow of tin to consuming countries and profits for producing countries. However, the buffer stock was not large enough, and for most of those 29 years, tin prices rose, sometimes sharply, especially from 1973 to 1980, when rampant inflation plagued many of the world's economies. In the late 1970s and early 1980s, US government tin inventories were in an aggressive sales mode, in part to take advantage of historically high tin prices. The slump of 1981-82 was quite harsh for the tin industry. Tin consumption dropped sharply. MCO was able to avoid a truly drastic reduction by accelerating purchases for its buffer stock; these activities required MCOs to borrow on a large scale from banks and metal trading firms to increase their resources. MCO continued to borrow funds until the end of 1985, when it reached its credit limit. Immediately after this came the great “tin crisis”, and then tin was excluded from trading on the London Metal Exchange for a period of three years, the MCO soon collapsed, and tin prices, already in a free market, plummeted to $4 per pound (453 g) , and remained at this level until the 1990s. The price increased again by 2010 with a rebound in consumption following the 2008–09 World Economic Crisis, accompanying renewed and continued growth in consumption in the developing world. The London Metal Exchange (LME) is the main trading platform for tin. Other tin markets are Kuala Lumpur Tin Market (KLTM) and Indonesia Tin Exchange (INATIN).

Applications

In 2006, about half of all tin produced was used in solders. The remaining uses were divided between tin plating, tin chemicals, brass and bronze alloys, and niche uses.

Solder

Tin has long been used in alloys with lead as solder, in quantities ranging from 5 to 70%. Tin forms a eutectic mixture with lead in the proportion of 63% tin and 37% lead. Such solders are used to join pipes or electrical circuits. On 1 July 2006, the European Union's Waste Electrical and Electronic Equipment Directive (WEEE Directive) and the RoHS Directive came into force. The lead content in such alloys has decreased. Replacing lead comes with many problems, including higher melting points and the formation of tin whiskers. Tin plague can occur in lead-free solders.

Tinning

Tin bonds take well to ironing and are used to coat lead, zinc and steel to prevent corrosion. Tinned steel containers are widely used for food preservation, and this forms a large part of the tin metal market. In London in 1812, the first tin canister was made for preserving food. In British English these are called "tins", but in America they are called "cans" or "tin cans". The slang name for a can of beer is "tinnie" or "tinny". Copper cooking vessels such as pots and pans are often lined with a thin layer of tin, since the combination of acidic foods with copper can be toxic.

Specialized alloys

Tin combines with other elements to form many useful alloys. Tin is most often alloyed with copper. Tin-lead alloy has 85-99% tin; Bearing metal also contains a high percentage of tin. Bronze is primarily copper (12% tin), while the addition of phosphorus produces phosphor bronze. Bell bronze is also a copper-tin alloy containing 22% tin. Tin was sometimes used in coins to create American and Canadian pennies. Because copper was often the base metal in these coins, sometimes including zinc, they may be called bronze and/or brass alloys. The niobium-tin compound Nb3Sn has been commercially used in superconducting magnet coils due to its high critical temperature (18 K) and critical magnetic field (25 T). A superconducting magnet weighing just two kilograms can create the same magnetic field as electromagnets with normal weight. A small proportion of tin is added to zirconium alloys for cladding nuclear fuel. Most metal pipes on an organ have varying amounts of tin/lead, with 50/50 alloys being the most common. The amount of tin in the pipe determines the tone of the pipe, as tin gives the instrument the desired resonance. When a tin/lead alloy cools, the lead cools slightly faster and produces a mottled or mottled effect. This metal alloy is called spotted metal. The main benefits of using tin for pipes are its appearance, performance and corrosion resistance.

Other Applications

Perforated tinned steel is a craft technique that originated in Central Europe to create household items that were both functional and decorative. Perforated tin lanterns are the most common application of this technique. Candle light passing through the perforations creates a decorative light pattern. Lanterns and other perforated tin items have been created in the New World since the earliest European settlements. A famous example is the Revere lantern, named after Paul Revere. Before the modern era, in some areas of the Alps, goat or ram horns were sharpened and metal was punched through it in the shape of the alphabet and numbers from one to nine. This teaching tool was known simply as the "horn". Modern reproductions feature motifs such as hearts and tulips. In America, wooden cabinets of various styles and sizes were used for cakes and food before refrigeration, designed to repel pests and insects and keep perishable foods from dust. These were either floor or hanging cabinets. These cabinets had tin inserts in the doors and sometimes on the sides. Window glass is most often made by placing molten glass on molten tin (float glass - sheet glass produced from molten metal), resulting in a perfectly smooth surface. This is also called the Pilkington process. Tin is also used as the negative electrode in modern lithium-ion batteries. Its use is somewhat limited by the fact that some tin surfaces catalyze the decomposition of carbonate electrolytes used in lithium-ion batteries. Stann(II) fluoride is added to some dental care products (SnF2). Tin(II) fluoride can be mixed with calcium abrasives, while the more common sodium fluoride gradually becomes biologically inactive in the presence of calcium compounds. It has also been shown to be more effective than sodium fluoride in controlling gingivitis.

Organotin compounds

Among all the chemical compounds of tin, organic tin compounds are the most commonly used. Their global industrial production probably exceeds 50,000 tons.

PVC stabilizers

The main commercial use of organotin compounds is in the stabilization of PVC plastic. In the absence of such stabilizers, PVC would otherwise rapidly degrade when exposed to heat, light and atmospheric oxygen, resulting in a discolored and brittle product. Tin scavenges labile chloride ions (Cl−), which would otherwise cause HCl to be lost from plastic. Typical tin compounds are carboxylic acid derivatives of dibutyltin dichloride, such as dibutyltin dilaurate.

Biocides

Some organotin compounds are relatively toxic, which has its advantages and disadvantages. They are used for their biocidal properties as fungicides, pesticides, algaecides, wood preservatives and anti-rot agents. Tributyltin oxide is used as a wood preservative. Tributyltin was used as a marine paint additive to prevent the growth of marine organisms on ships, although use decreased after organotin compounds were recognized as persistent organic pollutants with extremely high toxicity to some marine organisms (eg, scarlet grass). The EU banned the use of organotin compounds in 2003, while concerns about the toxicity of these compounds to marine life and damage to the reproduction and growth of some marine species (some reports describe biological effects on marine life at concentrations of 1 nm per liter) led to a worldwide prohibited by the International Maritime Organization. Currently, many states restrict the use of organotin compounds to vessels longer than 25 m.

Organic chemistry

Some tin reagents are useful in organic chemistry. In its most common application, stannous chloride is a common reducing agent for the conversion of nitro and oxime groups to amines. The Style reaction links organotin compounds with organic halides or pseudohalides.

Lithium-ion batteries

Tin forms several intermetallic phases with lithium metal, making it a potentially attractive material for battery applications. The large volumetric expansion of tin upon lithium doping and the instability of the organotin electrolyte interface at low electrochemical potentials are the greatest challenges for use in commercial cells. The problem was partially resolved by Sony. Tin intermetallic compounds with cobalt and carbon are marketed by Sony in its Nexelion cells released in the late 2000s. The composition of the active substance is approximately Sn0.3Co0.4C0.3. Recent studies have shown that only certain crystalline facets of tetragonal (beta)Sn are responsible for undesirable electrochemical activity.

Tin element name. What is tin? Properties and uses of tin. Description of tin. Tin sulfide compounds

Action of tin

Daily norm

Lack of tin in the human body

Harm from excess tin intake

What foods does it contain?

Indications for use

Story

Production

Application

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Tin oxide compounds

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Characteristics

Physical

Chemical properties

Isotopes

Etymology

Story

Compounds and chemistry

Inorganic compounds

Hydrides

Organotin compounds

Emergence

Production

Price and exchange

Applications

Solder

Tinning

Specialized alloys

Other Applications

Organotin compounds

PVC stabilizers

Biocides

Organic chemistry

Lithium-ion batteries