Structure of the tin atom. Chemical element tin

Light non-ferrous metal, a simple inorganic substance. In the periodic table it is designated Sn, stannum. Translated from Latin it means “durable, resistant.” Initially, this word was used to refer to an alloy of lead and silver, and only much later did they begin to call pure tin this way. The word "tin" has Slavic roots and means "white".

Metal is a trace element, and not the most common on earth. It occurs in nature in the form of various minerals. The most important for industrial mining: cassiterite - tin stone, and stannin - tin pyrite. Tin is extracted from ores, usually containing no more than 0.1 percent of this substance.

Properties of tin

Lightweight, soft, ductile metal with a silvery-white color. It has three structural modifications, passes from the α-tin (gray tin) state to β-tin (white tin) at a temperature of +13.2 °C, and to the γ-tin state at +161 °C. The modifications differ greatly in their properties. α-tin is a gray powder that is classified as a semiconductor, β-tin (“ordinary tin” at room temperature) is a silvery malleable metal, γ-tin is a white brittle metal.

In chemical reactions, tin exhibits polymorphism, that is, acidic and basic properties. The reagent is quite inert in air and water, as it quickly becomes covered with a durable oxide film that protects it from corrosion.

Tin easily reacts with non-metals, but with difficulty with concentrated sulfuric and hydrochloric acid; does not interact with these acids in a diluted state. It reacts with concentrated and dilute nitric acid, but in different ways. In one case, tin acid is obtained, in the other, tin nitrate. It reacts with alkalis only when heated. With oxygen it forms two oxides, with oxidation states 2 and 4. It is the basis of a whole class of organotin compounds.

Impact on the human body

Tin is considered safe for humans, it is present in our body and every day we get it in minimal quantities from food. Its role in the functioning of the body has not yet been studied.

Tin vapor and its aerosol particles are dangerous, since with prolonged and regular inhalation it can cause lung diseases; Organic tin compounds are also poisonous, so you need to wear protective equipment when working with it and its compounds.

A tin compound such as tin hydrogen, SnH 4, can cause severe poisoning when eating very old canned food, in which organic acids have reacted with the layer of tin on the walls of the can (the tin from which cans are made is a thin sheet of iron, coated on both sides with tin). Tin hydrogen poisoning can even be fatal. Symptoms include seizures and a feeling of loss of balance.

When the air temperature drops below 0 °C, white tin transforms into a modification of gray tin. In this case, the volume of the substance increases by almost a quarter, the tin product cracks and turns into gray powder. This phenomenon came to be called the “tin plague.”

Some historians believe that the “tin plague” was one of the reasons for the defeat of Napoleon’s army in Russia, as it turned the buttons on the clothes of French soldiers and belt buckles into powder, and thereby had a demoralizing effect on the army.

But here is a real historical fact: the expedition of the English polar explorer Robert Scott to the South Pole ended tragically, partly because all their fuel spilled out of the tanks sealed with tin, they lost their snowmobiles, and they did not have enough strength to walk.

Application

Most of the smelted tin is used in metallurgy for production of various alloys. These alloys are used for the production of bearings, foil for packaging, tinplate, bronze, solders, wires, and typographic fonts.
- Tin in the form of foil (staniol) is in demand in the production of capacitors, tableware, art objects, and organ pipes.
- Used for alloying structural titanium alloys; for applying anti-corrosion coatings to products made of iron and other metals (tinning).
- The alloy with zirconium has high refractoriness and resistance to corrosion.
- Tin (II) oxide - used as an abrasive in the processing of optical glasses.
- Part of the materials used to make batteries.
- In the production of gold paints and dyes for wool.
- Artificial radioisotopes of tin are used as a source of γ-radiation in spectroscopic research methods in biology, chemistry, and materials science.
- Tin dichloride (tin salt) is used in analytical chemistry, in the textile industry for dyeing, in the chemical industry for organic synthesis and production of polymers, in oil refining - for decolorizing oils, in the glass industry - for glass processing.
- Tin boron fluoride is used for the production of tin, bronze, and other alloys needed by industry; for tinning; lamination.

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TIN (lat. Stannum), Sn, chemical element with atomic number 50, atomic mass 118.710. There are various guesses about the origin of the words “stannum” and “tin”. The Latin "stannum", which is sometimes derived from the Saxon "sta" - strong, hard, originally meant an alloy of silver and lead. “Tin” was the name given to lead in a number of Slavic languages. Perhaps the Russian name is associated with the words “ol”, “tin” - beer, mash, honey: tin vessels were used to store them. In English literature the word tin is used to name tin. The chemical symbol for tin Sn reads "stannum".

Natural tin consists of nine stable nuclides with mass numbers 112 (in a mixture of 0.96% by mass), 114 (0.66%), 115 (0.35%), 116 (14.30%), 117 (7. 61%), 118 (24.03%), 119 (8.58%), 120 (32.85%), 122 (4.72%), and one weakly radioactive tin-124 (5.94%). 124Sn is a b-emitter, its half-life is very long and amounts to T1/2 = 1016-1017 years. Tin is located in the fifth period in group IV of D.I. Mendeleev’s periodic system of elements. The configuration of the outer electronic layer is 5s25p2. In its compounds, tin exhibits oxidation states +2 and +4 (valency II and IV, respectively).

The metallic radius of the neutral tin atom is 0.158 nm, the radii of the Sn2+ ion are 0.118 nm and the Sn4+ ion is 0.069 nm (coordination number 6). The sequential ionization energies of the neutral tin atom are 7.344 eV, 14.632, 30.502, 40.73 and 721.3 eV. According to the Pauling scale, the electronegativity of tin is 1.96, that is, tin is on the conventional border between metals and non-metals.

Chemistry information

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Tin(lat. stannum), sn, chemical element of group IV of the periodic system of Mendeleev; atomic number 50, atomic mass 118.69; white shiny metal, heavy, soft and ductile. The element consists of 10 isotopes with mass numbers 112, 114-120, 122, 124; the latter is weakly radioactive; The isotope 120 sn is the most common (about 33%).

Historical reference. Alloys of gold with copper - bronze - were known already in the 4th millennium BC. e., and pure metal in the 2nd millennium BC. e. In the ancient world, jewelry, dishes, and utensils were made from ointment. The origin of the names "stannum" and "tin" is uncertain.

Distribution in nature. O. is a characteristic element of the upper part of the earth’s crust, its content in the lithosphere is 2.5·10–4% by mass, in acidic igneous rocks 3·10–4%, and in deeper basic rocks 1.5·10–4%; even less O. in the mantle. The concentration of oxygen is associated both with magmatic processes (there are known “tin-bearing granites” and pegmatites enriched with oxygen) and with hydrothermal processes; Of the 24 known O minerals, 23 were formed at high temperatures and pressures. The main industrial value is cassiterite sno 2, stannin cu 2 fesns 4 is of lesser importance. O. migrates weakly in the biosphere, in sea water it is only 3·10–7%; aquatic plants with a high oxygen content are known. However, the general trend in the geochemistry of oxygen in the biosphere is dispersion.

Physical and chemical properties. O. has two polymorphic modifications. The crystal lattice of ordinary b-sn (white O.) is tetragonal with periods a = 5.813 å, With=3.176 å; density 7.29 G/ cm 3. At temperatures below 13.2 ° C, a -sn (gray O.) cubic diamond-type structure is stable; density 5.85 G/ cm 3. The b ® a transition is accompanied by the transformation of the metal into powder, t pl 231.9 ° C, t kip 2270 ° C. Temperature coefficient of linear expansion 23·10 –6 (0-100 ° C); specific heat capacity (0 °C) 0.225 kj/(kg K), i.e. 0.0536 feces/(G°C); thermal conductivity (0 ° C) 65.8 Tue/(m K), i.e. 0.157 feces/(cm·- sec°C); electrical resistivity (20 ° C) 0.115 10 –6 ohm· m, i.e. 11.5·10 –6 ohm· cm. Tensile strength 16.6 Mn/ m 2 (1,7 kgf/ mm 2) " , relative elongation 80-90%; Brinell hardness 38.3-41.2 Mn/ m 2 (3,9-4,2 kgf/ mm 2). When bending O. rods, a characteristic crunch is heard from the mutual friction of the crystallites.

In accordance with the configuration of the outer electrons of atom 5 s 2 5 p 2 O. has two oxidation states: +2 and +4; the latter is more stable; sn (P) compounds are strong reducing agents. O. practically does not oxidize in dry and humid air at temperatures up to 100 ° C: it is protected by a thin, durable and dense film sno 2. O. is stable in relation to cold and boiling water. The standard electrode potential of O. in an acidic environment is - 0.136 V. From dilute hcl and h2so4 in the cold, oxygen slowly displaces hydrogen, forming sncl2 chloride and snso4 sulfate, respectively. In hot concentrated h 2 so 4 when heated, oxygen dissolves, forming sn (so 4) 2 and so 2. Cold (O ° C) dilute nitric acid acts on oxygen according to the reaction:

4sn + 10hno 3 = 4sn (no 3) 2 + nh 4 no 3 + 3h 2 o.

When heated with concentrated hno 3 (density 1.2-1.42 G/ cm 3) O. oxidizes with the formation of a precipitate of metatinic acid h 2 sno 3, the degree of hydration of which is variable:

3sn+ 4hno 3+ n h 2 o = 3h 2 sno 3 · n h 2 o + 4no.

When oxygen is heated in concentrated alkali solutions, hydrogen is released and hexahydrostannate is formed:

sn + 2KOH + 4H 2 O = k 2 + 2h 2.

Oxygen in the air passivates oxygen, leaving a film of sno 2 on its surface. Chemically, sno 2 dioxide is very stable, but sno oxide oxidizes quickly and is obtained indirectly. sno 2 exhibits predominantly acidic properties, sno - basic ones.

O. does not directly combine with hydrogen; hydride snh 4 is formed by the interaction of mg 2 sn and hydrochloric acid:

mg 2 sn + 4hcl = 2mgcl 2 + snh 4.

It is a colorless poisonous gas t kip -52 ° C; it is very fragile, at room temperature it decomposes into sn and h 2 within a few days, and above 150 ° C - instantly. It is also formed by the action of hydrogen at the moment of release on oxygen salts, for example:

sncl 2 + 4hcl + 3mg = 3mgcl 2 + snh 4.

With halogens, oxygen produces compounds of the composition snx 2 and snx 4. The former are salt-like and produce sn 2+ ions in solutions, the latter (except snf 4) are hydrolyzed by water, but are soluble in non-polar organic liquids. By reacting O. with dry chlorine (sn + 2cl 2 = sncl 4) tetrachloride sncl 4 is obtained; it is a colorless liquid that dissolves sulfur, phosphorus, and iodine well. Previously, the above reaction was used to remove oxygen from failed tinned products. Nowadays the method is not widely used due to the toxicity of chlorine and high O losses.

Tetrahalides snx 4 form complex compounds with h 2 o, nh 3, nitrogen oxides, pcl 5, alcohols, ethers and many organic compounds. With hydrohalic acids, oxygen halides form complex acids that are stable in solutions, for example h 2 sncl 4 and h 2 sncl 6 . When diluted with water or neutralized, solutions of simple or complex chlorides hydrolyze, giving white precipitates sn (oh) 2 or h 2 sno 3 n h 2 o. With sulfur, oxygen produces sulfides that are insoluble in water and dilute acids: brown sns and golden yellow sns 2.

Receipt and application. Industrial production of oxygen is advisable if its content in placers is 0.01%, in ores 0.1%; usually tenths and units of percent. O. in ores is often accompanied by w, zr, cs, rb, rare earth elements, Ta, nb and other valuable metals. Primary raw materials are enriched: placers - mainly by gravity, ores - also by flotation gravity or flotation.

Concentrates containing 50-70% oxygen are fired to remove sulfur and purified from iron by the action of hcl. If there are impurities of wolframite (fe, mn) wo 4 and scheelite cawo 4, the concentrate is treated with hcl; the resulting wo 3 ·h 2 o is extracted using nh 4 oh. By smelting concentrates with coal in electric or flame furnaces, rough carbon (94-98% sn) is obtained containing impurities cu, pb, fe, as, sb, bi. When released from the furnaces, rough iron is filtered at a temperature of 500-600 ° C through coke or centrifuged, thereby separating the bulk of the iron. The remainder of fe and cu is removed by mixing elemental sulfur into the liquid metal; impurities float to the surface in the form of solid sulfides, which are removed from the surface of the oxygen. From arsenic and antimony, oxygen is refined in the same way - by mixing aluminum, from lead - using sncl 2. Sometimes bi and pb are evaporated in vacuum. Electrolytic refining and zone recrystallization are used relatively rarely to obtain especially pure oxygen.

About 50% of all metal produced is secondary metal; it is obtained from waste tinplate, scrap and various alloys. Up to 40% of O. is used for tinning tin plate, the rest is spent on the production of solders, bearing and printing alloys. Sno 2 dioxide is used for the production of heat-resistant enamels and glazes. Salt - sodium stannite na 2 sno 3 ·3h 2 o is used in mordant dyeing of fabrics. Crystal sns 2 (“gold leaf”) is included in paints that imitate gilding. Niobium stannide nb 3 sn is one of the most used superconducting materials.

N. N. Sevryukov.

The toxicity of O. itself and most of its inorganic compounds is low. Acute poisonings caused by elemental oxygen, widely used in industry, practically do not occur. Some cases of poisoning described in the literature are apparently caused by the release of ash 3 when water accidentally gets into waste from arsenic purification. Workers at tin smelters with prolonged exposure to dust may develop oxygen oxide (so-called black oxygen, sno). pneumoconiosis, workers involved in the manufacture of tin foil sometimes experience cases of chronic eczema. O. tetrachloride (sncl 4 5h 2 o) when its concentration in the air is over 90 mg/ m 3 irritates the upper respiratory tract, causing coughing; When O. chloride gets on the skin, it causes ulceration. A strong convulsive poison is stannic hydrogen (stannomethane, snh 4), but the likelihood of its formation under industrial conditions is negligible. Severe poisoning when eating canned food that has been produced for a long time can be associated with the formation of snh 4 in the cans (due to the action of organic acids in the contents of half the cans). Acute poisoning with tin hydrogen is characterized by convulsions and imbalance; Possible death.

Organic oxygen compounds, especially di- and trialkyl compounds, have a pronounced effect on the central nervous system. Signs of poisoning with trialkyl compounds: headache, vomiting, dizziness, convulsions, paresis, paralysis, visual disturbances. Coma, cardiac and respiratory disturbances often develop, leading to death. The toxicity of dialkyl O. compounds is somewhat lower; the clinical picture of poisoning is dominated by symptoms of damage to the liver and biliary tract. Prevention: compliance with occupational hygiene rules.

O. as an artistic material. Excellent casting properties, malleability, pliability to the cutter, and noble silver-white color determined the use of O. in decorative and applied arts. In Ancient Egypt, jewelry was made from O. soldered onto other metals. From the end of the 13th century. In Western European countries, vessels and church utensils made of gold appeared, similar to silver ones, but softer in outline, with a deep and rounded engraving stroke (inscriptions, ornaments). In the 16th century F. Briot (France) and K. Enderlein (Germany) began casting ceremonial bowls, dishes, and cups from O. with relief images (coats of arms, mythological, genre scenes). A. Sh. Boule introduced O. into marquetry when finishing furniture. In Russia, products made from glass (mirror frames, utensils) became widespread in the 17th century; in the 18th century In the north of Russia, the production of copper trays, teapots, and snuff boxes, finished with tin plates and enamels, flourished. By the beginning of the 19th century. O. vessels gave way to faience ones and the use of O. as an artistic material became rare. The aesthetic advantages of modern decorative objects made from ointment lie in the clear identification of the structure of the object and the mirror-like cleanliness of the surface, achieved by casting without subsequent processing.

Lit.: Sevryukov N.N., Tin, in the book: Brief chemical encyclopedia, vol. 3, M., 1963, p. 738-39; Metallurgy of Tin, M., 1964; Nekrasov B.V., Fundamentals of General Chemistry, 3rd ed., vol. 1, M., 1973, p. 620-43; Ripan p., Ceteanu I., Inorganic chemistry, part 1 - Chemistry of metals, trans. from rum., M., 1971, p. 395-426; Occupational diseases, 3rd ed., M., 1973; Harmful substances in industry, part 2, 6th ed., M, 1971; tardy, les e tains fran c ais, pt. 1-4, p., 1957-64; Mory L., Sch o nes Zinn, Munch., 1961; Haedeke H., Zinn, Braunschweig, 1963.

1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 2 4p 5 .

Valence electrons are shown in bold. Belongs to the family of p-elements. Since the largest principal quantum number is 4, and the number of electrons in the outer energy level is 7, bromine is located in the 4th period, group VIIA of the Periodic Table. The energy diagram for valence electrons looks like:

Germanium.

1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 2 4p 2 .

Valence electrons are shown in bold. Belongs to the family of p-elements. Since the largest principal quantum number is 4, and the number of electrons in the outer energy level is 4, germanium is located in the 4th period, group IVA of the Periodic Table. The energy diagram for valence electrons looks like:

Cobalt.

1s 2 2s 2 2p 6 3s 2 3p 6 3d 7 4s 2 .

Valence electrons are shown in bold. Belongs to the family of d-elements. Cobalt is located in the 4th period, VIIB group of the Periodic Table. The energy diagram for valence electrons looks like:

Copper.

1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 1 .

Valence electrons are shown in bold. Belongs to the family of d-elements. Since the largest principal quantum number is 4, and the number of electrons in the outer energy level is 1, copper is located in the 4th period, Group I of the Periodic Table. The energy diagram for valence electrons looks like this.