The chemical element is tin. Properties and application of tin

Each chemical element of the periodic system and the simple and complex substances formed by it are unique. They have unique properties, and many make an undeniably significant contribution to human life and existence in general. Not an exception and the chemical element of tin.

Acquaintance of people with this metal goes back to antiquity. This chemical element played a decisive role in the development of human civilization, to this day the properties of tin are widely used.

Tin in history

The first mention of this metal, which, as people believed before, even some magical properties, can be found in the biblical texts. Tin played a decisive role in improving the life during the "bronze" century. At that time, the most durable metal alloy that a man possessed was bronze, it can be obtained if a chemical element is added to the copper in tin. For several centuries, everything was made from this material, from tools to jewelry.

After the discovery of the properties of iron, the alloy of tin did not cease to be used, of course, it is not used on the previous scale, but bronze and many other alloys are actively used today by man in industry, engineering and medicine, along with the salts of this metal, for example, such as chloride Tin, which is obtained by the interaction of tin with chlorine, this liquid boils at 112 degrees Celsius, dissolves well in water, forms crystalline hydrates and smokes in air.

Position of the element in the periodic table

The chemical element of tin (the Latin name stannum, "stannum", is written with the symbol Sn), Dmitri Ivanovich Mendeleyev rightfully placed number fifty, in the fifth period. It has a number of isotopes, the most common is isotope 120. This metal is also in the main subgroup of the sixth group, together with carbon, silicon, germanium and fleurium. Its location predicts the amphoteric properties, as well as acidic and basic characteristics, which are described in more detail below.

In the periodic table, the atomic mass of tin is also indicated, which is equal to 118.69. The electronic configuration is 5s ² 5p ² , which in the composition of complex substances allows the metal to exhibit oxidation states of +2 and +4, giving two electrons only from the p-sublevel or four with s- and p-, completely emptying the entire outer layer.

Electronic characteristic of the element

According to the atomic number, the near-nuclear space of the tin atom contains as many as fifty electrons, they are located on five levels, which, in turn, are split into a number of sublevels. The first two have only s- and p-sublevels, and beginning with the third one there is a triple splitting into s-, p-, d-.

Consider an external electronic level, since it is its structure and filling by electrons that determine the chemical activity of an atom. In the unexcited state, the element exhibits a valence of two, upon excitation, one electron moves from the s-sublevel to the vacant place of the p-sublevel (it can contain three unpaired electrons as much as possible). In this case, the tin exhibits valence and oxidation state-4, since there are no paired electrons, and so in the process of chemical interaction on the sublevels, they are not retained.

A simple metal substance and its properties

A simple substance tin is a silver metal, belongs to the group of low-melting. The metal is soft, comparatively easy to deform. A number of features are inherent in such a metal as tin. The temperature below 13.2 degrees Celsius is the boundary of the transition of the metallic modification of tin into a powdered one, which is accompanied by a change in color from silvery-white to gray and a reduction in the density of matter. The tin melts at 231.9 degrees, and boils at 2270 degrees Celsius. The crystalline tetragonal structure of white tin explains the characteristic cracking of the metal when it bends and heats up at the point of inflection by the crystals of matter rubbing against each other. Gray tin has a cubic syngony.

The chemical properties of tin have a dual essence, it enters both acidic and basic reactions, manifesting amphotericity. The metal reacts with alkalis, as well as with acids, such as sulfuric and nitric, which reacts with halogens.

Alloys of tin

Why more often than pure metals use their alloys with a certain percentage of the components? The fact is that the alloy has properties that are not found in the individual metal, or these properties are much stronger (for example, electrical conductivity, resistance to corrosion, passivation or activation of the physical and chemical characteristics of metals, if necessary, etc.). Tin (photo shows a sample of pure metal) is a part of many alloys. It can be used as an additive or basic substance.

To date, we know a large number of alloys of such a metal as tin (the price for them varies widely), we will consider the most popular and applied ones (we will discuss the use of these or those alloys in the corresponding section). In general, the stannum alloys have the following characteristics: high plasticity, low melting point, small hardness and strength.

Some examples of alloys

• The alloy of tin and lead with some alloying additives (antimony, copper, cadmium, zinc, silver, indium) is the so-called tin for soldering, the percentage of stannum in it for achieving the best binding properties should be 49-51 or 59-61 percent. The strength of the joint ensures the formation of tin by a solid solution with fastened metal surfaces.
• Garth - the alloy of tin, lead and antimony - is the basis of printing ink (that's why it is not recommended to wrap food products in newspapers, in order to avoid getting unwanted concentrations of these metals in them).
• Babbit - an alloy of tin, lead, copper and antimony - is characterized by low coefficient of friction, high wear resistance.
• The indium-tin alloy is a low-melting material with refractory properties, corrosion resistance and considerable strength.

The most important natural compounds

Tin forms a number of natural compounds - ores. The metal forms 24 mineral compounds, the most important for the industry has tin oxide - cassiterite, and also the bed - Cu ₂ FeSnS ₄ . Tin is scattered in the earth's crust, and the compounds formed by it have a magnetic origin. The industry also uses salts of polyolic acids and tin silicates.

Tin and human body

The chemical element tin is a microelement in its quantitative content in the human body. Its main cluster is in the bone tissue, where the normal content of the metal contributes to its timely development and the overall functioning of the musculoskeletal system. In addition to bones, tin concentrates in the gastrointestinal tract, lungs, kidneys and the heart.

It is important to note that excessive accumulation of a given metal can lead to a general poisoning of the organism, and a longer exposure - even to adverse gene mutations. Recently, this problem is quite urgent, since the ecological state of the environment leaves much to be desired. There is a high probability of tin intoxication among residents of megacities and neighborhoods near industrial zones. Most often, poisoning occurs by accumulation in the lungs of tin salts, for example, such as tin chloride and others. At the same time, the lack of a trace element can trigger a slowdown in growth, loss of hearing and loss of hair.

Application

Metal is available in many metallurgical plants and companies. Produced in the form of pigs, rods, wire, cylinders, anodes, made of a pure simple substance, such as tin. The price ranges from 900 to 3000 rubles per kilogram.

Tin in its pure form is rarely used. Its alloys and compounds - salts are mainly used. Tin for soldering is used in case of fastening parts that are not exposed to high temperatures and strong mechanical loads made of copper alloys, steel, copper, but not recommended for aluminum or its alloys. The properties and characteristics of tin alloys are described in the corresponding section.

Solders are used for soldering chips, in this situation, alloys based on a metal such as tin are also ideally suited. The photo depicts the process of using tin-lead alloy. With the help of it you can perform fairly fine work.

In view of the high resistance of tin to corrosion, it is used for the production of tinned iron (tinplate) - tin cans for food products. In medicine, in particular in dentistry, tin is used to perform tooth filling. Tin covered home pipelines, from its alloys made bearings. Invaluously important is the contribution of this substance to electrical engineering.

Aqueous solutions of such tin salts, as fluoroborates, sulfates, and also chlorides, are used as electrolytes. Tin oxide is the glaze for ceramics. By introducing various tin derivatives into plastic and synthetic materials, it is possible to reduce their inflammability and the release of harmful fumes.