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. The chemical element tin is no exception.
People's acquaintance with this metal goes back to ancient times. 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 had some magical properties, can be found in biblical texts. Tin played a decisive role in improving life during the Bronze Age. At that time, the most durable metal alloy that a person possessed was bronze, which can be obtained by adding the chemical element tin to copper. For several centuries, everything has been made from this material, from tools to jewelry.
After the discovery of the properties of iron, the tin alloy did not cease to be used, of course, it is not used on the same scale, but bronze, as well as many of its other alloys, are actively involvedtoday a person in industry, technology and medicine, along with s alts of this metal, such as tin chloride, 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.
The position of the element in the periodic table
The chemical element tin (the Latin name stannum - “stannum”, written with the symbol Sn) Dmitry Ivanovich Mendeleev rightfully placed at number fifty, in the fifth period. It has a number of isotopes, the most common isotope 120. This metal is also in the main subgroup of the sixth group, along with carbon, silicon, germanium and flerovium. Its location predicts amphoteric properties, tin has equally acidic and basic characteristics, which will be described in more detail below.
The periodic table also shows the atomic mass of tin, which is 118.69. The electronic configuration is 5s25p2, which complex substances allows the metal to exhibit oxidation states +2 and +4, giving up two electrons only from the p-sublevel, or four from s- and p-, completely emptying the entire outer level.
Electronic characteristic of the element
In accordance with the atomic number, the circumnuclear 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 starting from the third, there is a triple splittingto s-, p-, d-.
Let's consider the external electronic level, since it is its structure and filling with electrons that determine the chemical activity of the atom. In the unexcited state, the element exhibits a valence equal to two; upon excitation, one electron passes from the s-sublevel to a vacancy in the p-sublevel (it can contain a maximum of three unpaired electrons). In this case, tin exhibits valence and oxidation state - 4, since there are no paired electrons, which means that nothing holds them at the sublevels in the process of chemical interaction.
Simple substance metal and its properties
Simple substance tin is a silver-colored metal, belongs to the group of fusible. The metal is soft and relatively easy to deform. A number of features are inherent in such a metal as tin. A temperature below 13.2 degrees Celsius is the boundary of the transition of the metal modification of tin to powder, which is accompanied by a change in color from silver-white to gray and a decrease in the density of the substance. Tin melts at 231.9 degrees and boils at 2270 degrees Celsius. The crystalline tetragonal structure of white tin explains the characteristic crunching of the metal when it is bent and heated at the point of inflection by rubbing the crystals of the substance against each other. Gray tin has a cubic syngony.
The chemical properties of tin have a dual essence, it enters into both acidic and basic reactions, showing amphoterism. The metal interacts with alkalis, as well as acids, such as sulfuric andnitric, is active when reacting with halogens.
Tin alloys
Why are their alloys with a certain percentage of constituent components used more often instead of pure metals? The fact is that the alloy has properties that an individual metal does not have, or these properties are much stronger (for example, electrical conductivity, corrosion resistance, passivation or activation of the physical and chemical characteristics of metals, if necessary, etc.). Tin (the photo shows a sample of pure metal) is part of many alloys. It can be used as an additive or base substance.
Today, a large number of alloys of such a metal as tin are known (the price for them varies widely), let's consider the most popular and used ones (the use of certain alloys will be discussed in the appropriate section). In general, stannum alloys have the following characteristics: high ductility, low melting point, low hardness and strength.
Some examples of alloys
- An 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 should be 49-51 or 59-61 percent. The strength of the bond ensures that the tin forms a solid solution with the bonded metal surfaces.
- Garth is an alloy of tin, lead andantimony is the basis of printing ink (which is why it is not recommended to wrap food in newspapers to avoid getting undesirable concentrations of these metals).
- Babbit - an alloy of tin, lead, copper and antimony - is characterized by low friction, high wear resistance.
- Indium-tin alloy is a low-melting material, which is characterized by refractoriness, corrosion resistance and significant strength.
The most important natural compounds
Tin forms a number of natural compounds - ores. The metal forms 24 mineral compounds, the most important for industry is tin oxide - cassiterite, as well as frame - Cu2FeSnS4. Tin is scattered in the earth's crust, and the compounds formed by it are of magnetic origin. The industry also uses polyol s alts and tin silicates.
Tin and the human body
The chemical element tin is a microelement in terms of its quantitative content in the human body. Its main accumulation 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 is concentrated in the gastrointestinal tract, lungs, kidneys and heart.
It is important to note that excessive accumulation of this metal can lead to general poisoning of the body, and longer exposure can even lead to adverse gene mutations. Recently, this problem is quite relevant, since the ecological state of the environmentThe environment leaves much to be desired. There is a high probability of tin intoxication among residents of megacities and areas nearby near industrial zones. Most often, poisoning occurs through the accumulation of tin s alts in the lungs, for example, such as tin chloride and others. At the same time, a micronutrient deficiency can cause growth retardation, hearing loss and hair loss.
Application
Metal is commercially available from many smelters and companies. It is produced in the form of ingots, rods, wires, cylinders, anodes made from a pure simple substance such as tin. The price ranges from 900 to 3000 rubles per kg.
Pure tin is rarely used. Its alloys and compounds are mainly used - s alts. Soldering tin is used in the case of fastening parts that are not exposed to high temperatures and strong mechanical loads, made of copper alloys, steel, copper, but is not recommended for those made of aluminum or its alloys. The properties and characteristics of tin alloys are described in the corresponding section.
Solders are used for soldering microcircuits, in this situation alloys based on a metal such as tin are also ideal. The photo depicts the process of applying a tin-lead alloy. With it, you can perform quite delicate work.
Due to the high resistance of tin to corrosion, it is used to make tinned iron (tinplate) - cans for food products. In medicine, in particular in dentistry, tin is used forperforming dental fillings. House pipelines are covered with tin, bearings are made of its alloys. The contribution of this substance to electrical engineering is also invaluable.
Aqueous solutions of tin s alts such as fluoroborates, sulfates, and chlorides are used as electrolytes. Tin oxide is a glaze for ceramics. By introducing various tin derivatives into plastic and synthetic materials, it seems possible to reduce their flammability and the emission of harmful fumes.
