home Auditorium 8 Silicon metal. Some physical and chemical properties of silicon and its compounds. Applications of pure silicon

Silicon metal. Some physical and chemical properties of silicon and its compounds. Applications of pure silicon

Silicon. Physical and chemical properties of silicon

Silicon is an element of the main subgroup of the fourth group of the third period of the periodic table of chemical elements by D.I. Mendeleev, with atomic number 14. Denoted by the symbol Si (lat. Silicium), non-metal. Physical properties: crystalline silicon has a metallic luster, refractory, very hard, semiconductor. 2. Chemical properties: silicon is inactive: a) at elevated temperatures (400-600

b) from complex substances, silicon reacts with alkalis
c) reacts with metals to form silicides

Silica, its properties and applications. Natural and industrial silicates. Their use in construction

Silicon(IV) oxide (silicon dioxide, silica SiO2) - colorless crystals, melting point 1713--1728 °C, have high hardness and strength.

Silicon dioxide is used in the production of glass, ceramics, abrasives, concrete products, for the production of silicon, as a filler in the production of rubber, in the production of silica refractories, in chromatography, etc. Quartz crystals have piezoelectric properties and therefore are used in radio engineering, ultrasonic installations, and lighters . Silicon dioxide is the main component of almost all terrestrial rocks, in particular diatomaceous earth. 87% of the mass of the lithosphere consists of silica and silicates. Amorphous non-porous silicon dioxide is used in the food industry as an excipient E551, which prevents caking and caking, parapharmaceuticals (toothpastes), in the pharmaceutical industry as an excipient (included in most Pharmacopoeias), as well as a food additive or drug as an enterosorbent. Artificially produced films of silicon dioxide are used as an insulator in the production of microcircuits and other electronic components. Also used for the production of fiber optic cables. Pure fused silica is used with some special ingredients added to it. Silica filament is also used in heating elements of electronic cigarettes, as it absorbs liquid well and does not collapse under the heating of the coil. Large clear quartz crystals are used as semi-precious stones; colorless crystals are called rock crystal, violet crystals are called amethysts, and yellow crystals are called citrine. In microelectronics, silicon dioxide is one of the main materials. It is used as an insulating layer and also as a protective coating. It is obtained in the form of thin films by thermal oxidation of silicon, chemical vapor deposition, and magnetron sputtering. Silicon dioxide SiO2 is an acidic oxide that does not react with water. Chemically resistant to acids, but reacts with hydrogen fluoride gas

and hydrofluoric acid:

These two reactions are widely used for glass etching. When SiO2 fuses with alkalis and basic oxides, as well as with carbonates of active metals, silicates are formed - salts of very weak, water-insoluble silicic acids of the general formula xH2O ySiO2 that do not have a constant composition (quite often in the literature it is not silicic acids that are mentioned, but silicic acid, although in fact we are talking about the same substance).

For example, sodium orthosilicate can be obtained:

calcium metasilicate:

or mixed calcium and sodium silicate:

From silicate

Na2CaSi6O14 (Na2O CaO 6SiO2)

manufacture window glass. Most silicates do not have a constant composition. Of all the silicates, only sodium and potassium silicates are soluble in water. Solutions of these silicates in water are called liquid glass. Due to hydrolysis, these solutions are characterized by a highly alkaline environment. Hydrolyzed silicates are characterized by the formation of not true, but colloidal solutions. When solutions of sodium or potassium silicates are acidified, a gelatinous white precipitate of hydrated silicic acids precipitates. The main structural element of both solid silicon dioxide and all silicates is the group in which the silicon atom Si is surrounded by a tetrahedron of four oxygen atoms O. In this case, each oxygen atom is connected to two silicon atoms. Fragments can be connected to each other in different ways. Among the silicates, according to the nature of the connections in their fragments, they are divided into island, chain, ribbon, layered, frame and others. Silicates are a broad class of compounds formed by silicon dioxide (silica) and oxides of other elements. SILICATES IN NATURE. In order to understand the role of silicates in human life, let us first look at the structure of the globe. According to modern concepts, the globe consists of a number of shells. The outer shell of the Earth, the earth's crust, or lithosphere, is formed by granite and basalt shells and a thin sedimentary layer. The granite shell mainly consists of granite - dense intergrowths of feldspars, mica, amphiboles and pyroxenes, and the basalt shell - of such granite-like, but heavier silicate rocks as gabbro, diabase and basalts. Sedimentary rocks are formed by the destruction of other rocks under the influence of conditions characteristic of the Earth's surface. A component of the sedimentary layer are, in particular, clays, the basis of which is the silicate mineral kaolinite. Lithosphere at 95 wt. % formed by silicates. Its average thickness in the continental area is 30-40 km. Then there is the simatic shell, or upper mantle, whose minerals are probably dominated by iron and magnesium silicates. This shell covers the entire globe and extends to a depth of 1200 km. Further from 1200 to 2900 km there is an intermediate shell. Its composition is controversial, but the existence of silicates is assumed in it. Under this shell at a depth of 2900 to 6370 km is the core. Recently, it has been suggested that the core also has a silicate composition. When moving from the surface of the Earth to its center, the density and basicity of the constituent rocks increase (the ratio between the content of metal oxides and silica), pressure and temperature increase. The oldest tools were made by man from flint - a dense aggregate of chalcedony, quartz and opal (800-60 thousand years BC). Later, jasper, rock crystal, agate, obsidian (volcanic silicate glass), jade began to be used for this. There is no generally accepted taxonomy (mineralogical nomenclature) for silicate minerals; their names most often come from the appearance of the crystals, their physical properties, location or name the scientist who discovered them. Plagioclase translated from Greek means obliquely split, and pyroxene means refractory, which corresponds to the properties of these minerals. Quartz minerals, depending on the nature of the impurities, have a wide range of colors, which determines their names: amethyst - purple, citrine - yellow, rock crystal - ice. Modifications of silica stishovite and coesite and the mineral biotite originate from the names of the scientists who discovered them, S.M. Stishov, L. Koes and Zh.B. Bio, and the mineral kaolinite gets its name from Mount Kaoling in China, where clay has long been mined for the production of porcelain. Natural silicates and silica itself play an important role as raw materials and end products in industrial processes. Aluminosilicates - plagioclase, potassium feldspar and silica are used as raw materials in the ceramic, glass and cement industries. For the manufacture of fireproof and electrically insulating textile products (fabrics, cords, ropes), asbestos belonging to hydrosilicates - amphiboles - is widely used. Some types of asbestos have high acid resistance and are used in the chemical industry. Biotites, representatives of the mica group, are used as electrical and thermal insulation materials in construction and instrument making. Pyroxenes are used in metallurgy and stone foundry production, and LiAl pyroxene is used to produce lithium metal. Pyroxenes are a component of blast furnace slag and non-ferrous metallurgy slag, which, in turn, are also used in the national economy. Rocks such as granites, basalts, gabbros, and diabases are excellent building materials. SILICATES OF ARTIFICIAL ORIGIN. Without silicate materials - various types of cement, concrete, slag concrete, ceramics, glass, coatings in the form of enamels and glazes, one can hardly imagine our daily life. The scale of production of silicate materials seems to be impressive figures. In this article we will not touch on the nature and use of glass. These issues have already been discussed in. The most ancient silicate materials are ceramic, obtained from clays and their mixtures with various mineral additives, fired to a stone-like state. In the ancient world, ceramic products were distributed throughout the Earth. From the second half of the 19th century to the present day, the industrial ceramics industry has immeasurably expanded the production and range of ceramics. An example of an artificial silicate material is Portland cement, one of the most common types of mineral binders. Cement is used to bind building parts together to produce massive building blocks, slabs, pipes and bricks. Cement is the basis of such widely used building materials as concrete, slag concrete, and reinforced concrete. Construction of any scale cannot exist without cement. The school course in chemistry gives basic ideas about the chemical composition and technology of cement, so we will dwell only on some clarifying details. First of all, cement clinker is the product of firing a mixture of clay and limestone, and cement is finely ground clinker with mineral additives that regulate its properties. Cement is used in a mixture with sand and water. Its astringent properties are due to the ability of cement minerals to interact with H2O and SiO2 and at the same time harden, forming a strong stone-like structure. When cement sets, complex processes occur: hydration of minerals with the formation of hydrosilicates and hydroaluminates, hydrolysis, formation of colloidal solutions and their crystallization. Research into the hardening processes of cement mortar and cement clinker minerals played a major role in the development of the science of silicates and their technology. Our construction sites consume large quantities of cement, bricks, facing slabs, tiles, sewer pipes, glass and various natural building materials.

Silicon (Si) – stands in period 3, group IV of the main subgroup of the periodic table. Physical properties: silicon exists in two modifications: amorphous and crystalline. Amorphous silicon is a brown powder with a density of 2.33 g/cm3, soluble in metal melts. Crystalline silicon is dark gray crystals with a steely luster, hard and brittle, with a density of 2.4 g/cm3. Silicon consists of three isotopes: Si (28), Si (29), Si (30).

Chemical properties: electronic configuration: 1s22s22p63 s23p2 . Silicon is a non-metal. At the outer energy level, silicon has 4 electrons, which determines its oxidation states: +4, -4, -2. Valency – 2.4. Amorphous silicon has greater reactivity than crystalline silicon. Under normal conditions, it interacts with fluorine: Si + 2F2 = SiF4. At 1000 °C Si reacts with non-metals: CL2, N2, C, S.

Of the acids, silicon reacts only with a mixture of nitric and hydrofluoric acids:

It behaves differently in relation to metals: in molten Zn, Al, Sn, Pb it dissolves well, but does not react with them; Silicon interacts with other metal melts - with Mg, Cu, Fe - to form silicides: Si + 2Mg = Mg2Si. Silicon burns in oxygen: Si + O2 = SiO2 (sand).

Silicon dioxide or silica– stable connection Si, widely distributed in nature. It reacts by fusing it with alkalis and basic oxides, forming silicic acid salts - silicates. Receipt: in industry, silicon in its pure form is obtained by reducing silicon dioxide with coke in electric furnaces: SiO2 + 2C = Si + 2CO?.

In the laboratory, silicon is obtained by calcination of white sand with magnesium or aluminum:

SiO2 + 2Mg = 2MgO + Si.

3SiO2 + 4Al = Al2O3 + 3Si.

Silicon forms acids: H2 SiO3 – meta-silicic acid; H2 Si2O5 is dimethasilicic acid.

Finding in nature: quartz mineral – SiO2. Quartz crystals are shaped like a hexagonal prism, colorless and transparent, and are called rock crystal. Amethyst is a rock crystal colored purple with impurities; smoky topaz is brownish in color; agate and jasper are crystalline varieties of quartz. Amorphous silica is less common and exists in the form of the opal mineral – SiO2 nH2O. Diatomite, tripoli or diatomaceous earth (diatomaceous earth) are earthy forms of amorphous silicon.

42. The concept of colloidal solutions

Colloidal solutions– highly dispersed two-phase systems, consisting of a dispersion medium and a dispersed phase. The particle sizes are intermediate between true solutions, suspensions and emulsions. U colloidal particles molecular or ionic composition.

There are three types of internal structure of primary particles.

1. Suspensoids (or irreversible colloids)– heterogeneous systems, the properties of which can be determined by the developed interphase surface. Compared to suspensions, they are more highly dispersed. They cannot exist for a long time without a dispersion stabilizer. They are called irreversible colloids due to the fact that their sediments do not form sols again after evaporation. Their concentration is low - 0.1%. They differ slightly from the viscosity of the dispersed medium.

Suspensoids can be obtained:

1) methods of dispersion (crushing large bodies);

2) condensation methods (production of insoluble compounds using exchange reactions, hydrolysis, etc.).

The spontaneous decrease in dispersity in suspensions depends on the free surface energy. To obtain a long-lasting suspension, conditions are necessary to stabilize it.

Stable disperse systems:

1) dispersion medium;

2) dispersed phase;

3) stabilizer of the dispersed system.

The stabilizer can be ionic, molecular, but most often high-molecular.

Protective colloids– high-molecular compounds that are added for stabilization (proteins, peptides, polyvinyl alcohol, etc.).

2. Associative (or micellar colloids) – semicolloids that arise when there is a sufficient concentration of molecules consisting of hydrocarbon radicals (diphilic molecules) of low molecular weight substances when they associate into aggregates of molecules (micelles). Micelles are formed in aqueous solutions of detergents (soaps), organic dyes.

3. Molecular colloids (reversible or lyophilic colloids) – natural and synthetic high-molecular substances with high molecular weight. Their molecules have the size of colloidal particles (macromolecules).

Dilute solutions of colloids of high molecular weight compounds are homogeneous solutions. When highly diluted, these solutions obey the laws of dilute solutions.

Non-polar macromolecules dissolve in hydrocarbons, polar ones - in polar solvents.

Reversible colloids– substances, the dry residue of which, when adding a new portion of the solvent, goes back into solution.

DEFINITION

Silicon- the fourteenth element of the Periodic Table. Designation - Si from the Latin "silicium". Located in the third period, group IVA. Refers to non-metals. The nuclear charge is 14.

Silicon is one of the most common elements in the earth's crust. It makes up 27% (wt.) of the part of the earth’s crust accessible to our study, ranking second in abundance after oxygen. In nature, silicon is found only in compounds: in the form of silicon dioxide SiO 2, called silicon anhydride or silica, in the form of salts of silicic acids (silicates). Aluminosilicates are the most widespread in nature, i.e. silicates containing aluminum. These include feldspars, micas, kaolin, etc.

Like carbon, which is part of all organic substances, silicon is the most important element of the plant and animal kingdom.

Under normal conditions, silicon is a dark gray substance (Fig. 1). It looks like metal. Refractory - melting point is 1415 o C. Characterized by high hardness.

Rice. 1. Silicon. Appearance.

Atomic and molecular mass of silicon

The relative molecular mass of a substance (M r) is a number showing how many times the mass of a given molecule is greater than 1/12 the mass of a carbon atom, and the relative atomic mass of an element (A r) is how many times the average mass of atoms of a chemical element is greater than 1/12 mass of a carbon atom.

Since in the free state silicon exists in the form of monatomic Si molecules, the values of its atomic and molecular masses coincide. They are equal to 28.084.

Allotropy and allotropic modifications of silicon

Silicon can exist in the form of two allotropic modifications: diamond-like (cubic) (stable) and graphite-like (unstable). Diamond-like silicon is in a solid aggregate state, and graphite-like silicon is in an amorphous state. They also differ in appearance and chemical activity.

Crystalline silicon is a dark gray substance with a metallic luster, and amorphous silicon is a brown powder. The second modification is more reactive than the first.

Isotopes of silicon

It is known that in nature silicon can be found in the form of three stable isotopes 28 Si, 29 Si and 30 Si. Their mass numbers are 28, 29 and 30, respectively. The nucleus of an atom of the silicon isotope 28 Si contains fourteen protons and fourteen neutrons, and the isotopes 29 Si and 30 Si contain the same number of protons, fifteen and sixteen neutrons, respectively.

There are artificial isotopes of silicon with mass numbers from 22 to 44, among which the longest-lived is 32 Si with a half-life of 170 years.

Silicon ions

At the outer energy level of the silicon atom there are four electrons, which are valence:

1s 2 2s 2 2p 6 3s 2 3p 2 .

As a result of chemical interaction, silicon can give up its valence electrons, i.e. be their donor and turn into a positively charged ion, or accept electrons from another atom, i.e. be an acceptor, and turns into a negatively charged ion:

Si 0 -4e → Si 4+ ;

Si 0 +4e → Si 4- .

Silicon molecule and atom

In the free state, silicon exists in the form of monatomic Si molecules. Here are some properties characterizing the silicon atom and molecule:

Silicon alloys

Silicon is used in metallurgy. It serves as a component of many alloys. The most important of them are alloys based on iron, copper and aluminum.

Examples of problem solving

EXAMPLE 1

Exercise

How much silicon (IV) oxide containing 0.2 mass impurities is required to obtain 6.1 g of sodium silicate.

Solution

Let us write the reaction equation for producing sodium silicate from silicon (IV) oxide:

SiO 2 + 2NaOH = Na 2 SiO 3 + H 2 O.

Let's find the amount of sodium silicate:

n(Na 2 SiO 3) = m (Na 2 SiO 3) / M(Na 2 SiO 3);

n(Na 2 SiO 3) = 6.1 / 122 = 0.05 mol.

According to the reaction equation n(Na 2 SiO 3) : n(SiO 2) = 1:1, i.e. n(Na 2 SiO 3) = n(SiO 2) = 0.05 mol.

The mass of silicon (IV) oxide (without impurities) will be equal to:

M(SiO 2) = Ar(Si) + 2×Ar(O) = 28 + 2×16 = 28 + 32 = 60 g/mol.

m pure (SiO 2) = n(SiO 2) ×M(SiO 2) = 0.05 × 60 = 3 g.

Then the mass of silicon (IV) oxide required for the reaction will be equal to:

m(SiO 2) =m pure (SiO 2)/w impurity = 3 / 0.2 = 15 g.

Answer

15 g

EXAMPLE 2

Exercise

What mass of sodium silicate can be obtained by fusing silicon (IV) oxide with 64.2 g of soda, the mass fraction of impurities in which is 5%?

Solution

Let us write the reaction equation for producing sodium silicate by fusing soda and silicon (IV) oxide:

SiO 2 + Na 2 CO 3 = Na 2 SiO 3 + CO 2 -.

Let's determine the theoretical mass of soda (calculated using the reaction equation):

n(Na 2 CO 3) = 1 mol.

M(Na 2 CO 3) = 2×Ar(Na) + Ar(C) + 3×Ar(O) = 2×23 + 12 + 3×16 = 106 g/mol.

m(Na 2 CO 3) = n(Na 2 CO 3) ×M(Na 2 CO 3) = 1 × 106 = 106g.

Let's find the practical mass of soda:

w pure (Na 2 CO 3) = 100% - w impurity = 100% - 5% = 95% = 0.95.

m pure (Na 2 CO 3) = m (Na 2 CO 3) ×w pure (Na 2 CO 3);

m pure (Na 2 CO 3) = 64.2 × 0.95 = 61 g.

Let's calculate the theoretical mass of sodium silicate:

n(Na 2 SiO 3) = 1 mol.

M(Na 2 SiO 3) = 2×Ar(Na) + Ar(Si) + 3×Ar(O) = 2×23 + 28 + 3×16 = 122 g/mol.

m(Na 2 SiO 3) = n(Na 2 SiO 3) ×M(Na 2 SiO 3) = 1 × 122 = 122g.

Let the practical mass of sodium silicate be x g. Let’s make the proportion:

61 g Na 2 CO 3 - x g Na 2 SiO 3;

106 g Na 2 CO 3 - 122 g Na 2 SiO 3.

Hence x will be equal to:

x = 122 × 61 / 106 = 70.2 g.

This means the mass of released sodium silicate is 70.2 g.

Answer

70.2 g

CPU? Sand? What associations do you have with this word? Or maybe Silicon Valley?
Be that as it may, we come across silicon every day, and if you are interested in finding out what Si is and what it is eaten with, please refer to the cat.

Introduction

As a student at one of the Moscow universities with a specialty in Nanomaterials, I wanted to introduce you, dear reader, to the most important chemical elements of our planet. I spent a long time choosing where to start, carbon or silicon, and still decided to stop at Si, because the heart of any modern gadget is based on it, so to speak, of course. I will try to express my thoughts in an extremely simple and accessible way. By writing this material, I was counting mainly on beginners, but more advanced people will also be able to learn something interesting. I would also like to say that the article was written solely to broaden the horizons of those interested. So let's get started.

Silicium

Silicon (lat. Silicium), Si, chemical element of group IV of the periodic system of Mendeleev; atomic number 14, atomic mass 28.086.
In nature, the element is represented by three stable isotopes: 28Si (92.27%), 29Si (4.68%) and 30Si (3.05%).
Density (at no.) 2.33 g/cm³
Melting point 1688 K

Powder Si

Historical reference

Silicon compounds, widespread on earth, have been known to man since the Stone Age. The use of stone tools for labor and hunting continued for several millennia. The use of Silicon compounds associated with their processing - glass production - began around 3000 BC. e. (in Ancient Egypt). The earliest known Silicon compound is SiO2 oxide (silica). In the 18th century, silica was considered a simple solid and classified as an “earth” (as reflected in its name). The complexity of the composition of silica was established by I. Ya. Berzelius. For the first time, in 1825, he obtained elemental silicon from silicon fluoride SiF4, reducing the latter with potassium metal. The new element was given the name “silicon” (from the Latin silex - flint). The Russian name was introduced by G. I. Hess in 1834.

Silicon is very common in nature as part of ordinary sand.

Distribution of Silicon in nature

Silicon is the second most abundant element in the earth's crust (after oxygen), its average content in the lithosphere is 29.5% (by mass). In the earth's crust, Silicon plays the same primary role as carbon in the animal and plant world. For the geochemistry of silicon, its extremely strong connection with oxygen is important. About 12% of the lithosphere is silica SiO2 in the form of the mineral quartz and its varieties. 75% of the lithosphere is composed of various silicates and aluminosilicates (feldspars, micas, amphiboles, etc.). The total number of minerals containing silica exceeds 400.

Physical properties of Silicon

I think there is no point in dwelling here, all physical properties are freely available, but I will list the most basic ones.
Boiling point 2600 °C
Silicon is transparent to long-wave infrared rays
Dielectric constant 11.7
Silicon Mohs hardness 7.0
I would like to say that silicon is a brittle material; noticeable plastic deformation begins at temperatures above 800°C.
Silicon is a semiconductor, which is why it is widely used. The electrical properties of silicon are very dependent on impurities.

Chemical properties of Silicon

There’s a lot that could be said here, of course, but I’ll focus on the most interesting. In Si compounds (similar to carbon) 4-valentene.
In air, silicon is stable even at elevated temperatures due to the formation of a protective oxide film. In oxygen it oxidizes starting at 400 °C, forming silicon oxide (IV) SiO2.
Silicon is resistant to acids and dissolves only in a mixture of nitric and hydrofluoric acids, and easily dissolves in hot alkali solutions with the release of hydrogen.
Silicon forms 2 groups of oxygen-containing silanes - siloxanes and siloxenes. Silicon reacts with nitrogen at temperatures above 1000 °C. Of great practical importance is the nitride Si3N4, which does not oxidize in air even at 1200 °C, is resistant to acids (except nitric) and alkalis, as well as to molten metals and slags, which makes it is a valuable material for the chemical industry, as well as for the production of refractories. Silicon compounds with carbon (silicon carbide SiC) and boron (SiB3, SiB6, SiB12) are characterized by high hardness, as well as thermal and chemical resistance.

Obtaining Silicon

I think this is the most interesting part, let’s take a closer look here.
Depending on the purpose there are:
1. Electronic quality silicon(so-called “electronic silicon”) - the highest quality silicon with a silicon content of over 99.999% by weight, the electrical resistivity of electronic quality silicon can be in the range from approximately 0.001 to 150 Ohm cm, but the resistance value must be ensured exclusively a given impurity, i.e., the entry of other impurities into the crystal, even if they provide a given electrical resistivity, is, as a rule, unacceptable.
2. Solar grade silicon(so-called “solar silicon”) - silicon with a silicon content of over 99.99% by weight, used for the production of photovoltaic converters (solar batteries).

3. Technical silicon- silicon blocks of polycrystalline structure obtained by carbothermic reduction from pure quartz sand; contains 98% silicon, the main impurity is carbon, characterized by a high content of alloying elements - boron, phosphorus, aluminum; mainly used to produce polycrystalline silicon.

Technical purity silicon (95-98%) is obtained in an electric arc by reducing silica SiO2 between graphite electrodes. In connection with the development of semiconductor technology, methods have been developed for producing pure and highly pure silicon. This requires the preliminary synthesis of the purest initial silicon compounds, from which silicon is extracted by reduction or thermal decomposition.
Polycrystalline silicon (“polysilicon”) is the purest form of industrially produced silicon - a semi-finished product obtained by purifying technical silicon using chloride and fluoride methods and used for the production of mono- and multicrystalline silicon.
Traditionally, polycrystalline silicon is obtained from technical silicon by converting it into volatile silanes (monosilane, chlorosilanes, fluorosilanes) with subsequent separation of the resulting silanes, rectification purification of the selected silane and reduction of the silane to metallic silicon.
Pure semiconductor silicon is obtained in two forms: polycrystalline(reduction of SiCl4 or SiHCl3 with zinc or hydrogen, thermal decomposition of SiI4 and SiH4) and monocrystalline(crucible-free zone melting and “pulling” a single crystal from molten silicon - Czochralski method).

Here you can see the process of growing silicon using the Czochralski method.

Czochralski method- a method of growing crystals by pulling them upward from the free surface of a large volume of melt with the initiation of crystallization by bringing a seed crystal (or several crystals) of a given structure and crystallographic orientation into contact with the free surface of the melt.

Application of Silicon

Specially doped silicon is widely used as a material for the manufacture of semiconductor devices (transistors, thermistors, power rectifiers, thyristors; solar photocells used in spacecraft, as well as many other things).
Since silicon is transparent to rays with wavelengths from 1 to 9 microns, it is used in infrared optics.
Silicon has diverse and expanding applications. In metallurgy Si
used to remove oxygen dissolved in molten metals (deoxidation).
Silicon is a component of a large number of alloys of iron and non-ferrous metals.
Typically, Silicon gives alloys increased resistance to corrosion, improves their casting properties and increases mechanical strength; however, at higher levels Silicon can cause brittleness.
The most important are iron, copper and aluminum alloys containing silicon.
Silica is processed by glass, cement, ceramics, electrical and other industries.
Ultra-pure silicon is primarily used for the production of single electronic devices (for example, your computer processor) and single-chip microcircuits.
Pure silicon, ultra-pure silicon waste, purified metallurgical silicon in the form of crystalline silicon are the main raw materials for solar energy.
Monocrystalline silicon - in addition to electronics and solar energy, is used to make gas laser mirrors.

Ultrapure silicon and its products

Silicon in the body

Silicon is found in the body in the form of various compounds, mainly involved in the formation of hard skeletal parts and tissues. Some marine plants (for example, diatoms) and animals (for example, siliceous sponges, radiolarians) can accumulate especially large amounts of silicon, forming thick deposits of silicon (IV) oxide when they die on the ocean floor. In cold seas and lakes, biogenic silts enriched with silicon predominate; in tropical seas, calcareous silts with a low silicon content predominate. Among terrestrial plants, cereals, sedges, palm trees, and horsetails accumulate a lot of silicon. In vertebrates, the content of silicon (IV) oxide in ash substances is 0.1-0.5%. Silicon is found in the largest quantities in dense connective tissue, kidneys, and pancreas. The daily human diet contains up to 1 g of silicon. When there is a high content of silicon (IV) oxide dust in the air, it enters the human lungs and causes the disease silicosis.

Conclusion

Well, that's all, if you read to the end and delve a little deeper, then you are one step closer to success. I hope I didn’t write in vain and at least someone liked the post. Thank you for your attention.

Chemistry