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What Is Silicon? Characteristics and Properties

What is silicon? Characteristics and properties

Silicon is a grayish crystalline elemental mineral with a metallic luster, very hard, brittle and with very high melting and boiling points. Furthermore, it is an intrinsic semiconductor. The amorphous form of the element occurs in brown, electrically conductive powders that can be easily melted and vaporized.

It is a widely used material in photovoltaic panels for its semiconductor properties. Its physical and chemical properties are very favorable to promote the so-called photovoltaic effect.

From a biological point of view, in some cases it has an important role and is the basic material for the construction of the cell wall of various algae.

Continued breathing of siliceous dust causes a serious lung disease, silicosis, in humans.

Silicon on the Periodic Table

It is a chemical element with atomic number 14 and symbol Si. This chemical element belongs to group IV A of the periodic table .

Regarding the chemical properties, we highlight the following:

  • It presents very notable differences with carbon, the first element of group IV A of the periodic table.

  • Unlike carbon, it has a much smaller electronegativity.

  • It has a great tendency to combine with oxygen to form very stable polymeric or discrete structures.

  • It is essentially non-metallic

  • Its reactivity depends mainly on the degree of division.

  • It acts practically exclusively with valence 4 given its electronic structure.

  • Its compounds are essentially covalent.

Types of Crystalline Silicon

There are two types that depend on the crystalline structures that it forms:

Monocrystalline

Monocrystalline silicon is the base material of the electronics industry. It is composed of a single silicon crystal, which has a continuous crystal lattice, without interruption throughout the solid.

The monocrystalline composition is also used in the production of high-performance photovoltaic cells. Solar cells, unlike microcircuits, can, however, tolerate, within certain limits, small structural imperfections.

Polycrystalline

Polycrystalline silicon is a material made from misaligned (polycrystalline) silicon crystal.

Polycrystalline structures often replace aluminum for the production of metal parts within semiconductor electronic devices due to the improved mechanical strength to the integrated circuit production process. It is also used for conducting capacitors in an integrated environment.

The manufacturing process for polycrystalline structures is simpler.

Where Is Silicon Obtained From?

Silicon is, after oxygen, the most abundant element in the earth's crust, of which it constitutes 26% by weight.

What is silicon? Characteristics and propertiesIt is made up of a mixture of three stable, natural isotopes, with masses 28 (92.21%), 29 (4.70%) and 30 (3.09%), which determine an atomic weight of 28.086. Five artificial radioisotopes of the element are also known, with masses ranging from 25 to 32.

This chemical element is widely diffused in nature, and its presence has been detected in the Sun, in stars and in meteorites.

How Is Silicon Obtained?

Obtaining silicon is done by various methods according to the purpose of the element. The most important commercial method is the reduction of the silica with carbon in an electric furnace.

The preparation of high purity silicon (99.7%) is obtained by transforming impure silicon into the volatile tetrachloride (SiCl4), purifying it by distillation and subsequent reduction with zinc.

In electronics it is obtained by zonal purification, to eliminate boron, aluminum, phosphorus, gallium, arsenic, indium and antimony. Subsequently, a single crystal is obtained by the Czochralski method. This method consists of immersing a small single crystal in a bath of liquid silicon heated to the melting temperature and slowly withdrawing it to cause the growth of the single crystal. Normally, doping of the single crystal is performed simultaneously.

What Is Silicon For?

Silicon plays an important role in electronics, for the manufacture of semiconductor devices.

These semiconductors are also used in photovoltaic solar energy to make solar cells. These solar cells are used to make solar panels and convert solar energy into electricity.

Photovoltaic panels can be built with amorphous or crystalline silicon. Solar panels made of one type or another vary in price and efficiency.

In metallurgy it is used for the preparation of special steels and other alloys and in the preparation of various compounds.

In compound form (silicates, silica, silicones), it is used in a very general way.

Health Properties of Silicon

Silicon is one of the essential trace elements that is present in the human body as part of the body's functioning in muscles, skin, bones, cartilage, tendons and other connective tissues.

In the diet it is included in natural foods rich in silicon. Silicon supplements are also manufactured.

Silicon deficiency can affect collagen production as it activates the enzyme that synthesizes collagen which is a vital protein for elasticity and helps maintain good strength in bones and other tissues.

What Foods Include Silicon?

Silicon is present mainly in foods of plant origin, such as green beans, fruits, and whole grains. Some liquids such as water and other liquids such as coffee and beer can also provide this element. On the other hand, silicon is a mineral that can acquire very different chemical forms, many of which are very difficult for the body to absorb. For this reason, many dietary supplements include organic silicon that allows the body to process it better.

Some food supplements include silicon dioxide (E551) as an anti-caking agent to prevent clumping.

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Published: May 13, 2015
Last review: October 4, 2021