Silicon: The Element

The chemical element silicon is a metalloid substance. That means, they have the intermediate properties of metals and non-metals. Sometimes, they are referred to as semi-metals. Silicon has derived its name from the Latin word silicium. Silicon was first discovered in 1787 by the father of modern chemistry, Antoine Lavoisier.

Silicon comprises almost one-fourth of the Earth's crust. Despite its abundance on the surface of the Earth, it is rarely found in a free elemental state. It is mostly available in the different minerals of silicon dioxide or silica and silicates. Flint, quartz, amethyst, jasper and opal are few of the minerals which contain silica. Pyroxene, mica and feldspar are some of the important silicate minerals. We can obtain these minerals from stones like granite, and in sand and clay.

Properties of Silicon

Silicon is found in a crystalline form. The pure form of silicon is gray in color with a metallic luster. It has some of its properties similar to glass. It is a strong, yet brittle in nature.

Chemically, silicon is denoted by the symbol Si. The atomic number of silicon is 14 and atomic weight is 28.08. It is a tetravalent element and contains four electrons in its outermost orbit. Silicon is a not a very chemically reactive element. It does not react with most of the acidic compounds. However, it reacts with dilute alkalies and halogens. Due to the presence of four electrons in its outer shell, it is capable of bonding with some other elements and compounds under certain circumstances.

Compounds of Silicon

When silicon reacts with some metallic elements like magnesium, it forms magnesium silicide (Mg₂Si), which is a highly reactive compound. On reaction with carbon, it gives silicon carbide (SiC), which is an abrasive substance with a high melting point. Silane (SiH₄) is formed due to reaction of hydrogen and silicon, and this compound tends to catch fire very easily. Silicon dioxide is one such compound of silicon that is found in a variety of shapes of crystals.

Uses of Silicon

Silicon is most widely used for the purpose of making aluminum-silicon alloys which is used in the automobile industry. Silicon is used as a component of electrical steel in order to modify its electrical resistance and magnetic properties. When silicon is added to molten cast iron, it helps to improve the quality and performance of the cast iron. Compounds of silicon like silica and silicate are used in glass, ceramic and cement industry

Another very important application of silicon is in the preparation of silicones, a compound that made up of silicon-oxygen and silicon-carbon bonds. This compound is capable of forming polymers and possesses the property like impermeability to water. The compound silicone has various uses including waterproofing treatments, and also for creating mechanical seals, high temperature greases and waxes, etc.

Silicon, in its purest form, is a valuable element in the semiconductor industry. It is very popular because it can retain the properties of a semiconductor even at a very high temperature, which other elements like germanium cannot. It is used for making thin slices of silicon wafers that are required in electronic equipments. Highly purified silicon is often doped with certain elements to regulate its electrical conductivity. This kind of regulation is required in solar cells, transistors, integrated circuits or microchips, microprocessors and several other semiconductor devices that have usage in electronics and high-tech materials.

The element silicon or its compounds have no major harmful effects on plants, animals or the environment. Rather, silicon is quite important for the metabolism of certain types of grasses. These, besides its various uses that we have seen above.