Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, and lead are below it. It is relatively unreactive. Because of its high chemical affinity for oxygen, it was not until 1823 that Jöns Jacob Berzelius was first able to prepare it and characterize it in pure form. Its melting and boiling points of 1414 °C and 3265 °C respectively are the second-highest among all the metalloids and nonmetals, being only surpassed by boron. Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earths crust. It is most widely distributed in dusts, sands, planetoids, and planets as various forms of silicon dioxide (silica) or silicates. Over 90% of the Earths crust is composed of silicate minerals, making silicon the second most abundant element in the Earths crust (about 28% by mass) after oxygen.
Most silicon is used commercially without being separated, and often with little processing of the natural minerals. Such use includes industrial construction with clays, silica sand, and stone. Silicates are used in Portland cement for mortar and stucco, and mixed with silica sand and gravel to make concrete for walkways, foundations, and roads. Clay bars and ceramic parts are also formulated from mixtures of silica with various metals. Silicones are used in sealants, adhesives, lubricants, medicine, cooking utensils, and exploring space. Silicates are also used inWhiteware ceramics such as dishes, pottery, and bathroom fixtures. Silicon is an important constituent of some steels and a few types of aluminium alloys.
Silicon is a principal component of electronics such as computer chips, transistors and diodes. Silicon is the basis of the widely used synthetic polymers called silicones. In 1854, Louis Pasteur observed that quartz amethyst crystals, which are piezoelectric materials, could become electrically charged after exposure to light. In 1881, the German scientist Ferdinand Braun invented the crystal diode detector, which is the basis for modern radio receivers. Silicon, as a semiconductor possessing the properties of both an electrical conductor and an insulator, has found wide application in the modern electronics industry. In 1952, Texas Instruments and Fairchild Semiconductor Corporation, led by William Shockley, developed the first commercial silicon transistor. Since then, the electronic industry has grown exponentially, and silicon has become a major part of modern life.
Silicon is one of the most important materials used in modern industry, and it has a wide variety of applications. Silicon is the material used to make semiconductors, a key element in the development of computer technology. It is also used to make transistors, the tiny switches that control all electronics and communication systems. Silicon is also used for energy storage, in solar cells, as well as for medical applications, to make implants and prostheses, and as a food additive. In addition, silicon is used in many consumer products, from cosmetics to lubricants. Finally, silicon is an important component of some metals, such as aluminum and steel, and it helps make these materials stronger and more durable.
