Siliciums

Silicium, commonly known as silicon in English, is the chemical element with symbol Si and atomic number 14. It is a metalloid and the second most abundant element in the Earth's crust by mass, after oxygen. The name silicium is the historical Latin form; today the English name is silicon, and cognate names persist in many languages (for example silicium, Silizium, silicio).

Silicon is tetravalent and forms a vast array of compounds. In its crystalline form it adopts a diamond cubic lattice and has a high melting point of about 1,414°C. Pure silicon is a poor conductor at room temperature, behaving as a semiconductor. Its electrical properties can be controlled by doping with elements such as boron or phosphorus to create p-type or n-type semiconductors.

Silicon occurs mainly as silicon dioxide (silica) and silicate minerals in the Earth's crust; free silicon is not found in nature. Industrial production involves reduction of SiO2 with carbon to produce metallurgical-grade silicon, which is then purified to electronic-grade silicon through processes such as the Siemens process to yield polysilicon for semiconductors and solar cells. Silicon carbide (SiC) is another important silicon compound used as an abrasive and high-temperature material.

Applications of silicon include microelectronics and photovoltaics, where silicon-based semiconductors are dominant. Silicon is also a component of glass and cement, and silicon-containing polymers known as silicones are widely used in coatings, adhesives, and medical devices.

Historical note: Jöns Jakob Berzelius first prepared silicon in 1824 by reducing silica with a metal; the Latin form silicium gave way to the modern English "silicon" name in subsequent decades. Health considerations: crystalline silica dust can cause lung diseases such as silicosis; proper dust control is essential in industrial settings.