Silicon

Silicon is a chemical element (an element being a substance that cannot be decomposed by ordinary chemical means) with the symbol Si and atomic number 14. It belongs to group 14 of the periodic table and has intermediate properties between metals and nonmetals; it is therefore called a metalloid.

In pure form, silicon is a hard, dark gray substance with a metallic sheen. In nature it does not occur uncombined; it is found mainly in compounds of silicon and oxygen called silica and silicates. Sand, seawater, rocks, and soil consist of these materials.

Physical and chemical properties

Silicon has a crystalline structure similar to that of diamond, where each atom is bonded to four others. It is a semiconductor, meaning its ability to conduct electric current is lower than that of metals but higher than that of insulators. This property can be altered by heat or by introducing small foreign atoms, a process called doping.

Extraction and production

Silicon is one of the most abundant elements in the Earth's crust, second only to oxygen by mass. Factories produce silicon from quartz sand by heating it with carbon in electric furnaces. The result is commercial silicon, which is further refined when electronic-grade purity is required.

Uses

The most common use is in electronics: computer chips, transistors, and integrated circuit boards are built on silicon wafers. It is also used in alloys of iron, aluminum, bronze, cement, and solar panels for electricity generation. Silicone (a polymer containing silicon, oxygen, and carbon) is a distinct material from the element itself.