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 luster, and is a tetravalent metalloid and semiconductor. Here are some key points about silicon:
Silicon was discovered by Jöns Jakob Berzelius in 1824, although it was first isolated in an impure form by Antoine Lavoisier in 1787. Berzelius heated chips of Potassium in a silica container and washed away the residue, leaving behind an impure form of silicon. The pure element was eventually obtained by Henri Étienne Sainte-Claire Deville in 1854 through electrolysis.
Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earth's 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 Earth's crust is composed of silicate minerals, making silicon the second most abundant element in the Earth's crust after Oxygen.
Silicon forms a large number of compounds. Here are some notable ones:
Silicon is commercially prepared by heating silica or quartz with Carbon in an electric arc furnace using the reaction:
SiO2 + 2C → Si + 2CO
This process yields metallurgical grade silicon, which contains about 98-99% silicon. For electronics, silicon must be further purified through the Siemens process or the fluidized bed reactor process.