Silicon, denoted by the chemical symbol Si, is a chemical element with atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre and is the second most abundant element in the Earth's crust after oxygen, making up about 27.7% of it by mass. Silicon does not occur naturally in its pure form but is found in silica, silicates, and other compounds.
Silicon was first identified by Antoine Lavoisier in 1787 as a component of silicic acid. However, it wasn't until 1824 that the element was isolated in an impure form by Jöns Jacob Berzelius by heating silicon tetrafluoride with potassium. Berzelius is credited with naming the element "silicon", deriving it from the Latin "silex" or "silicis", which means flint or hard stone.
Silicon's role in technology is pivotal:
Silicon is primarily produced through the reduction of silicon dioxide with carbon in an electric arc furnace:
SiO₂ + 2C → Si + 2CO
This process yields metallurgical grade silicon, which is further refined for electronic applications through processes like the Siemens process to produce high-purity polysilicon.
The production of silicon, particularly for solar cells and electronics, has environmental implications. The energy-intensive processes involved in refining silicon can contribute to greenhouse gas emissions, though advances in recycling and more efficient production methods are mitigating these impacts.