Silicon (called silicon in Taiwan Province Province and Hongkong) is a chemical element with the chemical symbol of Si, formerly known as silicon. The atomic number is 14 and the relative atomic mass is 28.09. There are two kinds of allotropes: amorphous and crystalline, and allotropes include amorphous silicon and crystalline silicon. Quasi-metallic elements belonging to IVA group in the periodic table of elements.

Crystalline silicon is steel gray and amorphous silicon is black, with a density of 2.4g/cm3, a melting point of 1420℃ and a boiling point of 2355℃. Crystalline silicon is an atomic crystal, hard and shiny, with semiconductor characteristics. Silicon has active chemical properties and can combine with oxygen and other elements at high temperature. Insoluble in water, nitric acid and hydrochloric acid, soluble in hydrofluoric acid and alkali solution, used to make ferrosilicon, silicon steel and other alloys. Monocrystalline silicon is an important semiconductor material, which is used to manufacture high-power transistors, rectifiers, solar cells and so on. Silicon is widely distributed in nature, accounting for about 27.6% in the crust. It mainly exists in the form of silica and silicate. Crystalline silicon is dark blue and fragile, which is a typical semiconductor. The chemical properties are very stable. It is difficult to react with substances other than hydrogen fluoride at room temperature.