Silicon Tetrachloride: Formula and Uses

Silicon Tetrachloride

Silicon Tetrachloride is a volatile but colourless liquid with a pungent odour. These non-flammable liquid fumes in the air lead to corrosion of metals, in presence of moisture. It is a by-product formed during the production of wafers of solar panels. The thermal decomposition of silicon tetrachloride causes white clouds due to silica oxide and hydrochloric acid. It is highly reactive to ammonia or other compounds having hydrogen.

Silicon Tetrachloride Formula

The silicon tetrachloride formula is SiCl₄. The formula for silicon tetrachloride indicates that it has one silicon-bonded with four chlorine atoms. Both silicon and chlorine indulge in a covalent bond with each other.

How is Silicon Tetrachloride prepared?

Silicon tetrachloride is made by the chlorination of other silicon compounds such as silicon dioxide, silicon carbide, or ferrosilicon. Of all of these, ferrosilicon is the most used compound to make silicon tetrachloride.

Hydrolysis of Silicon tetrachloride

Silicon tetrachloride is readily reactive with water and undergoes hydrolysis. Hydrolysis of this compound will result in the formation of silicon dioxide and hydrochloric acid. SiCl₄ + 2H₂O → SiO₂ + 4HCl

Silicon Tetrachloride Uses

• Silicon tetrachloride is mainly used in the commercial production of semiconductors
• It is also used as a primary material in the mass production of silica gel and silicic esters, which is a binder for ceramic materials
• Silicon tetrachloride is a common electrophile which upon reaction with hydrides gives silane
• HIghly pure silicon tetrachloride is used for making optical fibres. Its purity here refers to the absence of hydrogen-containing impurities such as trichlorosilane. The process here involves the oxidation of silicon tetrachloride to make pure silica
• Another use is to make polysilicon which is used in the solar industry. Here, it is prepared by using silicon and chlorine under high temperature which will lead to the formation of polysilicon having multiple silicon molecules