Silicon tetrachloride or tetrachlorosilane is an inorganic compound with the chemical formula SiCl4. It is a colorless, volatile liquid that fumes in air. It is used to produce high-purity silicon and silica for commercial applications. It is part of the chlorosilane family.

Silicon tetrachloride is prepared by chlorinating various silicon compounds such as ferrosilicon, silicon carbide or mixtures of silicon dioxide and carbon. The Silicon Railway line is the most common. [3]

In the laboratory, SiCl4 can be prepared by treating silicon with chlorine at 600 °C (1,112 °F):[1]

Si + 2 Cl2 → SiCl4

It was first prepared in 1823 by Jöns Jakob Berzelius.

When chlorine production is a by-product of the metal refining process of metal chloride ores, brines can be contaminated with silica. In rare cases, when the contaminated brine is electrolyzed, the silicon dioxide in the silica is converted to silicon tetrachloride.

Like other chlorosilanes or silanes, silicon tetrachloride reacts readily with water:

SiCl4 + 2 H2O → SiO2 + 4 HCl

In contrast, carbon tetrachloride is not easily hydrolyzed. The reaction can be noticed when the liquid is exposed to air, and when it reacts with moisture, the vapor produces fumes, forming cloudy hydrochloric acid aerosols.