SiF4

Silicon tetrafluoride (SiF4) is a colorless inorganic compound consisting of a silicon atom tetrahedrally coordinated by four fluoride ligands. It is a volatile gas at room temperature with a low boiling point, and it condenses to a liquid only at very low temperatures. The molecule is tetrahedral and acts as a relatively strong Lewis acid, readily accepting fluoride ligands under suitable conditions.

SiF4 is highly reactive with water and moisture. It hydrolyzes readily to silicon dioxide and hydrogen fluoride: SiF4 + 2 H2O → SiO2 + 4 HF. In fluoride-rich environments it can form adducts with fluoride bases, for example SiF4 + 2 F− → [SiF6]2−.

Industrial production is achieved by fluorinating silicon-containing materials. Common routes include reaction of silicon dioxide with hydrofluoric acid: SiO2 + 4 HF → SiF4 + 2 H2O, or direct fluorination of silicon: Si + 2 F2 → SiF4. Because it is a reactive gas, production and handling are performed with appropriate containment to prevent contact with moisture.

Applications include serving as a fluorinating agent in organic and inorganic synthesis and as a source of fluorine in semiconductor processing. In microelectronics, SiF4 is used in plasma etching and deposition processes involving silicon-containing films, contributing to device fabrication workflows.

Safety and handling considerations are significant. SiF4 is corrosive and releases toxic hydrogen fluoride upon hydrolysis, presenting inhalation and dermal hazards. It should be stored and used under strictly dry conditions in well-ventilated facilities, with appropriate protective equipment and procedures for handling HF hazards.