CF4

CF4, also known as tetrafluoromethane, is a colorless, odorless, non-flammable gas with the chemical formula CF4. It is one of the simplest fluorinated compounds and is characterized by strong carbon–fluorine bonds, which confer exceptional chemical inertness. CF4 is denser than air and exists as a gas at room temperature and pressure.

In terms of physical properties, CF4 has a boiling point of about −128 °C and a melting point well below that, indicating it remains gaseous under standard conditions. It has a molecular weight of 88.0 g/mol and a tetrahedral molecular geometry. CF4 is nonpolar and only sparingly soluble in water. It is highly stable and resists reaction with most reagents, though it can decompose at very high temperatures to form carbon dioxide and hydrogen fluoride in the presence of suitable catalysts or flames.

CF4 is produced industrially by direct fluorination of methane (CH4 + 4 F2 → CF4 + 4 HF) and can also arise as a byproduct in various fluorination processes. It is principally used as a process gas in the semiconductor industry for plasma etching of silicon and silicon dioxide, where its chemical stability allows precise material removal. It has limited chemical reactivity, which makes it useful in certain specialized low-reactivity applications.

Environmentally, CF4 is a potent greenhouse gas with a very long atmospheric lifetime, contributing to climate change far more per unit mass than CO2 over long timescales. It is subject to regulation under climate and industrial gas control frameworks. Safety considerations include the risk of asphyxiation in enclosed spaces, since CF4 can displace oxygen; it is non-toxic at typical industrial exposures but should be handled with appropriate ventilation and containment.