Freon 12 ($\text{CCl}_2\text{F}_2$) is one of the most common freons in industrial use and is manufactured from tetrachloromethane by the Swarts reaction . The Swarts reaction is specifically used for the synthesis of alkyl fluorides, which is accomplished by heating an alkyl chloride or bromide in the presence of a metallic fluoride such as $\text{AgF}$, $\text{Hg}_2\text{F}_2$, $\text{CoF}_2$, or $\text{SbF}_3$ .