1,2-Dichloro-1,1,2-trifluoroethane

1,2-Dichloro-1,1,2-trifluoroethane is a volatile liquid chlorofluoroalkane composed of carbon, hydrogen, chlorine and fluorine, and with structural formula CClF2CHClF. It is also known as a refrigerant with the designation R-123a.

Formation
1,1,2-Trichloro-1,2,2-trifluoroethane can be biotransformed in sewage sludge to 1,2-dichloro-1,1,2-trifluoroethane.

Properties
The critical temperature of R-123a is 461.6 K. The rotation of the molecule appears to be hindered by the present of chlorine on each carbon atom, but is eased at higher temperatures.

Use
Although not deliberately used, R-123a is a significant impurity in its isomer, the widely used 2,2-dichloro-1,1,1-trifluoroethane (R-123).