R-123 is a transitional “hydrochlorofluorocarbon”, its use being limited in time by the Montreal Protocol.

Used for industrial air conditioning and building climatisation for water and intermediary fluids cooling. In order to preserve the stratosferic ozone layer, R-123 is used as a replacement for R-11 (CFC) for high power air conditioning systems, fitted with centrifugal compressors (one or more stages).