The compound 2,2‐dichloro‐1,1,1‐trifluoroethane, CF3CHCl2, has been selected in an exhaustive search as the most promising working material for potentially viable laser separation of deuterium. Highly isotopically selective absorption in CF3CDCl2occurs near 10.2 and 10.6 &mgr;m, accessible with the normal CO2laser. The single‐step deuterium isotopic enrichment factor attains a value of 1400 at a fluence of 10 J/cm2for the dominant photoproduct, trifluoroethene (CF2=CFD and CF2=CFH). The probability for CF3CDCl2dissociation into CF2=CFD photoproduct occurs with a fluence threshold near 1.5 J/cm2and appears to saturate near 100% yield above 15 J/cm2. Liquid‐phase base‐catalyzed H/D exchange occurs rapidly with water without hydrolysis to permit redeuteration of the CF3CHCl2working material.