in diethyl ether; hexane Irradiation (UV/VIS); (N2 or Ar); Cr(CO)6 in ether irradiated, a soln. of carbene in hexane added at 0°C; evapd. (vac.), Cr(CO)6 sublimed off (vac., 30°C), extd. (ambient temp., hexane), evapd. (ambient temp., vac.), mixed with hexane, chromd.(hexane/ether), evapd.; elem. anal.;