The microwave spectra of four isotopic species of the unstable molecule chloroketene ClHCCO have been observed from the flowpyrolysis of monochloroacetyl chloride and from the pyrolytic reaction of dichloroacetyl chloride with zinc metal. The spectra, which consist only of b??type transitions, were observed in the frequency range 26.5–80 GHz. Accurate rotational constants and quartic and sextic centrifugal distortion constants have been ...
