Fourier-transform microwave and submillimeter-wave spectroscopy of chloroiodomethane, CH2ICl

► Fourier transform microwave and millimeter-wave spectroscopy of CH2ICl. ► Two chlorine isotopologues observed in their ground vibrational state. ► Hyperfine structures due to I and Cl quadrupolar nuclei analyzed. ► Accurate set of molecular constants determined for CH2ICl. ► An r0 structure was obtained.