Microwave Spectrum and Structure of Chlorine Azide

The microwave spectra of four isotopic species of chlorine azide, ClN3, have been observed in the frequency range 26–48 GHz. From the measured values of the rotational constants, the molecule has been deduced to be planar with the following internuclear parameters: r(Cl–N(1)) = 1.745 ± 0.005 Å, r(N(1)–N(2)) = 1.252 ± 0.010 Å, r(N(2)–N(3)) = 1.133 ± 0.010 Å, ∠ClN(1)N(2) = 108°40′ ± 30′, ∠N(1)N(2)N(3) = 171°56′ ± 30′, with Cl and N(3) trans. Values for the chlorine quadrupole coupling constants were obtained for all isotopic species, and for the most abundant, 35Cl14N3, were transformed into the principal field gradient axis system. The values obtained are consistent with the deduced structure.