PROPERTIES OF THE INTERMEDIATE ETHYNE...CL2 FROM ITS ROTATIONAL SPECTRUM AND SOME GENERALIZATIONS FOR A SERIES B...CL2

A T-shaped planar complex of ethyne and Cl2 has been isolated in a mixture of the substances using a pulsed-nozzle, FT microwave spectrometer and characterised through its rotational spectrum. Rotational constants (A0, B0, C0), centrifugal distortion constants (DELTA(J), DELTA(JK), delta(J)), and Cl-nuclear quadrupole coupling constants chi(aa)(Cl) and chi(bb)(Cl)-chi(cc)(Cl) of both Cl nuclei are reported for the isotopomer (HC-CH, Cl-35(2)). The angular geometry, electric charge redistribution within the Cl2 subunit and intermolecular force constant k(sigma) as derived from the spectroscopic constants, are compared with those of other B...Cl2 and of the corresponding series B...HCl to give some generalisations.