ELECTRON-DIFFRACTION INVESTIGATION OF THE MOLECULAR-STRUCTURE OF COF3

A comprehensive electron-diffraction and mass-spectral investigation o f the saturated vapor above cobalt trifluoride at 812 +/- 20 K was und ertaken. It was confirmed that evaporation is congruent in nature and that the gas phase consists of monomeric molecules. The structural par ameters of the CoS3 molecule were determined, and D3h symmetry was est ablished for its equilibrium configuration. The vibration frequencies of the CoF3 molecule were obtained. The relationships governing the va riation of the molecular parameters of the trifluorides of elements in the first transition series are examined in the context of crystal fi eld theory.