VIBRATIONAL SPECTRUM AND STRUCTURE OF $CF_{3}PCl_{4}$

Author Institution: Bell Telephone Laboratories, IncorporatedThe vibrational spectrum of the thermally unstable $CF_{3}PCl_{4}$ molecule was observed in the Raman effect $(\Delta \nu=50-1500 cm^{-1})$ and in infrared absorption $(280-2000 cm^{-1})$. The data agree with that expected for a molecule having a trigonal bipyramidal structure in which the $CF_{3}$ group assumes an axial position. Although all of the active fundamentals are assigned, the existence of an appreciable torsional barrier to internal rotation of the $CF_{3}$ group is not confirmed. The phosphorus atom, however, is apparently coplanar with the three equatorial chlorine atoms. Other structures involving an equatorial $CF_{3}$ group in a trigonal bipyramid or an axial $CF_{3}$ group in a tetragonal pyramind are considered and rejected