Molecular structure of the chlorine difluoride and chlorine tetrafluoride radicals. A theoretical study

Abstract

ClF/sub 2/ and ClF/sub 4/ are two interesting inorganic radicals whose quantitative molecular structures have not been determined experimentally. A priori electronic structure theory has been used in the present research to predict the structures of these radicals and their positive and negative ions. Self-consistent-field theory has been employed in conjunction with both minimum and double zeta basis sets. For ClF/sub 2/ more extended basis sets were used in addition. The ClF/sub 2//sup +/ ion has a bent (bond angle 97.4/sup 0/) structure quite similar to that of the isoelectronic SF/sub 2/ molecule, while ClF/sub 2//sup -/ is linear. ClF/sub 2/ is predicted C/sub 2v/ with bond length 1.72 A and bond angle near 148/sup 0/. Both minimum and double zeta basis sets predict ClF/sub 4//sup +/ to be square pyramidal, in contrast with the known structure of the isoelectronic SF/sub 4/ molecule. Finally, both ClF/sub 4/ and ClF/sub 4//sup -/ are predicted to be planar. However, these structural predictions are qualitatively altered when chlorine 3d functions are added to the basis set. Electronic structures are discussed in terms of orbital energies and Mulliken populations.