Electron Diffraction Study of the Molecular Structures of Sulfur Tetrafluoride (SF4) and Thionyl Tetrafluoride (SOF4)

The molecular structures of SF4 and SOF4 in the gaseous state were determined by electron diffraction using sector-microphotometer data. Both molecules were confirmed to have trigonal bipyramidal structures (C2v symmetry), with two nonequivalent sets of F–S bond distances. The bond lengths, in terms of the center of gravity parameter, rg, and the bond angles are as follows: For SF4:rg(equatorial S–F)=1.542±0.005 Å,rg(polar S–F)=1.643±0.005 Å,∠(equatorial F–S–F)=103.8∘±0.6∘,∠(polar F–S–F)=176.8∘±2.5∘.For SOF4:rg(equatorial S–F)=1.539±0.005 Å,rg(polar S–F)=1.602±0.005 Å,rg(S–O)=1.422±0.008 Å,∠(equatorial F–S–F)=122.8∘±1.8∘,∠(polar F–S–F)=182.8∘±0.7∘. The polar F–S–F angles are measured along an arc which bisects the equatorial FSF angle.