Structure and methyl groups internal rotation of difluorodimethylsilane

The rotational spectra of the normal and 13C isotopomers of difluorodimethylsilane have been measured by molecular beam Fourier-transform microwave (FTMW) and free-jet absorption millimeter-wave (FJ-AMMW) spectroscopy. Each rotational transition is split into several component lines due to the two methyl groups internal rotations. The corresponding V3 barrier has been determined to be 5.256(3) kJ mol−1. A r0 structure of the heavy atoms skeleton has been obtained. The silicon atom lies-accidentally-on the center of mass of the molecule.