Absence of halogen center dot center dot center dot halogen interactions in chlorotrimethylsilane polymorphs

摘要

The structures of in situ pressure- frozen chlorotrimethylsilane crystals, ( CH3) 3SiCl, have been determined at 0.23, 0.30 and 0.58 GPa. The molecular arrangements in the low- temperature and high- pressure phases are two- dimensionally isostructural, but different in the third perpendicular direction. Consequently, a striking similarity exists between the unitcell dimensions of these polymorphs. The absence of short Cl center dot center dot center dot Cl contacts, both in the low- temperature or pressure-frozen phases of ( CH3) 3SiCl, has been rationalized in terms of the favoured packing patterns and comparable energies of halogen center dot center dot center dot halogen interactions and other van der Waals forces.