Structural studies of crystalline octamethylsilsesquioxane (CH3)8Si8O12

The crystalline form of (CH3)8Si8O12 (T8) was obtained by a novel, high yield synthetic route from cyclosiloxanes. The structure of the compound has been widely studied by vibrational spectroscopy (infrared and Raman spectroscopy), X-ray diffraction and scanning electron microscopy. Applying ab initio calculations with comparison to the vibrational spectra we were able to determine T8 molecule structure. Results of the comparison were treated as initial parameters for full-pattern fit of the X-ray diffraction results. Ideal symmetry, Oh   (m3¯m) of the T8 molecule and rhombohedral crystal structure of the compound was determined and visualized by graphical model. Microscopic crystallinity was observed by means of SEM.