Silica gels atomic distances

The bicyclic silanol endo-3-methyl-exo-3-hydroxy-3-silabicyclo-[3.2.1]octane may be prepared by treating the corresponding methoxysi-lane with silica gel. Although the position of the OH hydrogen atom was found to be disordered 253), the intermolecular 0---0 distances of 2.69 and 2.71 A suggest that the molecules are joined into zigzag chains as shown in Fig. 8 210). 

The somewhat random distribution of atoms required in the amorphous structure of the silica-alumina cracking catalyst makes it unreasonable to suggest a single exact distance between the aluminum atoms in the active sites along the edges of the catalyst ribbon. Furthermore, catalysts formed by impregnation of silica gel with alumina may be represented as forming by the condensation of aluminum hydroxyls with hydroxyls on adjacent... 

In a number of studies stable imidazoline nitroxides were employed for investigating the structure of the nearest environment to the radicals on the surface and in frozen solutions. The ability of the mentioned radicals to undergo complexation was used for estimating the distances between palladium atoms in fixed complexes on the surface of silica gel (Semikolenov... 

---