Filonenko O. Theoretical study on the structure and properties of fullerene-like molecular forms of silicon dioxide.

The calculations of the equilibrium structure and cohesive energy with related to structural units of fullerene-like molecules of silicon dioxide (FMSD) have testified the thermodynamic stability of the (SiO2)N - structures of fully coordinated FMSD. The binding energy of fully coordinated molecules (SiO2)N differs by a small amount from the respective experimentally obtained energy value for solid samples of silicon dioxide, suggesting the possibility of experimentally obtaining such structures. Hydrolytic instability of fully coordinated FMSD has been shown. In the presence of water molecules, they are converted to hydroxylated molecules. Hydroxylated FMSD (SiO2)N(H2O)N/2 can exist in solutions of silicic acids as intermediate during hydrothermal and sol-gel syntheses of silicon dioxide based systems. Calculations of frequencies, types and intensities of normal vibrations of atoms in the (SiO2)20(H2O)10 molecule showed quite good agreement with the experimental spectrum of multi-hollow silica nanospheres and silica oligomers, which have similar structural elements. Because of this, molecules like (SiO2)N(H2O)N/2 can be useful for studying the properties of the synthesized hollow nanospheres which have particular scientific and practical interest. A possibility to use C60 fullerene molecules as a template for the synthesis of silicon dioxide (SiO2)60(H2O)30 molecules has been shown.