Interactions of 30% aqueous solution of H2O2 with nanosilica (409 m(2)/g) in CCl4 or CD3Cl media with addition of CD3CN or (CD3)(2)SO were studied using H-1 NMR spectroscopy and quantum chemistry methods. In nonpolar medium, two types of structures are formed with strongly associated water (delta(H) = 4-6 ppm) including different amounts of H2O2 center dot H2O/H2O2 bound to silica in weakly polar CD3Cl with addition of CD3CN or DMSO form three types of clusters with: (i) concentrated H2O2 at delta(H) = 9-11 ppm; (ii) concentrated water and dissolved co-solvents; and (iii) organic solvents containing certain amounts of water and H2O2. (C) 2012 Elsevier B.V. All rights reserved.