Synthesis and structural characterization of novel tin and titanium potassium silicates K4M2Si6O18

摘要

The synthesis of a new potassium titanosilicate, K4Ti2Si6O18 (Ti-AV-11), possessing the crystal structure of potassium stannosilicate AV-11, has been reported. The unit cell of this material is trigonal, space group R3 (no. 146), Z = 3, a = 10.012, c = 14.8413 Angstrom, gamma = 120degrees, V = 1289 Angstrom(3). The structure of AV-11 is built up of MO6 (M = Sn, Ti) octahedra. and SiO4 tetrahedra by sharing corners. The SiO4 tetrahedra form helix chains, periodically repeating every six tetrahedra. These chains extend along the [001] direction and are linked by isolated MO6 octahedra, thus producing a mixed octahedral-tetrahedral oxide framework. AV-11 materials have been further characterized by bulk chemical analysis, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Si-29 and Sn-119 magic-angle spinning (MAS) NMR spectroscopy. (C) 2003 Elsevier Inc. All rights reserved. [References: 15]