title: Ab initio structure determination of a small-pore framework sodium stannosilicate.
abstract: The structure of a small-pore framework sodium stannosilicate Na(2)SnSi(3)O(9).2H(2)O (AV-10) has been determined ab initio from powder X-ray diffraction data (XRD). The unit cell is orthorhombic (space group C222(1), Z = 4) with cell dimensions a = 7.9453(5), b = 10.3439(7), c = 11.6252(7) A, V = 955 A(3). The structure of AV-10 is composed of corner sharing SnO(6) octahedra and SiO(4) tetrahedra, forming a three-dimensional framework structure. The SiO(4) tetrahedra form helix chains along [001] interconnected by SnO(6) octahedra. The SnO(6) octahedra are isolated by SiO(4) tetrahedra and, thus, there are no Sn-O-Sn linkages. AV-10 has been characterized by chemical analysis, powder XRD, scanning electron microscopy, (29)Si, (119)Sn, single- and (FAM) triple-quantum (23)Na MAS NMR spectroscopy, thermogravimetry (TGA), and nitrogen adsorption isotherms. The zeolitic water of AV-10 is reversibly lost. The dehydrated material has been studied in situ by powder XRD, TGA, and, in particular, triple-quantum (23)Na MAS NMR.
authors: ESTGA, University of Aveiro, 3810-193 Aveiro, Portugal, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors: A
authors: A
authors: Ferreira
authors: Z
authors: Z
authors: Lin
authors: J
authors: J
authors: Rocha
authors: C M
authors: CM
authors: Morais
authors: M
authors: M
authors: Lopes
authors: C
authors: C
authors: Fernandez