Two new silicate structures based on a rhodesite-type heteropolyhedral microporous framework.

Two new members of the mero-plesiotype rhodesite series [Sr(2)Na(2)(Si(8)O(19)).4H(2)O, abbreviated as TR09; SrNa(4)(Si(8)O(19)).4H(2)O, TR10] have been hydrothermally synthesized in Teflon-lined autoclaves at 503 K and structurally characterized using X-ray diffraction single-crystal data. The crystal structures were solved by direct methods and refined to R = 0.021 [TR09; 3317 reflections with I(o) > 2sigma(I(o))] and R = 0.033 [TR10; 5007 reflections with I(o) > 2sigma(I(o))]. Both structures are based on a rhodesite-type microporous heteropolyhedral framework, where two types of channels are within the double silicate layer that alternates with an ;octahedral' O sheet. The large Sr(2+) cation constrains to the roughly ellipsoidal shape of the channels. The H(2)O molecules are located both in the O sheets and in the channels, where they are loosely hydrogen bonded. The crystal-chemical features that allow flexibility to the rhodesite-type microporous heteropolyhedral framework and make it interesting for possible technological applications are discussed.

[1]  N. Chukanov,et al.  Crystal chemistry of delhayelite and hydrodelhayelite , 2009 .

[2]  G. Ferraris,et al.  Two new members of the rhodesite mero-plesiotype series close to delhayelite and hydrodelhayelite: synthesis and crystal structure , 2009 .

[3]  S. Krivovichev.  Structural Crystallography of Inorganic Oxysalts , 2009 .

[4]  P. Brandão,et al.  Isomerization of d-glucose to d-fructose over metallosilicate solid bases , 2008 .

[5]  G. Sheldrick.  A short history of SHELX. , 2008, Acta crystallographica. Section A, Foundations of crystallography.

[6]  G. Ferraris,et al.  Polysomatic aspects of microporous minerals - heterophyllosilicates, palysepioles and rhodesite-related structures , 2005 .

[7]  J. Rocha,et al.  Microporous Mixed Octahedral-Pentahedral-Tetrahedral Framework Silicates , 2005 .

[8]  L. Carlos,et al.  The first examples of X-ray phosphors, and C-band infrared emitters based on microporous lanthanide silicates , 2004 .

[9]  Giovanni Ferraris,et al.  Crystallography of Modular Materials , 2004 .

[10]  J. Rocha,et al.  Novel Microporous and Layered Luminescent Lanthanide Silicates , 2004 .

[11]  E. Belluso,et al.  THE CRYSTAL STRUCTURE OF SEIDITE-(Ce), Na4(Ce,Sr)2{Ti(OH)2(Si8O18)}(O,OH,F)4·5H2O, A MODULAR MICROPOROUS TITANOSILICATE OF THE RHODESITE GROUP , 2003 .

[12]  L. McCusker,et al.  NOMENCLATURE OF STRUCTURAL AND COMPOSITIONAL CHARACTERISTICS OF ORDERED MICROPOROUS AND MESOPOROUS MATERIALS WITH INORGANIC HOSTS , 2003 .

[13]  L. Carlos,et al.  Novel microporous europium and terbium silicates. , 2001, Journal of the American Chemical Society.

[14]  L. McCusker,et al.  Nomenclature of structural and compositional characteristics of ordered microporous and mesoporous materials with inorganic hosts(IUPAC Recommendations 2001) , 2001 .

[15]  J. Rocha,et al.  The First Microporous Framework Cerium Silicate , 2000 .

[16]  Louis J. Farrugia,et al.  WinGX suite for small-molecule single-crystal crystallography , 1999 .

[17]  M. Grutzeck,et al.  Synthesis of double-layer silicates from recycled glass cullet: A new type of chemical adsorbent , 1999 .

[18]  P. Brandão,et al.  Synthesis and Structural Characterization of Microporous Yttrium and Calcium Silicates , 1998 .

[19]  Louis J. Farrugia,et al.  ORTEP-3 for Windows - a version of ORTEP-III with a Graphical User Interface (GUI) , 1997 .

[20]  S. Merlino,et al.  Crystal structure of rhodesite, HK1 −xNax+ 2yCa2 −y{lB,3,2∞2}[Si8O19] · (6 –z) H2O, from three localities and its relation to other silicates with dreier double layers , 1992 .

[21]  L. D. Ceukelaire.  The determination of the most common crystalline alkali-silica reaction product , 1991 .

[22]  G. Ivaldi,et al.  Bond valence vs bond length in O…O hydrogen bonds , 1988 .

[23]  S. Merlino.  The structure of reyerite, (Na,K)2Ca14Si22Al2O58(OH)8.6H2O , 1988, Mineralogical Magazine.

[24]  S. Merlino.  Gyrolite: Its Crystal Structure and Crystal Chemistry , 1988, Mineralogical Magazine.

[25]  C. Campana,et al.  Symmetry and crystal structure of montregianite, Na 4 K 2 Y 2 Si 16 O 38 .10H 2 O, a double-sheet silicate with zeolitic properties , 1987 .

[26]  G. Chiari,et al.  The water molecule in crystalline hydrates studied by neutron diffraction , 1981 .