کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
77124 49157 2007 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Synthesis, characterization and crystal structure of EMS-2 – a novel microporous stannosilicate
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
Synthesis, characterization and crystal structure of EMS-2 – a novel microporous stannosilicate
چکیده انگلیسی

EMS-2, a novel mixed tetrahedral–octahedral microporous stannosilicate, has been synthesized under hydrothermal conditions using Na and K ions as structure directing agents. EMS-2 has been characterized by laboratory and synchrotron X-ray powder diffraction, 23Na, 29Si and 119Sn MAS NMR, elemental, thermogravimetric and scanning electron microscopy analyses. The powder diffraction pattern of EMS-2 has been indexed with a monoclinic unit cell with parameters: a = 10.289 Å, b = 15.938 Å, c = 9.182 Å and β = 104.6° and a space group C2/m. EMS-2 is the synthetic tin-counterpart of the rare zirconosilicate mineral lemoynite. The structure of EMS-2 consists of “silicate slabs” of SiO4 tetrahedra, parallel to [0 1 0], joined together by isolated SnO6 octahedra. It has 10-membered ring channels, with pore openings of 6.47 × 4.61 Å, which host cations and water molecules. NMR confirms the unique occurrence (in stannosilicates) of three distinct silicon environments, Si(2Si, 2Sn), Si(3Si, 1Sn) and Si(4Si), and the high Na coordination symmetry foreseen by the diffraction structure. To our knowledge, EMS-2 is the only reported stannosilicate containing Si(4Si) sites.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Microporous and Mesoporous Materials - Volume 101, Issues 1–2, 19 April 2007, Pages 43–49
نویسندگان
, , , , , , ,