Synthesis and Characterization of Zincosilicates with the SOD Topology
The incorporation of Zn^(2+) into tetrahedral framework positions of zeolites with the sodalite topology (SOD) is obtained by direct synthesis. The zincosilicates are characterized by thermal analyses, a Rietveld refinement of powder X-ray diffraction (XRD) data, and infrared (IR) and ^1H, ^(23)Na, ^(13)C, and ^(29)Si MAS NMR spectroscopies. A zinc substitution level as high as Si/Zn = 6-7 is achieved and constitutes by far the largest extent of isomorphous substitution by a doubly charged heteroatom in the framework of a zeolite. Two types of β-cage occupancies (TMA^+ and Na^+) are observed.
© 1994 American Chemical Society. Received June 29, 1994. Revised Manuscript Received September 2, 1994. Support for this work was provided by the NSF Alan T. Waterman Award to M.E.D. We acknowledge D. E. Cox for assistance in collecting the synchrotron data. The XRD data were collected at X7A beam line, National Synchrotron Light Source, Brookhaven National Laboratory, which is supported by the Department of Energy, Division of Material Sciences and Division of Chemical Sciences. We thank Dr. S. Zones (Chevron) for the C, H, N analyses and Dr. J. Higgins (Mobil) for collecting the synchrotron XRD pattern. M.A.C. gratefully acknowledges the Spanish Ministry of Science and Education and the Fulbright Commission for a postdoctoral fellowship, and the Instituto de Tecnologia Quimica (Valencia, Spain) for permission to leave.