Structure of the Polycrystalline Zeolite Catalyst IM-5 Solved by Enhanced Charge Flipping

• Published in: Science (American Association for the Advancement of Science) Vol. 315; no. 5815; pp. 1113 - 1116
• Main Authors: Baerlocher, Christian, Gramm, Fabian, Massüger, Lars, McCusker, Lynne B, He, Zhanbing, Hovmöller, Sven, Zou, Xiaodong
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 23.02.2007; The American Association for the Advancement of Science
• Subjects: Algorithms; Alloys; Analytical chemistry; Atoms; Catalysis; Catalysts; Ceramics; Channels; Chemistry; Colloidal state and disperse state; Crystal structure; Diffraction; Diffraction patterns; Electrical phases; Electron density; Electronic structure; Exact sciences and technology; General and physical chemistry; Impurities; Ion-exchange; Porous materials; Surface physical chemistry; Symmetry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Wave diffraction; Zeolites; Zeolites: preparations and properties; Heterogeneous catalysis; High resolution; Transmission electron microscopy; Investigation method; Polycrystal; Zeolite; Structure; Algorithm; Porous material; Catalyst; Molecular sieve
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1137920

Despite substantial advances in crystal structure determination methodology for polycrystalline materials, some problems have remained intractable. A case in point is the zeolite catalyst IM-5, whose structure has eluded determination for almost 10 years. Here we present a charge-flipping structure-solution algorithm, extended to facilitate the combined use of powder diffraction and electron microscopy data. With this algorithm, we have elucidated the complex structure of IM-5, with 24 topologically distinct silicon atoms and an unusual two-dimensional medium-pore channel system. This powerful approach to structure solution can be applied without modification to any type of polycrystalline material (e.g., catalysts, ceramics, pharmaceuticals, complex metal alloys) and is therefore pertinent to a diverse range of scientific disciplines.