@article {3696,
	title = {The structure of the low temperature (20 K) form of zeolite ZSM-11 derived from Si-29 MAS NMR spectroscopy, lattice energy minimization and Rietveld refinement},
	journal = {Zeitschrift Fur Kristallographie},
	volume = {211},
	number = {4},
	year = {1996},
	note = {ISI Document Delivery No.: UG444Times Cited: 8Cited Reference Count: 17},
	pages = {221-227},
	type = {Article},
	abstract = {The crystal structure of the low temperature form of ZSM-11 (structure code MEL) was refined from high resolution synchrotron X-ray powder diffraction data, recorded at 20 K. Based on the results of 2D Si-29 NMR investigations a model was obtained by energy minimization the Rietveld refinement of which converged in space group <I(4)over bar> (No. 82) [a = 20.019(2) Angstrom; c = 13.380(1) Angstrom] to R(I) = 0.143 and R(wp) = 0.126. Comparison of the theoretically predicted and experimentally determined structures against results from NMR experiments using the average T-T distance relationship between the structural parameters and the isotropic Si-29 chemical shifts did not show any correlation with the results of the structure refinement. However, with the values obtained from the energy-minimized structure model a good correlation between the structural parameters and the chemicals shifts of Si was obtained for one of the two possible assignments of the NMR chemical shifts to Si-sites. The fit of the energy minimized model to the experimental data set gave R(I) = 0.179 and R(wp) = 0.157. Since the NMR experiment gives direct information about the local ordering and structural state of the material this demonstrates the potential of the modeling experiment and also reveals the limits in accuracy and precision of the Rietveld structure refinement.},
	keywords = {beta, COMBINATION, CONNECTIVITIES, lattice energy minimization, NATURAL-ABUNDANCE, Rietveld refinement, Si-29 NMR, SOLID-STATE NMR, X-RAY-DIFFRACTION, zeolites},
	isbn = {0044-2968},
	url = {<Go to ISI>://A1996UG44400001},
	author = {Hochgrafe, M. and Marler, B. and Gies, H. and Fyfe, C. A. and Feng, Y. and Grondey, H. and Kokotailo, G. T.}
}
@inbook {3404,
	title = {Powder x-ray diffraction and solid state NMR techniques for zeolite structure determination},
	booktitle = {Catalysis by Microporous Materials},
	series = {Studies in Surface Science and Catalysis},
	volume = {94},
	year = {1995},
	note = {ISI Document Delivery No.: BE31JTimes Cited: 4Cited Reference Count: 33Proceedings PaperInternational Symposium on Catalysis by Microporous Materials (ZEOCAT 95)JUL 09-13, 1995SZOMBATHELY, HUNGARYSARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	pages = {78-100},
	publisher = {Elsevier Science Publ B V},
	organization = {Elsevier Science Publ B V},
	address = {Amsterdam},
	abstract = {The synthesis of zeolites, porous aluminosilicates, had a large impact on the development of catalyst materials. The framework structures of these systems consist of Si and Al atoms, referred to as T-atoms, tetrahedrally coordinated to oxygen atoms to form topologies with well defined and regular channel systems. Cations are necessary to satisfy the charge on the Al atoms and are exchangeable. The T-atoms may also consist of any atom capable of isomorphorus substitutions for Si. Since good quality large zeolite crystals are not available, powder X-ray diffraction is used to derive structural information, and with improvements in powder diffraction instrumentation and the availability of synchrotron and rotating anode high intensity Xray sources, much higher quality structure data is obtained. The combined application of solid state NMR which probes short-range order, X-ray diffraction which is a long-range order technique and Rietveld refinement has greatly increased both the quantity and quality of structural information available.},
	keywords = {aluminum, COMBINATION, SI-29, ZSM-11},
	isbn = {0-444-82049-3},
	url = {<Go to ISI>://A1995BE31J00009},
	author = {Kokotailo, G. T. and Fyfe, C. A. and Feng, Y. and Grondey, H. and Gies, H. and Marler, B. and Cox, D. E.},
	editor = {Beyer, H. K. and Karge, H. G. and Kiricsi, I. and Nagy, J. B.}
}
