@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.}
}
@article {7023,
	title = {THE COMBINATION OF SYNCHROTRON POWDER DIFFRACTION AND HIGH-RESOLUTION SOLID-STATE NMR EXPERIMENTS},
	journal = {Journal of Physics and Chemistry of Solids},
	volume = {52},
	number = {10},
	year = {1991},
	note = {ISI Document Delivery No.: GU763Times Cited: 18Cited Reference Count: 22},
	pages = {1235-1241},
	type = {Article},
	abstract = {Structural investigations on three zeolites, ZSM-11, ZSM-12 and ZSM-5, have been carried out by a combination of high-resolution solid-state Si-28 NMR experiments and Rietveld refinement of synchrotron X-ray powder data. These techniques, being sensitive to short- and long-range order, respectively, gave a most complete picture of the structure of the solid state. Variable temperature NMR experiments of ZSM-11 revealed a displacive phase transition with a change in symmetry at about 300 K. A Rietveld refinement of a data set recorded at 373 K confirmed the proposed structure model. The structure of ZSM-12 was refined from room temperature synchrotron powder data. Space group ambiguities because of pseudo-symmetry of the silica framework of the zeolite were resolved with the aid of Si-29 NMR experiments leading to C2/c as the true space group symmetry. Si-29 NMR and X-ray studies of ZSM-5 showed that the symmetry of the crystal structure depends on the temperature, the concentration of the guest molecule, and on the number of Al atoms in the framework. A full pattern refinement of silica-ZSM-5 loaded with two molecules p-dichlorobenzene per unit cell showed that the site occupied by the sorbed molecule is not at the intersection of the channels but shifted by 1/4 along b0.},
	keywords = {3-DIMENSIONAL LATTICE CONNECTIVITIES, CRYSTAL-STRUCTURE, ORTHORHOMBIC FRAMEWORK, Rietveld refinement, Si-29 NMR, SINGLE-CRYSTAL, SORBATE, ZEOLITE H-ZSM-5, zeolites, ZSM-11, ZSM-12, ZSM-5},
	isbn = {0022-3697},
	url = {<Go to ISI>://A1991GU76300006},
	author = {Gies, H. and Marler, B. and Fyfe, C. and Kokotailo, G. and Feng, Y. and Cox, D. E.}
}
@article {7021,
	title = {ONE-DIMENSIONAL AND 2-DIMENSIONAL HIGH-RESOLUTION SOLID-STATE NMR-STUDIES OF ZEOLITE LATTICE STRUCTURES},
	journal = {Chemical Reviews},
	volume = {91},
	number = {7},
	year = {1991},
	note = {ISI Document Delivery No.: GP764Times Cited: 106Cited Reference Count: 90},
	month = {Nov},
	pages = {1525-1543},
	type = {Review},
	keywords = {C-13 NMR, CRYSTAL-STRUCTURE, CRYSTALLOGRAPHICALLY INEQUIVALENT SITES, HIGH-SILICA ZEOLITE, MAS-NMR, NUCLEAR MAGNETIC-RESONANCE, NUCLEI, ORTHORHOMBIC FRAMEWORK, QUADRUPOLAR, Si-29 NMR, X-RAY-DIFFRACTION},
	isbn = {0009-2665},
	url = {<Go to ISI>://A1991GP76400014},
	author = {Fyfe, C. A. and Feng, Y. and Grondey, H. and Kokotailo, G. T. and Gies, H.}
}
