@article {1119,
	title = {Determining the geometry of strongly hydrogen-bonded silanols in a layered hydrous silicate by solid-state nuclear magnetic resonance},
	journal = {Journal of Chemical Physics},
	volume = {122},
	number = {5},
	year = {2005},
	note = {ISI Document Delivery No.: 895RGTimes Cited: 7Cited Reference Count: 45},
	month = {Feb},
	pages = {10},
	type = {Article},
	abstract = {High-resolution solid-state NMR spectroscopy is exploited to obtain structural constraints involving strongly hydrogen-bonded silanols in octosilicate, a prominent member of the layered hydrous sodium silicates. Proton-silicon cross-polarization dynamics reveals that octosilicate contains two types of Q(3) silicons present in hydrogen-bonded -Si-O-H...O-Si- and -Si-O{\textendash}type sites which can only be distinguished by their different abilities to cross polarize and the different mobilities of neighboring hydrous species. The theoretical analysis of the oscillating components of the polarization transfer buildup curves suggests that the model of heteronuclear pairs is an adequate description of the quantum spin system within hydrogen-bonded -Si-O-H...O-Si- fragments. We also show that dipolar modulated, slow speed magic-angle Si-29 NMR spectrum provides unique geometric information on strongly hydrogen-bonded silanols. The dipolar modulated spinning sidebands contain all the information necessary to determine the internuclear Si...H distances as well as the magnitude and orientation of the principal elements of the Si-29 chemical shielding tensor in the molecular frame. The data provide definite proof of the intralayer character of strongly hydrogen-bonded silanol groups in a bridging, albeit not symmetric, position between neighboring tetrahedra. The approach developed in this work may be useful to obtain structural information on related layered alkali metal silicates, silica gels as well as on other classes of microporous materials. (C) 2005 American Institute of Physics.},
	keywords = {DYNAMICS, MAGADIITE, MAS, NMR CROSS-POLARIZATION, RESOLUTION, ROTATING SOLIDS, SIDE-BAND, SPECTRA, SPECTROSCOPY, SPIN-EXCHANGE},
	isbn = {0021-9606},
	url = {<Go to ISI>://000226880100042},
	author = {Gardiennet, C. and Marica, F. and Fyfe, C. A. and Tekely, P.}
}
@article {5081,
	title = {Solid-state NMR characterization of the mineral searlesite and its detection in complex synthesis mixtures},
	journal = {Inorganic Chemistry},
	volume = {40},
	number = {23},
	year = {2001},
	note = {ISI Document Delivery No.: 488JRTimes Cited: 5Cited Reference Count: 34},
	month = {Nov},
	pages = {5906-5912},
	type = {Article},
	abstract = {The mineral searlesite (NaBSi2O5(OH)(2)) was synthesized and characterized by H-1, B-11, Na-23, and Si-29 magic-angle spinning (MAS) NMR spectroscopy. From these spectra, the B-11 and Na-23 quadrupole coupling parameters and isotropic chemical shifts and the Si-29 chemical shift anisotropies have been precisely determined. These parameters are all consistent with the local environments obtained from the crystal structure for searlesite from X-ray diffraction, and they demonstrate that the synthetic sample has a high degree of both short- and long-range order. Furthermore, these anisotropic parameters are found to provide a unique fingerprinting of searlesite in complex mixtures where the presence of this mineral is not anticipated. This is demonstrated for product mixtures formed in attempts to incorporate boron in the structures of the layer silicates magadiite and kenyaite. These. mixtures have been investigated by B-11, Na-23, and Si-29 MAS NMR which clearly reveal that the samples are mixtures of searlesite and magadiite/kenyaite and that searlesite production consumes all of the boron in these synthesis mixtures. However, the Si-29 MAS NMR spectra of these mixtures indicate that the presence of boron in the reaction mixtures nevertheless has an important influence on the quality of the magadiite and kenyaite layer silicates produced.},
	keywords = {BORATE, BORON, ISOMORPHOUS SUBSTITUTION, LAYERED SILICATES, MAGADIITE, MAS NMR, QUADRUPOLAR NUCLEI, SATELLITE, SILICON, TRANSITIONS},
	isbn = {0020-1669},
	url = {<Go to ISI>://000171932500026},
	author = {Fyfe, C. A. and Skibsted, J. and Schwieger, W.}
}
@inbook {3511,
	title = {Isomorphous substitution of silicon by boron or aluminum in layered silicates},
	booktitle = {Catalysis by Microporous Materials},
	series = {Studies in Surface Science and Catalysis},
	volume = {94},
	year = {1995},
	note = {ISI Document Delivery No.: BE31JTimes Cited: 7Cited Reference Count: 15Proceedings PaperInternational Symposium on Catalysis by Microporous Materials (ZEOCAT 95)JUL 09-13, 1995SZOMBATHELY, HUNGARYSARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	pages = {47-54},
	publisher = {Elsevier Science Publ B V},
	organization = {Elsevier Science Publ B V},
	address = {Amsterdam},
	abstract = {In order to systematically change the properties of layered silicate materials, we have investigated the possibility of isomorphous substitution of silicon by aluminum or boron. It is demonstrated that addition of boron and/or aluminum compounds to the reaction mixture leads directly to boron and aluminum containing layered materials in a hydrothermal crystallization process without further treatment. The layered materials obtained were identified as hectorite types, magadiite and kenyaite-like types. The isomorphous substitutions were pr-oven by B-11, Al-27, and Si-29 solid state MMR spectroscopy.},
	keywords = {MAGADIITE, NMR, SODIUM, STATE},
	isbn = {0-444-82049-3},
	url = {<Go to ISI>://A1995BE31J00005},
	author = {Schwieger, W. and Pohl, K. and Brenn, U. and Fyfe, C. A. and Grondey, H. and Fu, G. and Kokotailo, G. T.},
	editor = {Beyer, H. K. and Karge, H. G. and Kiricsi, I. and Nagy, J. B.}
}
