@article {611,
	title = {Influence of F content on the composition of Al-rich synthetic phlogopite: Part 1. New information on structure and phase-formation from Si-29, H-1, and F-19 MAS NMR spectroscopies},
	journal = {American Mineralogist},
	volume = {88},
	number = {1},
	year = {2003},
	note = {ISI Document Delivery No.: 635DVTimes Cited: 6Cited Reference Count: 27},
	month = {Jan},
	pages = {47-53},
	type = {Article},
	abstract = {The influence of F content on the formation and stability of Al-rich phlogopite has been investigated. Samples with varying OH/F-ratios and nominal gel compositions of K(Mg3-xAlx)(Al1+xSi3-xO10)(OH)(y) (F)(2-y) (0.0 less than or equal to x less than or equal to 0.8 and 0.5 less than or equal to y less than or equal to 1.8) were studied using Si-29, H-1, and F-19 MAS NMR spectroscopies, powder X-ray diffraction, electron-probe microanalysis, and scanning electron microscopy. The synthetic phlogopites were synthesized from sol-gels in cold-seal pressure vessels at 1073 K, 2 kbar. The main phase (phlogopite) and three other impurity phases [corundum (alpha-Al2O3), kalsilite (KAlSiO4), and potassium aluminum hexafluoride (K3AlF6.0.5H(2)O)] were clearly identified by powder X-ray diffraction and electron-probe microanalysis. For phlogopite, the unit-cell parameters a(0) and b(0) decrease whereas c(0) increases with increasing Al-content (x). The average crystal size of phlogopite is about 1-2 mum. The Si-29 MAS NMR spectra show up to four resonances at approximately -91,-87, -83, and -80ppm, which can be assigned as Q(3)(nAl) signals with n = 0 - 3. The ideal Si/Al-IV ratio calculated from the initial composition is always lower than that derived experimentally. Hydroxyl-rich compositions indicate an increased Al-content in the tetrahedral sheets, suggesting a stabilizing effect on the formation of Al-rich phlogopite. These conclusions are supported by H-1 and F-19 MAS NMR spectra. The H-1 MAS NMR spectra show a water signal at 4.7 ppm, a signal due to Mg2AlOH at 1.8 ppm, and a signal due to Mg3OH at 0.7 ppm. The F-19 MAS NMR spectra exhibit a signal for Mg2AlF at -150 ppm, one due toAlF(6) (K3AlF6.0.5H(2)O) at -157 ppm, and one for Mg3F at -174 ppm. Comparison of the H-1 and F-19 MAS NMR spectra for different Al- and F- contents reveals a non-statistical distribution of F- and OH-groups at the crystallographic sites in the octahedral sheets where F prefers sites coordinated by three Mg, and OH sites with Al in the next-nearest coordination sphere.},
	keywords = {AL-27, FLUORINE, GLASSES, GRANITES, KALSILITE, KALSIO4, NUCLEAR-MAGNETIC-RESONANCE, PETROGENESIS, SILICATE MELTS, SOLUBILITY},
	isbn = {0003-004X},
	url = {<Go to ISI>://000180383600006},
	author = {Fechtelkord, M. and Behrens, H. and Holtz, F. and Fyfe, C. A. and Groat, L. A. and Raudsepp, M.}
}
@article {4951,
	title = {First observation of a residual inter-cationic correlation in the {\textquoteright}super{\textquoteright}-ionic conductor, Ag9GaSe6: Ag-109-Ag-107 double-resonance NMR study of ion dynamics},
	journal = {Solid State Ionics},
	volume = {132},
	number = {1-2},
	year = {2000},
	note = {ISI Document Delivery No.: 347GATimes Cited: 4Cited Reference Count: 37},
	month = {Jul},
	pages = {87-92},
	type = {Article},
	abstract = {A double-resonance nuclear magnetic resonance, NMR, signal between the very mobile nuclei of a superionic conductor has been detected for the first time in a silver conductor. The heteronuclear double-resonance signal between mobile nuclei should not be observed in the fast motion limit if the inter-cationic interactions are completely removed. However, a Ag-109-Ag-107 double-resonance signal has in fact been observed in a superionic conductor of 0.1-1 S m(-1), namely Ag9GaSe6. This implies that the cationic motion is correlated in this solid electrolyte and some residual interactions, perhaps including chemical bonds among very mobile cations, may remain even in the fast motion limit. (C) 2000 Elsevier Science B.V. All rights reserved.},
	keywords = {DIFFUSION, double resonance NMR, ECHO DOUBLE-RESONANCE, GLASSES, ion dynamics, MODEL, SILVER IONS, silver superionic conductor},
	isbn = {0167-2738},
	url = {<Go to ISI>://000088918700008},
	author = {Tansho, M. and Fyfe, C. A. and Grondey, H. and Markus, T. and Wada, H.}
}
