Penta-co-ordinated aluminium: a solid-state 27Al, n.m.r. study

Cruickshank, Michael C.; Glasser, Leslie; Barri, Sami A. I.; Poplett, Ian J. F.

doi:10.1039/c3986000023b

Cited by 61 publications

(92 citation statements)

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“…On the basis of symmetry and simple point-charge calculations 5-coordinate Al is expected to always have a large electric field gradient, with square pyramidal coordination generally giving larger efgs than trigonal bipyramidal coordination. Thus the value of C---1.9 MHz appears to be lower than expected (or observed) for Al in compounds known to have 5-coordinate Al [20,22,23]. Sato et al [21] have recently reported the observation of a broad peak near 28 ppm in the 27Al spectra of "super quenched" aluminosilicate glasses and utilized the peak positions at two magnetic field strengths to estimate mean values for Z of 3-3.5 MHz, their spectra thus have features in common with uor metakaolinite spectra.…”

Section: Assignment Of the 27 Ppm Peakmentioning

confidence: 54%

High-field27Al mas NMR studies of the formation of metakaolinite by flash calcination of kaolinite

1993

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Flash calcination was used to dehydroxylate kaolinite and produced calcines kineticaUy frozen at various stages during metakaolinite formation. I--Iigh speed magic-angle spinning 27A1 NMR, in magnetic fields of 14.1 and 11.8 T, enabled new features to be observed in the metakaolinite spectrum. The dependence on magnetic field of simulated and experimental spectra is discussed, and the effects of a dist¡ of elect¡ field gradients is examined. The evolution of the metakaolinite peaks is followed during dehydroxylation.

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Section: Assignment Of the 27 Ppm Peakmentioning

confidence: 54%

High-field27Al mas NMR studies of the formation of metakaolinite by flash calcination of kaolinite

1993

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“…It also has an Al(~) site with Cq--15.6 MHz (Table 4). Early MAS work using moderate spinning speeds (< 4 kHz) could only reveal the Al(5) site with the only evidence for the other aluminium species being a broad underlying resonance [60,61]. Subsequem smdies at higher fields (> 11.7 T) and Ÿ MAS (> 15 kHz) showed both lines [59,62,63].…”

Section: Cq~mentioning

confidence: 99%

Application of27Al NMR techniques to structure determination in solids

1993

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Abstraer. There have been great improvements in the quality of 27A1 NMR spectra from solids over the last decade. The impact of this technique on structure determination fora wide range of solids is briefly reviewed. Emphasis is placed on the effects arising from the presence of the quadrupolar interaction and strategies that allow unambiguous spectral interpretation. It is demonstrated that in addition to the chemical shift, the quadrupolar interaction itself can be a rich source of local information about solids. The insight obtalned from 27A1 NMR hato atomic level structure often contains surprises, such that previous models of structure and properties have to be reassessed.

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“…Andalusite has received considerable attention from NMR spectroscopists because it is such an unusual and challenging solid [9][10][11][12][13][14][15][16]. It is one of the few solids known to have A105 units.…”

Section: Outline Of the Papermentioning

confidence: 99%

Critical factors in obtaining meaningful fast MAS NMR spectra of non-integral spin quadrupolar nuclei. A review with particular emphasis on27Al MAS NMR of catalysts and minerals

Alemany

1993

Appl. Magn. Reson.

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In the last decade, magic angle spinning (MAS) NMR has become an extremely important method for studying the structure of inorganic solids. Advances in NMR technology have greatly aided in understanding the structure of catalysts, minerals, clays, ceramics, glasses, etc. Obtaining meanin~ul MAS spectra of spin-1/2 nuclei such as 29Si and 31p is relatively straightforward and well understood. In contrast, obtaining meaningful MAS spectra is far from simple with non-integral spin quadrupolar nuclei such as 11B (I= 3/2), 170 (I=5/2), 23Na (I= 3/2), 27A1 (I= 5/2), 69Ga (I= 3/2), and 71Ga (I= 3/2) -to name some of the most commonly studied nuclei. Many additional factors have to be considered. This paper will deal with these factors and the utility of vely fast MAS for studying non-integral spin quadrupolar nuclei in inorganic solids.

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Penta-co-ordinated aluminium: a solid-state 27Al, n.m.r. study

Cited by 61 publications

References 0 publications

High-field27Al mas NMR studies of the formation of metakaolinite by flash calcination of kaolinite

High-field27Al mas NMR studies of the formation of metakaolinite by flash calcination of kaolinite

Application of27Al NMR techniques to structure determination in solids

Critical factors in obtaining meaningful fast MAS NMR spectra of non-integral spin quadrupolar nuclei. A review with particular emphasis on27Al MAS NMR of catalysts and minerals

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