Setting the magic angle using a quadrupolar nuclide

Frye, James S.; Maciel, Gary E.

doi:10.1016/0022-2364(82)90243-8

Cited by 144 publications

(144 citation statements)

References 5 publications

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“…48 The analogous perchlorate material LiAl 2 OH 6 ClO 4 ÐnH 2 O as well as the magnesium analog Mg 3 Al OH 6 ClO 4 ÐnH 2 O were also examined. 46 The activation energy for perchlorate reorientation in this latter compound was determined to be 10.7 kJ mol 1 . A further detailed study of LiAl 2 OH 6 ClÐnH 2 O revealed that the hydrated paste form of this material exhibits three distinct chloride resonances, the most interesting of which is dominated by an axially symmetric CS interaction.…”

Section: Chlorine-35/37mentioning

confidence: 93%

“…4). 45,161 Quadrupolar products, P Q , of 0.5-0.8 MHz were observed for 'basic' Na 8 1 . Studies of mixed Cl/Br and Br/I sodalite systems yielded quadrupolar products of 0.3-0.7 MHz (Cl/Br system) and 0.3-1.0 MHz (Cl/I system).…”

Section: Bromine-79/81mentioning

confidence: 97%

“…Frye and Maciel proposed that the 79 Br resonance of powdered KBr be used to set the magic angle. 1 In addition to the high receptivity of 79 Br (allowing its observation in a single scan), the resonance frequency of 79 Br is within 1% of that of 13 C, making it convenient for setting the angle prior to carrying out 13 C CP/MAS experiments without significant retuning of the probe. NaBr was found to be an inferior standard for setting the angle, in part due to the effects of 23 Na- 79 Br dipolar interactions.…”

Section: Bromine-79/81mentioning

confidence: 99%

“…1 In this review article, we present several other diverse applications of quadrupolar halogen SSNMR spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

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Solid-state NMR spectroscopy of the quadrupolar halogens: chlorine-35/37, bromine-79/81, and iodine-127

Bryce

Sward

2006

Magn. Reson. Chem.

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Section: Chlorine-35/37mentioning

confidence: 93%

Section: Bromine-79/81mentioning

confidence: 97%

Section: Bromine-79/81mentioning

confidence: 99%

“…1 In this review article, we present several other diverse applications of quadrupolar halogen SSNMR spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Solid-state NMR spectroscopy of the quadrupolar halogens: chlorine-35/37, bromine-79/81, and iodine-127

Bryce

Sward

2006

Magn. Reson. Chem.

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“…For selected samples, 27A1 MAS spectra were recorded using a spinning speed of 13.5 kHz in 5-ram Si3N4 rotors. The magic angle was set by observing the rotational echoes in the FID of the 79Br resonance for KBr (Frye and Maciel, 1982) in a dynamic mode. For the 27A1 MAS experiments, the magic angle was checked and set accurately in the same manner using the 27A1 resonance for a sample of hydrated calcium aluminate cement (Ca~A1206" 6D20; Jakobsen et al, 1988a).…”

Section: Zai and 29si Mas-nmr Spectroscopymentioning

confidence: 99%

Diagenetic Structural Transformations in North Sea Jurassic Illite/Smectite

Lindgreen

1991

Clays and clay miner.

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Abstract--The Kimmeridgian-Volgian(-Ryazanian) claystone is the principal oil source rock in the troughs of the North Sea. Randomly (R0) ordered mixed-layer illite/smectite (US) appears to have transformed to RI-(IS) or R3-(ISII) ordered simultaneously with oil generation. The proportion of illite layers in I/S increased to 95% d,aring diagenesis in these claystones. Exceptions are three samples of I/S of probably bentonitic origin; these have apparently changed during diagenesis to R0-0rdered I/S containing 40-50% illite layers. Fine fractions of the claystones dominated by I/S were analyzed by ZTAl and 29Si magic-angle spinning (MAS)-nuclear magnetic resonance (NMR) spectroscopy, ~TFe Mrssbauer spectroscopy, and X-ray powder diffraction (XRD), and for total chemical composition. Si/AI ratios determined from MAS-NMR agree closely with those calculated from total chemical analysis; however, tetrahedral and octahedral AI occupancies were most accurately determined by NMR. An increase in the percentage of illite layers and in the ordering of the I/S was accompanied by fixation of K ~ and NH4 + in the I/S, by tetrahedral AIfor-Si substitution, and by octahedral Al-for-(Mg + Fe) substitution, resulting both in an increase of charge in the 2:1 layers and in a migration of charge from octahedral to tetrahedral sheets. The I/S of probably bentonitic origin had a larger tetrahedral and a smaller octahedral charge than expected from its content of illite layers. MAS-NMR showed a significantly higher content of tetrahedral AI (most likely in smectitic sites) than expected from the percentage ofillite layers calculated from XRD. Correspondingly, XRD of K+-saturated and glycolated specimens showed that several smectite layers possessed a significant charge. A constant b-dimension of the I/S and the presence of a significant charge in the smectite layers suggest that a transformation of smectite to illite layers in the I/S by tetrahedral Al-for-Si substitution followed by interlayer cation fixation and interlayer contraction is the most probable genesis for the I/S investigated.

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Analysis of Physical Transformation of API During Manufacture and Storage

Stephenson

2008

Formulation and Analytical Development for Low‐Dose Oral Drug Products

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Setting the magic angle using a quadrupolar nuclide

Cited by 144 publications

References 5 publications

Solid-state NMR spectroscopy of the quadrupolar halogens: chlorine-35/37, bromine-79/81, and iodine-127

Solid-state NMR spectroscopy of the quadrupolar halogens: chlorine-35/37, bromine-79/81, and iodine-127

Diagenetic Structural Transformations in North Sea Jurassic Illite/Smectite

Analysis of Physical Transformation of API During Manufacture and Storage

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