Structural Characterization of AION by27 Al Mas NMR and Quantum Chemistry Method

1998 ◽  
Vol 538 ◽  
Author(s):  
Ying Dai ◽  
Xin-Min Min ◽  
Ce-Wen Nan ◽  
Xin-Mei Pei ◽  
Hai-Lan Ren
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Quantum Chemistry ◽  
Spinel Phase ◽  
Tetrahedral Site ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Aluminum Oxynitride ◽  
Chemistry Calculation ◽  
Nuclear Magnetic

AbstractAluminum oxynitride (AlON) is a nitrogen-stabilized defective spinel phase of alumina (y-Al2O3). Its structure has not been well understood so far. Solid-state27 Al magic-angle spinning nuclear magnetic resonance and quantum chemistry calculation are used to characterize y-Al2O3 and AMON ceramics in the present study. The resonance spectra clearly show different units (e.g. [AlN4], [AlO4] and [AlO6]) and vary with composition. The calculation shows that the vacancy located at octahedral site is more stable than that located at the tetrahedral site, and nitrogen atoms preferentially replace oxygen atoms in the tetrahedral site, which is in agreement with the experimental analysis by nuclear magnetic resonance.

Nuclear magnetic resonance (NMR) studies of sintering effects on the lithium ion dynamics in Li1.5Al0.5Ti1.5(PO4)3

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Edda Winter ◽  
Philipp Seipel ◽  
Tatiana Zinkevich ◽  
Sylvio Indris ◽  
Bambar Davaasuren ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Lithium Ion ◽  
Magic Angle Spinning ◽  
Spin Lattice Relaxation ◽  
Magic Angle ◽  
Nmr Studies ◽  
Lithium Ions ◽  
Jump Dynamics ◽  
Nuclear Magnetic

Abstract Various nuclear magnetic resonance (NMR) methods are combined to study the structure and dynamics of Li1.5Al0.5Ti1.5(PO4)3 (LATP) samples, which were obtained from sintering at various temperatures between 650 and 900 °C. 6Li, 27Al, and 31P magic angle spinning (MAS) NMR spectra show that LATP crystallites are better defined for higher calcination temperatures. Analysis of 7Li spin-lattice relaxation and line-shape changes indicates the existence of two species of lithium ions with clearly distinguishable jump dynamics, which can be attributed to crystalline and amorphous sample regions, respectively. An increase of the sintering temperature leads to higher fractions of the fast lithium species with respect to the slow one, but hardly affects the jump dynamics in either of the phases. Specifically, the fast and slow lithium ions show jumps in the nanoseconds regime near 300 and 700 K, respectively. The activation energy of the hopping motion in the LATP crystallites amounts to ca. 0.26 eV. 7Li field-gradient diffusometry reveals that the long-range ion migration is limited by the sample regions featuring slow transport. The high spatial resolution available from the high static field gradients of our setup allows the observation of the lithium ion diffusion inside the small (<100 nm) LATP crystallites, yielding a high self-diffusion coefficient of D = 2 × 10−12 m2/s at room temperature.

Trifluoroethanol and19F Magic Angle Spinning Nuclear Magnetic Resonance as a Basic Surface Hydroxyl Reactivity Probe for Zirconium(IV) Hydroxide Structures

Langmuir ◽  
2011 ◽  
Vol 27 (15) ◽  
pp. 9458-9464 ◽  
Author(s):  
Jared B. DeCoste ◽  
T. Grant Glover ◽  
Gregory Mogilevsky ◽  
Gregory W. Peterson ◽  
George W. Wagner
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Surface Hydroxyl ◽  
Angle Spinning ◽  
Nuclear Magnetic
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