High-pressure δ-AI(OH)3 and δ-A1OOH phases and isostructural hydroxides/oxyhydroxides:: New structural insights from high-resolution 1H and 27Al NMR

被引:71
作者
Xue, Xianyu [1 ]
Kanzaki, Masami [1 ]
机构
[1] Okayama Univ, Inst Study Earths Interior, Tottori 6820193, Japan
关键词
ALUMINA-WATER SYSTEM; X-RAY-DIFFRACTION; CRYSTAL-STRUCTURE; NEUTRON-DIFFRACTION; DELTA-ALOOH; MAS-NMR; STRETCHING FREQUENCIES; HYDROUS PHASE; SPECTROSCOPY; SEQUENCES;
D O I
10.1021/jp073968r
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
In order to shed light on the proton distributions and order/disorder in high-pressure delta-Al(OH)(3) and delta-AlOOH phases, two-dimensional, high-resolution H-1 CRAMPS (FSLG)-MAS NMR and Al-27 3QMAS NMR spectra have been obtained. For delta-Al(OH)(3), the H-1 CRAMPS-MAS NMR revealed two peaks with an intensity ratio close to 2:1. The Al-27 MAS and 3QMAS NMR suggest a single Al site with a well-defined local structure. For delta-AlOOH, the H-1 and Al-27 NMR indicate the presence of a single H and Al site each. These results are consistent with crystal structures refined from X-ray diffraction. For comparison, 1H MAS and CRAMPS-MAS NMR spectra were also obtained for several other hydroxides/oxyhydroxides, including In(OH)(3) and InOOH that have similar structures to delta-Al(OH)(3) and delta-AlOOH, respectively. These data not only provide additional insights into the proton distributions in these important crystal structure classes but also together provide a better defined quantitative correlation between 1H chemical shift and hydrogen-bonding O center dot center dot center dot O distance.
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页码:13156 / 13166
页数:11
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