Correlations between B-11 NMR parameters and structural characters inborate and borosilicate minerals investigated by high-resolution MAS NMRand ab initio calculations

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	Correlations between B-11 NMR parameters and structural characters inborate and borosilicate minerals investigated by high-resolution MAS NMRand ab initio calculations
	Zhou, Bing; Sun, Zhaohua; Yao, Yefeng; Pan, Yuanming
	2012
发表期刊	PHYSICS AND CHEMISTRY OF MINERALS
ISSN	0342-1791
卷号	39 期号:5 页码:363-372
关键词	Ultra High Field High-resolution Solid-state Nmr Borates
摘要	Borates consisting of diverse fundamental building blocks (FBB) formed from complex polymerization of planar triangular [BI center dot(3)] groups and tetrahedral [BI center dot(4)] groups, where I center dot = O and OH, provide an excellent opportunity for investigation of correlations between the NMR parameters and local structures. However, previous studies suggested that the B-11 NMR parameters in borates are insensitive to local structural environments other than the B coordination number, in contrast to those documented for Si-29, Na-23 and Al-27 in silicates, and no correlation between B-11 chemical shifts and the sum of bond valences has been established for borate minerals with hydroxyl groups or molecular water in the structures. In this study, high-resolution NMR spectra have been acquired at the ultra high field of 21 T as well as at 14 T for selected borate and borosilicate minerals, and have been used to extract high-precision NMR parameters by using combined ab initio theoretical calculations and spectral simulations. These new NMR parameters reveal subtle correlations with various structural characters, especially the effects of the B-11 chemical shifts from the bridging oxygen atom(s), site symmetry, symmetry of FBB, the sum of bond valences, as well as the next-nearest-neighbor cations and hydrogen bonding. Also, these results provide new insights into the shielding mechanism for B-11 in borate and borosilicate minerals. In particular, this study demonstrates that the small variation in B-11 chemical shifts can still be used to probe the local structural environments and that the established correlations can be used to investigate the structural details in borates and amorphous materials. Borates consisting of diverse fundamental building blocks (FBB) formed from complex polymerization of planar triangular [BI center dot(3)] groups and tetrahedral [BI center dot(4)] groups, where I center dot = O and OH, provide an excellent opportunity for investigation of correlations between the NMR parameters and local structures. However, previous studies suggested that the B-11 NMR parameters in borates are insensitive to local structural environments other than the B coordination number, in contrast to those documented for Si-29, Na-23 and Al-27 in silicates, and no correlation between B-11 chemical shifts and the sum of bond valences has been established for borate minerals with hydroxyl groups or molecular water in the structures. In this study, high-resolution NMR spectra have been acquired at the ultra high field of 21 T as well as at 14 T for selected borate and borosilicate minerals, and have been used to extract high-precision NMR parameters by using combined ab initio theoretical calculations and spectral simulations. These new NMR parameters reveal subtle correlations with various structural characters, especially the effects of the B-11 chemical shifts from the bridging oxygen atom(s), site symmetry, symmetry of FBB, the sum of bond valences, as well as the next-nearest-neighbor cations and hydrogen bonding. Also, these results provide new insights into the shielding mechanism for B-11 in borate and borosilicate minerals. In particular, this study demonstrates that the small variation in B-11 chemical shifts can still be used to probe the local structural environments and that the established correlations can be used to investigate the structural details in borates and amorphous materials.
文献类型	期刊论文
条目标识符	http://ir.isl.ac.cn/handle/363002/2059
专题	青海盐湖研究所知识仓储中国科学院青海盐湖研究所
推荐引用方式 GB/T 7714	Zhou, Bing,Sun, Zhaohua,Yao, Yefeng,et al. Correlations between B-11 NMR parameters and structural characters inborate and borosilicate minerals investigated by high-resolution MAS NMRand ab initio calculations[J]. PHYSICS AND CHEMISTRY OF MINERALS,2012,39(5):363-372.
APA	Zhou, Bing,Sun, Zhaohua,Yao, Yefeng,&Pan, Yuanming.(2012).Correlations between B-11 NMR parameters and structural characters inborate and borosilicate minerals investigated by high-resolution MAS NMRand ab initio calculations.PHYSICS AND CHEMISTRY OF MINERALS,39(5),363-372.
MLA	Zhou, Bing,et al."Correlations between B-11 NMR parameters and structural characters inborate and borosilicate minerals investigated by high-resolution MAS NMRand ab initio calculations".PHYSICS AND CHEMISTRY OF MINERALS 39.5(2012):363-372.