Ashbrook S E, MacKenzie K J, Wimperis S
School of Chemistry, University of Exeter, United Kingdom.
Solid State Nucl Magn Reson. 2001 Nov-Dec;20(3-4):87-99. doi: 10.1006/snmr.2001.0032.
Two-dimensional 27Al multiple-quantum magic angle spinning (MQMAS) NMR experiments are used to study mixtures of bayerite (alpha-Al(OH)3) with either silicic acid (SiO2.nH2O) or silica gel (SiO2) that have been ground together for varying lengths of time. This mechanical treatment produces changes in the 27Al MAS and MQMAS NMR spectra that correspond to the formation of new Al species. Mean values of the quadrupolar interaction (PQ) and isotropic chemical shift (deltacs) are extracted from the two-dimensional 27Al NMR spectra for each of these species. The presence of significant distributions of both 27Al quadrupolar and chemical shift parameters is demonstrated and the effect of grinding duration on the magnitudes of these distributions is discussed.
二维27Al多量子魔角旋转（MQMAS）核磁共振实验用于研究拜耳石（α-Al(OH)3）与硅酸（SiO2·nH2O）或硅胶（SiO2）混合并研磨不同时长后的混合物。这种机械处理会使27Al MAS和MQMAS核磁共振谱发生变化，这些变化对应于新铝物种的形成。从二维27Al核磁共振谱中提取出这些物种各自的四极相互作用（PQ）和各向同性化学位移（δcs）的平均值。结果表明27Al四极和化学位移参数均存在显著分布，并讨论了研磨时长对这些分布大小的影响。
