Local Geometry of Tetrahedrally Coordinated Boron Correlates with 11B NMR Chemical Shifts in Borosilicate Minerals

Chemical shifts from the 11B nuclear magnetic resonance (NMR) spectra of crystalline borosilicate minerals with highly ordered, tetrahedrally coordinated boron atoms (B) linearly correlate with the local geometric parameters related to the B–O–T angles (T denotes a tetrahedrally coordinated atom) obtained from single-crystal X-ray diffraction. The correlations between the 11B NMR chemical shifts and structural parameters are similar in functional form to the well-known correlations of 29Si and 27Al NMR chemical shifts with structural features of silicates and aluminosilicates, respectively. These correlations enable the use of 11B NMR chemical shifts to elucidate the local geometry of tetrahedrally coordinated B and aid in establishing B ordering among the crystallographic T-sites within crystalline borosilicates.

具有高度有序四面体配位硼原子（B）的结晶硼硅酸盐矿物的11B核磁共振（NMR）光谱化学位移，与通过单晶X射线衍射获得的、与B–O–T键角（T代表四面体配位原子）相关的局域几何参数呈线性相关。11B NMR化学位移与结构参数间的相关性，在函数形式上与已知的29Si、27Al NMR化学位移分别对应硅酸盐、铝硅酸盐结构特征的相关性高度相似。此类相关性使得我们可借助11B NMR化学位移解析四面体配位硼的局域几何结构，并有助于确定结晶硼硅酸盐中晶体学T位点间的硼原子有序排布情况。