Crystal chemical characterization of mullite-type aluminum borate compounds
Crystal chemical characterization of mullite-type aluminum borate compounds
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DOI：
10.1016/j.jssc.2016.12.027
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发表时间：
2017-03
影响因子：
3.3
通讯作者：
K. Hoffmann;T. Hooper;Haishuang Zhao;U. Kolb;M. Murshed;M. Fischer;H. Lührs;G. Nénert;P. Kudějová;A. Senyshyn;H. Schneider;J. Hanna;T. Gesing;R. Fischer
中科院分区：
文献类型：
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作者：
K. Hoffmann;T. Hooper;Haishuang Zhao;U. Kolb;M. Murshed;M. Fischer;H. Lührs;G. Nénert;P. Kudějová;A. Senyshyn;H. Schneider;J. Hanna;T. Gesing;R. Fischer
采用不同的合成路线和不同的Al/B比制备了富铝硼酸铝，并用衍射法、能谱和快速伽马活化分析对其进行了表征。11B核磁共振数据表明，所有样品中都有少量的BO4物种。化学分析表明，Al/B比有一种趋势，而不是一个固定的成分。用电子衍射法对富B的Al_4B_2O_9(C_2/m，a=1488，b=553m，c=1502m，？？=90.6°)的结构进行了重新研究，结果表明，富B的Al_4B_2O_9(C_2/m，a=1488，b=553m，c=1502m，？=90.6°)的结构发生了变化。在大多数区域中，原子是有序分布的，没有显示出假设的通道氧原子O5的信号。密度泛函理论计算支持O_5的不存在。其他结构域显示出O5和O10的可能无序构型，这由沿双向的扩散散射所指示。
Al-rich aluminum borates were prepared by different synthesis routes using various Al/B ratios, characterized by diffraction methods, spectroscopy and prompt gamma activation analysis. The11B NMR data show a small amount of BO4species in all samples. The chemical analysis indicates a trend in the Al/B ratio instead of a fixed composition. Both methods indicate a solid solution Al5−xB1+xO9where Al is substituted by B in the range of 1–3%.The structure of B-rich Al4B2O9(C2/m,a=1488 pm,b=553 pm,c=1502 pm,ß=90.6°), was re-investigated by electron diffraction methods, showing that structural details vary within a crystallite. In most of the domains the atoms are orderly distributed, showing no signal for the postulated channel oxygen atom O5. The absence of O5 is supported by density functional theory calculations. Other domains show a probable disordered configuration of O5 and O10, indicated by diffuse scattering along thebdirection.