Institut für Geowissenschaften, Goethe Universität Frankfurt, Frankfurt aM, Germany.
J Phys Condens Matter. 2010 Dec 22;22(50):505401. doi: 10.1088/0953-8984/22/50/505401. Epub 2010 Nov 26.
The crystal structure of the bismuth silicon oxide Bi(12)SiO(20) was determined by single-crystal x-ray diffraction at ambient conditions and at high pressure. Single-crystal intensity data between 0.0001 and 16.8(3) GPa were collected in house with Mo Kα radiation and with synchrotron radiation (λ = 0.45 Å) at HASYLAB (D3), while lattice parameters were measured up to 23.0(3) GPa. The large cavities which exist in the crystal structure and host the lone electron pairs of the Bi(3 + ) ions are considerably compressed at high pressure. The crystal structure, however, remains stable and the lone electron pair is stereochemically active up to at least 16.8 GPa. A larger compression in the direction of the lone electron pairs by shear deformation was not observed. Raman spectra of Bi(12)SiO(20) were measured on powder samples during pressure decrease from 39.1(1) GPa down to ambient pressure and on single crystals during pressure increase up to 12.50(3) GPa. Density functional perturbation theory was used to compute Raman frequencies and intensities at ambient pressure and to investigate pressure-induced changes up to 50 GPa.
环境条件和高压下的氧化硅铋 Bi(12)SiO(20)的晶体结构通过单晶 X 射线衍射确定。在 HASYLAB(D3) 用 Mo Kα 辐射和同步辐射（λ=0.45Å）在 0.0001 到 16.8(3)GPa 之间收集单晶强度数据，而晶格参数则测量至 23.0(3)GPa。晶体结构中存在的大空腔容纳 Bi(3+)离子的孤电子对，在高压下会被相当大地压缩。然而，晶体结构仍然稳定，孤电子对在至少 16.8GPa 时仍具有立体化学活性。没有观察到沿孤电子对方向的剪切变形的更大压缩。在压力从 39.1(1)GPa 降低到环境压力的过程中，对 Bi(12)SiO(20)的粉末样品进行了拉曼光谱测量，并在压力升高到 12.50(3)GPa 的过程中对单晶进行了拉曼光谱测量。密度泛函微扰理论用于计算环境压力下的拉曼频率和强度，并研究高达 50GPa 的压力诱导变化。
