Observation of the Sixth Polymorph of BiB3O6: In Situ High-Pressure Raman Spectroscopy and Synchrotron X-ray Diffraction Studies on the 尾-Polymorph

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• 作者：Rihong Cong ; Tao Yang ; Junliang Sun ; Yingxia Wang ; Jianhua Lin
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：July 1, 2013
• 年：2013
• 卷：52
• 期：13
• 页码：7460-7466
• 全文大小：547K
• 年卷期：v.52,no.13(July 1, 2013)
• ISSN：1520-510X

文摘

尾-BiB₃O₆ was compressed in a diamond anvil cell at room temperature and studied using a combinstion of in situ high-pressure Raman scattering and angle-dispersive synchrotron X-ray diffraction. The results reveal that 尾-BiB₃O₆ retains its structure below 9.0 GPa and undergoes a structural phase transition that starts at 11.5 GPa and finishes at 18.5 GPa. No other phase transition occurred with increasing pressure up to 46 GPa. It was also found that the high-pressure phase is different from the already-reported five polymorphs of BiB₃O₆. Therefore, the new phase is denoted as 味-BiB₃O₆, which could be indexed by an orthorhombic unit cell (a 鈮?12.5 脜, b 鈮?6.7 脜, c 鈮?4.0 脜) from the powder XRD pattern collected at 22.2 GPa. Moreover, 味-BiB₃O₆ can be quenched to ambient conditions. The investigation of the pressure dependence of the lattice parameters reveals that both 尾-BiB₃O₆ and 味-BiB₃O₆ exhibit a large amount of crystallographic anisotropy. An unusual expansion of the c-axis of 味-BiB₃O₆ was observed. Assignments for the Raman spectra of 尾-BiB₃O₆, 纬-BiB₃O₆, and 未-BiB₃O₆ under ambient conditions were also performed. Currently, we cannot solve the crystal structure of 味-BiB₃O₆ but give some speculations based on its relationship with 尾-BiB₃O₆.