Comprehensive Structural Study of Glassy and Metastable Crystalline BaTi2O5
Comprehensive Structural Study of Glassy and Metastable Crystalline BaTi2O5
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DOI：
10.1021/cm802483w
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发表时间：
2009-01
影响因子：
8.6
通讯作者：
Jianding Yu;S. Kohara;K. Itoh;S. Nozawa;S. Miyoshi;Y. Arai;A. Masuno;H. Taniguchi;M. Itoh;M. Takata;T. Fukunaga;S. Koshihara;Y. Kuroiwa;S. Yoda
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文献类型：
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作者：
Jianding Yu;S. Kohara;K. Itoh;S. Nozawa;S. Miyoshi;Y. Arai;A. Masuno;H. Taniguchi;M. Itoh;M. Takata;T. Fukunaga;S. Koshihara;Y. Kuroiwa;S. Yoda
通过组合 X 射线和中子衍射、XANES 分析和计算机模拟，对无容器法制备的玻璃态和亚稳态晶体 BaTi2O5 的结构进行了全面研究。通过对衍射数据进行逆蒙特卡罗 (RMC) 建模模拟的玻璃状 BaTi2O5 (g-BaTi2O5) 的三维原子结构表明，与共享角和共享边的氧互连的极度扭曲的 TiO5 多面体形成了比仅共享角 SiO4 多面体的传统硅酸盐玻璃更高的堆积密度结构。此外，XANES测量表明，在结晶的亚稳α-和β-BaTi2O5相中可形成五配位的TiO5多面体。通过从头计算求解亚稳态β-BaTi2O5的结构，并通过Rietveld精修精修为具有单位晶格a = 10.23784(4) A、b = 3.92715(1) A、c = 10.92757(4) A的群Pnma。我们的结果表明，无容器工艺增强了玻璃形成能力...
The structures of glassy and metastable crystalline BaTi2O5 fabricated by the containerless method were comprehensively investigated by combined X-ray and neutron diffractions, XANES analyses, and computer simulations. The three-dimensional atomic structure of glassy BaTi2O5 (g-BaTi2O5), simulated by Reverse Monte Carlo (RMC) modeling on diffraction data, shows that extremely distorted TiO5 polyhedra interconnected with both corner- and edge-shared oxygen formed a higher packing density structure than that of conventional silicate glass linked with only corner-sharing of SiO4 polyhedra. In addition, XANES measurement revealed that five-coordinated TiO5 polyhedra were formable in the crystallized metastable α- and β-BaTi2O5 phases. The structure of metastable β-BaTi2O5 was solved by ab initio calculation, and refined by Rietveld refinement as group Pnma with unit lattices a = 10.23784(4) A, b = 3.92715(1) A, c = 10.92757(4) A. Our results show that the glass-forming ability enhanced by containerless proces...