High-pressure synthesis, crystal structures, and properties of perovskite-like BiAlO3 and pyroxene-like BiGaO3
High-pressure synthesis, crystal structures, and properties of perovskite-like BiAlO3 and pyroxene-like BiGaO3
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DOI：
10.1021/cm052020b
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发表时间：
2006-01-10
影响因子：
8.6
通讯作者：
Takayama-Muromachi, E
中科院分区：
文献类型：
--
作者：
Belik, AA;Wuernisha, T;Takayama-Muromachi, E
采用高压高温技术在6 GPa和1273-1473 K下制备了新的氧化物BiAlO 3和BiGaO 3。BiAlO 3与多铁性类钙钛矿BiFeO 3是同位素，并且具有八面体配位的Al 3+离子。由实验室X射线粉末衍射数据（空间群R3 c; Z = 6; a = 5.37546（5）angstrom和c = 13.3933（l）angstrom）修正了BiAlO 3的结构参数。BiGaO 3具有与类辉石KVO 3密切相关的结构，由飞行时间中子粉末衍射数据（空间群Pcca; Z = 4; a = 5.4162（2）angstrom，B = 5.1335（3）angstrom，c = 9.9369（5）angstrom）修正了BiGaO 3的结构参数。BiGaO 3中的GaO 4四面体通过角连接，形成沿着a轴的无限（GaO 3）（3-）链。BiGaO_3中的Bi ~（3+）离子具有6重配位。BiAlO 3和BiGaO 3在环境压力下加热到820 K以上时均分解，得到Bi 2 M4 O 9和Bi 25 MO 39（M = Al和Ga）。利用拉曼光谱研究了BiAlO 3和BiGaO 3的振动特性。在BiAl_（1-x）Ga_xO_3固溶体中，发现了一个与PbTiO_3结构相关的C心单斜相，其晶格参数为a = 5.1917（4）埃，B = 5.1783（4）埃，c = 4.4937（3）埃，β = 91.853（3）度。
New oxides, BiAlO3 and BiGaO3, were prepared using a high-pressure high-temperature technique at 6 GPa and 1273-1473 K. BiAlO3 is isotopic with multiferroic perovskite-like BiFeO3 and has octahedrally coordinated Al3+ ions. Structure parameters of BiAlO3 were refined from laboratory X-ray powder diffraction data (space group R3c; Z = 6; a = 5.37546(5) angstrom and c = 13.3933(l) angstrom). BiGaO3 has the structure closely related to pyroxene-like KVO3, Structure parameters of BiGaO3 were refined from time-of-flight neutron powder diffraction data (space group Pcca; Z = 4; a = 5.4162(2) angstrom, b = 5.1335(3) angstrom, and c = 9.9369(5) angstrom). The GaO4 tetrahedra in BiGaO3 are joined by corners forming infinite (GaO3)(3-) chains along the a axis. Bi3+ ions in BiGaO3 have 6-fold coordination. Both BiAlO3 and BiGaO3 decompose at ambient pressure on heating above 820 K to give Bi2M4O9 and Bi25MO39 (M = Al and Ga). Vibrational properties of BiAlO3 and BiGaO3 were studied by Raman spectroscopy. In solid solutions of BiAl1-xGaxO3, a C-centered monoclinic phase structurally related to PbTiO3 with lattice parameters of a = 5.1917(4) angstrom, b = 5.1783(4) angstrom, c = 4.4937(3) angstrom, and beta = 91.853(3)degrees was found.