Preparation and crystal structure of layered niobium oxides:: Rb(Mg0.34Nb1.66)O5 and K(Fe0.43Nb1.57)O5
Preparation and crystal structure of layered niobium oxides:: Rb(Mg0.34Nb1.66)O5 and K(Fe0.43Nb1.57)O5
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DOI：
10.1016/s0025-5408(98)00186-x
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发表时间：
1998-12-01
影响因子：
5.4
通讯作者：
Kinomura, N
中科院分区：
文献类型：
--
作者：
Kumada, N;Iwase, E;Kinomura, N
层状铌氧化物Rb（Mg0.34Nb1.66）O-5和K（Fe0.43Nb1.57）O-5的单晶在1200 ℃下制备。晶体结构为KTiNbO 5型，空间群为Pnma，Z = 4，Rb的晶格常数为a = 6.571（1），B = 3.858（1），c = 19.077（1）埃（Mg 0.34 Nb 1.66）O-5，K（Fe 0.43 Nb 1.57）O-5的a = 6.533（1），B = 3.820（2），c = 18.682（2）埃。单晶结构细化导致Rb（Mg0.34Nb1.66）O-5的R = 0.032和R-w = 0.031，K（Fe0.43Nb1.57）O-5的R = 0.049和R-w = 0.064。铌和铁/镁原子在统计上分布在共享边缘的双八面体单元中。中间层中的碱性离子与质子进行离子交换，得到水合质子化化合物H（M，Nb）（2）O-5。nH（2）O（M = Mg，Fe）. (C)1999 Elsevier Science Ltd.
Single crystals of layered niobium oxides, Rb(Mg0.34Nb1.66)O-5 and K(Fe0.43Nb1.57)O-5, were prepared at 1200 degrees C. The niobium oxides crystallized in the KTiNbO5-type structure and have the orthorhombic space group Pnma with Z = 4 and the lattice parameters are a = 6.571(1), b = 3.858(1), and c = 19.077(1) Angstrom for Rb(Mg0.34Nb1.66)O-5, and a = 6.533(1), b = 3.820(2), and c = 18.682(2) Angstrom for K(Fe0.43Nb1.57)O-5. The single-crystal structure refinements led to R = 0.032 and R-w = 0.031 for Rb(Mg0.34Nb1.66)O-5 and to R = 0.049 and R-w = 0.064 for K(Fe0.43Nb1.57)O-5. The niobium and iron/magnesium atoms an statistically distributed in a unit of doubled octahedra sharing edges. Alkaline ions in the interlayer were ion exchanged with protons to yield hydrated protonated compounds, H(M,Nb)(2)O-5. nH(2)O (M = Mg,Fe). (C) 1999 Elsevier Science Ltd.