X-ray diffraction study of bond character of rutile-type SiO2, GeO2 and SnO2
X-ray diffraction study of bond character of rutile-type SiO2, GeO2 and SnO2
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金红石型SiO2、GeO2、SnO2键合特性的X射线衍射研究
DOI：
10.1524/zkri.2000.215.7.424
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
J. Mimaki
中科院分区：
文献类型：
--
作者：
T. Yamanaka;R. Kurashima;J. Mimaki
采用单极精细化的x射线衍射方法研究了SiO2、GeO2和SnO2的金红石型结构的电荷密度和键合特性。电荷密度的细化采用最小二乘细化，包括Κ-parameter和x射线原子散射参数中的电子占比。三种氧化物的氧值Κ-parameters分别为0.91 （SiO2）、1.06 （GeO2）、1.14 （SnO2）。SiO2、GeO2和SnO2的氧价电子分别为1.06(8)e、1.10(16)e和1.13(15)e。这些值表明，随着阳离子原子序数的增加，电子分布更加局域化。每个样品的差分傅里叶图显示了阳离子价电子的变形密度。重叠的电子轨道导致MO6八面体的金红石型结构发生变形。相邻八面体中O-O共享边与非共享边之比以及顶端与赤道间的M-O原子间距离之比随着阳离子的离子性和两阳离子之间的排斥力的增大而减小。
The charge density and bond character of the rutile-type structures of SiO2, GeO2 and SnO2 were studied by X-ray diffraction using monopole refinement. The refinement of the charge density was performed by least-squares refinement including the Κ-parameter and the electron population in the X-ray atomic scattering parameters. The oxygen′s Κ-parameters of three oxides are 0.91 (SiO2), 1.06 (GeO2), 1.14 (SnO2). The oxygen valence electron of each sample is 1.06(8)e for SiO2, 1.10(16)e for GeO2 and 1.13(15)e for SnO2. These values indicate that the electron distributions are more localized with an increase in the cation atomic number. The difference Fourier map of each sample shows the deformation density of the valence electrons of cations. The overlapping electron orbitals cause the deformation of MO6 octahedra of rutile-type structures. The ratio between O-O shared and unshared edge and the ratio between the apical and equatorial M-O interatomic distances decrease with the cation ionicity and the repulsive force between the two cations in adjacent octahedra.