The infrared spectra of rare earth element oxide orthosilicates
The infrared spectra of rare earth element oxide orthosilicates
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稀土元素氧化物原硅酸盐的红外光谱
DOI：
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发表时间：
1963
期刊：
影响因子：
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通讯作者：
N. Toropov
中科院分区：
文献类型：
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作者：
A. N. Lazarev;T. F. Tenisheva;I. A. Bondar;N. Toropov
1.
对稀土金属LN_2(SiO_4)O的氧化物正硅酸盐的红外光谱研究表明，根据三种结构类型的存在，可以将这些化合物分为三类。
2.
在某些氧化物正硅酸盐的光谱中，发现了含有O2-−的Ln-O-Ln键的振动带。这些带是部分共价的，它们的共价性随着La→Lu(和La→Y→Sc)系列阳离子碱性强度的降低而增加。
3.
Ln~(3+)离子在三种结构类型的氧化物正硅酸盐中配位不同的观点与(Ln‘Ln“)_2(SiO_4)_O体系相图的研究结果相一致。位于两基团”边界“附近的化合物在少量添加剂的影响下结晶的能力也证实了这一观点。
4.
比较了焦硅酸盐和氧化物正硅酸盐系列中稀土金属阳离子的结构变化(阳离子配位)与离子半径的变化，结果表明，在氧化物正硅酸盐系列中，阳离子有效半径的幅度较小。这种差异归因于O2−阴离子较强的电子接受能力以及它与阳离子形成的键的部分共价性。
1.
Study of the infrared spectra of the oxide orthosilicates of the rare earth metals Ln2(SiO4)O makes it possible to divide these compounds into three groups in accordance with the existence of three structural types.
2.
Bands for the vibrations of Ln-O-Ln bonds involving “oxide ions” O2− have been identified in the spectra of some of the oxide orthosilicates. These bands are partly covalent and their covalent character increases with decrease in the basic strength of the cations in the series La→Lu (and La→Y→Sc).
3.
The suggestion that the coordination of the Ln3+ ions is different in the three structural types of oxide orthosilicate agrees with the results of the study of the phase diagrams for systems of the type (Ln′ Ln″)2(SiO4)O. The ability of compounds lying close to the “boundary” between two groups to crystallize under the influence of small quantities of additives with the structure of the neighboring group, also confirms this suggestion.
4.
Comparison of the changes in structure (coordination of the cations) with change in the ionic radius of the rare earth metal cations in the pyrosilicate and oxide orthosilicate series indicates that the magnitude of the effective radius of the cation is smaller in the latter group of compounds. This difference is attributed to the stronger electron-accepting power of the O2− anions and the partial covalent character of the bonds which it forms with the cations.