Structural characterisations of the NaxSi136 and Na8Si46 silicon clathrates using the Rietveld method
Structural characterisations of the NaxSi136 and Na8Si46 silicon clathrates using the Rietveld method
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DOI：
10.1039/a804565h
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发表时间：
1998
影响因子：
--
通讯作者：
E. Reny;P. Gravereau;C. Cros;M. Pouchard
中科院分区：
文献类型：
--
作者：
E. Reny;P. Gravereau;C. Cros;M. Pouchard
采用Rietveld方法对非化学计量比的Na x Si 136硅包合物的晶体结构进行了修正，以准确地确定钠原子在两个有效位置内的分布。与先前的数据一致，发现当x≤8时，碱原子仅占据，而不仅仅是优先占据8个较大的Si 28位。当8<x<24时，随着x的增加，16个较小的Si 20笼逐渐被填充，然后观察到晶胞参数略有增加。化学计量比的Na8Si46笼形物，这是目前作为杂质在所研究的样品中，晶体结构也被细化。
The crystal structure of the non-stoichiometric Na x Si 136 silicon clathrate has been refined using the Rietveld method, in order to determine accurately the distribution of the sodium atoms within the two available sites. In agreement with the previous data, it was found that for x≤8, the alkali atoms occupy exclusively, and not only preferentially the eight larger Si 28 sites. For 8<x<24, the filling of the sixteen smaller Si 20 cages occurs gradually with increasing x, and a slight increase of the unit cell parameter is then observed. The crystal structure of the stoichiometric Na 8 Si 46 clathrate, which is present as impurity in the studied samples, has also been refined.