The crsytal structure of the phase β Mg2Al3
The crsytal structure of the phase β Mg2Al3
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DOI：
10.1107/s0365110x65005133
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发表时间：
1965-09
期刊：
影响因子：
--
通讯作者：
S. Samson
中科院分区：
文献类型：
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作者：
S. Samson
已经进行了通常被称为fl Mg 2Al 3的相的晶体结构的测定，并且已经通过三维最小二乘技术对结构进行了细化。1215次反射的最终一致性指数R为0.061。晶体属立方晶系，空间群Fd 3 m（07），a0= 28.239+_0.001/~。单位晶胞中大约有1168个原子。这些分布在23个晶体学上不同的位置，作为部分无序的结果，描述了41个不同的多面体。无序的一个有趣的特征是，它导致结构单元中二十面体的数量增加，超过理想化有序模型中的数量。单位立方体包含672个二十面体、252个弗里奥夫多面体和244个配位数为10到16的不规则多面体。
A determination of the crystal structure of the phase commonly referred to as fl Mg2A13 has been carried out and the structure has been refined by three-dimensional, least-squares techniques. The final agreement index R is 0.061 for 1215 reflections. The crystals are cubic, space group Fd3m (07) with a0= 28.239+ _ 0.001/~. There are approximately 1168 atoms in the unit cell. These are distributed over 23 crystallographically different positions which, as a result of partial disorder, describe 41 different polyhedra. An interesting feature of the disorder is that it results in an increase in the number of icosahedra in the unit of structure, over that found in the idealized ordered model. The unit cube contains 672 icosahedra, 252 Friauf polyhedra, and 244 miscellaneous, more-or-less irregular polyhedra of ligancy 10 to 16.