Pay Gómez Cesar, Lidin Sven
Inorganic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden.
Chemistry. 2004 Jul 5;10(13):3279-85. doi: 10.1002/chem.200305463.
The quasicrystal approximant Eu(4)Cd(25), formerly designated EuCd(6), was synthesized and characterized by means of single-crystal X-ray diffraction. Superstructure reflections corresponding to an F-centered cubic unit cell with a doubled cell-parameter relative to the I-centered cubic sub-cell could be observed in the diffraction data. This gives the largest cubic unit cell reported to date among binary alloys. The superstructure exhibits structural features that are found in all the RE-Cd(6) approximants as well as a further ordering between vacant/occupied Cd(8) cubes and oriented Cd(4) tetrahedra, which causes the superstructure. A reversible high-temperature phase-transition was observed at 782 K by means of DSC.
准晶近似物Eu(4)Cd(25)（以前称为EuCd(6)）通过单晶X射线衍射进行了合成和表征。在衍射数据中可以观察到与面心立方晶胞相对应的超结构反射，其晶胞参数相对于体心立方子晶胞加倍。这给出了迄今为止二元合金中报道的最大立方晶胞。该超结构具有在所有RE-Cd(6)近似物中都能找到的结构特征，以及空位/占据的Cd(8)立方体和定向的Cd(4)四面体之间的进一步有序排列，这导致了超结构的形成。通过差示扫描量热法（DSC）在782 K观察到了可逆的高温相变。
