Crystal structure of a new 1/1-rational approximant for the Al–Cu–Ru icosahedral phase
Crystal structure of a new 1/1-rational approximant for the Al–Cu–Ru icosahedral phase
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Al-Cu-Ru 二十面体相的新 1/1-有理近似晶体结构
DOI：
10.1016/s0925-8388(99)00677-5
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发表时间：
2000
影响因子：
6.2
通讯作者：
Kaichi Saito
中科院分区：
文献类型：
--
作者：
K. Sugiyama;Takeshi Kato;Toshiyuki Ogawa;K. Hiraga;Kaichi Saito
采用单晶x射线结构分析方法，确定了Al-Cu-Ru 20面体相的1/1理性近似al57.3 cu31.4 ru11.3立方相的结构：空间群Pm3 (No. 200), a=12.3773(8) Å， V=1896.2(2) Å3, MoKα （λ=0.71073 Å）；原子/细胞=122.6，F(000)=2645, Dcalc=5.04 Mg/m3， R=0.0495, >4.0σ(Fobs.)。富Cu和富ru的二十烷十二面体原子团簇分别位于单元胞的1a和1b位点。原子团簇以Ru为中心，其周围直径约2.5 Å的第一壳层表现出严重的无序特征，局部二十面体对称性被部分破坏。这些具有化学和拓扑修饰的麦凯类原子团簇应该被归类为f型Al-Cu-Ru二十面体相的基本结构单元。
The structure of a cubic Al57.3Cu31.4Ru11.3phase, which is referred to as an 1/1-rational approximant of an Al–Cu–Ru icosahedral phase, was determined by means of a single crystal X-ray structural analysis: space group Pm3 (No. 200), a=12.3773(8) Å, V=1896.2(2) Å3, MoKα (λ=0.71073 Å); atoms/cell=122.6, F(000)=2645, Dcalc=5.04 Mg/m3, R=0.0495 for the observed 1140 reflections with Fobs.>4.0σ(Fobs.). Cu- and Ru-rich icosidodecahedral atom clusters are recognized at the 1a and 1b sites of the unit cell, respectively. The atom clusters possess Ru centers and the surrounding first shells of about 2.5 Å in diameter show heavily disordered features with partial breakdown of the local icosahedral symmetry. These chemically and topologically decorated Mackay-like atom clusters should be classified as the fundamental structural units for the F-type Al–Cu–Ru icosahedral phase.