Synthesis and Structure of Five Sc3CuyZn18-y-Type Compositions (0 ≤ y ≤ ∼2.2), 1/1 Crystalline Approximants of a New Icosahedral Quasicrystal. Direct Example of Tuning on the Basis of Size Effects and Hume−Rothery Concepts
Synthesis and Structure of Five Sc3CuyZn18-y-Type Compositions (0 ≤ y ≤ ∼2.2), 1/1 Crystalline Approximants of a New Icosahedral Quasicrystal. Direct Example of Tuning on the Basis of Size Effects and Hume−Rothery Concepts
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五种 Sc3CuyZn18-y 型组合物 (0 ≤ y ≤ ~2.2) 的合成和结构，新二十面体准晶体的 1/1 晶体近似基于尺寸效应和休谟−罗瑟概念的调整的直接示例。
DOI：
10.1021/ic030265p
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发表时间：
2004
影响因子：
4.6
通讯作者：
J. Corbett
中科院分区：
文献类型：
--
作者：
Q. Lin;J. Corbett
通过四次合成、结构和 EDX 分析，对所报道的 Sc(3)Zn(17) 中 0-4 Zn 被 Cu 系统取代以及校正的 Sc(3)Zn(18) (ScZn(6)) 组成所形成的近似物范围进行了四次合成、结构和 EDX 分析，接近了新报道的大约 Sc(3)Cu(2.1)Zn(12.9) 的二十面体准晶相。 0、1、2、3 Cu 原子步骤的高产率产物的结构全部精炼为同型 Sc(3)Cu(y)Zn(18-y) 相（Im(-)3, Z = 8, a = 13.8311(5) 至 13.7528(5) A for 0 < or = y < or =2.2），基本上与许多已知的 RCd(6) 相同构稀土元素。目前的相都表现出在四个同心多面体簇中心无序锌四面体的新特征：五角十二面体（Zn/Cu）、二十面体（Sc）、二十面体（Zn）和三十面体（Zn）。 Cu 调谐过程将每个原子的平均电子数 (e/a) 降低至 2.04，并降低平均原子尺寸，直到大部分贫锌准晶与靠近四个添加的 Cu 的当前正常晶相分离。 Cu 是无序 Zn 原子的重要邻居。近似结构重复地表现出具有伪二十面体对称性的组件。
The newly reported icosahedral quasicrystalline phase approximately Sc(3)Cu(2.1)Zn(12.9) was approached through four synthetic, structural, and EDX analyses of the range of approximants formed by systematic substitutions of 0-4 Zn by Cu in the reported Sc(3)Zn(17) as well as for the corrected Sc(3)Zn(18) (ScZn(6)) composition. Structures of high yield products of the 0, 1, 2, 3 Cu atom steps all refined as isotypic Sc(3)Cu(y)Zn(18-y) phases (Im(-)3, Z = 8, a = 13.8311(5) to 13.7528(5) A for 0 < or = y < or =2.2), basically isostructural with RCd(6) phases known for many rare-earth elements. The present phases all exhibit the novel feature of disordered zinc tetrahedra in the center of four concentric polyhedral clusters: pentagonal dodecahedron (Zn/Cu), icosahedron (Sc), icosidodecahedron (Zn), and triacontahedron (Zn). The Cu tuning process reduces both the average electron count per atom (e/a) to 2.04 and the average atom size until major amounts of the zinc-poorer quasicrystal separate along with the present normal crystalline phase near four added Cu. The Cu is an important neighbor to the disordered Zn atoms. The approximant structure repeatedly exhibits components with pseudo-icosahedral symmetry.