Structural variability versus structural flexibility. A case study of Eu9Cd4+xSb9 and Ca9Mn4+xSb9 (x ≈ (1)/2).
Structural variability versus structural flexibility. A case study of Eu9Cd4+xSb9 and Ca9Mn4+xSb9 (x ≈ (1)/2).
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DOI：
10.1021/ic5023505
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发表时间：
2015-02
影响因子：
4.6
通讯作者：
Xiao-Cun Liu;Zhenfa Wu;S. Xia;X. Tao;S. Bobev
中科院分区：
文献类型：
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作者：
Xiao-Cun Liu;Zhenfa Wu;S. Xia;X. Tao;S. Bobev
本文的重点是新型三元锑化物Eu(9)Cd(4+x)Sb(9)和Ca(9)Mn(4+x)Sb(9) (x ≈ (1)/2)的合成和结构表征。尽管这些化合物具有类似的化学组成和分子式，这可能表明它们具有同型性，但它们实际上属于两种不同的结构类型。 Eu(9)Cd(4.45(1))Sb(9)与之前报道的Eu(9)Zn(4.5)Sb(9) (Pbam)是同构的，其结构具有晶胞参数a = 12.9178(11) Å、b = 23.025(2) Å和c = 4.7767(4) Å。 Ca(9)Mn(4.41(1))Sb(9)在斜方空间群Pnma中结晶，晶胞尺寸为a = 12.490(2) Å，b = 4.6292(8) Å，c = 44.197(8) Å，并构成新的结构类型。对两种结构进行了比较和对比，讨论了结构关系。针对这两种类型的砷基类似物的探索性工作导致了 Ca(9)Zn(4.46(1))As(9) 的鉴定，并形成了后一种结构 [a = 11.855(2) Å、b = 4.2747(8) Å 和 c = 41.440(8) Å]。对 Ca(9)Zn(4+x)As(9) 单晶进行的差热分析和电阻率测量表明其具有高热稳定性和半导体行为。 Eu(9)Cd(4+x)Sb(9) 样品的磁化率测量证实了预期的Eu(2+) ([Xe]4f(7)) 基态。
The focus of this article is on the synthesis and structural characterization of the new ternary antimonides Eu(9)Cd(4+x)Sb(9) and Ca(9)Mn(4+x)Sb(9) (x ≈ (1)/2). Although these compounds have analogous chemical makeup and formulas, which may suggest isotypism, they actually belong to two different structure types. Eu(9)Cd(4.45(1))Sb(9) is isostructural with the previously reported Eu(9)Zn(4.5)Sb(9) (Pbam), and its structure has unit cell parameters a = 12.9178(11) Å, b = 23.025(2) Å, and c = 4.7767(4) Å. Ca(9)Mn(4.41(1))Sb(9) crystallizes in the orthorhombic space group Pnma with unit cell dimensions a = 12.490(2) Å, b = 4.6292(8) Å, and c = 44.197(8) Å and constitutes a new structure type. The two structures are compared and contrasted, and the structural relationships are discussed. Exploratory work aimed at the arsenic-based analogues of either type led to the identification of Ca(9)Zn(4.46(1))As(9), forming with the latter structure [a = 11.855(2) Å, b = 4.2747(8) Å, and c = 41.440(8) Å]. Differential thermal analysis and electrical resistivity measurements, performed on single crystals of Ca(9)Zn(4+x)As(9), indicate high thermal stability and semiconducting behavior. Magnetic susceptibility measurements on Eu(9)Cd(4+x)Sb(9) samples confirm the expected Eu(2+) ([Xe]4f(7)) ground state.