KCaEr2CuS5: A New Pentanary Rare-Earth Layered Chalcogenide without Substitutional Disorder

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• 作者：Hui-Yi Zeng ; Hansjü ; rgen Mattausch ; Arndt Simon ; Fa-Kun Zheng ; Zhen-Chao Dong ; Guo-Cong Guo ; Jin-Shun Huang
• 刊名：Inorganic Chemistry
• 出版年：2006
• 出版时间：September 18, 2006
• 年：2006
• 卷：45
• 期：19
• 页码：7943 - 7946
• 全文大小：232K
• 年卷期：v.45,no.19(September 18, 2006)
• ISSN：1520-510X

文摘

A new pentanary rare-earth chalcogenide without substitutional disorder, KCaEr₂CuS₅, was obtained from reactionof the Er-Ca-Cu-S precursor with KBr flux by either a two-step flux method or a direct reaction of the mixture ofthe binary components (1Cu₂S:2Er₂S₃:3CaS) with excess KBr as flux. KCaEr₂CuS₅ crystallizes in the orthorhombicspace group Cmcm (No. 63) with a = 3.9327(5) Å, b = 13.410(2) Å, c = 17.042(2) Å, V = 898.8(3) ų, Z = 4,R = 0.0632, and R_w = 0.0627. The KCaEr₂CuS₅ structure consists of four different building units: ErS₆ octahedra,CaS₆ octahedra, CuS₄ tetrahedra, and KS₆ trigonal prisms; it is characterized by [Er₂CuS₅]^3- layers that areformed by the interconnection of double ErS₆ octahedral chains with CuS₄ tetrahedral chains in the a-c plane. K⁺and Ca²⁺ cations are located in the cavities defined by S^2- anions between the [Er₂CuS₅]^3- layers. KCaEr₂CuS₅is a semiconductor with an estimated band gap of 2.4 eV and shows a Curie-Weiss paramagnetic behavior in the5-300 K range.