Refined Crystal Structure and Idealized Structure of Mixed-Valent Eu4F5(CN2)2: Transition Possible

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• 作者：Leonid Unverfehrt ; Markus Stro虉bele ; Jochen Glaser ; Thorsten Langer ; Rolf-Dieter Hoffmann ; Rainer Po虉ttgen ; H.-Ju虉rgen Meyer
• 刊名：Inorganic Chemistry
• 出版年：2011
• 出版时间：July 4, 2011
• 年：2011
• 卷：50
• 期：13
• 页码：6010-6018
• 全文大小：1124K
• 年卷期：v.50,no.13(July 4, 2011)
• ISSN：1520-510X

文摘

The new europium fluoride carbodiimide Eu₄F₅(CN₂)₂ was synthesized by solid state reaction from mixtures of EuF₃ and Li₂(CN₂) at 700 掳C. The crystal structure as refined by single crystal X-ray diffraction (P4̅2₁c, no. 114, a = 16.053(1) 脜, c = 6.5150(6) 脜, Z = 8) reveals three crystallographically distinct [N鈺怌鈺怤]^{2鈥?/sup> ions in the structure of mixed-valent Eu₄F₅(CN₂)₂. The presence of one Eu3+ and three Eu2+ per formula unit Eu₄F₅(CN₂)₂ is confirmed by magnetic measurements and 151Eu鈥揗枚ssbauer spectroscopy. The arrangement of Eu ions and gravity centers of [NCN]2鈥?/sup> ions in the structure of Eu₄F₅(CN₂)₂ follow the motif formed by atoms in the CuAl₂-type structure. A possible high-symmetry structure of Eu₄F₅(CN₂)₂ is discussed on the basis of a group-subgroup scheme.}