Topochemical Fluorination of Sr3(M0.5Ru0.5)2O7 (M = Ti, Mn, Fe), n = 2, Ruddlesden鈥揚opper Phases

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• 作者：Fabio Denis Romero ; Paul A. Bingham ; Susan D. Forder ; Michael A. Hayward
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：March 18, 2013
• 年：2013
• 卷：52
• 期：6
• 页码：3388-3398
• 全文大小：513K
• 年卷期：v.52,no.6(March 18, 2013)
• ISSN：1520-510X

文摘

Reaction of the appropriate Sr₃(M_0.5Ru_0.5)₂O₇ (M = Ti, Mn, Fe), n = 2, Ruddlesden鈥揚opper oxide with CuF₂ under flowing oxygen results in formation of the oxide鈥揻luoride phases Sr₃(Ti_0.5Ru_0.5)₂O₇F₂, Sr₃(Mn_0.5Ru_0.5)₂O₇F₂, and Sr₃(Fe_0.5Ru_0.5)₂O_5.5F_3.5 via a topochemical anion insertion/substitution process. Analysis indicates the titanium and manganese phases have Ti⁴⁺, Ru⁶⁺ and Mn⁴⁺, Ru⁶⁺ oxidation state combinations, respectively, while M枚ssbauer spectra indicate an Fe³⁺, Ru^5.5+ combination for the iron phase. Thus, it can be seen that the soft fluorination conditions employed lead to formation of highly oxidized Ru⁶⁺ centers in all three oxide鈥揻luoride phases, while oxidation states of the other transition metal M cations remain unchanged. Fluorination of Sr₃(Ti_0.5Ru_0.5)₂O₇ to Sr₃(Ti_0.5Ru_0.5)₂O₇F₂ leads to suppression of magnetic order as the fluorinated material approaches metallic behavior. In contrast, fluorination of Sr₃(Mn_0.5Ru_0.5)₂O₇ and Sr₃(Fe_0.5Ru_0.5)₂O₇ lifts the magnetic frustration present in the oxide phases, resulting in observation of long-range antiferromagnetic order at low temperature in Sr₃(Mn_0.5Ru_0.5)₂O₇F₂ and Sr₃(Fe_0.5Ru_0.5)₂O_5.5F_3.5. The influence of the topochemical fluorination on the magnetic behavior of the Sr₃(M_0.5Ru_0.5)₂O_xF_y phases is discussed on the basis of changes to the ruthenium oxidation state and structural distortions.