Topochemical Synthesis of Alkali-Metal Hydroxide Layers within Double- and Triple-Layered Perovskites

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• 作者：Dariush Montasserasadi ; Debasish Mohanty ; Ashfia Huq ; Luke Heroux ; Edward Andrew Payzant ; John B. Wiley
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：February 3, 2014
• 年：2014
• 卷：53
• 期：3
• 页码：1773-1778
• 全文大小：359K
• ISSN：1520-510X

文摘

The formation of alkali-metal hydroxide layers within lamellar perovskites has been accomplished by a two-step topochemical reaction strategy. Reductive intercalation of ALaNb₂O₇ with alkali metal (A = K, Rb) and RbCa₂Nb₃O₁₀ with Rb leads to A₂LaNb₂O₇ and Rb₂Ca₂Nb₃O₁₀, respectively. Oxidative intercalation with stoichiometric amounts of water vapor, produced by the decomposition of calcium oxalate monohydrate in a sealed ampule, allows the insertion hydroxide species. Compounds of the form (A₂OH)LaNb₂O₇ (A = K, Rb) and (Rb₂OH)Ca₂Nb₃O₁₀ are accessible. X-ray diffraction data indicates a clear layer expansion of almost 3 脜 on the insertion of hydroxide relative to that of the parent. Rietveld refinement of neutron diffraction data collected on deuterated samples of (Rb₂OD)LaNb₂O₇ (P4/mmm space group, a = 3.9348(1) 脜, c = 14.7950(7) 脜) finds that both rubidium and oxygen species reside in cubic sites forming a CsCl-like interlayer structure between niobate perovskite blocks. Hydrogens, attached to the interlayer oxygens, are disordered over a 4-fold site in the x鈥?i>y plane and have O鈥揌 bond distances (0.98 脜) consistent with known hydroxide species. This synthetic approach expands the library of available topochemical reactions, providing a facile method for the construction of alkali-metal hydroxide layers within receptive perovskite hosts.