From Order to Disorder and Back Again: In Situ Hydrothermal Redox Reactions of Uranium Phosphites and Phosphates

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• 作者：Eric M. Villa ; Connor J. Marr ; Juan Diwu ; Evgeny V. Alekseev ; Wulf Depmeier ; Thomas E. Albrecht-Schmitt
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：January 18, 2013
• 年：2013
• 卷：52
• 期：2
• 页码：965-973
• 全文大小：626K
• 年卷期：v.52,no.2(January 18, 2013)
• ISSN：1520-510X

文摘

Five new uranium phosphites, phosphates, and mixed phosphate鈥損hosphite compounds were hydrothermally synthesized using H₃PO₃ as an initial reagent. These compounds are Cs₄[(UO₂)₈(HPO₄)₅(HPO₃)₅]路4H₂O (1), Cs[U^IV(PO₄)(H_1.5PO₄)]₂ (2), Cs₄[U^IV₆(PO₄)₈(HPO₄)(HPO₃)] (3), Cs₁₀[U^IV₁₀(PO₄)₄(HPO₄)₁₄(HPO₃)₅]路H₂O (4), and Cs₃[U^IV₄(PO₄)₃(HPO₄)₅] (5). The first contains uranium(VI) and the latter four uranium(IV). Of the U^IV structures, two have extensive disordering among the cesium cation positions, one of which also contains disordering at some of the phosphate鈥損hosphite positions. These intermediate compounds are bookended by nondisordered phases. The isolation of these transitional phases occurred at the higher of the pH conditions attempted here. Both the starting pH and the duration of the reactions have a strong influence on the products formed. Herein, we explore the second series of in situ hydrothermal redox reactions of uranyl nitrate with phosphorous acid and cesium carbonate. The isolation of these disordered crystalline products helps to illuminate the complex reaction pathways that can occur in hydrothermal syntheses.