From Yellow to Black: Dramatic Changes between Cerium(IV) and Plutonium(IV) Molybdates

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• 作者：Justin N. Cross ; Patrick M. Duncan ; Eric M. Villa ; Matthew J. Polinski ; Jean-Marie Babo ; Evgeny V. Alekseev ; Corwin H. Booth ; Thomas E. Albrecht-Schmitt
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：February 20, 2013
• 年：2013
• 卷：135
• 期：7
• 页码：2769-2775
• 全文大小：428K
• 年卷期：v.135,no.7(February 20, 2013)
• ISSN：1520-5126

文摘

Hydrothermal reactions of CeCl₃ and PuCl₃ with MoO₃ and Cs₂CO₃ yield surprisingly different results. Ce₃Mo₆O₂₄(H₂O)₄ crystallizes as bright yellow plates (space group C2/c, a = 12.7337(7) 脜, b = 22.1309(16) 脜, c = 7.8392(4) 脜, 尾 = 96.591(4)掳, V = 2194.6(2) 脜³), whereas CsPu₃Mo₆O₂₄(H₂O) crystallizes as semiconducting black-red plates (space group C2/c, a = 12.633(5) 脜, b = 21.770(8) 脜, c = 7.743(7) 脜, 尾 = 96.218(2)掳, V = 2117(2) 脜³). The topologies of the two compounds are similar, with channel structures built from disordered Mo(VI) square pyramids and (RE)O₈ square antiprisms (RE = Ce(IV), Pu(IV)). However, the Pu(IV) compound contains Cs⁺ in its channels, while the channels in Ce₃Mo₆O₂₄(H₂O)₄ contain water molecules. Disorder and an ambiguous oxidation state of Mo lead to the formula CsPu₃Mo₆O₂₄(H₂O), where one Mo site is Mo(V) and the rest are Mo(VI). X-ray absorption near-edge structure (XANES) experiments were performed to investigate the source of the black color of CsPu₃Mo₆O₂₄(H₂O). These experiments revealed Pu to be tetravalent, while the strong pre-edge absorption from the distorted molybdate anions leaves the oxidation state ambiguous between Mo(V) and Mo(VI).