Speciation and Unusual Reactivity in PuO2+x

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• 作者：Steven D. Conradson ; Bruce D. Begg ; David L. Clark ; Christophe Den Auwer ; Francisco J. Espinosa-Faller ; Pamela L. Gordon ; Nancy J. Hess ; Ryan Hess ; D. Webster Keogh ; Luis A. Morales ; Mary P. Neu ; Wolf
• 刊名：Inorganic Chemistry
• 出版年：2003
• 出版时间：June 16, 2003
• 年：2003
• 卷：42
• 期：12
• 页码：3715 - 3717
• 全文大小：140K
• 年卷期：v.42,no.12(June 16, 2003)
• ISSN：1520-510X

文摘

Pu L₃ XAFS measurements show that the excess oxygen in singlephase PuO_2+x occurs as oxo groups with Pu-O distances of 1.83-1.91 Å. This distance and the energy of the edge (via comparisonwith a large number of related compounds) are more consistentwith a Pu(IV/V) than a Pu(IV/VI) mixture. Analogous to Pu(IV)colloids, although the Pu-Pu pair distribution remains single siteeven when it shows substantial disorder, the Pu-O distributioncan display a number of additional shells at specific distances upto 3.4 Å even in high fired materials when no oxo groups arepresent, implying intrinsic H⁺/OH^-(/H₂O). The number of oxo atomsincreases when samples are equilibrated with humid air at ambienttemperature, indicating that the Pu reactivity in this solid systemdiffers notably from that of isolated complexes and demonstratingthe importance of nanoscale cooperative phenomena and totalfree energy in determining its chemical properties.