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Pu L3 W-ray near edge absorption spectra for Pu(0-VII) for more than 60 chalcogenides, chlorides, hydrates, hydroxides, nitrates, carbonates, oxy-hydroxides and other compounds both as solids and in solution are reported.

Research has been conducted on PuO (sub)2+x. The authors report that the number of oxo atoms increases when the samples are equilibrated with humid air, and indicate that Pu reactivity in this system differes from that of isolated complexes.

Pu L[sub 3] XAFS measurements show that the excess oxygen in single phase PuO[sub 2+x] occurs as oxo groups with Pu-O distances of 1.831.91 Å. This distance and the energy of the edge (via comparison with a large number of related compounds) are more consistent with a Pu(IV/V) than a Pu(IV/VI) mixture. Analogous to Pu(IV) colloids, although the Pu-Pu pair distribution remains single site even when it shows substantial disorder, the Pu-O distribution can display a number of additional shells at specific distances up to 3.4 Å even in high fired materials when no oxo groups are present, implying intrinsic H[sup +]/OH[sup -](/H[sub 2]O). The number of oxo atoms increases when samples are equilibrated with humid air at ambient temperature, indicating that the Pu reactivity in this solid system differs notably from that of isolated complexes and demonstrating the importance of nanoscale cooperative phenomena and total free energy in determining its chemical properties. [ABSTRACT FROM AUTHOR]