Yaxing Wang, Yumin Wang, Linjuan Zhang, Lanhua Chen, Zhiyong Liu, Xuemiao Yin, Daopeng Sheng, Juan Diwu, Jiangqiang Wang, Ning Liu, Zhifang Chai, Shuao Wang *,“Substitutional Disorder of SeO32-/IO3- in Crystalline Solid Matrix: Insights into Fate of Radionuclides 79Se and 129I in the Environment”. Inorg. Chem. 2017, accepted.
ABSTRACT
As the crucial soluble species of long lived radionuclides 129I and 79Se, iodate and selenite anions commonly share similar geometry of trigonal pyramid XO3 (X=I, Se) but in different valence states. Although large amounts of investigations have been performed aiming at understanding the environmental behavior of these two anions individually, studies on cases when they coexist are extremely scarce. Structurally well-characterized natural/synthetic crystalline solids simultaneously incorporate these two anions as potential solubility-limiting products at the nuclear waste geological depository, remain elusive. We report here a crystalline solid Th(IO3)2(SeO3) representing the first example of aliovalent substitution between IO3- and SeO32- sharing the same structural site, as demonstrated by single crystal X-ray diffraction, Laser ablation inductively coupled pla**a mass spectrometry ****ysis, and spectroscopic techniques including infrared, Raman, and X-ray absorption spectroscopies. Sequentially, in the Eu(IO3)3 solid matrix, we demonstrated that IO3- site can be sufficiently substituted by SeO32-in the presence of Th4+ via simultaneous incorporation of Th4+ and SeO32- in a charge-balancing mechani**. The obtained results provide insights into the environmental behavior of fission products 79Se and 129I: they may co-crystallize in one solid matrix and may be efficiently immobilized by incorporation into each other’s solid phase through solid solution.
