Probing the Influence of Acidity and Temperature to Th(IV) on Hydrolysis, Nucleation, and Structural Topology

摘要

Thorium, as the most abundant radioactive element innature, has attracted intensive interests for the last decadesowing to the following reasons. First, as the softest of thetetravalent ions with high charge density and large ionicradius, hydrolysis and condensation reactions are prevalentin aqueous chemistry of Th(Ⅳ), leading to the formation ofoxo-hydroxo clusters. A variety of polynuclear Th(Ⅳ)complexes have been isolated from the solution viahydrolysis, nucleation, and condensation. The consequenceof the formation of these oligomeric species is themodification of the mobility of the thorium, which largelyaffects the fate and migration of it in the environment.Second, thorium has long been used as a surrogate orbenchmark for studying the tetravalent transuranic ions,especially Pu(Ⅳ) due to their similarities in coordination.Both Th(Ⅳ) and Pu(Ⅳ) are typically bonded to eight ornine oxygen atoms, yielding coordination geometries basedon square antiprism, tricapped trigonal prism, monocappedsquare antiprism, etc. In many cases, however, thoriumare not proper mimics of transuranium elements both insolution and in the solid state. Third, although most of thecurrent research is focused on the chemical properties ofthorium, perhaps its most revolutionary potential useinvolves thorium molten-salt reactor (TMSR). The thoriumblueprints, which gathered dust in the archives for decades,have retrieved great attentions because of its advancedsafety features and its abundance in the earth’s crustcompared to uranium.