Reactions of Thorium Oxide Clusters with Water: the Effects of Oxygen Content.

Thorium oxide has many important applications in industry. In this article, theoretical calculations have been carried out to explore the hydrolysis reactions of the ThO n (n = 1-3) clusters. The reaction mechanisms of the O-deficient ThO and the O-rich ThO3 are compared with the stoichiometric ThO2. The theoretical results show good agreement with the prior experiments. It is shown that the hydrolysis mainly occurred on the singlet potential surface. The overall reactions consist of two hydrolysis steps which are all favourable in energy. The effects of oxygen content on the hydrolysis are elucidated. Interestingly, among them, the peroxo group O 2 2- in ThO 3 is converted to the HOO- ligand, behaving like the terminal O 2- in the hydrolysis which is transformed into the HO- groups. In addition, natural bond orbital (NBO) analyses were employed to further understand the bonding of the pertinent species and to interpret the differences in hydrolysis.