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Oxidation state is a key chemical quantity that allows the understanding and prediction of the majority of chemical reactions; however, the main deficiency using the formal oxidation state comes from the materials containing multivalent metals. Among them, the most complicated element plutonium (Pu) is an outstanding instance. Here, we calculate the orbital occupation numbers under the frameworks of first-principles density functional theory (DFT) + U methods to quantitatively determine the Pu-oxidation state of the recently reported complex molecular solids: [K(crypt)]Pu[C5H3(SiMe3)2]3, Pu3(DPA)5(H2O)2, and Pu3(DPA)6H. The results show that the oxidation state of Pu is an extremely low Pu2+ in the former and a mixed Pu3+/Pu4+ in the latter two compounds, which is consistent with the experimental identifications. The steric effects and the environmentally sensitive localization → delocalization transition of Pu 5f electrons can rationally elucidate the formation of the unusual oxidation states. Such atomi...

Ceria and ceria-based materials have versatile technological and industrial applications physically ascribed to the flexible fluctuation of the Ce oxidation state between Ce4+ and Ce3+. Considerabl...

The low-lying isomeric structures in the shapes of hexagonal prisms and cuboids for (MO)n, M = Cd, Sr, and Ba for n ≤ 45 were explored using density functional theory. The rocksalt cuboid structures are found to be the lowest energy isomers for (MO)n for almost all sizes. Among the cuboid isomers, the particles in approximate aspect ratio of 1:1:1 are found to be most energetically favorable for particles of the same size. Density functional theory exchange-correlation functionals for predicting the stability of the (MO)n particles at the cluster and bulk limits were benchmarked against correlated molecular orbital theory. A fragment-based structure–energy relationship model was used to predict the particle position-related surface energy density and size-related particle aspect ratio transitions for rocksalt (MO)n nanoclusters. The critical sizes at which transitions of the particle aspect ratio may occur for the rocksalt particles were predicted. Linear correlations were found between the ionization pot...