Lewis electron pair (LEP) model has established electron pair as one of the most useful concepts in chemistry in the 20th century. The importance of this model can hardly be overstated because of the role it plays in chemistry in interpreting structures and bonding of chemical compounds, although it was established prior to the finding of quantum mechanics. In the Periodic Table, each period row corresponds to the filling of electrons in quantized shells. The elements in the same group column usually have similar properties due to the same electron configuration in their valence shell. However, heavier p-block main-group elements tend to have more or less different chemical bonding from those of 2p elements partly due to quantum primogenic effect. Here we discuss the U-A (A = C, Si, Ge, Sn, Pb, Fl) chemical bondings of F3UAH complexes based on quantum chemical analyses of density functional theory (DFT) and ab initio wavefunction theory (WFT). We have shown that while U-C maintains perfect multiple bonds in F3UCH, the naively anticipated “Lewis electron pairs” between U-A in F3UAH (A = Si, Ge, Sn, Pb, Fl) were broken, leading to a multi-radical bonding scenario. The implication of this finding to chemical bonding in heavy-elements will be discussed.

Electronic structures of F3UAH (A = C - Fl) molecules: Lewis Electron-Pair (LEP) model revisited

253rd National Meeting (2017)

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