On the basis of the X-ray photoelectron spectroscopy data and results of
theoretical calculations for the NpO2Cl4 (D4h) cluster, the electronic
structure and the chemical bond nature in , was done in the binding
Cs2NpO2Cl4 single crystal, containing the neptunyl group NpO2 energy range
of 0 eV to ~35 eV. The filled Np 5f electronic states were established to
form in the valence band of Cs2NpO2Cl4. This was attributed to the direct
participation of the Np 5f electrons in the chemical bonding. The Np
6p electrons were shown to participate in formation of both the
inner valence band (~15 eV-~35 eV) and the outer valence band (0 eV-~15
eV). The filled Np 6p and the O 2s, Cl 3s electronic shells were found to
make the largest contribution to the formation of the inner
valence molecular orbitals. The molecular orbitals composition and the
sequence order in the binding energy range 0 eV-~35 eV in Cs2NpO2Cl4, were
established. For the first time the quantitative scheme of
molecular orbitals for the NpO2Cl4 cluster in the binding energy range 0
eV-~35 eV, was built. This scheme reflects neptunium close environment in
the studied compound and is fundamental for both understanding the chemical
bond nature in Cs2NpO2Cl4 and the interpretation of other X-ray spectra
of Cs2NpO2Cl4. The contributions to the chemical binding for the
NpO2Cl4 cluster were evaluated to be: the outer valence molecular orbitals
contribution - 73 %, and the inner valence molecular orbitals contribution -
27 %.
Cover Picture: Towards a Molecular Understanding of Cation-Anion Interactions-Probing the Electronic Structure of Imidazolium Ionic Liquids by NMR Spectroscopy, X-ray Photoelectron Spectroscopy and Theoretical Calculations (Chem. Eur. J. 30/2010)
