Features of the electron density in MgB2 reconstructed from room-temperature single-crystal X-ray diffraction intensities using a multipole model are considered. Topological analysis of the total electron density has been applied to characterize the atomic interactions in magnesium diboride. The sharedtype B - B interaction in the B-atom layer reveals that both σ and π components of the bonding are strong. A closed-shell-type weak B - B π interaction along the c axis of the unit cell has also been found. The Mg - B closed-shell interaction exhibits a bond path that is significantly curved towards the vertical Mg-atom chain ( direction). The latter two facts reflect two sorts of bonding interactions along the  direction. Integration of the electron density over the zero-flux atomic basins reveals a charge transfer of ∼1.4 (1) electrons from the Mg atoms to the B-atom network. The calculated electric-field gradients at nuclear positions are in good agreement with experimental NMR values. The anharmonic displacement of the B atoms is also discussed. Calculations of the electron density by tight-binding linear muffin-tin orbital (TB-LMTO) and full-potential non-orthogonal local orbital (FPLO) methods confirm the results of the reconstruction from X-ray diffraction; for example, a charge transfer of 1.5 and 1.6 electrons, respectively, was found.
|ジャーナル||Acta Crystallographica Section B: Structural Science|
|出版ステータス||Published - 2003 10|
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