Electron density distribution in the vanadocene crystal on the basis of X-ray diffraction data at 108 K

Accurate molecular and crystal structure and experimental electron density distribution in the vanadocene single crystal were established on the basis of the precise X-ray diffraction data at 108 K. A characteristic asymmetry of the deformation electron density in the vicinity of the metal atom was found which is attributed to the different occupancies of the 3d-metal orbitals of the vanadium atom. A multipole analysis of the diffraction data was performed and the numerical values of the 3d-metal orbital occupancies in vanadocene were first calculated directly from these data. The results obtained are in agreement with the quantum-chemical calculations of vanadocene and other 3d-metallocenes.