Estimation of the Barrier to Rotation of Benzene in the (η<sup>6</sup>-C<sub>6</sub>H<sub>6</sub>)<sub>2</sub>Cr Crystal via Topological Analysis of the Electron Density Distribution Function

The high-resolution X-ray diffraction analysis of the electron density distribution and plane-wave density functional theory has been applied to estimate the lattice energy and barrier to rotation of a benzene ring in the crystal of (η<sup>6</sup>-C<sub>6</sub>H<sub>6</sub>)<sub>2</sub>Cr. Experimental data made it possible to perform analysis of the metal−(π-ligand) bond and estimate the nature and energy of weak H···H and H···C intermolecular interactions in the crystal. Summation of the intermolecular H···H and H···C interaction energies makes it possible to reproduce the experimental sublimation enthalpy value with high accuracy.