High‐Resolution X‐Ray Powder Diffraction Structure Determination of C₆₀F₄₈

Abstract

Whereas previously reported X‐ray powder diffraction experiments could be interpreted using an isotropic spherical two‐shell model, our recently obtained data cannot. Rather, they were Rietveld‐analyzed using three distinct anisotropic models for the C₆₀F₄₈ molecule featuring the S₆, D₃ and T_h molecular symmetries, respectively. The best fit was obtained for the D₃ model, which is consistent with the ¹⁹ F NMR characterization of our sample. The χ² dependence upon the Euler angles of the C₆₀F₄₈ molecule is found to be substantial. The unit cell is very nearly (if not) tetragonal and P 2₁/n turns out to be a satisfactory space group.

Keywords:

• Fluorofullerenes
• C₆₀F₄₈
• high‐resolution X‐ray powder diffraction
• rigid body Rietveld refinement
• molecular modeling

Acknowledgments

This work was supported in part by the Russian Foundation for Basic Research (grant 05‐03‐32808). The authors gratefully acknowledge the use of the Bilbao Crystallographic Server <http://www.cryst.ehu.es>.