Although it is difficult to interpret a set of these parameters intuitively, the model polyhedron structure for a defined coordination number can be used to evaluate the degree of the shape and its symmetry. The positions of n point charges on the spherical surface were optimized to minimize the Coulombic energy. This optimization problem is known as the Thomson problem. Model structures with n = 6-12 were derived from numerical minimization of the Coulombic energy by optimizing charge positions to compare with all the AIMD-derived structures in Figs. S7-S10. These structures have the same minimum Coulombic energy reported in a previous study. The model polyhedron structures are displayed in Fig. . All the parameters for the inertia tensor, spherical harmonics, and Voronoi tessellation analysis for the model structure are summarized in Table for comparison purposes.