Comparison of group 14 elements in sp 3 and sp 2 environment by fragment structure energy analysis

To explore the characteristics of group 14 elements in sp 3 and sp 2 hybrid environments systematically, the concept of fragment structure energy (FSE) was proposed through ab initio molecular orbital method. A fragment in this study means a building block of molecular structure and the energy of each kind of fragments (FSE) is obtained from the total electronic energy of different size of model compounds by just a simple algebraic method. The model compounds are the hydrogen‐terminated diamond and graphene analogs as the typical compounds in the ideal sp 3 ‐ and sp 2 ‐environment, respectively. As a result, the sp 3 environment was found to be more stable than the sp 2 for all the group 14 elements (C–Pb) in the ideal hybrid environment. Furthermore, a mixing effect of carbon and heavier group 14 elements (E = Si, Ge, Sn, and Pb) was investigated by comparing the E/C‐alternately mixed‐ and the pure FSEs.