Cina Foroutan-Nejad

A century after G. N. Lewis introduced his foundational model of chemical bonding, its core principles remain central to our understanding of molecular structure. Traditionally, neighboring atoms in a Lewis structure are assumed to share stabilizing interactions. However, this assumption begins to falter at the boundary between covalent and noncovalent bonding. Our work reveals that, in certain molecules with the general formula MAX₃, where (M) is a metal, (A) a nonmetal, and (X) an electron-rich or electron-withdrawing group, the interaction between adjacent M and A atoms can be destabilizing. Remarkably, the overall structure is preserved due to strong interactions between electron-deficient metals and the X groups.1–6 This phenomenon gives rise to unconventional structures, such as the inverted LiCF₃, where lithium interacts preferentially with fluorine atoms over the central carbon in the gas phase. Our recent investigations suggest that these collective interactions extend beyond organometallic compounds and offer insight into anomalous bond dissociation energies and stability trends across a wide range of molecules, from organometallics to perhaloalkanes.