Planar Tetracoordinate Oxygen Atoms

Abstract

Planar tetracoordinate oxygen (ptO) atoms are rare, with only a few examples confirmed to date. This study systematically investigates 515 potential structures, formulated as OXnYmq, where n+m=4, q ranging from +2 to −2, and following the 18-valence electron rule. High-level ab initio calculations identified 35 global minima containing a ptO atom, predominantly stabilized by Group 13 elements. Bonding analysis reveals a spectrum of interactions, from covalent to polar ionic, and confirms high electron delocalization. The findings challenge traditional bonding paradigms, improve the understanding of ptO-containing clusters, and propose viable ptO clusters for gas-phase detection, advancing the study of unconventional oxygen bonding.