O©Li ₅ F ₅ ^2– : A Global Minimum with a Planar Pentacoordinate Oxygen

Herein, we present a systematic investigation of dianionic clusters of the form of O©M₅X₅^2- (M = Li-Cs; X = F-I) aimed at identifying viable planar pentacoordinate oxygen (ppO) motifs. Across the complete combinatorial space examined, only the starlike <i>D</i>_5<i>h</i>-O©Li₅F₅^2- cluster emerges as a true global minimum. Detailed bonding and magnetic response analyses reveal that this structure is stabilized predominantly by electrostatic interactions rather than by multicenter covalent bonding. These findings establish <i>D</i>_5<i>h</i>-O©Li₅F₅^2- as the second confirmed ppO system and demonstrate that planar pentacoordinate oxygen can be realized under appropriate electrostatic confinement.