A planar pentacoordinate sulfur atom

Abstract

Planar pentacoordinate sulfur atoms (ppS) are rare, with only one example experimentally verified to date. Herein, we report a planar pentacoordinate sulfur atom (ppS) as the global minimum [Mg₅S₆]²⁻ cluster. Despite dianionic nature, it is stable towards spontaneous electron detachment making it a suitable candidate for experimental detection. The global minimum of this cluster features perfect D_5h symmetry. Detailed electronic structure calculations reveal the presence of significant covalency in the Mg–S bonds.