Hückel Arenes with Ten π Electrons: Cyclic Zintl Anions Si and Ge, Isosteric to P and As

Abstract

A new Zintl anion X (X = Si, Ge) appears in the compounds Ba 4 Li 2 Si 6 , B 4 Li 2 Ge 6 , and Ba 10 Ge 7 O 3 . Bonding within the anion and its interaction with the crystal field is described in terms of the electron localization function (ELF), which allows the visualization of covalent bonds, n electron pairs, and core shells. The existence of such cyclic anions indicates that in the solid‐state structures of heavier Group 14 elements the formation of ten π electron Hückel arenes is preferred over the formation of discrete double bonds.