Linear triatomic [ZnBi2]4− in K4ZnBi2

Abstract

The linear triatomic [ZnBi₂]⁴⁻ found in the diamagnetic K₄ZnBi₂ was prepared as the first discrete Zn–Bi Zintl cluster anion in the neat solid state from the unique K–Zn–Bi system. The tetraanionic trimer has sixteen valence electrons isovalent with CO₂, accounting for its nearly linear triatomic structure (Zn–Bi–Zn, 177.3(3)°) and multiple ZnBi bonds revealed by the unprecedentedly short bond length (2.553(3) Å) and DFT π-bonding analyses, on the basis of the established 16-electron counting rule for a linear triatomic species. The VASP theoretical calculations reveal that K₄ZnBi₂ is a narrow gap direct semiconductor that is expected to present promising optical properties.