BiZn Bond Formation in Liquid Ammonia Solution: [BiZnBi]⁴⁻, a Linear Polyanion that is Iso(valence)‐electronic to CO₂

Abstract

Reactions of the zinc(I) complex [Zn 2 (Mesnacnac) 2 ] (Mesnacnac = [(2,4,6-Me 3 C 6 H 2 )NC(Me)] 2 CH) with solid K 3 Bi 2 dissolved in liquid ammonia yield crystals of the compound K 4 [ZnBi 2 ]·(NH 3 ) 12 (1), which contains the molecular, linear heteroatomic [Bi À Zn À Bi] 4À polyanion (1 a). This anion represents the first example of a three-atomic molecular ion of metal atoms being iso(valence)-electronic to CO 2 and being synthesized in solution. The analogy of the discrete [BiÀ ZnÀBi] 4À anion and the polymeric 1 1 [(ZnBi 4/2 ) 4À ] unit to monomeric CO 2 and polymeric SiS 2 is rationalized.

Functional-Unit-Based Material Design: Ultralow Thermal Conductivity in Thermoelectrics with Linear Triatomic Resonant Bonds

“…Thus, the linear chain [Sb−Cu−Sb] 5− can be considered as an isolated unit, and their electronic structure can be illustrated with a molecular orbital (MO) diagram. 49 Figure 3a shows the three possible resonance structures 35 of the structural unit [Sb−Cu−Sb] 5− . To verify the existence of these resonant structures, we calculate the molecular orbital diagram for the linear [Sb−Cu−Sb] 5− unit at the PBE0/def2-TZVPP level with polarizable continuum model (PCM) approaches for charge compensation.…”

“…Similar conclusion on the resonant structures in the 16 valence electron linear chain [Bi−Zn−Bi] 4− has been confirmed. 35 We now turn to the chemical bonding of the compound K 5 CuSb 2 , which we investigate using the density functional theory (DFT). In particular, we check the extent to which the molecular [Sb−Cu−Sb] 5− as a functional unit in the compound still retains the resonant bonds.…”

“…34 Some of these (e.g., the linear triatomic chain [Bi−Zn− Bi] 4− with 16 valence electrons) have been confirmed to possess resonant electronic structures. 35 These anion clusters are stabilized by alkali metal or alkaline earth metal ions in Zintl compounds. 34 The direct electronic contributions of alkali metals and alkaline earth metals are usually far from the Fermi level due to their high electropositivities; instead, these elements contribute charge to the anionic units and stabilize the structures through the Coulomb potential and steric considerations.…”