Tetrahedral [Tt₄]^4– Zintl Anions Through Solution Chemistry: Syntheses and Crystal Structures of the Ammoniates Rb₄Sn₄·2NH₃, Cs₄Sn₄·2NH₃, and Rb₄Pb₄·2NH₃

Abstract

The crystalline isotypic solvates Rb4Sn4·2NH3, Cs4Sn4·2NH3, and Rb4Pb4·2NH3 have been synthesized using the direct reduction of elemental tin or tetraphenyltin, respectively, with heavier alkali metals or the dissolution of the binary phase RbPb in liquid ammonia. These compounds contain the cluster ions [Sn4]4– or [Pb4]4– respectively. This is the first time that[Tt4]4– ions (Tt = tetrels) are detected as result of a solution reaction. The accommodation of the ammonia molecules, which build up ion‐dipole interactions to alkali metal cations, requires some modifications of the crystal structures compared to the binary phases RbSn, CsSn, and RbPb. The tetrahedral [Tt4]4– anions have a slightly lower coordination by Rb+ or Cs+ cations and, furthermore, the intercluster distances show a remarkable increase.

First Incorporation of the Tetrahedral [Sn4]4- Cluster into a Discrete Solvate Na4[Sn4] (NH3)13 from Solutions of Na4Sn4 in Liquid Ammonia

“…Regarding the chemistry of the tetrahedral group 14 Zintl clusters [E 4 ] 4− , the number of species isolated from solution-based reactions is rather limited, even though A 4 E 4 Zintl phases (A = alkali metal) with tetrahedral units have been known since 1953 [11] [12]. Related reactions of alkali metals and elemental Sn in molten 18-crown-6, in contrast, lead to the formation of nine-atomic [Sn 9 ] 4− clusters [16].…”

NaRb7(Si4–xGex)2 – Soluble Zintl Phases Containing Heteroatomic Tetrahedral ­[Si4–xGex]4– Clusters

“…[6][7][8][9] 13 and Rb 4 Pb 4 (NH 3 ) 2 were isolated from the tetrahedral Zintl phases Na 4 Sn 4 and Rb 4 Pb 4 , respectively. [10] Residual experiments were carried out with A 12 E 17 phases (A = K-Cs, E = Si, Si/Ge) [7,[11][12][13] containing [E 9 ] 4-clusters next to phase with exclusively tetrahedral clusters that readily dissolves in liquid ammonia. The nature of the heteroatomic clusters was further investigated by dissolution of NaRb 7 -(Si 4-x Ge x ) 2 with x = 2 in liquid ammonia.…”

Dissolving Silicides: Syntheses and Crystal Structures of New Ammoniates Containing Si5 2– and Si9 4– Polyanions and the Role of Ammonia of Crystallisation

“…Besides the nine atom cluster, the tetrahedral E 4 4− anions are well-known in solid-state materials [12], and evidence for their existence in solution was recently presented for E = Sn, Pb [13]. For E = Si, Ge, no congruent dissolution was observed yet.…”