Dynamic Disorder of Bi₈²⁺ Clusters in the Plastic Phase (Bi₈)₃Bi[InI₄]₉

Abstract

Black, air-insensitive crystals of the bismuth-rich tetraiodido-indate(III) (Bi 8

Low-Temperature Ordering in the Cluster Compound (Bi8)Tl[AlCl4]3

“…The new bismuth-rich metalate (Bi 8 )Tl[AlCl 4 ] 3 consists of 1 ∞ [Tl(AlCl 4 )] 2− strands and isolated Bi 8 2+ polycations. The latter shows dynamic disorder at room temperature but order upon slow cooling to 170 K. Similar dynamics had been observed in other compounds with isolated polyhedral ions [2,6,9,10,12,[15][16][17]. However, in most of those cases, cooling led either to a freezing of dynamic to static disorder or to low symmetric structures with enormously enlarged unit cells and multiple twinning that could not be resolved.…”

“…Since the symmetry of the coordination environment of the bismuth polycation is typically higher than its point group, (almost) energetically equivalent orientations can be adopted. Therefore, orientational disorder is a common phenomenon in such structures [2,6,9,10,12,[15][16][17]. This ranges from resolvable disorder on a few alternative positions [12] to the formation of plastic crystals, where the superposition of orientations in time and space creates an averaged electron density resembling a hollow sphere [17].…”

The Subbromide Bi5Br4 – On the Existence of a Hidden Phase

“…It is well known from other structures with bismuth polycations, that such a spacious cave, especially in combination with isolated anionic groups, allows for strong vibrations of the guest. [13,43] The observed fast decay of the scattering intensity with increasing diffraction angle is in line with strong dynamic effects in the structure. is revealed by the structure solution.…”

Synthesis of the (Sn4Bi4)2− Anion by Mild Oxidation of (Sn2Bi2)2−

“…[13,14] The largest variety of compounds based on tetragonal antiprisms are those comprising the Bi 8 2 + cation, thus Bi 8 [X] 2 (X = AlCl 4 , GaCl 4 , InBr 4 ), [15][16][17] Bi 8 A[AlCl 4 ] 3 (A = Cs, Rb), [18] (Bi 8 )Bi[InI 4 ] 9 , and Bi 8 [Ta 2 O 2 Br 7 ] 2 . [19,20] Two further, nondeltahedral eight-vertex anions are (Sn 3 Bi 5 ) 3À (Figure 3d), which was isolated from solution as its [Rb(crypt-222)]-salt, and (Sn 4 Bi 4 ) 4À (Figure 3e), which could be crystallized as a [Cs( [18]crown-6)] + salt. [21,22] Nevertheless, these two examples are more electron-rich (40 valence electrons or 24, i. e., 2 • n + 8, skeletal electrons), and would therefore comply with hyphotype cluster units according to Wade-Mingos rules; indeed, capping of the square face and the two pentagonal faces would lead these structures back to a parental 11-vertex closotype architecture.…”

“… [12] The isostructural Sb 8 2+ cation was observed in the compounds Sb 8 [GaX 4 ] 2 (X=Br, Cl) [13,14] . The largest variety of compounds based on tetragonal antiprisms are those comprising the Bi 8 2+ cation, thus Bi 8 [X] 2 (X=AlCl 4 , GaCl 4 , InBr 4 ), [15–17] Bi 8 A[AlCl 4 ] 3 (A=Cs, Rb), [18] (Bi 8 )Bi[InI 4 ] 9 , and Bi 8 [Ta 2 O 2 Br 7 ] 2 [19,20] . Two further, non‐deltahedral eight‐vertex anions are (Sn 3 Bi 5 ) 3− (Figure 3d), which was isolated from solution as its [Rb(crypt‐222)]‐salt, and (Sn 4 Bi 4 ) 4− (Figure 3e), which could be crystallized as a [Cs([18]crown‐6)] + salt [21,22] .…”