Optimized Synthesis of the Bismuth Subiodides Bi_mI₄ (m = 4, 14, 16, 18) and the Electronic Properties of Bi₁₄I₄ and Bi₁₈I₄

Abstract

We optimized the syntheses of αand -Bi 4 I 4 and transferred the method to the very bismuth-rich iodides Bi 14 I 4 , Bi 16 I 4 , and Bi 18 I 4 . Phase-pure, microcrystalline powders of Bi m I 4 (m = 4, 14, 18) can now by synthesized on a multigram scale. Conditions for the growth of single crystals of Bi 16 I 4 and Bi 18 I 4 were determined. The redetermination of the crystal structure of Bi 16 I 4 hints at a stacking disorder or the presence of 1 ∞ [Bi m I 4 ] ribbons with m = 14 and 18 among the dominant type along with m = 16. The electronic band structures for m = 14, 16, [a]

Assembling Polyiodides and Iodobismuthates Using a Template Effect of a Cyclic Diammonium Cation and Formation of a Low-Gap Hybrid Iodobismuthate with High Thermal Stability

“…Bismuth is the heaviest chemical element to possess stable isotopes [1]. For decades, it has amused chemists by an astonishing variety of its molecular and condensed clusters that have no analogues among lighter elements [2][3][4][5][6][7][8]. Recently, other compounds of bismuth have become the objects of rapt attention.…”

The Subbromide Bi5Br4 – On the Existence of a Hidden Phase

“…Bi 5 Br 4 is the bismuth‐richest compound among the bismuth subhalides containing isolated polycations (Bi 6 Br 7 , Bi 6 Cl 7 ,, Bi 7 Cl 10 ). Only subhalides with infinite ribbons of bismuth atoms (BiBr = Bi 4 Br 4 , BiI = Bi 4 I 4 ,, Bi 14 I 4 ,, Bi 16 I 4 ,, Bi 18 I 4 , ) can have similar or even higher bismuth content. In the bismuth‐bromine phase diagram, Bi 5 Br 4 is now the bismuth‐richest known binary phase (Figure ).…”

“…However, as we have shown such a sub-solidus reaction is kinetically hindered and disfavored. In many syntheses targeting BiBr -the latter was recently predicted to be a topological insulator [50] -or even bismuth-richer phases in analogy to Bi m I 4 (m = 14,16,18), [44][45][46][47][48] we never obtained Bi 5 Br 4 (or other Bi m Br 4 with m Ͼ 4). The discovery of this hidden phase as a by-product in a ternary reaction mixture was mere serendipity.…”

The Mixed‐Valence Catena‐Heteropolycation (Bi2S2)+

“…What comes closest are the infinite stripes of bismuth atoms in the subiodides Bi n I 4 (n = 4, 14, 16, 18), in which the bismuth(II) atoms at the edges of the stripes are covalently bonded to iodine. [42] All other extended positively charged chains formed by bismuth, e. g. in Bi 4 RuI 2 , [43] Bi 9 Ir 2 I 3 , [44] Bi 12 Ni 4 I 3 , [45] or Bi 28 Ni 25 I 5 , [46] contain transition metal atoms as an integral part of the cationic network. [47][48][49] A first hint at the existence of infinite Pn-Ch polycations was reported by Klapötke who assumed the formation of a 1 1 ðPSeÞ þ cation based on IR spectroscopic data.…”

“…The three‐ and four‐fold connectivity of Pn atoms and Pn + cations is expected to create highly interconnected networks. What comes closest are the infinite stripes of bismuth atoms in the subiodides Bi n I 4 ( n =4, 14, 16, 18), in which the bismuth(II) atoms at the edges of the stripes are covalently bonded to iodine [42] . All other extended positively charged chains formed by bismuth, e. g. in Bi 4 RuI 2 , [43] Bi 9 Ir 2 I 3 , [44] Bi 12 Ni 4 I 3 , [45] or Bi 28 Ni 25 I 5 , [46] contain transition metal atoms as an integral part of the cationic network [47–49] …”