Syntheses and Crystal Structures of the Thallium(I) Iodobismuthates(III) Tl₇Bi₃I₁₆ and Tl₃BiI₆

Abstract

Dark grey (dark red with transmitting light) crystals of heptathallium(I) hexadecaiodo‐tribismuthate(III), Tl7Bi3I16, were obtained by slow cooling of a melt from 800 K to ambient temperature and, with higher crystal quality via solvothermal synthesis in aqueous HI by slowly cooling from 428 to 363 K. The compound is diamagnetic and melts congruently at 630(5) K. X‐ray diffraction on single‐crystals revealed that Tl7Bi3I16 crystallizes in the orthorhombic space group Cmcm with lattice parameters a = 2473.4(5), b = 1441.9(2), c = 3616.9(7) pm. The crystal structure can be interpreted as a layered intergrowth of fragments from the CsNiCl3 and K5Dy3I12 structure types with isolated [BiI6]3− octahedra and [Bi2I10]4− double octahedra. Rotation and distortion of the complex anions establish coordination numbers (c.n.) between 7 and 9 for the Tl+ cations. Dark red crystals of trithallium(I) hexaiodo‐bismuthate(III), Tl3BiI6, are only accessible via hydrothermal synthesis in aqueous HI and slowly cooling from 428 to 363 K. Thermal analysis reveals a peritectoid decomposition at 540(5) K into the neighboring phases Tl7Bi3I16 and TlI. Tl3BiI6 crystallizes in the monoclinic space group P21/c with lattice parameters a = 1352.6(3), b = 899.6(2), c = 1353.8(3) pm, and β = 104.18(3)°. In the crystal structure isolated [BiI6]3− octahedra are arranged according to the motif of a face‐centered pseudo‐cubic packing. Due to the tilted orientation of the [BiI6]3− groups the Tl+ cations have c.n. of 8 and 9. Although the crystal structure of Tl3BiI6 looks like a distorted variant of the elpasolith type, there is no symmetry relation according to a group subgroup formalism.

The Water‐Rich Iodidobismuthate (H3O)Rb3BiI7·4H2O

“…The 2 ∞ [RbI 3 ] 2– layer is slightly puckered so that the [BiI 6 ] 3– octahedra are tilted and not strictly in plane. Such 2 ∞ [ A 2 MX 6 ] – layers, yet less corrugated and thus closer to the symmetry of the sectional layer group P 3 m 1, have also been found in Rb 7 Sb 3 Br 16 and Tl 7 Bi 3 I 16 …”

The Rb7Bi3−3xSb3xCl16 Family: A Fully Inorganic Solid Solution with Room‐Temperature Luminescent Members

“…This quasi-0D structure is comprised of alternating layers of isolated [Sb 2 Cl 10 ] 4À edgeshared dimers and [SbCl 6 ] 3À octahedra;t hese layers are stacked along the c-axis.I ntriguingly,t he [Sb 2 Cl 10 ] 4À edgesharing dimer unit is distorted with aslight bend towards one side,w hich might be ac onsequence of the lone pair of the central Sb III cations,assuggested by Ruck et al for the similar compound, Tl 7 Bi 3 I 16 . [24] Every other dimer layer exhibits threefold rotational disorder in the a-b plane,with equal onethird occupancyfor each possible rotation providing the best structural refinement (Supporting Information, Figures S3, S4). This asymmetry also affects the [SbCl 6 ] 3À octahedral layers adjacent to the disordered dimer layers,asthe thermal parameters of the neighboring Cl atoms are significantly higher than those on faces neighboring the ordered dimer layer (Supporting Information, Figure S5).…”

The Polymorphic Nature of M3BiBr6 Halides (M=Cs, Rb) and their Reversible Intercalation with Water to Isomorphous Hydrates at Room Temperature

“…oP ‐Rb 3 BiBr 6 ⋅ H 2 O (space group Pnma ) and oP ‐Cs 3 BiBr 6 ⋅ H 2 O (space group Pbcm ) are not isostructural. mP ‐Rb 3 BiBr 6 crystallizes with a new structure type, which is not isostructural to Tl 3 BiI 6 , [23] although the unit cell parameters are similar and the space group ( P 2 1 / c ) is the same. All investigated crystals had stacking faults that can be interpreted either as twins or as small domains of the other polytype in the system.…”

“…Their asymmetric units, including the displacement parameters of the atoms, are very similar (Figures S9 and S10). [23] although the unit cell parameters are similar and the space group (P2 1 /c) is the same. All investigated crystals had stacking faults that can be interpreted either as twins or as small domains of the other polytype in the system.…”