Structural Variety of Defect Perovskite Variants M3E2X9 (M = Rb,Tl, E = Bi,Sb, X = Br,I)

The compounds Rb₃Sb₂Br₉, Rb₃Sb₂I₉, Rb₃Bi₂Br₉, Rb₃Bi₂I₉, and Tl₃Bi₂Br₉ were synthesized and their crystal structures determined from single crystal X‐ray diffraction data. The compounds Rb₃Sb₂Br₉, Rb₃Sb₂I₉, and Rb₃Bi₂I₉ crystallize in the Tl₃Bi₂I₉ type of structure (space group P2₁/n, no. 14). Rb₃Bi₂Br₉ and Tl₃Bi₂Br₉ crystallize in a new but closely related type of structure (space group P2₁/a, no. 14). Both structure types feature characteristic double layers comprising corner‐sharing EX₆ octahedra. The space groups are set in a way that the stacking direction of the layers is the [001] direction. The group‐subgroup relations to cubic perovskite ABO₃ are discussed. Differences between M₃E₂X₉ types are attributed to distortions of the underlying MX₃ close packing. Depending on the atomic size ratio, the distortions are quantified by an order parameter.     

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

Low-dimensional ns²-metal halide compounds have received immense attention for applications in solid-state lighting, optical thermometry and thermography, and scintillation. However, these are based primarily on the combination of organic cations with toxic Pb²⁺ or unstable Sn²⁺, and a stable inorganic luminescent material has yet to be found. Here, the zero-dimensional Rb₇Sb₃Cl₁₆ phase, comprised of isolated [SbCl₆]³⁻ octahedra and edge-sharing [Sb₂Cl₁₀]⁴⁻ dimers, shows room-temperature photoluminescence (RT PL) centered at 560 nm with a quantum yield of 3.8±0.2 % at 296 K (99.4 % at 77 K). The temperature-dependent PL lifetime rivals that of previous low-dimensional materials with a specific temperature sensitivity above 0.06 K⁻¹ at RT, making it an excellent thermometric material. Utilizing both DFT and chemical substitution with Bi³⁺ in the Rb₇Bi_3−3xSb_3xCl₁₆ (x≤1) family, we present the edge-shared [Sb₂Cl₁₀]⁴⁻ dimer as a design principle for Sb-based luminescent materials.     

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

Low‐dimensional ns²‐metal halide compounds have received immense attention for applications in solid‐state lighting, optical thermometry and thermography, and scintillation. However, these are based primarily on the combination of organic cations with toxic Pb²⁺ or unstable Sn²⁺, and a stable inorganic luminescent material has yet to be found. Here, the zero‐dimensional Rb₇Sb₃Cl₁₆ phase, comprised of isolated [SbCl₆]^3? octahedra and edge‐sharing [Sb₂Cl₁₀]^4? dimers, shows room‐temperature photoluminescence (RT PL) centered at 560 nm with a quantum yield of 3.8±0.2 % at 296 K (99.4 % at 77 K). The temperature‐dependent PL lifetime rivals that of previous low‐dimensional materials with a specific temperature sensitivity above 0.06 K^?1 at RT, making it an excellent thermometric material. Utilizing both DFT and chemical substitution with Bi³⁺ in the Rb₇Bi_3?3xSb_3xCl₁₆ (x≤1) family, we present the edge‐shared [Sb₂Cl₁₀]^4? dimer as a design principle for Sb‐based luminescent materials.     

Colloidal Synthesis and Photophysics of M3Sb2I9 (M=Cs and Rb) Nanocrystals: Lead‐Free Perovskites

Herein we report the colloidal synthesis of Cs₃Sb₂I₉ and Rb₃Sb₂I₉ perovskite nanocrystals, and explore their potential for optoelectronic applications. Different morphologies, such as nanoplatelets and nanorods of Cs₃Sb₂I₉, and spherical Rb₃Sb₂I₉ nanocrystals were prepared. All these samples show band‐edge emissions in the yellow–red region. Exciton many‐body interactions studied by femtosecond transient absorption spectroscopy of Cs₃Sb₂I₉ nanorods reveals characteristic second‐derivative‐type spectral features, suggesting red‐shifted excitons by as much as 79 meV. A high absorption cross‐section of ca. 10⁻¹⁵ cm² was estimated. The results suggest that colloidal Cs₃Sb₂I₉ and Rb₃Sb₂I₉ nanocrystals are potential candidates for optical and optoelectronic applications in the visible region, though a better control of defect chemistry is required for efficient applications.     

(H3O)3Sb2Br9: the first member of the M3E2X9 structure family with oxonium cations

(H₃O)₃Sb₂Br₉ [trihydroxonium enneabromidodiantimonate(III)] is the first representative of the M₃E₂X₉ family (M = cation, E = Sb and Bi, and X = Br and I) with oxonium cations. The metastable compound was obtained in trace amounts from a solution of CsBr and SbBr₃ in concentrated aqueous HBr. Single crystals were isolated from the mother liquor and investigated by single‐crystal X‐ray diffraction at 100 K. (H₃O)₃Sb₂Br₉ crystallizes with the Tl₃Bi₂I₉ structure type, which is a distorted defect variant of cubic perovskite. The crystal structure comprises characteristic ²_∞[SbBr₃Br_3/2] double layers of corner‐sharing SbBr₆ octahedra with a [001] stacking direction. Due to the small size of the H₃O⁺ cation and O—H…Br hydrogen bonding, the octahedra are tilted.     

Die FIR-Spektren gemischter Hexahalogeno-Osmate (IV) vom OsCl6-nXn-Typ (X = Br,I) und ihre Normalkoordinatenanalyse

The far infrared (FIR) spectra of [OsCl₅I]²⁻, cis-[OsCl₄I₂]²⁻, fac-[OsCl₃I₃]²⁻, [OsCl₅Br]²⁻ and cis-[OsCl₄Br₂]²⁻ (Cs-salts) have been recorded at temperatures down to 35 K. The measured band peaks are assigned to symmetry levels using group theory arguments and normal coordinate analyses starting from corresponding octahedral OsX²⁻₆ compounds. In general, OsX bonding properties can be transferred from one compound to another except for XOsY axes where distinct trans-effects are operative. Normal coordinates are also able to explain weak oscillator strengths when predicting small changes of transition dipole moments.     

Novel Antimony Complexes: [Ph4Sb]4 +[Sb4I16]4− · 2Me2C=O and [Ph4Sb]3 +[Sb5I18]3−

The [Ph₄Sb]₄ ⁺[Sb₄I₁₆]^4– · 2Me₂C=O and [Ph₄Sb]₃ ⁺[Sb₅I₁₈]^3– complexes were synthesized by reacting tetraphenylstibonium salts Ph₄SbX (X = I, OSO₂C₆H₄Me-4) with antimony triiodide in acetone. According to X-ray diffraction data, their tetra- and pentanuclear anions [Sb₄I₁₆]^4– and [Sb₅I₁₈]^3– have cyclic and linear structure, respectively.     

[Rb2(H2O)2][Re3(μ-Cl)3Br7(H2O)2]2 · H2O,ein gemischtes Halogenid-Hydrat mit anionischen Dimeren {[Re3(μ-Cl)3Br7(H2O)2]2 · H2O}2−

[Rb₂(H₂O)₂][Re₃(μ-Cl)₃Br₇(H₂O)₂]₂ · H₂O, a Mixed Halide-Hydrate with the Anionic Dimer {[Re₃(μ-Cl)₃Br₇(H₂O)₂]₂ · H₂O}^2? [Rb₂(H₂O)₂][Re₃(μ-Cl)₃Br₇(H₂O)₂]₂ · H₂O crystallizes as dark redbrown single crystals from an hydrobromic-acid solution of ReCl₃ and RbBr at 0°C. An important feature of the crystal structure (monoclinic, C2/c; a = 1494.61(8); b = 835.71(4); c = 3079.96(19) pm; β = 97.801(4)°; V_m = 573.9(4) cm³mol^?1; R = 0.060; R_w = 0.038) is the connection of two anions [Re₃(μ-Cl)₃Br₇(H₂O)₂]^? via a water molecule to dimers, {[Re₃(μ-Cl)₃Br₇(H₂O)₂]₂ · H₂O}^2?. These dimeric units are contained in slabs that are stacked in the [001] direction and held together by Rb⁺ cations and crystal water.     

Rational Synthesis,Structures and Properties of the Ionic Liquid Binary Iodine-Bromine Octahalide Series [InBr8−n]2− (n=0, 2, 3, 4)

A series of octanuclear iodine-bromine interhalides [I_nBr_8−n]²⁻ (n=0, 2, 3, 4) were prepared systematically in two steps. Firstly, addition of a dihalogen (Br₂ or IBr) to the triaminocyclopropenium bromide salt [C₃(NEt₂)₃]Br forms the corresponding trihalide salt with Br₃⁻ or IBr₂⁻ anions, respectively. Secondly, addition to Br₃⁻ of half an equivalent of Br₂ gives the octabromine polyhalide [Br₈]²⁻, whereas addition to IBr₂⁻ of half an equivalent of Br₂, IBr or I₂ gives the corresponding interhalides: [I₂Br₆]²⁻, [I₃Br₅]²⁻, and [I₄Br₄]²⁻, respectively. The four octahalides were characterized by X-ray crystallography, computational studies, Raman and Far-IR spectroscopies, as well as by TGA and melting point. All of the salts were found to be ionic liquids.     

Darstellung und Kristallstruktur von Rb4Br2O und Rb6Br4O

Syntheses and Crystal Structures of Rb₄Br₂O and Rb₆Br₄O In the quasi‐binary system RbBr/Rb₂O, the addition compounds Rb₄Br₂O and Rb₆Br₄O are obtained by solid state reaction of the boundary components RbBr and Rb₂O. Crystals of red‐orange Rb₄Br₂O as well as of orange Rb₆Br₄O decompose immediately when exposed to air. Rb₄Br₂O (Pearson code tI14, I4/mmm, a = 544.4(6) pm, c = 1725(2) pm, Z = 2, 175 symmetry independent reflections with I_o > 2σ(I), R₁= 0.0618) crystallizes in the anti K₂NiF₄ structure type; Rb₆Br₄O (Pearson code hR22, R3c, a = 1307.8(3) pm, c = 1646.6(5) pm, Z = 6, 630 symmetry independent reflections with I_o > 2σ(I), R₁ = 0.0759) in the anti K₄CdCl₆ structure type. Both structures contain characteristic ORb₆‐octahedra and can be understood as expanded perovskites, following the general systematics of alkaline metal oxide halides.     

Synthesis and Characterization of [Br3][MF6] (M=Sb,Ir), as well as Quantum Chemical Study of [Br3]+ Structure,Chemical Bonding,and Relativistic Effects Compared with [XBr2]+ (X=Br,I, At,Ts) and [TsZ2]+ (Z=F,Cl, Br,I, At,Ts)

[Br₃][SbF₆] and [Br₃][IrF₆] were synthesized by interaction of BrF₃ with Sb₂O₃ or iridium metal, respectively. The former compound crystallizes in the orthorhombic space group Pbcn (No. 60) with a=11.9269(7), b=11.5370(7), c=12.0640(6) Å, V=1660.01(16) ų, Z=8 at 100 K. The latter compound crystallizes in the triclinic space group P (No. 2) with a=5.4686(5), b=7.6861(8), c=9.9830(9) Å, α=85.320(8), β=82.060(7), γ=78.466(7)°, V=406.56(7) ų, Z=2 at 100 K. Both compounds contain the cation [Br₃]⁺, which has a bent structure and is coordinated by octahedron-like anions [MF₆]⁻ (M=Sb, Ir). Experimentally obtained cell parameters, bond lengths, and angles are confirmed by solid-state DFT calculations, which differ from the experimental values by less than 2 %. Relativistic effects on the structure of the tribromonium(1+) cation are studied computationally and found to be small. For the heaviest analogues containing At and Ts, however, pronounced relativistic effects are found, which lead to a linear structure of the polyhalogen cation.     

Zur Darstellung und Kristallstruktur von Rb2Sb4S7

On the Preparation and Crystal Structure of Rb₂Sb₄S₇ Rb₂Sb₄S₇ was prepared by methanolothermal reaction of Rb₂CO₃ with Sb₂S₃ at a temperature of 140°C. An X-ray structural analysis demonstrated that the compound contains polythioantimonate(III) anions (Sb₄S₇^2?)_n, for which the basic element is a ψ-trigonal (SbS₄)-bipyramid. Edge bridged SbS₄ polyhedra build vierer single chains (Sb₄S₈^4?)_n, which are linked via two symmetry related S atoms with neighbouring chains so that an (Sb₄S₇^2?)_n sheet is formed.     

Crystal Structures of MBi2Br7 (M = Rb,Cs) – Filled Variants of AX7 Sphere Packing

The reinvestigation of the pseudo‐binary systems MBr–BiBr₃ (M = Rb, Cs) revealed two new phases with composition MBi₂Br₇. Both compounds are hygroscopic and show brilliant yellow color. The crystal structures were solved from X‐ray single crystal diffraction data. The isostructural compounds adopt a new structure type in the triclinic space group P$\bar{1}$ . The lattice parameters are a = 755.68(3) pm, b = 952.56(3) pm, c = 1044.00(4) pm, α = 76.400(2)°, β = 84.590(2)°, γ = 76.652(2)° for RbBi₂Br₇ and a = 758.71(5) pm, b = 958.23(7) pm, c = 1060.24(7) pm, α = 76.194(3)°, β = 83.844(4)°, γ = 76.338(3)° for CsBi₂Br₇. The crystal structures consist of M⁺ cations in anticuboctahedral coordination by bromide ions and bromidobismuthate(III) layers ²_∞[Bi₂Br₇]^–. The 2D layers comprise pairs of BiBr₆ octahedra sharing a common edge. The Bi₂Br₁₀ double octahedra are further connected by common vertices. The bismuth(III) atoms increase their mutual distance in the double octahedra by off‐centering so that the BiBr₆ octahedra are distorted. The CsBi₂Br₇ type can be interpreted as a common hexagonal close sphere packing of M and Br atoms, in which 1/4 of the octahedral voids are filled by Bi atoms. The structure type was systematically analyzed and compared with alternative types of common packings. The existence of a compound with the suggested composition CsBiBr₄ could not be verified experimentally.     

Solvothermal Synthesis of two 2‐D Thioantimonates(III) with Metal Complexes as Template Ions, [M(dap)3]Sb4S7 (M = Ni2+ and Co2+)

Two new thioantimonates [M(dap)₃]Sb₄S₇ (M = Ni²⁺ ( 1 ) and Co²⁺ ( 2 )) were synthesized under solvothermal conditions by the reaction of NiS (or Co metal), Sb and S in an aqueous solution of 1,2‐diaminopropane (dap). Compounds 1 and 2 are isostructural. The polymeric [Sb₄S₇^2?]_n anion is composed of two SbS₃ trigonal pyramids and two SbS₄ units. The SbS₃ and SbS₄ units are interconnected by corners and edges to build a 2‐D puckered layer with Sb₄S₄ and Sb₁₆S₁₆ heterorings. The apertures of the large Sb₁₆S₁₆ hetero‐rings are filled by two [M(dap)₃]²⁺ complex cations which serve as template ions. The band gaps of 2.44 eV for 1 and 2.43 eV for 2 have been estimated from optical absorption spectra.     

Vibrational spectra of the trihalocyclopropenium ions [C3X3]+ (X = Cl,Br or I)

Vibrational spectra are reported and assigned for the planar D_3h symmetry cyclopropenium cations [C₃X₃]⁺ (X= Cl, Br or I) from investigations of the compounds C₃Cl₃AlCl₄, C₃Cl₃GaCl₄, C₃Cl₃FeCl₄, C₃Cl₃SbCl₆, C₃Br₃AlBr₄ and C₃l₄, using conventional infrared and Raman spectroscopy and Fourier transform Raman spectroscopy. The symmetric C—X stretching modes of [C₃X₃]⁺ occur at 458, 269 and 180 cm⁻¹ and the ring-breathing modes at 1790, 1732 and ca. 1650 cm⁻¹ in [C₃Cl₃]⁺, [C₃Br₃]⁺ and [C₃I₃]⁺, respectively. A normal coordinate calculation is performed for [C₃Cl₃]⁺.     

A Pd4Br4 macrocycle trapped by cocrystallization from a highly dynamic equilibrium of η3‐cycloheptatrienide complexes

In the coordination chemistry of palladium, dimers bridged via halides are a common motif. Higher oligomers, however, are still rare. We report the structure of an alternating eight‐membered [Pd₄Br₄]⁴⁻ ring framed by cycloheptatrienide ligands, which was obtained by cocrystallization of dimers and tetramers of the complex salt bromido{η³‐[3‐(2,6‐diisopropylphenyl)imidazolium‐1‐yl]cycloheptatrienido}palladium(II) tetrafluoroborate, namely bis[di‐μ‐bromido‐bis({η³‐[3‐(2,6‐diisopropylphenyl)imidazolium‐1‐yl]cycloheptatrienido}palladium(II))] cyclo‐tetra‐μ‐bromido‐tetrakis({η³‐[3‐(2,6‐diisopropylphenyl)imidazolium‐1‐yl]cycloheptatrienido}palladium(II)) octakis(tetrafluoroborate) dichloromethane octasolvate, [Pd₄Br₄(C₂₂H₂₆N₂)₄][Pd₂Br₂(C₂₂H₂₆N₂)₂]₂(BF₄)₈·8CH₂Cl₂. These dimers and tetramers form a highly dynamic equilibrium in solution which was studied by low‐temperature NMR spectroscopy. In the light of the presented results, tetrameric Pd^II species can be assumed to co‐exist as a second species in many cases where by current knowledge only a dimeric compound would be expected.     

Bi37InBr48: Eine polares Subhalogenid mit Bi95+‐Polykationen,komplexen Bromobismutat(III)‐Anionen [Bi3Br13]4— und [Bi7Br30]9— sowie Pentabromoindat(III)‐Anionen [InBr5]2—

Bi₃₇InBr₄₈: a Polar Subhalide with Bi₉⁵⁺ Polycations, Complex Bromobismuthate(III) Anions [Bi₃Br₁₃]^4— and [Bi₇Br₃₀]^9—, and Pentabromoindate(III) Anions [InBr₅]^2— Black crystals of Bi₃₇InBr₄₈ were synthesized from bismuth, indium and BiBr₃ by cooling stoichiometric melts from 570 K to 470 K. X‐ray diffraction on powders and single‐crystals revealed that the compound crystallizes with space group P 6₃ (a = 2262.6(4); c = 1305.6(2) pm). The Bi₉⁵⁺ polycations in the polar crystal structure have the shape of heavily distorted tri‐capped trigonal prisms with approximate C_s symmetry. The high complexity of the structure results from three coexisting types of anionic groups: Three edge‐sharing [BiBr₆] octahedra constitute the trigonal bromobismuthate(III) anion [Bi₃Br₁₃]^4—. Four [BiBr₆] and three [BiBr₅] polyhedra share common vertices to form the [Bi₇Br₃₀]^9— hemi‐sphere, in which the trigonal bipyramid of the pentabromoindat(III) ion [InBr₅]^2— is embedded.     

Ein oktaedrischer Niobcluster mit sechs terminalen Azidgruppen: Die Struktur von Rb4[Nb6Br12(N3)6](H2O)2

An Octahedral Niobium Cluster containing Six Terminal Azide Groups: The Structure of Rb₄[Nb₆Br₁₂(N₃)₆](H₂O)₂ Six terminal halide ligands of [Nb₆Br₁₂Br₆]^4? can be substituted in solution by azide ions. Single-crystals of Rb₄[Nb₆Br₁₂(N₃)₆](H₂O)₂ were obtained during the evaporation of the water/methanol solvent, and structurally characterized by X-ray methods: Space group P2₁/c, Z = 2, a = 970.8(5) pm, b = 1525.4(7) pm, c = 1280.0(7) pm, β = 97.15(6)°. The [Nb₆Br₁₂(N₃)₆]^4? ions contain six terminal azide groups at the corners of the octahedral niobium cluster (d _Nb–N = 227 pm). The [Nb₆Br₁₂(N₃)₆]^4? ions are interconnected by Rb⁺ and H₂O. Crystals of Rb₄[Nb₆Br₁₂(N₃)₆](H₂O)₂ are explosive towards heat or mechanic pressure.     

Ternary K2Zn5As4‐type pnictides Rb2Cd5As4 and Rb2Zn5Sb4, and the solid solution Rb2Cd5(As,Sb)4

Dirubidium pentacadmium tetraarsenide, Rb₂Cd₅As₄, dirubidium pentazinc tetraantimonide, Rb₂Zn₅Sb₄, and the solid‐solution phase dirubidium pentacadmium tetra(arsenide/antimonide), Rb₂Cd₅(As,Sb)₄ [or Rb₂Cd₅As_3.00(1)Sb_1.00(1)], have been prepared by direct reaction of the component elements at high temperature. These compounds are charge‐balanced Zintl phases and adopt the orthorhombic K₂Zn₅As₄‐type structure (Pearson symbol oC44), featuring a three‐dimensional [M₅Pn₄]²⁻ framework [M = Zn or Cd; Pn is a pnicogen or Group 15 (Group V) element] built of linked MPn₄ tetrahedra, and large channels extending along the b axis which host Rb⁺ cations. The As and Sb atoms in Rb₂Cd₅(As,Sb)₄ are randomly disordered over the two available pnicogen sites. Band‐structure calculations predict that Rb₂Cd₅As₄ is a small‐band‐gap semiconductor and Rb₂Zn₅Sb₄ is a semimetal.     

Bi24Ru3Br20: Ein pseudo-tetragonales Subbromid mit [RuBi6Br12]-Clustern und [Ru2Bi17Br4]-Gruppen

Bi₂₄Ru₃Br₂₀: A Pseudo-Tetragonal Structure with [RuBi₆Br₁₂] Clusters and [Ru₂Bi₁₇Br₄] Groups The melting reaction of Ru with Bi and BiBr yields black, lustrous, air insensitive crystals of the subbromide Bi₂₄Ru₃Br₂₀. The orthorhombic crystal structure (space group Pc2₁n, a = b = 1377.8(1) pm, c = 3222.3(4) pm, V = 6117.0 · 10⁶ pm³) deceives pseudo-symmetry with respect to the tetragonal space group P4/ncc leading to multiply twinned crystals. The structure can formally be subdivided in [RuBi₆Br₁₂] clusters, [Ru₂Bi₁₇Br₄] stacks, and [BiBr₄] groups.