Syntheses,Crystal Structures,and Properties of New Ternary Chalcogenides of Group 4 Metals: Rb4Ti3S14, Cs4Zr3S14, K4Hf3Se14, and K4ZrHf2Se14

The new ternary compounds Rb₄Ti₃S₁₄, Cs₄Zr₃S₁₄, K₄Hf₃Se₁₄, and K₄ZrHf₂Se₁₄ were prepared by reacting the respective transition metals in alkali metal polychalcogenide melts. Two crystallographically independent transition metal cations are present that are coordinated by eight chalcogen atoms (Q) in an irregular fashion or by seven chalcogen atoms yielding a distorted pentagonal bipyramid. The M(1)Q₈ and M(2)Q₇ polyhedra are connected by sharing common edges or trigonal faces leading to the formation of infinite linear one‐dimensional anionic chains running parallel to the [101] direction. The chains are separated by alkali metal cations. The optical band gaps determined are 1.59 eV for Rb₄Ti₃S₁₄, 2.35 eV for Cs₄Zr₃S₁₄, and 2.02 eV for K₄Hf₃Se₁₄. In‐situ X‐ray powder diffractometry demonstrates that Rb₄Ti₃S₁₄ decomposes at 430 °C into Rb₂S₅ and TiS. During the cooling cycle the re‐formation of the polysulfide is observed. According to this result the polysulfide could be prepared using TiS instead of metallic Ti as well.     

Darstellung und Kristallstruktur der Dialkalimetalltrichalkogenide Rb2S3, Rb2Se3, Cs2S3 und Cs2Se3

Preparation and Crystal Structure of the Dialkali Metal Trichalcogenides Rb₂S₃, Rb₂Se₃, Cs₂S₃, and Cs₂Se₃ Crystalline products were obtained by the reaction of the pure alkali metals with the chalcogens in the molar ratio 2:3 in liquid ammonia at pressures up to 3000 bar and temperatures around 600 K. The substances crystallize in the K₂S₃ type structure (space group Cmc2₁(NO. 36)). Unit cell constants see ?Inhaltsübersicht”?. The characteristic feature of this structure are bent polyanions X₃^2?:(X = S,Se). The new described compounds are compared with the other known alkali metal trichalcogenides.     

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

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.     

Über Alkalimetallmanganchalkogenide A2MnX2 mit A K,Rb oder Cs und X S,Se oder Te

Inhaltsübersicht. Die Verbindungen K₂MnS₂, Rb₂MnS₂, Cs₂MnS₂, K₂MnSe₂, Rb₂MnSe₂, Cs₂MnSe₂, K₂MnTe₂, Rb₂MnTe₂ und Cs₂MnTe₂ wurden durch Umsetzungen von Alkalimetall-carbonaten mit Mangan bzw. Mangantellurid in einem mit Chalkogen beladenen Wasserstoffstrom erhalten. Kristallstrukturuntersuchungen an Einkristallen ergaben, daß alle neun Verbindungen isotyp kristallisieren (K₂ZnO₂-Typ, Raumgruppe Ibam). Untersuchungen zum magnetischen Verhalten zeigen antiferromagnetische Kopplungen der Manganionen in den [MnX_4/2^2–]-Ketten, On Alkali Metal Manganese Chalcogenides A₂MnX₂ with A K, Rb, or Cs and X S, Se, or Te The compounds K₂MnS₂, Rb₂MnS₂, Cs₂MnS₂, K₂MnSe₂, Rb₂MnSe₂, Cs₂MnSe₂, K₂MnTe₂, Rb₂MnTe₂, and Cs₂MnTe₂ were synthesized by the reaction of alkali metal carbonates with Mn or MnTe in a stream of hydrogen charged with chalcogen. Structural investigations on single crystals show that all nine compounds crystallize in isotypic atomic arrangements (K₂ZnO₂ type, space group Ibam). The magnetic behaviour indicates antiferromagnetic interactions of the manganese ions within the [MnX_1/2^2–] chains.     

Über Hexafluoroferrate(III): Cs2TlFeF6, Cs2KFeF6, Rb2KFeF6, Rb2NaFeF6 und Cs2NaFeF6

On Hexafluoroferrates(III): Cs₂TlFeF₆, Cs₂KFeF₆, Rb₂KFeF₆, Rb₂NaFeF₆, and Cs₂NaFeF₆ New prepared are the compounds Cs₂TlFeF₆ (a = 9.21₁ Å), Cs₂KFeF₆ (a = 9.04₁ Å), Rb₂KFeF₆ (a = 8.86₈ Å) and Rb₂NaFeF₆ (a = 8.46 ₄Å) all cubic Elpasolithes as well as Cs₂NaFeF₆ (Cs₂NaCrF₆?type, hexagonal with a = 6.28₁, c = 30.53₂ Å), all colourless. Cs₂KFeF₆ was measured magnetically (70–297,2 K). The spectra of reflection were measured (9000–36000 cm^?1). The Madelung Part of Lattice Energy, MAPLE, is calculated and discussed.     

Zur Magnetochemie des zweiwertigen Silbers Neue Fluoroargentate(II): Cs2AgF4, Rb2AgF4 und K2AgF4

Magnetochemistry of Divalent Silver. New Fluoroargentates(II): Cs₂AgF₄, Rb₂AgF₄, and K₂AgF₄ Hitherto unknown blue compounds Rb₂AgF₄ and Cs₂AgF₄ are prepared. Guinier patterns show, that Cs₂AgF₄ cristallise in the K₂NiF₄ structure (a = 4.58₁, c = 14.19₂ Å). The structure of the Rb-compound is still unknown. The magnetic behaviour of K₂AgF₄, Rb₂AgF₄, and Cs₂AgF₄ is discussed.     

Zur Kristallstruktur von Rb2C2 und Cs2C2

On the Crystal Structure of Rb₂C₂ and Cs₂C₂ By reaction of rubidium or caesium solved in liquid ammonia with acetylene AC₂H with A = Rb, Cs was obtained, which was subsequently converted into the binary acetylide A₂C₂ in vacuum at temperatures of 520 K (Rb₂C₂) and 470 K (Cs₂C₂) using a surplus of the respective alkali metal. The crystal structures of the very air sensitive compounds were solved and refined by a combination of both neutron and X‐ray powder diffraction data. Rb₂C₂ as well as Cs₂C₂ coexist in two modifications. The hexagonal modification (P 6 2m, Z = 3) crystallises in the known Na₂O₂ structure type with two crystallographic independent sites for the C₂^2– dumbbells. For the orthorhombic modification (Pnma, Z = 4) a new structure type was found, which is related to the PbCl₂ structure type with ordered C₂^2– dumbbells occupying the Pb sites. Temperature dependent investigations between 4 K and the decomposition temperature by the means of neutron and X‐ray powder diffraction resulted in a very complex dynamic disorder of the C₂ dumbbells, which is still not completely understood. The frequencies of the C–C stretching vibration determined by the help of Raman spectroscopy fit nicely to the results obtained for other alkali metal acetylides and alkali metal hydrogen acetylides. These results seem to indicate that the electronegativity of the alkali metal has a strong influence on the frequency of the C–C stretching vibration.     

Neue Elpasolithvertreter mit CoIII: Cs2KCoF6, Rb2KCoF6, Rb2NaCoF6 (mit einer Notiz über Cs2NaCoF6)

New Elpasolithes with Co^III: Cs₂KCoF₆, Rb₂KCoF₆, Rb₂NaCoF₆ (with a Notice on Cs₂NaCoF₆) New prepared are the compounds Cs₂KCoF₆ (a = 8.97₉ Å), Rb₂KCoF₆ (a = 8.80₉ Å), Rb₂NaCoF₆ (a = 8.42₁ Å), all cubic Elpasolithes, as well as Cs₂NaCoF₆ (Cs₂NaCrF₆?type, hexagonal with a = 6.23, c = 30.32 Å) all of light blue colour. Cs₂KCoF₆ (72.7–299.7 K) and Rb₂KCoF₆ (71.4–298.0 K) have been measured magnetically. The Madelung Part of Lattice Energy (MAPLE) is calculated and discussed.     

Solubility in the systems Rb2SO4-H2SO4-H2O and Cs2SO4-H2SO4-H2O at 25°

Conclusions The solubility of rubidium and cesium sulfates in aqueous solutions of sulfuric acid was studied at 25°. Rubidium sulfate forms the compounds 3Rb₂SO₄· H₂SO₄, Rb₂SO₄ · H₂SO₄, Rb₂SO₄·3H₂SO₄ and Rb₂SO₄·7H₂SO₄ with sulfuric acid, while cesium sulfate forms the compounds Cs₂SO₄·H₂SO₄; Cs₂SO₄·3H₂SO₄ and Cs₂SO₄ · 7H₂SO₄.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1166–1170, June, 1968.     

Schwingungsspektren fester,flüssiger und gelöster Metallpolysulfide. II. Polysulfide Rb2Sn und Cs2Sn (n ⩾ 4) sowie Na2S4

Vibrational Spectra of Solid, Liquid, and Soluted Metal Polysulphides. II Polysulphides Rb₂S_n (n ? 4) and Na₂S₄ All compounds have been prepared from the elements in liquid ammonia. Whereas Rb₂S₄ has no defined composition, the vibrational spectra of Cs₂S₄ and their structure similar to Na₂S₄ indicate that Cs₂S₄ is a well-defined compound in contrast to former suggestions. Rb₂S₅ and Cs₂S₆ are the members with the greatest chainlength of their homologe series. While Na₂S₄ still exists of S₄^2? chains in the melt the other polysulhpides disproportionate to S₃^? radicals and probably monosulphide. In the melt of Cs₂S₆, quenched to room temperature, a double branched chain structure, the thio-analogue of dithionite, S₂S₄^2?, is suggested. All polysulphides have a mean valence frequency, which is independent of the cation and decreases with increasing chainlength.     

13 C nuclear magnetic resonance spectra of the reciprocal of macrotetrolide antibiotics with Na + , K + , Rb Rb + , Cs + , NH 4+ and Ba 2+

The ¹³C NMR. spectra of nonaction have been recorded at 22.6 MHz. Additivityrules, chemical shift reagents and spectra of model compounds enabled a full assignment of the lines to be made. A comparison of the spectra of the nonactin complexes with Na⁺, K⁺, Rb⁺, Cs⁺, NH₄⁺ and Ba²⁺ showed that no H-bridges between NH₄⁺ and the nonactin carbonyls exist. This is corroborated by the infrared spectra of the complexes.     

Die Kristallstruktur von Cs2S. mit einer Bemerkung über Cs2Se,Cs2Te,Rb2Se und Rb2Te

The Crystal Structure of Cs₂S and a Remark about Cs₂Se, Cs₂Te, Rb₂Se, and Rb₂Te Cs₂S crystallizes orthorhombic, a = 8.57₁, b = 5.38₃, c = 10.3₉ Å, Z = 4, d_rö = 4.13, d_pyk = 4.19 g · cm^?3, D–Pnma with \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {{\rm Cs}}\limits^|,\mathop {{\rm Cs}}\limits^\parallel $\end{document} and S in 4(c) each, for parameter see text. It is R = 10,4% for 202 of 222 possible reflexes. There is a sequence of S^2? corresponding to the hexagonal closest packing of sphares. Cs occupies half of “tetrahedron” and all “octahedron vacancies”; the deviation of \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {{\rm Cs}}\limits^|, $\end{document} in ?oktahedron vacancies”? is noticeable. Effective Coordination Numbers, ECoN, and the Madelung Part of Lattice Energy, MAPLE, are calculated and discussed.     

Hochdrucksynthese und Struktur von Rb2PtH6 und Cs2PtH6, ternären Hydriden mit K2PtCl6-Struktur

High-pressure Synthesis and Structure of Rb₂PtH₆ and Cs₂PtH₆, Ternary Hydrides with K₂PtCl₆-Structure The ternary platinum hydrides Rb₂PtH₆ and Cs₂PtH₆ were synthesized by the reaction of rubidium hydride and cesium hydride, respectively, with platinum sponge under a hydrogen pressure above 1 500 bar at 500°C. X-ray investigations on powdered samples and elastic neutron diffraction experiments on the deuterated compounds at the time-of-flight spectrometer POLARIS led to their complete structure determination. Their atomic arrangements are isotypic with that of K₂PtCl₆ containing isolated [PtH₆]^2?-octahedra (space group: Fm3 m, Z = 4).     

Die Kristallstruktur von Cs2PrO3, sowie über Cs2CeO3, Cs2TbO3, Rb2CeO3 und Rb2TbO3

Crystal Structure of Cs₂PrO₃ and also about Cs₂CeO₃, Cs₂TbO₃, Rb₂CeO₃, and Rb₂TbO₃ New prepared Cs₂PrO₃ (dark brown) is orthorhombic due to single crystal data, K₂PbO₃ type of structure (Cmc2₁) with a = 11.4₇, b = 7.72₂, c = 6.42₇ Å and Z = (4). Cs₂CeO₃ (colourless, a = 11.49₅, b = 7.75₃, c = 6.43₇ Å), Cs₂TbO₃ (red-brown, a = 11.3₇, b = 7.72₆, c = 6.14₂ Å), and the low-temperature form of (LT-) Rb₂TbO₃ (red-brown, a = 10.9₁, b = 7.39₀, c = 6.09₉ Å) are isotypic. Hitherto unknown HT-Rb₂CeO₃ (high-temperature form, colourless, a = 3.83₇, c = 18.4₇ Å, Z = 2, hexagonal) and “HT-Rb₂TbO₃” (red-brown, a = 3.77₃, c = 18.0₀ Å) correspond according to powder-data to the α-NaFeO₂ type of structure. Cs₂PrO₃ has been measured magnetically (100–300 K). The Madelung Part of Lattice Energy (MAPLE) is calculated and discussed.     

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.     

Cs3LiZn2(WO4)4 and Rb3Li2Ga(MoO4)4: different filled derivatives of the cation‐deficient Cs6Zn5(MoO4)8 structure

Two new compounds, namely cubic tricaesium lithium dizinc tetrakis(tetraoxotungstate), Cs₃LiZn₂(WO₄)₄, and tetragonal trirubidium dilithium gallium tetrakis(tetraoxomolybdate), Rb₃Li₂Ga(MoO₄)₄, belong to the structural family of Cs₆Zn₅(MoO₄)₈ (space group I 3d , Z = 4), with a partially incomplete (Zn_5/6□_1/6) position. In Cs₃LiZn₂(WO₄)₄, this position is fully statistically occupied by (Zn_2/3Li_1/3), and in Rb₃Li₂Ga(MoO₄)₄, the 2Li + Ga atoms are completely ordered in two distinct sites of the space group I 2d (Z = 4). In the same way, the crystallographically equivalent A ⁺ cations (A = Cs, Rb) in Cs₆Zn₅(MoO₄)₈, Cs₃LiZn₂(WO₄)₄ and isostructural A ₃LiZn₂(MoO₄)₄ and Cs₃LiCo₂(MoO₄)₄ are divided into two sites in Rb₃Li₂Ga(MoO₄)₄, as in other isostructural A ₃Li₂R (MoO₄)₄ compounds (AR = TlAl, RbAl, CsAl, CsGa, CsFe). In the title structures, the WO₄ and (Zn,Li)O₄ or LiO₄, GaO₄ and MoO₄ tetrahedra share corners to form open three‐dimensional frameworks with the caesium or rubidium ions occupying cuboctahedral cavities. The tetrahedral frameworks are related to that of mayenite 12CaO·7Al₂O₃ and isotypic compounds. Comparison of isostructural Cs₃M Zn₂(MoO₄)₄ (M = Li, Na, Ag) and Cs₆Zn₅(MoO₄)₈ shows a decrease of the cubic lattice parameter and an increase in thermal stability with the filling of the vacancies by Li⁺ in the Zn position of the Cs₆Zn₅(MoO₄)₈ structure, while filling of the cation vacancies by larger Na⁺ or Ag⁺ ions plays a destabilizing role. The series A ₃Li₂R (MoO₄)₄ shows second harmonic generation effects compatible with that of β′‐Gd₂(MoO₄)₃ and may be considered as nonlinear optical materials with a modest nonlinearity.     

Electronics structures of Rb,Cs and some of their metallic oxides studied by photoelectron spectroscopy

Photoemission measurements with He and Ne resonance lines and Al Kα radiation are reported on bulk samples of the alkali metals Rb, Cs, their suboxides Cs₇O, Cs₁₁O₃ and (Cs₁₁O₃)Rb₇. For comparison, the Hel spectrum of the “normal” oxide Cs₂O is added. The occurrence of ionic clusters in a metallic matrix is typical for the suboxides. Binding energies, Auger transitions, and electron concentrations are discussed. The spectra of the suboxides show a narrow non-bonding oxygen 2p band at 2.7 eV. Different binding energies are found for Cs atoms in the clusters and for the atoms in the metallic regions of (Cs₁₁O₃)Cs₁₀. The compound Cs₁₁O₃ consists of ionic [Cs₁₁O₃]^5? clusters, which are bound by 5 free electrons in accordance with the chemical bond model.     

Zintl‐Verbindungen mit Gold und Germanium: M3AuGe4 mit M = K,Rb und Cs

Zintl‐Compounds with Gold and Germanium: M₃AuGe₄ with M = K, Rb, Cs Black, brittle single crystals of M₃AuGe₄ with M = K, Rb, Cs were synthesized by reactions of alkali metal azides (MN₃) with gold sponge and germanium powder at T = 1120 K. The structures of the compounds (space group Pmmn, Z = 2, K₃AuGe₄: a = 6.655(1)Å, b = 11.911(2)Å, c = 6.081(1)Å; Rb₃AuGe₄: a = 6.894(1)Å, b = 12.421(1)Å, c = 6.107(1)Å; Cs₃AuGe₄: a = 7.179(1)Å, b = 12.993(2)Å, c = 6.112(2)Å) were determined from X‐ray single‐crystal diffractometry data. The semiconducting compounds contain equation/tex2gif-stack-2.gif[AuGe₄]‐chains with P₄‐analogous Ge₄‐tetrahedra which are connected by μ₂‐bridging gold atoms in a distorted tetrahedral Ge‐coordination.     

Enthalpy of Phase Transitions and Heat Capacity of Stoichiometric Compounds in LaBr3-MBr Systems (M=K,Rb, Cs)

Molar enthalpies of solid-solid and solid-liquid phase transitions of the LaBr₃, K₂LaBr₅, Rb₂LaBr₅, Rb₃LaBr₆ and Cs₃LaBr₆ compounds were determined by differential scanning calorimetry. K₂LaBr₅ and Rb₂LaBr₅ exist at ambient temperature and melt congruently at 875 and 864 K, respectively, with corresponding enthalpies of 81.5 and 77.2 kJ mol^-1. Rb₃LaBr₆ and Cs₃LaBr₆ are the only 3:1 compounds existing in the investigated systems. The first one forms from RbBr and Rb₂LaBr₅ at 700 K with an enthalpy of 44.0 kJ mol^-1 and melts congruently at 940 K with an enthalpy of 46.7 kJ mol^-1. The second one exists at room temperature, undergoes a solid-solid phase transition at 725 K with an enthalpy of 9.0 kJ mol^-1 and melts congruently at 1013 K with an enthalpy of 57.6 kJ mol^-1. Two other compounds existing in the CsBr-based systems (Cs₂LaBr₅ and CsLa₂Br₇) decompose peritectically at 765 and 828 K, respectively. The heat capacities of the above compounds in the solid as well as in the liquid phase were determined by differential scanning calorimetry. A special method - 'step method' developed by SETARAM was applied in these measurements. The heat capacity experimental data were fitted by a polynomial temperature dependence. This revised version was published online in July 2006 with corrections to the Cover Date.     

Stabilizing RbPbBr3 Perovskite Nanocrystals through Cs+ Substitution

ABX₃-type halide perovskite nanocrystals (NCs) have been a hot topic recently due to their fascinating optoelectronic properties. It has been demonstrated that A-site ions have an impact on their photophysical and chemical properties, such as the optical band gap and chemical stability. The pursuit of halide perovskite materials with diverse A-site species would deepen the understanding of the structure–property relationship of the perovskite family. In this work we have attempted to synthesize rubidium-based perovskite NCs. We have discovered that the partial substitution of Rb⁺ by Cs⁺ help to stabilize the orthorhombic RbPbBr₃ NCs at low temperature, which otherwise can only be obtained at high temperature. The inclusion of Cs⁺ into the RbPbBr₃ lattice results in highly photoluminescent Rb_1−xCs_xPbBr₃ NCs. With increasing amounts of Cs⁺, the band gaps of the Rb_1−xCs_xPbBr₃ NCs decrease, leading to a redshift of the photoluminescence peak. Also, the Rb_1−xCs_xPbBr₃ NCs (x=0.4) show good stability under ambient conditions. This work demonstrates the high structural flexibility and tunability of halide perovskite materials through an A-site cation substitution strategy and sheds light on the optimization of perovskite materials for application in high-performance optoelectronic devices.