Silver deposition from silver rubidium iodide

The halogenide (Cl^?, Br^?, I^?) complexes of indium(III) were investigated polarographically. The potential obtained in the presence of iodide ion (0.0004 M) was taken as the half-wave potential of “free” indium ion. The half-wave potentials at low halogenide concentrations were corrected for the kinetic effect. The approximate values of the stability constants read off from the curve (half-wave potential versus logarithm of ligand concentration) at points corresponding to the mean ligand numbers n=0.5, 1.5, 2.5, and 3.5 were then refined by the trial and error method. Four stability constants were found for each of the ligands investigated. The logarithms of β_1–4 are 2.70, 3.20, 4.20 and 3.30 for chloride ions, 2.10, 2.40, 2.50 and 0.60 for bromide ions and 1.35, 1.40, 1.30 and 0.50 for iodide ions. It was also assumed that the too high values of β₁ found by Bond resulted from neglect of the kinetic character of the waves.     

Geometry and electronic properties of alkali metal (rubidium) doped boron clusters

Alkali metal-doped boron clusters have captured much attention because of their novel electronic properties and structural evolution. In the study of RbB_n^0/− (n = 2–12) clusters, the minimum global search of the potential energy surface and structure optimization at the level of PBE1PBE by using the CALYPSO method and Gaussian package coupled with DFT calculation; the geometrical structures and electronic properties are systematically investigated. At n = 8, the ground-state structures are composed of an Rb atom above B atoms, forming a structurally stable pagoda cone. By stability analysis and charge transfer calculation, the RbB₈⁻ cluster shows more stability. It found that s-p hybridization between Rb atom and B atoms as well as s-p hybridization between B atoms is one of the reasons for the outstanding stability exhibited in the RbB₈^0/− clusters by using DOS and HOMO–LUMO orbital contour maps. The chemical bonding of the RbB₈^0/− groups was analyzed by using the AdNDP method, and B atoms with larger numbers readily form multi-center chemical bonds with the Rb atom. From the results of the bonding analysis, the interaction between the Rb atom and B atoms strengthens the stability of the RbB₈^0/− clusters. It is hoped that this work provides a direction for experimental manipulation.     

Synthesis,structure, ion mobility,phase transitions,and ion transport in rubidium ammonium hexafluorozirconates

Rubidium ammonium hexafluorozirconates Rb_2?x (NH₄)_x ZrF₆ (1.5 < x < 2.0) have been synthesized, and their structure, ion mobility (180–480 K), and electrophysical properties have been studied by X-ray crystallography, ¹H and ¹⁹F NMR, DTA, and impedance methods. Compounds with x > 1.5 are isostructural with (NH₄)₂ZrF₆. Rubidium cations are isomorphously substituted for the ammonium cations. The high-temperature modifications of the compounds, which form upon the phase transitions at 413–418 K, are characterized by translational diffusion of ions in the fluoride and ammonium sublattices. The ¹⁹F NMR spectra are characterized by uniaxial ¹⁹F magnetic shift anisotropy. The electrophysical properties of this series of compounds are studied in the temperature range 300–480 K.     

Crystal structure of rubidium cobalticyanide

The crystal structure of Rb₃[Co(CN)₆] was determined by X-ray diffraction analysis. The crystals are monoclinic, space group P2₁/c, a = 7.163(2), b = 10.601(3), c = 8.675(3) Å, β = 107.83(2)°, V = 627.1(3) ų, Z = 2, ρ_calcd = 2.497 g/cm³, R = 0.0844, wR = 0.2090 for 769 measured reflections. The coordination polyhedron of the Co atom is the regular octahedron [Co(CN)₆]. The Rb(1) atoms are in the cavities of the octahedral structure; the Rb(2) atoms are in the cavities of the trigonal prisms, additional two atoms being more distant. All the cyano groups of the complex are in terminal positions.     

Complex of cesium and rubidium fluorides with bromine trifluoride

Vibrational spectra are reported for the new complexes CsF·3BrF₃, RbF·3BrF₃, and RbF·2BrF₃ and the previously known complex CsF·2BrF₃. The spectra suggest that these compounds are salts having general formulas M⁺Br₃F^?₁₀ and M⁺Br₂F^?₇.     

Crystal growth,structural and electrical properties of rubidium and cesium vanadium oxide bronzes

Crystals of the following compounds were grown by cathodic reduction of CsV⁵⁺O or RbV⁵⁺O metls: Cs_0.3V₂O₅ (A), Cs₂V₅O₁₃ (B), CsV₂O₅ (C), Rb_0.4V₂O₅ (D), Rb_0.37V₂O_∼4.8 (E) (a new orthorhombic compound) and Rb_2−xV_3+2xO_8+2x (F). The crystal symmetry and cell parameters of the Rb compounds (which were known for F only) were determined, as well as those of Rb_0.3V₂O₅, which has the structure of A. Magnetic susceptibility and ESR measurements confirm the intermediate valence in E. A, C, and E are semiconductors with activation energies in the range 0.07–0.2 eV. Cs_0.3V₂O₅ (A), in which V⁴⁺ and V⁵⁺ do not occupy distinct crystallographic sites, has the highest electrical conductivity.     

Investigations on the formation of rubidium dimolybdate via thermal decomposition of rubidium oxomolybdenum(VI) oxalate

The complex Rb₂[Mo₂O₅(C₂O₄)₂(H₂O)₂] (RMO) was prepared and characterized by means of chemical analysis and IR spectral studies. Its thermal decomposition was studied by using TG and DTA techniques. RMO loses its water between 160 and 200°C, this immediately being followed by the decomposition of anhydrous RMO, which takes place in three stages. The first two stages occur in the temperature ranges 200–220 and 220–255°, to give intermediates with tentative compositions Rb₈[Mo₈O₂₂(C₂O₄)₆] and Rb₈[Mo₈O₂₆(C₂O₄)(CO₃)], respectively, the latter then decomposing in the third stage between 255 and 340° to give the end-product, rubidium dimolybdate (Rb₂Mo₂O₇). Thed spacings for Rb₂Mo₂O₇ are given for 2θ values between 10 and 70°.     

Electroconduction of rubidium pyrophosphate modified by divalent cations

Solid solutions based on rubidium pyrophosphate are synthesized in the Rb_{4 -2x}M_xP₂O₇ systems (M = Ca, Sr, Ba, Pb). The temperature and concentration dependences of their rubidium-cation conductivity are investigated. The X-ray data for the low and high-temperature forms of Rb₄P₂O₇ and also for solid solutions based on it are reported. The effect exerted by modifying cation M²⁺ on electrical properties of synthesized solid solutions is considered     

Crystal structures of cesium and rubidium 2-thiobarbiturates

The crystal structures of cesium 2-thiobarbiturate C₄H₃CsN₂O₂S (I) and rubidium 2-thiobarbiturate C₄H₃N₂O₂RbS (II) (C₄H₄N₂O₂S is 2-thiobarbituric acid, H₂TBA) have been determined. Isostructural crystals are monoclinic; a = 7.9609(3) Å,b = 11.8474(3) Å, c = 7.7317(2) Å, β = 101.285(3)°, V = 715.13(4) ų, space group C2/m, Z = 4 for I and a = 7.6369(2) Å, b = 11.7690(3) Å, c = 7.5568(2) Å, β = 100.212(1)°, V = 668.44(3) ų, space group C2/m, Z = 4 for II. Each metal ion in complexes I and II is bonded to four oxygen atoms and two sulfur atoms at the vertices of a six-vertex polyhedron. N-H…O hydrogen bonds link HTBA-ions into chains. The structure is also stabilized by the “head-to-tail” π-π interaction of HTBA-ions.     

Standard molar enthalpy of formation of rubidium diphosphate

Rubidium carbonate (Rb₂CO₃) and ammonium dihydrogen phosphate (NH₄H₂PO₄) were used for synthesizing rubidium diphosphate (Rb₄P₂O₇). The purity of the latter compound was checked up by X-ray diffraction. Rb₄P₂O₇ was involved in an hypothetical reaction and dissolved together with the other components in a 3.85 % (m/m) phosphoric acid solution, using a C-80 SETARAM calorimeter. Mixing processes were also realized in the calorimeter in order to get the standard molar enthalpy of formation of rubidium diphosphate (Rb₄P₂O₇). For that a thermochemical cycle was investigated and the obtained value for the standard molar enthalpy of formation of rubidium diphosphate is (?3,183.7) kJ mol^?1. The result is about 1.8 % lower than literature value.     

Cadmium vanadates of potassium,rubidium, and cesium

The solid-phase reactions between the components have been used to study the equilibrium phase composition of the systems M₂O(M₂CO₃)-CdO-V₂O₅ (M = K, Rb, or Cs) in the range of the subsolidus temperatures. New potassium cadmium vanadates KCd₃V₃O₁₁, K₂Cd₅(VO₄)₄, and K₂Cd₄V₄O₁₅ have been synthesized. A monoclinic solid solution has been identified on the basis of the KCd₄(VO₄)₃ structure. Double orthovanadate RbCdVO₄ has been prepared for the first time. Equilibrium phase diagrams have been constructed using both previously known compounds, and those synthesized by us. The effect of the size factor (the M⁺ ion radius) on the phase formation and phase equilibria in the systems in question has been traced.     

Synthesis of rubidium fluorophosphatozirconates in the ZrO2-H3PO4-RbF-H2O system and their luminescent properties

Rubidium fluorophosphatozirconates (RFPZs) were synthesized along sections of the ZrO₂-H₃PO₄-RbF-H₂O system where PO ₄ ^3? /Zr = 1–2 (mol/mol) and RbF/Zr = 1–5 (mol/mol) and the initial solution contains 2–5 wt % ZrO₂. The following RFPZs have been isolated for the first time: RbZrF₂PO₄ · 0.5H₂O, Rb₃H₃Zr₃F₃(PO₄)₅, and RbZr₃F₄(PO₄)₃ · 1.5H₂O. Their formation fields were determined. The compounds were characterized using powder X-ray diffraction, crystal-optical analysis, chemical analysis, electron probe microanalysis, thermal analysis, and IR spectroscopy. Luminescent properties of the compounds were measured. All RFPZs are orthophosphates, have high thermal durability, and X-ray luminescence (XRL). Rb₃H₃Zr₃F₃(PO₄)₅ has the highest XRL intensity.     

Synthesis, structure and VUV luminescent properties of rubidium rare-earth fluorides

RbF-LnF₃ (Ln=rare earth) systems were synthesized by hydrothermal technique. Under the hydrothermal condition, the light rare-earth elements form LnF₃ (Ln=La-Nd), while the heavy ones form RbLn₂F₇ (Ln=Y, Er, Yb and Lu) with the RbEr₂F₇ structure type. RbLn₃F₁₀ compounds were found for the in-between rare-earth cations (Ln=Eu-Tm and Y), which crystallize exclusively in the cubic γ-KYb₃F₁₀-type structure. The luminescent properties under vacuum ultraviolet light were studied for the Eu³⁺-doped RbLn₃F₁₀ (Ln=Y, Gd) and a high quantum efficiency of about 150% was observed for RbGd₃F₁₀:Eu³⁺.     

Thermodynamic properties of rubidium niobium tungsten oxide

In the present work temperature dependence of heat capacity of rubidium niobium tungsten oxide has been measured first in the range from 7 to 395 K and then between 390 and 650 K, respectively, by precision adiabatic vacuum and dynamic calorimetry. The experimental data were used to calculate standard thermodynamic functions, namely the heat capacity ^ (T), C_{\text{p}}^{\text{o}} (T), enthalpy H^\texto (T) - H^\texto (0) H^{\text{o}} ({\rm T}) - H^{\text{o}} (0) , entropy S^\texto (T) - S^\texto ( 0 ) S^{\text{o}} (T) - S^{\text{o}} \left( 0 \right) , and Gibbs function G^\texto (T) - H^\texto (0) G^{{^{\text{o}} }} ({\rm T}) - H^{{^{\text{o}} }} (0) , for the range from T→0 to 650 K. The high-temperature X-ray diffraction and the differential scanning calorimetry were used for the determination of temperature and decomposition products of RbNbWO₆.     

The nature of ion exchange selectivity of phenol-formaldehyde sorbents with respect to cesium and rubidium ions

The structure of aqua complexes of alkali metal ions Me⁺(H₂O) _n , n = 1−6, where Me is Li, Na, K, Rb, and Cs, and complexes of 2,6-dimethylphenolate anion (CH₃)₂PhO⁻ selected as a model of the elementary unit of phenol-formaldehyde ion exchanger with hydrated alkali metal cations Me⁺(H₂O) _n , n = 0−5, was studied by the density functional method. The energies of successive hydration of the cations and the energies of binding of alkali metal hydrated cations with (CH₃)₂PhO⁻ depending on the number of water molecules n were calculated. It was shown that the dimethylphenolate ion did not have specific selectivity with respect to cesium and rubidium ions. The energies of hydration and the energies of binding of alkali metal cations with (CH₃)₂PhO⁻ decreased in the series Li⁺ > Na⁺ > K⁺ > Rb⁺ > Cs⁺ as n increased. The conclusion was drawn that the reason for selectivity of phenol-formaldehyde and other phenol compounds with respect to cesium and rubidium ions was the predomination of the ion dehydration stage in the transfer from an aqueous solution to the phenol phase compared with the stage of binding with ion exchange groups.     

Hydrogen bond studies: 67. The crystal structure of rubidium trihydrogen selenite,RbH3(SeO3)2

The crystal structure of RbH₃(SeO₃)₂ has been determined from three-dimensional single crystal X-ray diffractometer data obtained at room temperature. Four formula units crystallize in an orthorhombic unit cell of dimensions: a = 5.9192(2), b = 17.9506(5), and c = 6.2519(3) Å. The space group is P2₁2₁2₁. The structure consists of two types of chains at a right angle. One chain is built up of H₂SeO₃ molecules linked by 2.594(8)-Å hydrogen bonds and the other of HSeO₃^? ions linked by 2.571(12)-Å hydrogen bonds. These two types of chains are cross-linked by a third hydrogen bond of length 2.521(7) Å. The rubidium ion is surrounded by eight oxygen atoms forming a distorted cube. The Rb⁺O distances are in the range 2.94–3.19 Å.     

Crystal Structure of Bis(dibenzo-18-crown-6)rubidium Triiodide

Crystalline bis(dibenzo-18-crown-6)rubidium triiodide complex [Rb(DB18C6)₂]⁺ · I₃ ^– (I) is synthesized and its structure is studied by X-ray diffraction analysis. The structure of I (space group Pnma, a = 23.854 Å, b = 23.612 Å, c = 7.863 Å, Z = 4) is solved by the direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.079 against 3990 independent reflections (CAD4 automated diffractometer, MoK ). Structural units of crystal I are the I₃ ^– anions and [Rb(DB18C6)₂]⁺ cations. The crystal has the structure intermediate between that of a standard host–guest complex and a sandwich complex. In the structure of complex I, the crystallographic plane with symmetry m passes through the I₃ ^– anion (perpendicularly to its axis) and complex cation. The coordination polyhedron of the Rb⁺ cation is a strongly distorted hexagonal pyramid with the O atom of one crown ligand at the axial vertex and a base of six O atoms of another DB18C6 crown ligand.     

A rubidium organic-inorganic hybrid complex with channels hosting decorated polyanion chains

A rubidium organic-inorganic hybrid complex, {H₂[Rb(PMo₁₂O₄₀)(CH₃CN)₃](dpdo)₂(H₂O)₂} _n (1), (where dpdo is 4,4′-bipyridine-N,N′-dioxide) with special channels for the chainlike assembly of decorated Keggin-type anions was synthesized and structurally characterized. The crystal structure was determined by single-crystal X-ray diffraction. The crystal is Orthorhombic space group Cmcm with a = 20.4713(18) ?, b = 17.0529(15) ?, c = 16.1968(14) ?, V = 5654.2(9) ?³, Z = 4, C₂₆H₃₁N₇O₄₆RbMo₁₂P, M = 2445.30, D _c = 2.873 Mg m⁻³, μ = 3.570 mm⁻¹, F(000) = 4640, the final R = 0.0438 and wR = 0.1350 for 2065 observed reflections with I > 2σ(I). Compound 1 exhibits a 3D network with large channels hosting decorated polyanion chains as guests.     

Crystal growth and electrical properties of lithium,rubidium, and cesium molybdenum oxide bronzes

Crystals of Li_0.33 MoO₃ (blue), Rb_0.23MoO₃ (blue) and Cs_0.31MoO₃ (red) were grown by electrolysis from MoO₃M₂MoO₄ melts (M =alkali metal) with composition 70–77 mole% MoO₃. Melts richer in M₂MoO₄ produced MoO₂ only. Correlation is made between bronze formation and the coordination of Mo in the melt and in the equilibrium solid phase M₂Mo₄O₁₃. Li_0.33MoO₃ and Cs_0.31MoO₃ are semiconductors with high-temperature-range activation energies 0.16 and 0.12 eV. Rb_0.23MoO₃ has an electrical behavior similar to that of blue K_xMoO₃ with a semiconductor-metal transition at (170 ± 5) K. ESR spectra observed in Li_0.33MoO₃ and Rb_0.23MoO₃ single crystals at 4.2 K show extensive delocalization of the 4d¹ electron associated with Mo(V) centers. Attempts to grow molybdenum bronzes containing Ca or Y were unsuccessful.