Rubidium Cations Research Articles

Crystal Structure of Rubidium Tetraiodothallate(III) Dihydrate, RbTlI4×2H2O.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Rb3In(H2O)Si5O13: A Novel Indium Silicate with a CdSO4‐Topological‐Type Structure.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of a chain of nine-atom germanium clusters accompanied with dimerization of the sequestering agent

Abstract [Rb2(4,2,1,1-crypt)]Ge9·en was synthesized from a precursor of nominal composition Li2RbGe17 that was dissolved in ethylenediamine. Red crystals of the compound were obtained after addition of 2,1,1-crypt and layering with THF. The structure (triclinic, P 1 _ , a = 11.1927(5), b = 15.0516(7), and c = 15.7847(7) A, α = 57.671(1), β = 83.594(1), and γ = 80.217(1)°, Z = 2) features infinite chains of (–Ge92––)∞, where each cluster of Ge92– is bonded to two other clusters via single Ge–Ge bonds. Most interestingly, the 2,1,1-crypt molecules form dimers by opening C–N bonds within the molecules and restoring them to another molecule. Each dimer sequesters two rubidium cations forming a complex dication that coordinates to the chain of clusters. To cite this article: A. Ugrinov, S.C. Sevov, C. R. Chimie 8 (2005).

Crystal Structure of Rubidium Tetraiodothallate(III) Dihydrate, RbTlI4·2H2O

AbstractThe crystal structure of RbTlI4·2H2O (cubic, ${\rm Fm}{\bar 3}\rm c$, Nr. 226, Z = 24, a = 1993.5(2) pm, 327 unique reflections with Io > 2σ(Io), R1 = 0.0305, wR2 = 0.0702, GooF = 1.1199, T = 298(2) K) is characterized by an ReO3 analogous arrangement of rubidium centered [TlI4] tetrahedra. The cuboctahedral cavities of this structure are filled with crystal water molecules and additional disordered rubidium cations.

Synthesis and Characterization of Two Quaternary Thorium Chalcophosphates: Cs4Th2P6S18 and Rb7Th2P6Se21.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Estimation of parameters characterizing the adsorption of sodium, potassium, and rubidium cryptates at the mercury electrode/solution interface

The adsorption of complexes formed by sodium, potassium, and rubidium cations with macrobicyclic ligand (kryptofix 222 with C18H36N2O6 composition) is studied as a function of the ligand concentration on a stationary mercury drop in 0.1 M solutions of corresponding sulfates and chlorides by using the differential capacitance technique. Based on the model of two parallel capacitors supplemented by the Frumkin isotherm, the adsorption parameters of studied cryptates are estimated by using the regression analysis technique. Differential capacitance curves calculated with the parameters found are compared with experimental data. The comparison of the found adsorption parameters makes it possible to reveal the effects of the nature of included cations and specifically adsorbed supporting-electrolyte anions on the adsorption behavior of cryptates under study.

Rb3In(H2O)Si5O13: A Novel Indium Silicate with a CdSO4-Topological-Type Structure

A novel indium silicate, Rb3In(H2O)Si5O13, has been synthesized using a high-temperature, high-pressure hydrothermal method and characterized by single-crystal X-ray diffraction. The structure consists of five-membered rings of corner-sharing SiO4 tetrahedra connected via corner sharing to four adjacent five-membered rings to form a 3D silicate framework that belongs to the CdSO4 topological type. The InO6 octahedron shares five of its corners with five different SiO4 tetrahedra to form a 3D frame-work that delimits two types of channels to accommodate the rubidium cations. The sixth corner of InO6 is coordinated H2O. The structure is related to that of the titanium silicate ETS-10, and these are the only two metal silicates that have the CdSO4-topological-type structure. In addition, the crystal of Rb3In(H2O)Si5O13 shows an intense second harmonic generation signal. Crystal data: H2Rb3InSi5O14, monoclinic, space group Cc (No. 9), a = 9.0697(5) A, b = 11.5456(6) A, c = 13.9266(8) A, beta = 102.300(1) degrees, V = 1424.8(1) A3, and Z = 4.

Structure of gramicidin D–RbCl complex at atomic resolution from low-temperature synchrotron data: interactions of double-stranded gramicidin channel contents and cations with channel wall

Gramicidin D (gD) is a naturally occurring ionophoric antibiotic that forms membrane channels specific for monovalent cations. The crystal structure of the RbCl complex of gD has been determined at 1.14 A resolution from low-temperature (100 K) synchrotron-radiation data with a final R of 16%. The structure was refined with anisotropic temperature factors for all non-H atoms and with partial occupancies for many of them. The asymmetric unit in the crystal contains four crystallographically independent molecules that form two right-handed antiparallel double-stranded dimers. There are seven distinct rubidium-binding sites in each dimeric channel. The occupancy factors of Rb cations are between 0.11 and 0.35 and the total ion contents of the two crystallographically independent channels are 1.59 and 1.22 ions, respectively. Although each channel is 'chemically symmetrical', the side-chain conformations, the distributions of rubidium cations and their binding sites in the two independent channels are not. Cations are 'coordinated' by delocalized pi-electrons of three to five carbonyl groups that together with peptide backbone chains form the gramicidin channel walls. The water:cation ratio in the channel interior is four or five:one, and five or six waters separate Rb cations during their passage through the channel.

Trirubidium cobalt tetrachloride nitrate(V), Rb3CoCl4NO3

The title compound, Rb3CoCl4NO3, is isostructural with K3ZnCl4NO3. It is built up from Rb+ cations, NO3− anions and [CoCl4]2− complex ions which form a layer-like arrangement: one layer contains only rubidium cations while the other contains a mixture of rubidium, nitrate and tetra­chloro­cobaltate ions. Both rubidium cations are ninefold coord­inated by three O atoms and six Cl ions. One Rb atom, the Co atom, two Cl atoms, the N atom and one O atom lie on a crystallographic mirror plane.

Synthesis and Characterization of Two Quaternary Thorium Chalcophosphates: Cs4Th2P6S18 and Rb7Th2P6Se21

Two new thorium chalcophosphates have been synthesized by the reactive flux method and characterized by single-crystal X-ray diffraction, diffuse reflectance, and Raman spectroscopy: Cs4Th2P6S18 (I); Rb7Th2P6Se21 (II). Compound I crystallizes as colorless blocks in the triclinic space group P1 (No. 2) with a = 12.303(4) A, b = 12.471(4) A, c = 12.541(4) A, alpha = 114.607(8) degrees, beta = 102.547(6) degrees, gamma = 99.889(7) degrees, and Z = 2. The structure consists of (Th2P6S18)(4-) layers separated by layers of cesium cations and only contains the (P2S6)(4-) building block. Compound II crystallizes as red blocks in the triclinic space group P1 (No. 2) with a = 11.531(3) A, b = 12.359(4) A, c = 16.161(5) A, alpha = 87.289(6) degrees, beta = 75.903(6) degrees, gamma = 88.041(6) degrees, and Z = 2. The structure consists of linear chains of (Th2P6Se21)(7-) separated by rubidium cations. Compound II contains both the (PSe4)(3-) and (P2Se6)(4-) building blocks. Both structures may be derived from two known rare earth structures where a rare earth site is replaced by an alkali or actinide metal to form these novel structures. Optical band gap measurements show that compound I has a band gap of 2.8 eV and compound II has a band gap of 2.0 eV. Solid-state Raman spectroscopy of compound I shows the vibrations expected for the (P2S6)(4-) unit. Raman spectroscopy of compound II shows the vibrations expected for both (PSe4)(3-) and (P2Se6)(4-) units. Our work shows the remarkable diversity of the actinide chalcophosphate system and demonstrates the phase space is still ripe to discover new structures.

Strukturen der Alkalimetallsalze aromatischer, heterocyclischer Amide: Synthese und Struktur von Kronenether‐Addukten der Alkalimetall‐Pyrrolide

AbstractStructures of Alkali Metal Salts of Aromatic, Heterocyclic Amides: Synthesis und Structure of Crown Ether Adducts of the Alkali Metal PyrrolidesThe synthesis of eight alkali metal pyrrolide crown ether complexes is reported: Lithium‐pyrrolide(12‐crown‐4) (1), sodium‐pyrrolide(15‐crown‐5) (2), potassium‐pyrrolide(18‐crown‐6) (3), rubidium‐pyrrolide(18‐crown‐6) (4), cesium‐pyrrolide(18‐crown‐6) (5), cesium‐pyrrolide(18‐crown‐6)(H2O)0.5 (6), rubidium‐pyrrolide(15‐crown‐5)2 (7), and rubidium‐hydrogendipyrrolide(15‐crown‐5)2 (8). The complexes 1 to 5 and 7 were synthesized from the alkali metal pyrrolide and the corresponding crown ether. Compound 6 was obtained from 5 and water, complex 8 from RbN(SiMe3)2, pyrrole, and 15‐crown‐5. The structures of 1, 2, 3, 4, 6, 7, and 8 could be determined by X‐ray diffraction. The complexes 1, 2, and 3 are mononuclear, the pyrrolide anion shows an η1(N)‐coordination to the metal cation. Complex 4 is also mononuclear, but with an unsymmetric η5‐side‐on‐coordination of the pyrrolide anion to the rubidium cation. In complex 6 two pyrrolide anions are bridged by a water molecule via hydrogen bonds and both pyrrolide anions are coordinated to cesium ions. Compounds 7 and 8 have a salt‐like structure with a sandwich‐like [Rb(15‐crown‐5)2]+ cation and an uncoordinated pyrrolide anion (7) or an uncoordinated hydrogen‐dipyrrolide anion (8).

Solid-state 87Rb NMR signatures for rubidium cations bound to a G-quadruplex

We report the first solid-state 87Rb NMR characterization for rubidium cations bound to G-quartet structures formed by self-association of guanosine 5'-monophosphate and 5'-tert-butyl-dimethylsilyl-2', 3'-O-isopropylidene guanosine.

Synthesis, physical properties, and atomic structure of niobium-doped RbTiOPO4 crystals

Single crystals of solid solutions Rb1−xTi1−xNbxOPO4(RTP: Nb) were grown and the temperature dependences of their dielectric and nonlinear optical properties and electric conductivity were studied. The maximum possible niobium content in these crystals is close to x = 0.1. The niobium impurities decelerate growth of {100} faces, and crystals take a plate-like habit. With increasing doping level, ferroelectric phase transitions diffuse and their temperature decreases. A specific feature of the dielectric properties of RTP: Nb crystals is the appearance of a broad relaxation maximum e33 in the temperature range 200–600°C caused by the formation of vacancies in the rubidium cation sublattice. The intensity of second-harmonic generation under laser irradiation decreases with increasing niobium content. The atomic structure of a crystal with x = 0.01 is studied and it is established that niobium substitutes for titanium only in Ti(1) positions.

Synthesis and Crystal Structure of Tetraamminelithium-Rubidiumtriselenide, Li(NH3)4RbSe3, and Pentaamminesodium-Rubidiumtriselenide-Ammonia(1/3), Na(NH3)5RbSe3?�?3NH3

The ammoniates Li(NH3)4RbSe3 and Na(NH3)5RbSe3 · 3NH3 were prepared by the reduction of Rb2Se5 with lithium or sodium in liquid ammonia. Single crystals were isolated and characterized by X-ray structure analysis using low temperature techniques. Both compounds contain triselenide anions Se32−, which coordinate to rubidium cations forming 1∞[RbSe3]− or 1∞[Rb(NH3)2Se3]− chains. The chains are separated in the crystal structures by the homoleptic ammine complexes Li(NH3)4+ and Na(NH3)5+.

N-Aryl Anions: Half Way between Amides and Carbanions

Abstract A ‘carbanion’ can coordinate to a metal like an ‘amide’ if there is a nitrogen atom present to withdraw electron density from the formally negatively charged carbon center. On the other hand, shifting the negative charge from the amido nitrogen atom to the carbon substituent should convert an ‘amidic’ into a ‘carbanionic’ coordination behavior. This seems feasible with various substituents at the aromatic ring in a primary amide. This paper is concerned with the influence of aromatic substitution, as well as with the nature of the metal ion on the coordination mode of an amide ligand. Discussed are the parent lithium anilide [(thf)2LiNH(C6H5)]2 (1), the pentafluorinated lithium anilide [(thf)2LiNH(C6F5)]2 (2) and the lithium amino benzonitrile [(thf)2LiNH(C6H4 pCN)]2 (3). All amide ligands coordinate the lithium cation exclusively with their amido nitrogen atom. In the dimeric structure of 1 the atom can be regarded to be sp2-hybridized. Fluorine substitution of the ring results in a slightly more pronounced coupling of the negative charge to the aromatic ring. A para-nitrile group further enhances quinoidal perturbation of the C6-perimeter from six-fold symmetry. Consequently, the ipso- and ortho-carbon atoms of the ring are partially negative charged. Those carbon atoms are only attractive for the soft rubidium cation in an aza allylic coordination in [(thf)2RbNH(C6H4 pCN)]n (4) but not to the hard lithium cation.

The first rubidium rare-earth(III) thiophosphates: Rb 3M3[PS 4] 4 ( M=Pr, Er)

The two non-isotypical rubidium rare-earth(III) thiophosphates Rb 3 M 3[PS 4] 4 of praseodymium and erbium can easily be obtained by the stoichiometric reaction of the respective rare-earth metal, red phosphorus and sulfur with an excess of rubidium bromide (RbBr) as flux and rubidium source at 950°C for 14 days in evacuated silica tubes. The pale green platelet-shaped single crystals of Rb 3Pr 3[PS 4] 4 as well as the pink rods of Rb 3Er 3[PS 4] 4 are moisture sensitive. Rb 3Pr 3[PS 4] 4 crystallizes triclinically in the space group P 1 ¯ ( a = 926.79 ( 5 ) pm , b = 1050.83 ( 5 ) pm , c = 1453.28 ( 7 ) pm , α = 84.329 ( 4 ) ° , β = 88.008 ( 4 ) ° , γ = 80.704 ( 4 ) ° ; Z = 2 ), Rb 3Er 3[PS 4] 4 monoclinically in the space group P 2 1 / n ( a = 915.97 ( 5 ) pm , b = 1575.86 ( 7 ) pm , c = 1843.32 ( 9 ) pm , β = 95.601 ( 6 ) ° ; Z = 4 ). In both structures, there are three crystallographically different rare-earth cations present. ( M1) 3+ is eightfold coordinated in the shape of a square antiprism, ( M2) 3+ and ( M3) 3+ are both surrounded by eight sulfur atoms as bicapped trigonal prisms each with a coordination number of eight as well as for the praseodymium, but better described as CN = 7 + 1 in the case of the erbium compound. These [ MS 8] 13− polyhedra form a layer according to ∞ 2 { [ M 3 [ PS 4 ] 4 ] 3 - } by sharing edges with the isolated [PS 4] 3− tetrahedra ( d(P–S)=200–209 pm, ∢(S–P–S)=102–116°). These layers are stacked with a repetition period of three in the case of the praseodymium compound, but of only two for the erbium analog. The rubidium cation (Rb1) + is located in cavities of these layers and tenfold coordinated in the shape of a tetracapped trigonal antiprism. The also tenfold but more irregularly coordinated rubidium cations (Rb2) + and (Rb3) + reside between the layers.

Low Dimensional Materials: Syntheses, Structures, and Optical Properties of Rb2CuTaS4, Rb2CuTaSe4, RbCu2TaSe4, K3Ag3Ta2Se8, and Rb3AgTa2Se12

The new compounds Rb2CuTaS4 (1), Rb2CuTaSe4 (2), RbCu2TaSe4 (3), K3Ag3Ta2Se8 (4), and Rb3AgTa2Se12 (5) have been synthesized by the reactive flux method at 773 or 873 K. Their crystal structures were determined by single crystal X-ray diffraction. Crystal data for 1: space group Fddd, a = 5.598(1), b = 13.512(4), c = 23.854(5) Å , Z = 8; Crystal data for 2: space group Fddd, a = 5.782(1), b = 13.924(3), c = 24.653(5) Å , Z = 8; Crystal data for 3: space group C2cm, a = 5.7218(3), b = 19.2463(13), c = 7.7456(5) Å , Z = 4; Crystal data for 4: space group C2/c, a = 25.1374(19), b = 6.1007(3), c = 14.4030(11) Å , β = 119.703(8)◦, Z = 4; Crystal data for 5: space group P21/n, a = 9.8186(6), b = 13.7462(11), c = 15.7368(9) Å , β = 96.681(7)◦, Z = 4. The compounds 1 and 2 are built up of 1 ∞[CuTaQ4]2− anionic chains which are formed by edge-sharing CuQ4 and TaQ4 tetrahedra. The rubidium cations are located between the chains. Compound 3 consists of 2 ∞[Cu2TaSe4]− anionic layers separated by rubidium cations. The anionic layers are formed by1 ∞[CuTaSe4]2− chains which are connected by CuSe4 tetrahedra that share common edges with the TaSe4 tetrahedra of neighboring chains. In compound 4 1 ∞[Ag3Ta2Se8]3− anionic chains are found which are separated by potassium cations. These chains are formed by successive corner sharing of AgSe4 tetrahedra and edge sharing between AgSe4 and TaSe4 tetrahedra. All three structures are closely related with the sulvanite (Cu3VS4) structure type. Compound 5 contains a one dimensional 1 ∞[AgTa2Se12]3− anionic chain formed by interconnection of AgSe4 tetrahedra and [Ta2Se11] units. In the structure three monoselenide, three diselenide, and one triselenide anions are found. Raman and far-IR spectroscopic data of compounds 1 and 4 were collected and an interpretation is presented.

Insights into the structures, energetics, and vibrations of aqua-rubidium(I) complexes: ab initio study.

We have carried out ab initio and density functional theory calculations of hydrated rubidium cations. The calculations involve a detailed evaluation of the structures, thermodynamic properties, and IR spectra of several plausible conformers of Rb+ (H2O)(n=1-8) clusters. An extensive search was made to find out the most stable conformers. Since the water-water interactions are important in hydrated Rb+ complexes, we investigated the vibrational frequency shifts of the OH stretching modes depending on the number of water molecules and the presence/absence of outer-shell water molecules. The predicted harmonic and anharmonic vibrational frequencies of the aqua-Rb+ clusters reflect the H-bonding signature, and would be used in experimental identification of the hydrated structures of Rb+ cation.

Crystal structure of tetrarubidium hexathiodisilicate(IV), Rb4Si2S6

Rb4S6Si2, monoclinic, CYUmX (no. 12), a = 13.23(2) A, b = 6.864(2) A , c = 9.53(1) A . / 3 = 125.15(5)°, V= 707.6 A 3 , Z = 2, Rgi(F) = 0.048, wflreffF) = 0.052, T = 296 K. Source of material Rb4Si2S6 was obtained by reacting a mixture of 4.4 mmol Rb2S with 4.4 mmol Si and 13 mmol S powder (99.999 % purity) in aluminum oxide crucibles which were sealed into evacuated silica ampoules at 973.15 K, followed by cooling at a constant rate of 3 K/h. The reaction product consisted of colorless prismatic crystals which were sensitive to air and humidity. Discussion Rb4Si2S6 is isostructural as confirmed by STRUCTURE TIDY [1] with Rb4Ge2Se6 [2] and Rb4Ge2S6 [3] both crystallizing with the Cs4Sn2See structure type [4]. The crystal structure is characterized by discrete centrosymmetric hexathiodisilicate(IV) anions [Si2S6] which are built up by two edge sharing SiS4tetrahedra. The two independent terminal bonds are virtually identical (d(Si—SI) = 2.063(4) A and d(Si—S2) = 2.063(6) A ) and are significantly shorter than the bridging bond (?(Si—S3) = 2.196(3) A ) . The bond angle Sl-Si-S2 calculates as 116.7(2)° while that to the bridging S3 atoms is almost rectangular (94.3(2)°). These values are in fair agreement with those found in 11(51256 [5] the only other compound where this anion has so far been reported. In the isoelectronic molecule Si2S2Cl4 [6] the bridging Si—S bond length is significantly shorter (?(Si—S) = 2.116 A ) . The crystal structure of the title compound contains two independent rubidium cations, both coordinated by seven sulfur atoms in distorted pentagonal bipyramidal configurations (d(Rb—S) = 3.326 A 3.814 A ) . Table 1. Data collection and handling. Crystal: Wavelength: /*• Diffractometer, scan mode: 20max: N(hkl)nKasimdy Wli/Junique: Criterion for /obs, N(hkl)gc. N(param)n fined: Programs: colorless prism, size 0.0S x 0.07 x 0.20 mm Mo Ka radiation (0.7107 Â) 147.40 cm Enraf-Nonius CAD4, o>IW 59.82° 1148,1105 /obs > 2 crf/obsj, 700 36 CrystalStmcture [7], SIR92 [8], CRYSTALS [9] Table 2. Atomic coordinates and displacement parameters (in Â). Atom Site Un UZ2 I/33 Un U13 Uz> Rb(l) Rb(2) S C I ) S(2) S(3) Si(l) 41 4 i 41 4/ 4g 4 i 0.5803(1) 0.8058(1) 0.1122(3) 0.2874(3) 0 0.1155(3) 0 0 0 0 0.2346(4) 0 0.3616(1) 0.1881(1) 0.3921(3) 0.2217(4) 0 0.1783(3) 0.0308(6) 0.0417(7) 0.029(2) 0.033(1) 0.037(2) 0.027(1) 0.0263(6) 0.0317(7) 0.035(2) 0.028(1) 0.011(1) 0.015(1) 0.0203(5) 0.0264(6) 0.024(1) 0.016(1) 0.018(1) 0.010(1) 0.0121(4) 0.0189(5) 0.017(1) 0.015(1) 0.008(1) 0.008(1)

Phase transitions in KTP isostructures: correlation between structure and Tc in germanium-doped RbTiOPO4.

Crystals of germanium-doped rubidium titanyl phosphate, Rb(2)(Ti)(Ge(0.121)Ti(0.879))O(2)(PO(4))(2) (GeRTP#1) and Rb(2)(Ge(0.125)Ti(0.875))(Ge(0.225)Ti(0.775))O(2)(PO(4))(2) (GeRTP#2), have been structurally characterized from X-ray diffraction data at room temperature. In addition, a third structure, Rb(2)(TiO)(2)(PO(4))(2) (RTP), has been reinvestigated. The exchange of titanium for germanium results in a less distorted octahedral coordination around the two crystallographically independent titanium sites. Additionally, rubidium split-cation positions have been found in these doped RTP crystals. Dielectric measurements show that the phase-transition temperature, T(c), decreases with increasing germanium concentration, and a direct correlation between the room-temperature split of the rubidium cations and T(c) has been discovered. General trends regarding the relationship between the room-temperature structures of KTP-like compounds and their T(c) values are discussed.