Cesium Compounds Research Articles

Synthesis of nanostructured silica via sol–gel process with incorporation of cesium compound

Cesium was incorporated into silica matrix by direct mixture of cesium chloride into the casting solution formed by water and tetramethylorthosilicate. The casting solutions were prepared with cesium content ranging from 0.035 to 4.9 wt.%. For structural characterization the techniques of nitrogen sorption, mercury pycnometry, thermogravimetric analysis (TGA), differential thermal analysis (DTA) and X-ray diffraction were employed. Specific surface area, pore-size distribution and bulk density of the gels were obtained by nitrogen sorption (BET) and mercury pycnometry. The pore morphology was inferred through curves of nitrogen-sorption hysteresis. After drying and heat treatment, the gels obtained with hydrofluoric (HF) as catalyst remained unbroken. The specific surface area of the silica gels decreases in the presence of cesium. The shape of curves of nitrogen-sorption hysteresis did not change with the cesium content studied. The presence of cesium makes the pore-size distribution narrower. Gels obtained with 1.1 wt.% Cs (content in casting solution) and treated at two dwell temperature (500+800°C) show the indication of a lower cesium leaching.

Trapping characteristics of cesium in off-gas stream using fly ash filter

The cesium trapping characteristics with changing reaction temperature, carrier gas and gas velocity by the fly ash filter were analyzed. The SEM (Scanning electron microscope) on the pore structure of the fly ash filter showed that pores up to 0.1 mm in diameter were widely interconnected with each other throughout the whole structure of the filter. According to the XRD (X-ray diffraction) analysis for the cesium compound trapped on the fly ash filter, the thermally stable pollucite phase was formed. The cesium trapping quantity of the fly ash filter was increased with increasing reaction temperature, whereas it was decreased with increasing gas velocity. SEM showed that the fly ash filter after trapping gaseous cesium had mullite phase of needle-like crystals and pollucite phase of bulky crystals with rough surface.

Alkalimetall-Oxosilicate A6[Si3O9] und A6[Si2O7] (A = Rb, Cs): Darstellung und Kristallstruktur/ The Alkaline Metal Oxo-Silicates A6[Si3O9] and A6[Si2O7] (A = Rb, Cs): Preparation and Crystal Structure

Abstract The title compounds were synthesized via reaction of quartz and AO2 (A = Rb, Cs) with the elemental alkali metals. Their crystal structures were determined on the basis of single crystal X-ray data. All compounds crystallize in the monoclinic system with space group P21/c and lattice constants a = 656.0(l)/684.7(3), b = 1329.7(3)/1375.7(4), c = 1647.6(3)/1703.6(8) pm, β = 107.78(3)/108.23(2)°, Z = 4 (A6[Si3O9], A = Rb/Cs) and a = 668.59(8)/711.4(1), b = 911.37(9)/952.1(2), c = 1121.09(9)/1192.7(7) pm, β = 125.52(9)/126.22(3)°, Z = 2(A6[Si2O7], A = Rb/Cs) respectively. The rubidium and cesium compounds are isotypic with the corresponding potassium silicates.

Preparation of cesium targets for gamma-spectroscopic studies

A procedure to prepare monoisotopic cesium compound targets for gamma-spectroscopic experiments is described. Using this procedure, uniform targets up to thicknesses of 0.6–1.2 mg/cm 2 were prepared and used for in-beam spectroscopic studies. The purity of the target was tested by energy dispersive X-ray fluorescence (EDXRF) measurements.

The interference of uptake of thallium-201 in cultured rat myocardial cells with existence of potassium related pharmaceuticals--a preliminary report.

Thallium-201 myocardial perfusion imaging is wildly used to detect and assess the extent of jeopardized myocardial ischemia in the coronary artery disease and the viability of myocardium post infarction. In recent years, there has been a great deal of pharmacological development of blockers and openers of potassium channel. In this study, we will discuss the interference of uptake of thallium-201 ion in cultured neonatal rat myocytes with existence of a variety of pharmacological agents. The cultures of neonatal rat myocardial cells were incubated with different agents such as potassium chloride, sodium-potassium ATPase pump inhibitor (ouabain), cesium compound, variable potassium channel blockers (4 AP, TEA and glibenclamide) and their openers (minoxidil, and cromakalim). The radioactivity of intracellular thallium-201 that could enter rat myocardial cells was detected by gamma counter sixty minutes after thallium-201 was added. In this study we found that thallium and potassium ions behave in an analogous manner in cultured rat myocardial cells. Both 2.5 mM and 5 mM concentration of extracellular potassium ion significantly result in reduction of thallium-201 ion influx in rat myocardial cells. 0.5 mM ouabain, an inhibitor of sodium-potassium ATPase pump, reduced about 40% of influx of thallium-201 ion in cultured rat myocardial cells via active transport. Combination of both potassium ion and ouabain inhibit most of thallium-201 ions influx in myocardial cells, but it is not completely inhibited. Cesium, a potassium antagonist, also interferes with the uptake of thallium-201 in cultured rat myocytes in our study. The most interesting finding in our investigation is that potassium channel blockers such as TEA and glibenclamide, inhibit the influx of thallium-201 in myocytes. However, potassium channel openers have no overt effect on influx of thallium-201 in cultured rat myocytes. We indirectly observe about 60% of influx of thallium-201 ion into cultured rat myocardial cells via active sodium-potassium ATPase pump. Potassium, cesium and potassium channel blockers, such as TEA and glibenclamide, inhibited the different percentage of influx of thallium-201 in cultured rat myocardial cells in this study.

Neutronen- und Röntgenbeugungsuntersuchungen an Pulvern und Einkristallen von Strukturverwandten des Berliner Blaus: CsMnIICrIII(CN)6 · D2O , NMe4MnII(Cr0,06,Mn0,94)III(CN)6 · 8 H2O , NMe4MnIICoIII(CN)6 · 8 H20 , Mn3 II[MnIII(CN)6]2 · 15 H2O und Cd3[FeIII(CN)6]2 · 15 H2O / Neutron and X-Ray Diffraction Studies on Powders and Single Crystals of Compounds Structurally Related to Prussian Blue: CsMnIICrIII(CN)6 · D2O, NMe4MnII(Cr0,06Mn0,94)III(CN)6 · 8

The results of a Rietveld refinement of CsMnCr(CN)6 · D2O neutron powder data (a = 1084.3(1) pm, F4̄3m, Z = 4) and of a neutron single crystal structure refinement of tetragonal NMe4MnII(Cr0,06Mn0,94)III(CN)6 · 8 H2O (a = 1065.8(21), c = 1064.6(26) pm, P4/n, Z = 2) at ambient temperature are reported. Single crystal X-ray analyses of the isostructural octahydrate NMe4MnCo(CN)6 · 8 H20 (a = 1062.1 (1), c = 1046.2( 1) pm) and of gel-grown crystals of cubic Mn3 II[MnIII(CN)6]2 - 15 H2O (a = 1062.6(3) pm, Fm3̄m, Z = 4/3) and Cd3[Fe(CN)6]2 · 15 H2O (a = 1067.7(3) pm) were performed as well. The latter “Prussian Blues” are highly disordered and intermediate with respect to cyano-bridging between the above three-dimensional cesium and one-dimensional tetramethylammonium compounds.

Syntheses, X-ray Powder Structures, and Preliminary Ion-Exchange Properties of Germanium-Substituted Titanosilicate Pharmacosiderites: HM3(AO)4(BO4)3·4H2O (M = K, Rb, Cs; A = Ti, Ge; B = Si, Ge)

This paper describes a continuing research effort that involves synthesizing new tunnel-type materials while attempting to understand their fundamental ion-exchange selectivities through the process of structural elucidation. For this study, we hydrothermally synthesized and characterized two germanium-substituted titanosilicates in the cesium phase and prepared their potassium forms by ion exchange. A mixed Si//Ti/Ge phase, HCs3(TiO)3.5(GeO)0.5(GeO4)2.5(SiO4)0.5·4H2O, crystallizes in the cubic space group P4̄3m with a = 7.9376(1) Å, while the cesium titanogermanate, HCs3(TiO)4(GeO4)3·4H2O, possesses a body-centered supercell belonging to space group I23, a = 15.9604(3) Å. Differences in symmetry between the two cesium compounds can be explained in terms of entropy and site mixing in the Si/Ti/Ge compound. Upon ion exchange with potassium, the resulting phases, HK3(TiO)3.5(GeO)0.5(GeO4)2.5(SiO4)0.5·4H2O and HK3(TiO)4(GeO4)3·4H2O, distorted to the tetragonal space group P4̄b2, with a = b = 11.1571(2), c = 7.9165(2) Å, and a = b = 11.215(1), c = 7.9705(2) Å, respectively. For the first time, we have observed tetragonal distortions with alkali cation forms of the pharmacosiderite analogues. As compared to HK3(TiO)4(SiO4)3·4H2O, these potassium germanium-substituted phases show remarkable increases in strontium and cesium selectivity, which proves very beneficial for nuclear waste remediation applications. An increase in selectivity can be explained in terms of their inherent structures and bond strengths associated with the charge-neutralizing cations and framework oxygens.

Preparation and crystal structure determination of triphenylmethanide cesium · 1.5 dimethoxyethane and of phenothiazine cesium diglyme

Abstract Reaction of triphenylmethane with cesium metal in dimethoxyethane (DME) or of phenothiazine in diglyme yields two organometallic cesium compounds as extremly air and moisture sensitive single crystals. In triphenylmethanide cesium · 1.5 DME, the counter cations form two structurally different contact ion pairs to symmetry-related triphenylmethanide anions and are solvated in addition by two crystallographically independent ether solvent molecules, which partly connect the resulting polymeric chains. In phenothiazine cesium diglyme, each counter cation is surrounded by three symmetry-related phenothiazine anions and one diglyme molecule predominantly via their oxygen, nitrogen and sulfur centers and again infinite polymer chains are formed. All structural results are discussed based on literature data of analogous complexes.

Synthesis and Crystal Structure of the First Polymeric Cesium Compound of a Carborane Ligand System

The reaction between a THF solution of (SiMe3)4C4B8H8 (1) and excess cesium metal, in the absence of either naphthalene or aromatic solvents, produced a paramagnetic intermediate that reacted further with cesium to give the EPR-silent species [exo-Cs(TMEDA)-1-Cs-2,4,7,9-(SiMe3)4-2,4,7,9-C4B8H8]n (2). Single-crystal X-ray analysis showed 2 to be a polymeric structure in which each C4B8 carborane fragment serves as a ligand to two Cs atoms and is bonded to one through an open six-membered face and to the other via upper- and lower-belt M−H−E (where E = B, C) interactions.

Cesium-133 NMR Study of CsCd(SCN)3: Relative Orientation of the Chemical Shift and Electric Field Gradient Tensors

Single-crystal NMR was used to characterize the cesium-133 chemical shift and electric field gradient (EFG) tensors in CsCd(SCN)3. The principal axes of the two interaction tensors are not coincident, a reflection of the general positioning of cesium nuclei within the unit cell. Relative orientations of the chemical shift and EFG tensors have been determined, but assignment of the two magnetically distinct sites remains elusive. The span of the chemical shift, 94.4 ppm, is moderate in comparison with other cesium salts, and the magnitude of the nuclear quadrupole coupling constant, 148 kHz, is in the midrange of those reported for cesium compounds. Excellent agreement is observed between experimental 133Cs NMR spectra of a stationary powder sample and spectra calculated using NMR parameters from the single-crystal analysis. Moreover, simulations indicate that the static line shape is very sensitive to the relative orientation of the chemical shift and EFG tensors. Experimental 133Cs NMR spectra obtained w...

Structural Chemistry of Alkali Metal Phenylhyrazides

AbstractThe crystal and molecular structures of a series of N‐phenyl‐substituted lithium hydrazides were determined in order to investigate possible Li···Ph π interactions. These are pronounced when there are no donor molecules present to solvate the Li centers. An η6‐Li···Ph interaction is particularly distinct in tetrameric (Me3Si)2N–N(Ph)Li but also in trimeric Ph2N–N(SiMe3)Li Deprotonation of N,N′ ‐diphenylhydrazine with butyllithium in ether resulted in the formation of Ph(Li)N–N(Ph)Li · 2 LiNPh2 · 2 OEt2 with phenyl group migration and N–N bond cleavage by a redox process. An increase of the size of the cations, as shown for Ph(Me3‐Si)N–N(Ph)Na · NH3 and the caesium salt (Me3‐Si)2N–N(Ph)Cs · nTHF, results in increased coordination of the metal ion to the phenyl group. The caesium compound forms a three‐dimensional network. Channels along the c axis are partially filled with THF molecules.

Preparation and crystal structures of the new gold rich thioaurates Rb 4Au 6S 5 and Cs 4Au 6S 5

The new thioaurates Rb 4Au 6S 5 and Cs 4Au 6S 5 were prepared by reacting the binary alkali sulphides (Rb 2S and Cs 2S respectively) with stoichiometric amounts of gold and sulphur at 500°C. Rb 4Au 6S 5 is hexagonal, space group P 62c with a = 9.983(6) A ̊ , c = 9.950(7) A ̊ , Z = 2 ; Cs 4Au 6S 5 is trigonal, space group P31 m, with a = 10.243(3) A ̊ , c = 5.290(2) A ̊ , Z = 1 . The crystal structures were determined from single crystal data (Mo Kα) and refined to conventional R factors of 0.023 (203 F os, 28 variables) for Rb 4Au 6S 5 and 0.048 (453 F os 28 variables) for Cs 4Au 6S 5. Though both thioaurates are characterized by essentially linear chalcogen coordinations of the gold atoms, the topology of the complex anions formed is entirely different. Rb 4Au 6S 5 contains discrete anionic clusters [Au 6S 5] 4− of trigonal bipyramidal shape with μ 3-S on the apices and μ 2-S forming in the equatorial plane ( d( AuS) = 2.32 A ̊ , ∠SAuS = 170.6°). The gold atoms in the cluster form a trigonal prism with shortest AuAu contacts of 3.163 Å. The caesium compound, however, is characterized by corrugated layers 2 x -Au 6S 5 4−, consisting of condensed Au 12S 12 rings with μ 3-S at the nodal positions ( d( AuS) = 2.3 A ̊ , ∠SAuS = 177.8°). Each gold atom has one close homonuclear neighbour at a distance of only 3.013 Å. Irrespective of their fundamental topological differences, both structures can be coherently described with a geometrical model based on a mixed alkali-sulphur packing.

Ternary chlorides in the systems [formula omitted] and [formula omitted

The phase diagram of the system RbCl ErCl 3 was investigated by means of DTA and the system CsCl ErCl 3 was re-investigated. The existence of the caesium compounds Cs 3ErCl 6 (dimorphic), Cs 2ErCl 5, Cs 3Er 2Cl 7 and CsEr 2Cl 7 was confirmed. In the system RbCl ErCl 3 , there are two dimorphic, congruently melting compounds, Rb 3ErCl 6 and RbEr 2Cl 7. The incongruently melting compound Rb 2ErCl 5 (Cs 2DyCl 5 structure) is stable at temperatures higher than 348°C. The thermodynamic stabilities of the compounds were determined by solution calorimetry and e.m.f. measurements in a galvanic chlorine cell for solid electrolytes.

Directed cesium deposition into a large volume negative-ion source

A compact, safe system for directed cesium deposition into large volume sources is described. It consists of a small oven mounted on a feedthrough, which permits one to rotate and move the oven across the discharge chamber length or to remove it from the vacuum box to reload the oven. Special industrial pellets containing the cesium compound (30% of cesium chromate +70% titanium) were used for a pure cesium release. The pellets are insensitive to pollution by air and can provide the cesium release during several cycles of heating and cooling in long-term experiments. There was no ‘‘poisoning’’ impurities degassing (oxygen, water) during the standard oven operation. The Cs system was reliably operated for cesium deposition in multiampere negative-ion source experiments.

Zirconium Bromide Cluster Chemistry. A New Tunnel Structure in A5Zr6Br15Be (A = Rb, Cs)

Reactions in the ABr-ZrBr{sub 4}-Be systems (A = Cs, Rb) at {approximately}850 {degree}C yield phases with a new tunnel structure constructed from a [Zr{sub 6}(Be)Br{sub 12}]Br{sub 6/3} network. Crystal refinements are given for hexagonal Rb{sub 5.0(1)}Zr{sub 6}Br{sub 15}Be (P6{sub 3}22, Z = 2, a = 13.009(1{angstrom}, c = 12.060(1) {angstrom}, R/R{sub w} = 4.4/4.8%)) and Cs{sub 4.60(8)}Zr{sub 6}Br{sub 15}Be (P6{sub 3}, Z = 2, a = 13.105(1) {angstrom}, c = 12.156(1) {angstrom}, R/R{sub w} = 4.93/3.5%). The boride also exists in the rubidium system. The alkali-metal cations all exhibit fractional occupancies, most being located within or on the walls of the tunnels defined by the bridged cluster array, some with only three close bromine neighbors. Some two-site disorder appears in the rubidium structure (and persists in a marginal refinement of it in P6{sub 3}), while this problem is absent in the cesium compound refinement in the lower symmetry. These characteristics are common in cluster network structures containing larger cations. The formation of 16-e clusters is achieved even with the limited binding of some cations, the cesium salt showing only temperature-independent paramagnetism. This structure type defines a new, fifth type of a M{sub 6}X{sub 12}X{sub 6/2} network.

ChemInform Abstract: Cesium Compounds in Heterogeneous Catalysis, Fluorination and Organic Synthesis

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: New Ternary Compounds of Cesium and Elements of the 8th Transition Metal Group and the 5th Main Group.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Infrared Studies of Adsorbed Dinitrogen on Supported Ruthenium Catalysts for Ammonia Synthesis: Effects of the Alumina and Magnesia Supports and the Cesium Compound Promoter

Infrared Studies of Adsorbed Dinitrogen on Supported Ruthenium Catalysts for Ammonia Synthesis: Effects of the Alumina and Magnesia Supports and the Cesium Compound Promoter

Anionic polymerization of hexafluoro‐1,3‐butadiene and characterization of the polymer

AbstractThe present review describes the anionic polymerization of hexafluoro‐1,3 ‐butadiene (HFBD) and the characterization of the polymer. HFBD which is hardly polymerized under radical polymerization conditions yielded the polymer with cesium and rubidium compounds as initiators in moderate conditions. X‐ray photoelectron spectra and Raman spectra showed the structure of the polymer was similar to that of poly(hexafluoro‐2‐butyne). The polymerization mechanism, an addition reaction of the propagating anion to the 2‐carbon of HFBD followed by isomerization of the propagating end group to yield the polyene structure, is proposed from the results of the investigation of initiation reaction and the structure of the polymers. Poly(HFBD) shows higher thermostability than poly(tetrafluoroethylene) in spite of bearing functional ‐CC‐groups in the polymer main chain.

ChemInform Abstract: Cesium Compounds in Heterogeneous Catalysis, Fluorination and Organic Synthesis

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.