Alkali metal suboxides: Intermediates between salts and metals

Rubidium and cesium form stable metal-rich oxides (suboxides) which have been investigated by thermal and structural analysis. The compounds Rb₉O₂, Rb₆O (? Rb₉O₂Rb₃), Cs₁₁O₃, Cs₄O (? Cs₁₁O₃Cs₁₀), Cs₁₁O₃Rb, and Cs₁₁O₃Rb₇ contain the characteristic ionic clusters Rb₉O₂ and Cs₁₁O₃. A simple model for the chemical bonding in alkali metal suboxides is described and proved by measuring the electrical properties and optical reflectivities as well as photoelectron spectra of these compounds. It is found that cesium suboxides play an important role in widely used photocathodes and image converters of type S1. The IR sensitivity of these devices is explained on the basis of surface plasmon-enhanced photoemission.     

Ionization energies of cesium and cesium oxide clusters

The vertical ionization potentials of 7 cesium and 86 oxidized cesium clusters were determined using the technique of photoionization mass spectrometry. The spectra were obtained using a tunablecw dye laser for clusters in a mass range 1 to 2024 amu. The vertical ionization potentials (IP) are presented as a function of size and composition. The ionization energies of cesium clusters, Cs_n, decrease with cluster size. Unusually low IP were observed for the enneamer, Cs₉, and for the cesium monoxide Cs₁₁ O. With increasing oxidation of the cesium metal clusters the IP decreases (suboxides) reaches a minimum at Cs(Cs₂O)_n and then increases (superoxides).     

Über Suboxide der Alkalimetalle. 10. Das „komplexe Metall”︁ Cs11O3

The “Complex Metal” Cs₁₁O₃ Preparation, crystal growth, and structure investigation of the stoichiometric compound Cs₁₁O₃ are described. Cs₁₁O₃ consists of discrete clusters of the same stoichiometry. According to the interatomic distances bonds within the clusters are ionic whereas bonds between different clusters are metallic. The metallic conductivity as well as the temperature independent paramagnetism of Cs₁₁O₃ corresponds to this bonding sceme.     

Über Alkalimetall-Suboxide. VII. Das metallreichste Cäsiumoxid—Cs7O

On Alkali Metal Suboxides. VII. The Caesium Oxide with the Highest Metal Content, CS₇O Preparation, crystal growth and X-ray investigations with modified Guinier technique and single crystal diffractometer between 0° and ?170°C are reported for the compound Cs₇O. A simple nitrogen evaporator is described. — The structure of Cs₇O corresponds to the formula [Cs₁₁O₃]Cs₁₀. Single crystal investigations at ?20 and ?l70°C lead to nearly identical atomic distances within the “ionic cluster” Cs₁₁O₃, whereas distances between these clusters and within the oxygen free parts of the structure vary as in metallic caesium.     

Dynamic computer simulations of Cs incorporation in Si during low‐energy (0.2–3 keV) irradiation

The incorporation of Cs atoms in silicon was investigated by dynamic computer simulations using the Monte‐Carlo code T‐DYN that takes into account the gradual change of the target composition due to the Cs irradiation. The implantation of Cs atoms at normal incidence was studied for four energies (0.2, 0.5, 1, and 3 keV) and three different Cs surface‐binding energies U_Cs (0.4, 0.8, and 2.4 eV). The total implantation fluences were 2 × 10¹⁷ Cs cm^?2 for 0.2 keV, 1.5 × 10¹⁷ Cs cm^?2 for 0.5 keV, and 1 × 10¹⁷ Cs cm^?2 for 1 and 3 keV. At these values, a stationary state has been reached. The steady‐state Cs‐surface concentrations exhibit a pronounced dependence both on impact energy and U_Cs, varying between ～1 (at 0.2 keV and U_Cs = 2.4 eV) and ～0.13 (3 keV and U_Cs = 0.4 eV). Under equilibrium, the partial sputtering yield of Si, Y_Si, experiences little influence of U_Cs, but varies with the Cs energy: at U_Cs = 0.8 eV from 0.09 to 1.0 Si atoms/Cs projectile. For all irradiation conditions a strongly preferential sputtering of Cs atoms as compared to Si atoms is found, increasing from 1.8 (at 3 keV and U_Cs = 2.4 eV) to 13.3 (at 0.2 keV and U_Cs = 0.4 eV). Preferential sputtering of Cs increases with decreasing irradiation energy and decreasing U_Cs. Copyright © 2008 John Wiley & Sons, Ltd.     

Accessibility of Lithium Cations in VSH-2 Zeotype: Structural Effects and Formation of Protonated Water Clusters

The accessibility of lithium cations in microporous vanadosilicate VSH-2Cs of composition Cs₂(VO)(Si₆O₁₄) ⋅ 3H₂O was investigated by Single Crystal X-ray Diffraction, Attenuated Total Reflection Fourier Transformed Infrared Spectroscopy and Density Functional Theory calculations. The topological symmetry of VSH-2Cs is described in space group Cmca. After Li-ion exchange, the structure of VSH-2Li adopted monoclinic symmetry (space group C2/c) with a=17.011(2) Å, b=8.8533(11) Å, c=12.4934(16) Å, β=91.677(4)°, V=1880.7(4) ų. The strong interactions between Li ions and oxygen-framework atoms drive the main deformation mechanism, which is based on cooperative rotation of SiO₄ and VO₅ units around their oxygen atoms that behave as hinges. Exchange of Cs⁺ by Li⁺ is incomplete and accompanied by the formation of protonated species to counterbalance the electrostatic charge. The incorporation of protons is mediated by the presence of water dimers in the structural channels. H₂O molecules in VSH-2Li account not only as “space-fillers” after the removal of large Cs ions but also mediate proton transfer to compensate the negative charge of the host vanadosilicate framework.     

Keggin-type cesium salt of first series transition metal-substituted phosphomolybdates: one-pot easy synthesis,structural, and spectral analysis

The Keggin-type cesium salt of transition metal-substituted phosphomolybdates, Cs₅[PCo(H₂O)Mo₁₁O₃₉]?·?6H₂O (1) and Cs₅[PMn(H₂O)Mo₁₁O₃₉]?·?6H₂O (2), were synthesized from commercially available H₃PMo₁₂O₄₀. The compounds were characterized by thermal, structural, and spectroscopic techniques. X-ray structural analysis reveals that, in these isostructural disordered compounds, the transition metal (Co/Mn) and Mo atoms are distributed over 12 positions. The presence of Co/Mn atoms was confirmed by powder XRD, FT-IR, DR-UV-Vis, ESR, and ³¹P NMR studies.     

Optical response of cesium coated C60

Photoabsorption spectra are reported for Cs _n ⁺ and C₆₀Cs_n ⁺ + clusters for n=40, 60, 120 and 310. The spectra were obtained by heating the mass selected clusters in a beam by means of photoabsorption until they evaporated metal atoms. The resulting mass loss was observed in a time-of-flight mass spectometer. The plasmon-like resonance in pure Cs clusters shifts to lower energies with decreasing cluster size. The collective electronic excitations in clusters containing C₆₀ are split in energy as would be expected for fullerene molecules coated with layers of metal.     

Crystal chemistry peculiarities of Cs2Te4O12

The Raman and IR-absorption spectra of the Cs₂Te₄O₁₂ lattice are first recorded and interpreted. Extraordinary features observed in the structure and Raman spectra of Cs₂Te₄O₁₂ are analyzed by using ab initio and lattice-dynamical model calculations. This compound is specified as a caesium-tellurium tellurate Cs₂Te^IV(Te^VIO₄)₃ in which Te^IV atoms transfer their 5p electrons to [Te^VIO₄]₃⁶⁻ tellurate anions, thus fulfilling (jointly with Cs atoms) the role of cations. The Te^VI-O-Te^VI bridge vibration Raman intensity is found abnormally weak, which is reproduced by model treatment including the Cs⁺ ion polarizability properties in consideration.     

Der erste röntgenstrukturanalytisch charakterisierte Cs+ – „in cavity”︁ – Komplex eines einundzwanziggliedrigen Coronanden: (Maleonitril-Dithio[21]krone-7)caesium-hexachloroantimonat

First X-ray Crystallographic Characterized Cs⁺ ‘‘in cavity”︁”︁ Complex of a Twenty-one Membered Coronand: (Maleonitrile-Dithio[21]crown-7)caesium Hexachloroantimonate A new maleonitrile-crown dithioether, the maleonitrile-dithio[21]crown-7 (mn–21 S₂O₅), was synthesized by high dilution cyclization of (Z)-1,2-disodium-1,2-dicyanoethene-1,2-dithiolate ( 1 ) with 1,17-dichloro-3,6,9,12,15-pentaoxaheptadecane ( 2 ) in ethanol/water mixtures. Mn–21 S₂O₅ forms with CsSbCl₆ in MeCN/MeNO₂ a 1 : 1 complex [Cs(mn–21 S₂O₅)]SbCl₆. X-ray crystal analysis revealed that the complex cation [Cs(mn–21 S₂O₅)]⁺ is an ‘‘in cavity”︁”︁ complex in which the Cs⁺ ion is coordinated by seven donor atoms (five O and two S atoms). This is the first X-ray crystallographic evidence of Cs⁺ coordination by seven donors in a hole of a twenty-one membered coronand.     

Cs2Ba(O3)4 · 2 NH3, das erste ionische Erdalkaliozonid

Cs₂Ba(O₃)₄ · 2 NH₃, the First Ionic Alkaline Earth Metal Ozonide Cs₂Ba(O₃)₄ · 2 NH₃ is the first ionic ozonide containing an alkaline earth metal cation. Its synthesis has been achieved via partial cation exchange of CsO₃ dissolved in liquid ammonia. According to a single crystal X‐ray structure determination (Pnnm; a = 6.312(2) Å, b = 12.975(3) Å, c = 8.045(2) Å; Z = 2; R₁ = 4.6%; 848 independent reflections) ozonide anions, cesium cations and ammonia molecules form a CsCl‐type arrangement, where Cs⁺ and NH₃ occupy one half of the cation sites, each. Ba²⁺ is coordinated by four ozonide groups and two ammonia molecules. Because of a short hydrogen bond to one of the terminal oxygen atoms, the respective O–O‐distance in the ozonide ion is longer than the other. The shortest intermolecular O–O‐distance ever observed in ionic ozonides has been found in this compound, which can be taken as a first clue for the radical ozonide anion to dimerize like the isoelectronic SO₂^– does.     

Temperature dependence of nqr spectra in MSbBrF3 (M=Na,Cs, NH4) and Cs3Sb2Br9

Conclusions We have studied the temperature dependence of the NQR parameters of¹²³Sb and⁸¹Br in the range 77–360 K for the complexes of MSbBrF₃ (M=Na, Cs, NH₄) and Cs₃Sb₂Br₉. We have established the temperature regions for which piezoelectric properties appear in the crystal hydrate NaSbBrF₃.H₂O, and in the compounds MSbBrF₃ (M=Na, NH₄) and Cs₃Sb₂Br₉ anomalous changes appear in the dependences of the quadrupole coupling constant, the asymmetry parameter of the electric field gradient for the antimony atoms and the resonance frequency of the bromine atoms.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1501–1504, July, 1987.     

Polysulfonylamine. CLXIII [1] Kristallstrukturen von Metall‐di(methansulfonyl)amiden. 12 [1] Das orthorhombische Doppelsalz Na2Cs2[(CH3SO2)2N]4·3H2O: Ein dreidimensionales Koordinationspolymer aus (Caesium‐Anion‐Wasser)‐Schichten und intercalierten Natriumionen

Polysulfonylamines. CLXIII. Crystal Structures of Metal Di(methanesulfonyl)amides. 12. The Orthorhombic Double Salt Na₂Cs₂[(CH₃SO₂)₂N]₄·3H₂O: A Three‐Dimensional Coordination Polymer Built up from Cesium‐Anion‐Water Layers and Intercalated Sodium Ions The packing arrangement of the three‐dimensional coordination polymer Na₂Cs₂[(MeSO₂)₂N]₄·3H₂O (orthorhombic, space group Pna2₁, Z′ = 1) is in some respects similar to that of the previously reported sodium‐potassium double salt Na₂K₂[(MeSO₂)₂N]₄·4H₂O (tetragonal, P4₃2₁2, Z′ = 1/2). In the present structure, four multidentately coordinating independent anions, three independent aquo ligands and two types of cesium cation form monolayer substructures that are associated in pairs to form double layers via a Cs(1)—H₂O—Cs(2) motif, thus conferring upon each Cs⁺ an irregular O₈N₂ environment drawn from two N, O‐chelating anions, two O, O‐chelating anions and two water molecules. Half of the sodium ions occupy pseudo‐inversion centres situated between the double layers and have an octahedral O₆ coordination built up from four anions and two water molecules, whereas the remaining Na⁺ are intercalated within the double layers in a square‐pyramidal and pseudo‐C₂ symmetric O₅ environment provided by four anions and the water molecule of the Cs—H₂O—Cs motif. The net effect is that each of the four independent anions forms bonds to two Cs⁺ and two Na⁺, two independent water molecules are involved in Cs—H₂O—Na motifs, and the third water molecule acts as a μ₃‐bridging ligand for two Cs⁺ and one Na⁺. The crystal cohesion is reinforced by a three‐dimensional network of conventional O—H···O=S and weak C—H···O=S/N hydrogen bonds.     

Polysulfonylamine. CLXV [1] Kristallstrukturen von Metall‐di(methansulfonyl)amiden. 14 [1] Cs3Ag[(MeSO2)2N]4 und CsAg[(MeSO2)2N]2: Ein dreidimensionales und ein schichtförmiges Koordinationspolymer mit Bis(dimesylamido‐N)argentat‐Baugruppen

Polysulfonylamines. CLXV. Crystal Structures of Metal Di(methanesulfonyl)amides. 14. Cs₃Ag[(MeSO₂)₂N]₄ and CsAg[(MeSO₂)₂N]₂: A Three‐Dimensional and a Layered Coordination Polymer Containing Bis(dimesylamido‐N)argentate Building Blocks Serendipitous formation pathways and low‐temperature X‐ray structures are reported for the coordination compounds Cs₃A₂[AgA₂] ( 1 ) and Cs[AgA₂] ( 2 ), where A^— represents the pentadentate dimesylamide ligand (MeSO₂)₂N^—. Both phases (monoclinic, space group C2/c, Z′ = 1/2) contain inversion‐symmetric bis(dimesylamido‐N)argentate units displaying exactly linear N—Ag—N cores and short, predominantly covalent Ag—N bonds [ 1 : 213.5(2), 2 : 213.35(12) pm]; in each case, the coordination number of the silver ion is extended to 2 + 6 by four internal and two external Ag···O secondary interactions. The three‐dimensional coordination polymer 1 is built up from alternating layer substructures [{Cs(1)}{A}_4/2]^— with Cs(1) lying on twofold rotation axes and [{Cs(2)}₂{AgA₂}_4/4]⁺ with Cs(2) occupying general positions. Within the substructural layers, both types of cesium cation have approximately planar O₄ environments, whereas the final coordination spheres including interlayer bonds are extended to O₆ for Cs(1) and to O₈N for Cs(2). Compound 2 , in contrast, forms a genuine layer structure. The layers are constructed from Cs⁺ chains located on twofold rotation axes, alternating with [AgA₂]^— stacks reinforced by Ag···O secondary interactions and weak C—H···O hydrogen bonds; Cs⁺ is embedded in an O₈ environment. Both structures are pervaded by a three‐dimensional C—H···O network.     

A novel In3O16 fragment in Cs3In3(PO4)4

The double phosphate Cs₃In₃(PO₄)₄, prepared by a flux technique, features a fragment of composition In₃O₁₆ formed by three corner‐sharing InO₆ polyhedra. The central In atom resides on a twofold rotation axis, while the other two In atoms are on general positions. The O atoms in this fragment also belong to PO₄ tetrahedra, which link the structure into an overall three‐dimensional anionic In–O–P network that is penetrated by tunnels running along c. Two independent Cs⁺ cations reside inside the tunnels, one of which sits on a centre of inversion. In general, the organization of the framework is similar to that of K₃In₃(PO₄)₄, which also contains an In₃O₁₆ fragment. However, in the latter case the unit consists of one InO₇ polyhedron and one InO₆ polyhedron sharing an edge, with a third InO₆ octahedron connected via a shared corner. Calculations of the Voronoi–Dirichlet polyhedra of the alkali metals give coordination schemes for Cs of [9+2] and [8+4] ( symmetry), and for K of [8+1], [7+2] and [7+2]. This structural analysis shows that the coordination requirements of the alkali metals residing inside the tunnels cause the difference in the In₃O₁₆ geometry.     

Crystal structure of [Cs2Na(H2O)2(C23H16O3)(C23H15O3)3]

The crystal structure of a double salt of sodium and cesium with 2-diphenylacetyl-1,3-indandione of the composition [Cs₂Na(H₂O)₂(C₂₃H₁₆O₃)(C₂₃H₁₅O₃)₃] (I) was studied by X-ray crystallography. The crystals of I are monoclinic, Z = 2, space group P2₁/n, a = 10.212(2) ?, b = 23.479(5) ?, c = 15.638(3) ?, β = 98.30(03)°. The compound contains [Cs₂NaO₁₀] trimers, in which the central Na atom shares two edges with two Cs atoms through deprotonated bridging ligands. The trimers are connected to adjacent trimers by paired C-H...O contacts to form layers. The layers form an infinite open framework via hydrogen bonds between the oxygen atoms of keto groups of noncoordinated indandione moieties and water molecules that enter the cesium coordination sphere in trimers of the adjacent layers.     

TinO2和TinO2-(n=1-10)团簇的几何结构、电子和磁性质

基于密度泛函理论(DFT)的B3LYP方法, 研究了Ti_nO₂和Ti_nO₂^- (n=1-10)团簇的几何结构、电子结构以及磁性. 结果表明, 两个氧以分离的原子状态吸附在金属团簇的表面, 呈现出以一个钛原子为中心的O-Ti-O 的相邻吸附形式. 中性团簇和阴离子团簇的能量最低结构相似. 稳定性分析表明Ti_nO₂具有很高的稳定性, 特别是TiO₂和Ti₇O₂. 此外, 详细讨论了团簇的电离势、电子亲和能、电子解离能和能隙. 基于最低能量结构, 讨论了团簇的磁性, 发现电荷从Ti 原子向O原子转移, 并且电荷转移主要发生在Ti_nO₂的Ti-3d、Ti-4s和O-2p轨道. 磁性团簇中反铁磁序占据主导, 磁矩主要来源Ti-3d电子的贡献, 而两个氧原子的贡献非常小.     

Cs2Cr4O13: a new structure type among alkali tetrachromates

Dicaesium tetrachromium(VI) tridecaoxide, Cs₂Cr₄O₁₃, contains finite [Cr₄O₁₃]²⁻ anions composed of four corner‐linked CrO₄ tetrahedra. These anions are linked by Cs⁺ cations whose Cs—O bond lengths range between 3.015 (2) and ∼3.7 Å. Although Cs₂Cr₄O₁₃ is not isotypic with its NH₄, K or Rb analogs, the [Cr₄O₁₃]²⁻ anions in all these compounds exhibit a similar zigzag‐like geometry.     

Simulation of radioactive decay by barium substitution for cesium in sodium aluminum-iron phosphate glass

Simulation of ¹³⁷Cs radioactive decay to ¹³⁷Ba by an equiatomic substitution of Cs with Ba in a 30 Na₂O, 10 Cs₂O, 10 Al₂O₃, 10 Fe₂O₃, 40 P₂O₅ (mol%) glass was studied by X-ray diffraction, scanning electron microscopy, Fourier Transform Infrared spectroscopy, Mössbauer spectroscopy, and measurement of hydrolytic durability. Gradual Ba substitution for Cs yielded minor changes in the structural network but did not offer appreciable effect on phase composition and hydrolytic durability of the glasses.