Interpretation of X-ray Diffraction from Liquid Alkali Metals

The new alkaline metal arsenates(III) were synthesized at a temperature of 500 °C via reaction of stoichiometric mixtures of the elemental alkali metals A and As2O3. In the crystal structures of the four title compounds, which have been determined by single crystal x-ray diffraction, the As(III) atoms are in ψ-tetrahedral coordination by oxygen exclusively. In NaAsO2 (orthorhombic, space group Pbcm, a = 1429.6(9), b = 677.3(3), c = 509.1(2) pm, Z = 8) and the compounds AAsO2 (A = K/Rb, orthorhombic, space group Pbcm, a = 715.1(2)/729.7(5), b =748.0(1)/775.2(5), c = 539.20(17)/541.1(3) pm, Z = 4) the AsO3 ψ-tetrahedra are condensed to form zig-zag chains [AsOO2/2]−. In the Cs phase Cs3As5O9 with a lower alkaline metal content (trigonal, space group P31m, a = 845.5(3), c = 602.6(2) pm, Z = 1) the two crystallographically independent ψ-tetrahedra AsO3/2 and AsOO2/2 are connected in a 2:3 ratio to give polar sheets [As5O9]3−.

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Die neuen Oxobismutate(III) Cs6Bi4O9, K9Bi5O13 und A2Bi4O7 (A = Rb, Cs) / The New Oxobismutates(III) Cs6Bi4O9, K9Bi5O13 and A2Bi4O7 (A = Rb, Cs)

Zeitschrift für Naturforschung B ◽

10.1515/znb-2002-1003 ◽

2002 ◽

Vol 57 (10) ◽

pp. 1090-1100

Author(s):

Franziska Emmerling ◽

Caroline Röhr

Keyword(s):

Single Crystal ◽

Crystal Structures ◽

Alkali Metals ◽

Mixed Valence ◽

Three Dimensional ◽

X Ray Diffraction ◽

X Ray ◽

Trigonal Bipyramidal ◽

Mixed Valence Compound

AbstractThe title compounds were synthesized at a temperature of 700 °C via oxidation of elemental Bi with the hyperoxides AO2 or via reaction of the elemental alkali metals A with Bi2O3. Their crystal structures have been determined by single crystal x-ray diffraction. They are dominated by two possible surroundings of Bi by O, the ψ-trigonal-bipyramidal three (B) and the ψ-tetrahedral four (T) coordination. Cs6Bi4O9 (triclinic, spacegroup P1̄, a = 813.82(12), b = 991.60(14), c = 1213.83(18) pm, α = 103.658(2), β = 93.694(3), γ = 91.662(3)°, Z = 2) contains centrosymmetric chain segmentes [Bi8O18]12- with six three- (T) and two four-coordinated (B) Bi(III) centers. K9Bi5O13 (monoclinic, spacegroup P21/c, a = 1510.98(14), b = 567.59(5), c = 2685.6(2) pm, β = 111.190(2)°, Z = 4) is a mixed valence compound with isolated [BivO4]3- tetrahedra and chains [BiIII4O9]6- of two T and two B coordinated Bi. In the compounds A2Bi4O7 (A = Rb/Cs: monoclinic, C2/c, a = 2037.0(3) / 2130.6(12), b = 1285.5(2) / 1301.9(7), c = 1566.6(2) / 1605.6(9) pm, β = 94.783(3) / 95.725(9)°, Z = 8) ribbons [Bi4O6O2/2]2- are formed, which are condensed to form a three-dimensional framework.

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Synthesis and Characterization of Large Single Crystals of Silicon and Germanium Clathrate-II Compounds and a New Tin Compound with Clathrate Layers

MRS Proceedings ◽

10.1557/proc-626-z13.5 ◽

2000 ◽

Vol 626 ◽

Cited By ~ 2

Author(s):

Svilen Bobev ◽

Slavi C. Sevov

Keyword(s):

Alkali Metal ◽

Single Crystals ◽

Alkali Metals ◽

Measured Temperature ◽

X Ray Diffraction ◽

X Ray ◽

Mixed Alkali ◽

Pauli Paramagnetism ◽

Silicon And Germanium

ABSTRACTWe have synthesized large single crystals of clathrate-II compounds with frameworks of silicon and germanium by employing mixed alkali metal countercations. The combinations of alkali metals are rationally selected in order to fit the different cages of the clathrate-II structure. This approach leads to the following stoichiometric and fully “stuffed” compounds: Cs8Na16Si136, Cs8Na16Ge136, Rb8Na16Si136 and Rb8Na16Ge136. The structures and the corresponding Si-Si and Ge-Ge distances are elucidated and established with high accuracy from extensive single crystal X-ray diffraction work. The compounds are stoichiometric, metallic, and are very stable at a variety of extreme conditions such as heat, concentrated acids, hydrothermal treatment etc. No evidence was found for vacancies in the silicon and germanium networks or partial occupancies of the alkali metal sites. The stoichiometry of these fully “stuffed” clathrates is consistent with the measured temperature independent Pauli paramagnetism, supported also by the conductivity measurements on single crystals and thermopower measurements on pellets. A new compound with novel clathrate-like structure forms when small and large cations are combined with tin. The new materials, A6Na18Sn46 (A = K, Rb, Cs), are made of clathrate layers and the interlayer space filled with Sn4-tetrahedra and alkali-metal cations. Its formula can be rationalized as A6Na6Sn34 + 3·Na4Sn4 (one clathrate layer and three tin tetrahedra). The compound is stable in air and is being currently tested at other conditions. Detailed measurements of its transport properties are under way.

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Multinuclear NMR and Powder X-ray Diffraction Studies of Si and Sn Clathrates of Alkali Metals: Vacancies, Disorder and Knight Shifts

MRS Proceedings ◽

10.1557/proc-691-g14.4 ◽

2001 ◽

Vol 691 ◽

Author(s):

Michael J. Ferguson ◽

Igor L. Moudrakovski ◽

Christopher I. Ratcliffe ◽

John S. Tse

Keyword(s):

Solid State ◽

Solid State Nmr ◽

Nmr Spectra ◽

Alkali Metals ◽

Rietveld Analysis ◽

X Ray Diffraction ◽

X Ray ◽

Multinuclear Nmr ◽

Binary Metal ◽

Knight Shifts

ABSTRACTThe Structure I type binary metal clathrates of K/Si, Rb/Si and Cs/Sn have been synthesised and studied by powder X-ray diffraction and solid state NMR. Rietveld analysis shows that in all three materials some of the cages are empty, and that in the Cs/Sn clathrate there are vacancies in the Sn framework. The NMR results yield Knight shifts for 29Si and 39K and confirm that the Cs/Sn clathrate is not conducting. Many of the features of the NMR spectra can be understood in terms of the distributions of atom vacancies.

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X-ray and neutron diffraction from liquid alkali metals

Acta Crystallographica Section A ◽

10.1107/s0567739479001042 ◽

1979 ◽

Vol 35 (3) ◽

pp. 431-445 ◽

Cited By ~ 90

Author(s):

M. J. van der Huijben ◽

W. Lugt

Keyword(s):

Neutron Diffraction ◽

Alkali Metals ◽

X Ray ◽

Liquid Alkali Metals

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A Study of Chemical Reactions in Molton Sodium-Potassium Hydrogen Sulfate Eutectic. IV. The Reaction of Eight Oxalates

Australian Journal of Chemistry ◽

10.1071/ch9851123 ◽

1985 ◽

Vol 38 (7) ◽

pp. 1123

Author(s):

JO Sabato ◽

SA Tariq

Keyword(s):

Alkali Metals ◽

Alkaline Earth ◽

Hydrogen Sulfate ◽

X Ray Diffraction ◽

Metal Sulfate ◽

Chemical Methods ◽

Sodium Potassium ◽

X Ray ◽

Potassium Hydrogen ◽

Wet Chemical

The reactions of oxalates of ammonium, alkali metals (Li, Na and K) and alkaline earth metals (Mg, Ca, Sr and Ba ) with sodium-potassium hydrogen sulfate eutectic were investigated. Oxalic acid was found to be an intermediate product in all these reactions. Final products of the reactions as determined by thermogravimetry , differential thermal analysis, X-ray diffraction, infrared and 'wet' chemical methods consisted of a mixture of H2O, CO, CO2 and the corresponding metal sulfate. The stoichiometries of the reactions were elucidated.

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Synthesis and characterization of N-silylated, C1-symmetric benzamidinates of lithium, sodium, and tin(II)

Canadian Journal of Chemistry ◽

10.1139/v05-250 ◽

2006 ◽

Vol 84 (2) ◽

pp. 269-276 ◽

Cited By ~ 12

Author(s):

Floria Antolini ◽

Peter B Hitchcock ◽

Alexei V Khvostov ◽

Michael F Lappert

Keyword(s):

Nmr Spectra ◽

Alkali Metals ◽

Membered Ring ◽

Molecular Structures ◽

Synthesis And Characterization ◽

Neutral Ligand ◽

X Ray Diffraction ◽

X Ray ◽

Ligand Free

The synthesis and characterization of complexes obtained from the reactions between Li[N-t-Bu(SiMe3)] (A) or the sodium analogue Na[N-t-Bu(SiMe3)] (B) and the cyanoarene RCN (R = Ph or 4-MeOC6H4) are discussed. These are the THF adduct [Li{µ-cis-N(t-Bu)C(Ph)N(SiMe3)}(THF)]2 (1), the TMEDA adduct Li[N(t-Bu)C(Ph)N(SiMe3)](TMEDA) (2), the neutral ligand-free lithium benzamidinate Li[N(t-Bu)C(C6H4OMe-4)N(SiMe3)] (3), and the THF adduct Li[N(t-Bu)C(C6H4OMe-4)N(SiMe3)](THF) (3a). The preparation and structure of the crystalline compound [Na{µ-cis-N(t-Bu)C(Ph)N(SiMe3)}(OEt2)]2 (4) is described. From the lithium benzamidinate 1 and Sn(II) chloride the tin(II) complex [Sn{N(t-Bu)C(Ph)N(SiMe3)}2] (5) was obtained. The molecular structures of the crystalline compounds 1, 4, and 5 were established by X-ray diffraction. In 1 and 4 the benzamidinato ligand is both chelating and bridging, with the Me3Si-substituted nitrogen atom as the bridging site. The central planar (MN)2 four-membered ring is a rhombus in 1, with almost equal LiN bond lengths, whereas in 4 the bonds to Na(1) are significantly longer than those to Na(2). In 5, the ligand is N,N′-chelating. Key words: alkali metals, tin(II), benzamidinates, NMR spectra, X-ray structures.

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Changes in Physico-Chemical and Catalytic Properties of Synthetic Erionite after Various Treatment

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19920845 ◽

1992 ◽

Vol 57 (4) ◽

pp. 845-852 ◽

Cited By ~ 2

Author(s):

Pavol Hudec ◽

Jozef Novanský ◽

Anna Bučinská ◽

Štefan Morávek ◽

Zdenek Židek

Keyword(s):

Alkali Metals ◽

Catalytic Properties ◽

X Ray Diffraction ◽

Ammonium Ions ◽

Pore System ◽

X Ray ◽

Physico Chemical ◽

Metals Extraction ◽

Hcl Solution ◽

Secondary Pore

Influence of decationization by ammonium ions and dealumination by HCl as well as calcination under self-steaming conditions at 1053 K with following treatment by ammonium ions or by HCl solution on the extent of alkali metals extraction was studied together with surface, sorption, acidic and catalytic properties of synthetic erionite. Samples were also characterized by X-ray diffraction spectra and IR skeletal vibration spectra. Results showed increasing catalytic activity and acidity after thermal treatment, followed by ion exchange with HCl or ammonium ions, which can be connected with deeper substitution of potassium cations of erionite. At the same time by the treatment under self-steaming conditions, as a result of framework dealumination, the zeolite obtained a secondary pore system, which resulted in increasing sorption capacity for aromatics, suppression of coking during o-xylene conversion and also increased diffusion of Hammet indicators into the zeolite.

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Synthesis of New Alkali-Metal-Intercalated Layered-Silicate Compounds and Their Magnetic Properties

MRS Proceedings ◽

10.1557/proc-453-95 ◽

1996 ◽

Vol 453 ◽

Cited By ~ 2

Author(s):

N. Wada ◽

Hideaki Okui ◽

Yasuyuki Omura ◽

Akihiko Fujiwara ◽

Hiroyoshi Suematsu ◽

...

Keyword(s):

Alkali Metals ◽

Layered Silicate ◽

Metallic Silver ◽

X Ray Diffraction ◽

Temperature Zone ◽

X Ray ◽

Intercalated Compounds ◽

Field Evidence ◽

Pauli Paramagnetism ◽

Two Temperature

AbstractSingle crystals and powders of vermiculite are dehydrated and then intercalated with alkali metals (K and Rb) using a two-temperature-zone furnace. The samples, originally transparent, exhibit metallic silver color upon intercalation. Our x-ray diffraction experiments indicate that the c-axis lattice constant becomes smaller after the intercalation process. A SQUID magnetometer is used to measure the magnetization of the samples as functions of temperature and magnetic field. Evidence for Pauli paramagnetism and enhancement of ferromagnetism are found in the Rb- and K-intercalated compounds, in addition to Curie paramagnetism due to iron impurities in the original vermiculite.

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The structure of H3O+-exchanged pharmacosiderite

Mineralogical Magazine ◽

10.1180/minmag.2010.074.3.487 ◽

2010 ◽

Vol 74 (3) ◽

pp. 487-492 ◽

Cited By ~ 11

Author(s):

S. J. Mills ◽

S. L. Hager ◽

P. Leverett ◽

P. A. Williams ◽

M. Raudsepp

Keyword(s):

Crystal Structure ◽

United Kingdom ◽

Single Crystal ◽

Alkali Metals ◽

Structure Type ◽

Sensu Stricto ◽

X Ray Diffraction ◽

X Ray ◽

Hydronium Ion ◽

A Site

AbstractThe crystal structure of H3O+-exchanged pharmacosiderite (pharmacosiderite is KFe4(AsO4)3(OH)4·nH2O, sensu stricto) has been determined by single-crystal X-ray diffraction and refined to R1 = 0.0418. H3O+-exchanged pharmacosiderite, (H3O+)Fe4(AsO4)3(OH)4·4.5H2O, is cubic, space group Pm, with a = 7.982(9) Å, V = 508.5(9) Å3 and Z = 1. The structure broadly conforms to that of the general pharmacosiderite structure type, with the hydronium ion generated by partial protonation of a site corresponding to a molecule of water of crystallization and its symmetry-related equivalents. In addition, the structure of a “pharmacosiderite” from Cornwall, United Kingdom, in which no alkali metals could be detected, has been re-evaluated and found to be consistent with that of the H3O+- exchanged structure. Its composition is (H3O+)Fe4(AsO4)3(OH)4·4H2O, with the partially occupied water found for the exchanged structure at (½, ½, ½) being absent in this case.

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