Darstellung und Kristallstruktur von Rb2Sn3S7 · 2H2O und Rb4Sn2Se6

Preparation and Crystal Structure of Rb₂Sn₃S₇ · 2 H₂O and Rb₄Sn₂Se₆ Rb₂Sn₃S₇ · 2 H₂O has been prepared by hydrothermal reaction of SnS₂ and Rb₂CO₃ in an with H₂S saturated aqueous solution at 190°C. The crystal lattice contains chain anions [Sn₃S₇^2?] which display both SnS₄ tetrahedra and SnS₆ octahedra. Methanolothermal reaction of SnCl₂ with Se and Rb₂CO₃ at 145°C leads to the formation of Rb₄Sn₂Se₆ which contains edge-bridged bitetrahedral [Sn₂Se₆]^4? anions.     

Hochdrucksynthese und Struktur von Rb2PtH6 und Cs2PtH6, ternären Hydriden mit K2PtCl6-Struktur

High-pressure Synthesis and Structure of Rb₂PtH₆ and Cs₂PtH₆, Ternary Hydrides with K₂PtCl₆-Structure The ternary platinum hydrides Rb₂PtH₆ and Cs₂PtH₆ were synthesized by the reaction of rubidium hydride and cesium hydride, respectively, with platinum sponge under a hydrogen pressure above 1 500 bar at 500°C. X-ray investigations on powdered samples and elastic neutron diffraction experiments on the deuterated compounds at the time-of-flight spectrometer POLARIS led to their complete structure determination. Their atomic arrangements are isotypic with that of K₂PtCl₆ containing isolated [PtH₆]^2?-octahedra (space group: Fm3 m, Z = 4).     

Über Hexafluorovanadate(III). Cs2MVF6 und Rb2MVF6 (MTl,K und Na); mit einer Bemerkung über Na3VF6

On Hexafluorovanadates(III). Cs₂MVF₆ and Rb₂MVF₆ (M?Tl, K. and Na); with a Remark on Na₃VF₆ By heating the binary fluorides in a closed system we obtained Cs₂TlVF₆ (a = 9.23₄ Å), Cs₂KVF₆ (a = 9.04₇ Å), Rb₂KVF₆ (a = 8.85₅ Å) and Rb₂NaVF₆ (a = 8.46₈ Å), all cubic Elpasolithes of soft green colour as well as Cs₂NaVF₆ (hexagonal a = 6.24 Å, c = 30.58 Å, isotypic with Cs₂NaCrF₆) and Na₃VF₆ (monoclinic a = 5.51₃ Å, b = 5.72₁ Å, c = 7.96₃ Å, β = 90.4₇°, isotypic with Na₃AlF₆). VF₃ (3.0–296.2°K), Cs₂TlVF₆, Cs₂KVF₆ and Rb₂KVF₆ (all from 70–299°K) have been measured magnetically. The spectra of reflection in the range of 9 000 to 33 000 cm^?1 of VF₃ and the new quaternary fluorides are measured and discussed. The Madelung Part of Lattice Energy (MAPLE) is calculated and discussed.     

Darstellung und Kristallstruktur der Dialkalimetalltrichalkogenide Rb2S3, Rb2Se3, Cs2S3 und Cs2Se3

Preparation and Crystal Structure of the Dialkali Metal Trichalcogenides Rb₂S₃, Rb₂Se₃, Cs₂S₃, and Cs₂Se₃ Crystalline products were obtained by the reaction of the pure alkali metals with the chalcogens in the molar ratio 2:3 in liquid ammonia at pressures up to 3000 bar and temperatures around 600 K. The substances crystallize in the K₂S₃ type structure (space group Cmc2₁(NO. 36)). Unit cell constants see ?Inhaltsübersicht”?. The characteristic feature of this structure are bent polyanions X₃^2?:(X = S,Se). The new described compounds are compared with the other known alkali metal trichalcogenides.     

Cs6Ta4S22

The reaction of Cs₂S₃, Ta and S yields single crystals of the new caesium tantalum chalcogenide hexacaesium tetratantalum docosa­sulfide, Cs₆Ta₄S₂₂, which is isotypic with Rb₆Ta₄S₂₂ and the niobium compounds A₆Nb₄S₂₂ (A = Rb, Cs). The structure consists of discrete [Ta₄S₂₂]^6? anions and Cs⁺ cations.     

Einkristallstrukturbestimmungen der kubischen Hochdruckelpasolithe Rb2LiFeF6 und Cs2NaFeF6: Druck-Abstands-Paradoxon ohne Änderung der Koordinationszahl

Single Crystal Structure Determinations of the Cubic High Pressure Elpasolites Rb₂LiFeF₆ and Cs₂NaFeF₆: Pressure-Distance Paradox without Change of Coordination Number At single crystals of metastable high pressure phases of Rb₂LiFeF₆ (a = 824.4 pm) and Cs₂NaFeF₆ (a = 873,9 pm) the parameters of the cubic elpasolite structure (Fm3 m, Z = 4) were determined by X-ray methods. Compared to the 12L-structures of the normal pressure phases (R3 m, hex. Z = 6) only the distances within the 12-coordination, Rb? F = 291.7 resp. Cs? F = 309.9 pm, are compressed by 2–3%. However, the octahedral distances Fe? F = 194.6 pm and Li? F = 217.6 pm resp. Fe? F = 194.9 pm and Na? F = 242.0 pm, are enlarged by 1–4%, though there was no increase in coordination number. This paradoxical behaviour is discussed. Difference Fourier syntheses reveal disorder only for the lithium positions in Rb₂LiFeF₆, which are 30 pm off-center, corresponding to a splitting of distances Li? F into 188, 247 and 4 × 220 pm.     

Das erste zweikernige Oxoferrat(II): „Cs2K4[O2FeOFeO2]”︁

The First Binuclear Oxoferrate(II): ?Cs₂K₄[O₂FeOFeO₂]”? For the first time ?Cs₂K₄[Fe₂O₅]”? was obtained by annealing intimate mixtures of Cs₂O, K₂O, and CsFeO₂ (molar ratio Cs : K : CsFeO₂ 1.3 : 2.1 : 1) in a closed Fe-cylinder (74 d; 470°C) in the form of red single crystals. The structure determination (four-circle diffractometer, MoKα , 760 out of 857 I_o(h kl); R = 5.8%, R_w = 4.6%) confirms the space group C2/m; a = 707.4, b = 1138.5, c = 699.7 pm, β = 91.76°, Z = 2. Essential part of the structure is the binuclear, planar [O(1)₂Fe? O(2)? FeO(1)₂]^6? group which is for the first time observed with oxoferrates(II). Despite different space groups the crystal structure is related to that of Rb₂Na₄[Co₂O₅].     

Alkalimanganselenide und -telluride A2Mn3X4 – Synthese,Kristall- und Spinstruktur

Alkali Metal Manganese Selenides and Tellurides – Synthesis, Crystal and Spin Structures The compounds Rb₂Mn₃Se₄, Cs₂Mn₃Se₄, Rb₂Mn₃Te₄ and Cs₂Mn₃Te₄ were synthesized by the reaction of alkali metal carbonates with chalcogen and Mn or MnCO₃ in a stream of hydrogen charged with chalcogen. Structural investigations show that all compounds crystallize in isotypic atomic arrangements (Cs₂Mn₃S₄-type, space group Ibam, Z = 4). Additionally neutron diffraction experiments were carried out and yielded the spin structures of Rb₂Mn₃Se₄ and Cs₂Mn₃Se₄ (Shubnikov space group Ibam'). The structural related selenides ALiMnSe₂ and ALiZnSe₂ (A = K, Rb or Cs) were synthesized by analogous reactions. All these compounds are isotypic and crystallize in the BaZn₂P₂-structure type.     

Die Selektivität Kristalliner Cer(IV)-Phosphatsulfathydrate gegenüber Li+, Na+, K+, Rb+, Cs+ und NH in absolutem Methanol und absolutem Dimethylsulfoxid

Selectivity of Crystalline Ce^IV Phosphate Sulphate Hydrates for Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, and NH in Absolute Methanol and Absolute Dimethylsulphoxide The sequence of exchange capacities of Cerium(IV) phosphate sulphate hydrate (CePO₄)₂(HPO₄)_0.74(SO₄)_0.26 · 4,74 H₂O for alkalimetal ions and ammoniumions in absolute methanol at 25°C for the case of a small excess of the exchanger (in relation to the equivalent amount) is given by K⁺ > Rb⁺ ≥ NH₄⁺ > Cs⁺ > Na⁺ > Li⁺. Between the exchange capacity A of these cations and their ionic radii r (given by Ladd) exists the simple relation A = const./r. For Na⁺ the radius of the inner hydration shell must be considered. In absolute dimethyl-sulphoxide under the same conditions the sequence is K⁺ ≥ NH₄ > Rb⁺ > Na⁺ > Cs⁺ > Li⁺. For K⁺, NH₄, Rb⁺ and Cs⁺ the exchange capacity is given by A = const./r + const. · r⁴. The sequences of the alkali ions in both solvents are among the group of 13 sequences which are physicaly significant according to EISENMANNS 's theory. The results are compared with the observations made with water as solvent.     

Drei Alkalimetall‐Erbium‐Thiophosphate: Von der Schichtstruktur bei KEr[P2S7] zur dreidimensionalen Vernetzung in NaEr[P2S6] und Cs3Er5[PS4]6

Three Alkali‐Metal Erbium Thiophosphates: From the Layered Structure of KEr[P₂S₇] to the Three‐Dimensional Cross‐Linkage in NaEr[P₂S₆] and Cs₃Er₅[PS₄]₆ The three alkali‐metal erbium thiophosphates NaEr[P₂S₆], KEr[P₂S₇], and Cs₃Er₅[PS₄] show a small selection of the broad variety of thiophosphate units: from ortho‐thiophosphate [PS₄]^3? and pyro‐thiophosphate [S₃P–S–PS₃]^4? with phosphorus in the oxidation state +V to the [S₃P–PS₃]^3? anion with a phosphorus‐phosphorus bond (d(P–P) = 221 pm) and tetravalent phosphorus. In spite of all differences, a whole string of structural communities can be shown, in particular for coordination and three‐dimensional linkage as well as for the phosphorus‐sulfur distances (d(P–S) = 200 – 213 pm). So all three compounds exhibit eightfold coordinated Er³⁺ cations and comparably high‐coordinated alkali‐metal cations (CN(Na⁺) = 8, CN(K⁺) = 9+1, and CN(Cs⁺) ≈ 10). NaEr[P₂S₆] crystallizes triclinically ( ; a = 685.72(5), b = 707.86(5), c = 910.98(7) pm, α = 87.423(4), β = 87.635(4), γ = 88.157(4)°; Z = 2) in the shape of rods, as well as monoclinic KEr[P₂S₇] (P2₁/c; a = 950.48(7), b = 1223.06(9), c = 894.21(6) pm, β = 90.132(4)°; Z = 4). The crystal structure of Cs₃Er₅[PS₄] can also be described monoclinically (C2/c; a = 1597.74(11), b = 1295.03(9), c = 2065.26(15) pm, β = 103.278(4)°; Z = 4), but it emerges as irregular bricks. All crystals show the common pale pink colour typical for transparent erbium(III) compounds.     

Tetrahedral [Tt4]4– Zintl Anions Through Solution Chemistry: Syntheses and Crystal Structures of the Ammoniates Rb4Sn4·2NH3, Cs4Sn4·2NH3, and Rb4Pb4·2NH3

The crystalline isotypic solvates Rb₄Sn₄·2NH₃, Cs₄Sn₄·2NH₃, and Rb₄Pb₄·2NH₃ have been synthesized using the direct reduction of elemental tin or tetraphenyltin, respectively, with heavier alkali metals or the dissolution of the binary phase RbPb in liquid ammonia. These compounds contain the cluster ions [Sn₄]^4– or [Pb₄]^4– respectively. This is the first time that[Tt₄]^4– ions (Tt = tetrels) are detected as result of a solution reaction. The accommodation of the ammonia molecules, which build up ion‐dipole interactions to alkali metal cations, requires some modifications of the crystal structures compared to the binary phases RbSn, CsSn, and RbPb. The tetrahedral [Tt₄]^4– anions have a slightly lower coordination by Rb⁺ or Cs⁺ cations and, furthermore, the intercluster distances show a remarkable increase.     

Alkalikationen-Spezifität und Träger-Eigenschaften der Antibiotica Nigericin und Monensin

It is shown by means of IR. spectroscopic methods that nigericin and monensin have a cyclic conformation similar to that of their silver salts. Complex formation constants with sodium and potassium ions follow the selectivity order determined by EMF. measurements on liquid membranes: nigericin: K⁺ > Rb⁺ > Na⁺ > Cs⁺ > Li⁺; monensin: Na⁺ > K⁺ > Li⁺ > Rb⁺ > Cs⁺. Transport experiments show that nigericin and monensin facilitate the diffusion of potassiumions across model membranes, although in electrolytic transport experiments the permeability is not affected.     

Ein neues Oxouranat(VI): K2Li4[UO6]. Mit einer Bemerkung über Rb2Li4[UO6] und Cs2Li4UO6

A New Oxouranate(VI): K₂Li₄[UO₆]. With a Remark about Rb₂Li₄[UO₆] and Cs₂Li₄[UO₆] For the first time K₂Li₄UO₆ has been prepared by an exchange reaction of α-Li₆UO₆ with K₂O [K:U = 2.0:1, sealed au-tube; 750°C; 30 d single crystals; 680°C, 10 d powder]. The irregular shaped single crystals, which are of yellow color and sensitive to moisture crystallize in P3 m1 (Z = 1) with a = 619.27(5), c = 533.76(6) pm. The structure determination (PW 1100, AgKα R = 4.80%, R_w = 4.81% for 220 unique reflexions) reveals a new type of structure. The characteristic elements are the isolated group [UO₆] and the C.N. = 12 for K⁺. While Li(1) has a nearly regular square of 4 O^2? as coordination polyhedron, Li(2) is octahedrally surrounded. The Madelung Part of Lattice Energy (MAPLE) is calculated and discussed. In addition to K₂Li₄[UO₆] the new oxides Rb₂Li₄[UO₆] and Cs₂Li₄[UO₆] are prepared as pale yellow powders which are little sensitive to moisture (both: au-tube, 680°C, 10 d). According to powder datas both compounds are isotypic with K₂Li₄[UO₆] [Rb₂Li₄[UO₆]: a = 622.91(5), c = 535.93(6) pm; Cs₂Li₄[UO₆]: a = 626.70(6), c = 539.92(6) pm].     

Zur Darstellung und Kristallstruktur von Rb2Sb4S7

On the Preparation and Crystal Structure of Rb₂Sb₄S₇ Rb₂Sb₄S₇ was prepared by methanolothermal reaction of Rb₂CO₃ with Sb₂S₃ at a temperature of 140°C. An X-ray structural analysis demonstrated that the compound contains polythioantimonate(III) anions (Sb₄S₇^2?)_n, for which the basic element is a ψ-trigonal (SbS₄)-bipyramid. Edge bridged SbS₄ polyhedra build vierer single chains (Sb₄S₈^4?)_n, which are linked via two symmetry related S atoms with neighbouring chains so that an (Sb₄S₇^2?)_n sheet is formed.     

Über Oxostannate(II). III. K2Sn2O3, Rb2Sn2O3 und Cs2Sn2O3 – ein Vergleich

On Oxostannates(II). III. K₂Sn₂0₃, Rb₂Sn₂0₃, and Cs₂Sn₂O₃ – a Comparison Hitherto unknown Rb₂Sn₂O₃ has been obtained by heating of mixtures of binary oxides [RbO_0.48 + SnO, Rb:Sn = 1.1:1, Al₂O₃?cylinders, Ar] as deep yellow powder or deep yellow single crystals. It is isotypic to K₂Sn₂O₃, R3 m-D with a = 6.086 Å, c = 15.101 Å, Z = 3, d_calc = 4.69, d_obs = 4.64 g X cm^?3. For 260 hkl it is R = 5.2₇% and R_w = 5.0₉% (MoKα, 4-circle diffractometer data). The structure of K₂Sn₂O₃ and Rb₂Sn₂O₃ is compared with that of Cs₂Sn₂O₃. For both types Effektive Coordination Numbers, ECoN, and the Madelung Part of Lattice Energy, MAPLE, have been calculated.     

Directed Dehydration of Na4Sn2S6 ⋅ 5H2O Generates the New Compound Na4Sn2S6: Crystal Structure and Selected Properties

The new thiostannate Na₄Sn₂S₆ was prepared by directed crystal water removal from the hydrate Na₄Sn₂S₆ ⋅ 5H₂O at moderate temperatures. While the structure of the hydrate comprises isolated [Sn₂S₆]⁴⁻ anions, that of the anhydrate contains linear chains composed of corner-sharing SnS₄ tetrahedra, a structural motif not known in thiostannate chemistry. This structural rearrangement requires bond-breakage in the [Sn₂S₆]⁴⁻ anion, movements of the fragments of the opened [Sn₂S₆]⁴⁻ anion and Sn−S−Sn bond formation. Simultaneously, the coordination environment of the Na⁺ cations is significantly altered and the in situ formed NaS₅ polyhedra are joined by corner- and edge-sharing to form a six-membered ring. Time-dependent in situ X-ray powder diffraction evidences very fast rehydration into Na₄Sn₂S₆ ⋅ 5H₂O during storage in air atmosphere, but recovery of the initial crystallinity requires several days. Impedance spectroscopy demonstrates a mediocre room-temperature Na⁺ ion conductivity of 0.31 μS cm⁻¹ and an activation energy for ionic transport of E_a=0.75 eV.     

Kristallstruktur und Schwingungsspektren der Caesium- und Kalium-Hexathiometadiphosphate Cs2P2S6 und K2P2S6

Crystal Structure and Vibration Spectra of Cs₂P₂S₆ and K₂P₂S₆ . Cs₂P₂S₆ and K₂P₂S₆ crystallize in the orthorhombic system, space group Immm, Z = 2 with the lattice constants . The compounds are isotypic to Tl₂P₂S₆. In the structure there are discrete P₂S₆^2? anions. Two PS₄ tetrahedra are connected by a common edge to hexathiometadiphosphate groups. The far infrared, infrared, and Raman spectra of these compounds are assigned on the basis of P₂S₆^2? units with D_2h symmetry in analogy to the isoelectronic Al₂Cl₆. The melting points are 440 ± 10°C for Cs₂P₂S₆ and 508 ± 10°C for K₂P₂S₆.     

Thiosilicate der Selten‐Erd‐Elemente: III. KLa[SiS4] und RbLa[SiS4] – Ein struktureller Vergleich

Thiosilicates of the Rare‐Earth Elements: III. KLa[SiS₄] and RbLa[SiS₄] – A Structural Comparison Pale yellow, platelet shaped, air‐ and water resistant single crystals of KLa[SiS₄] derived from the reaction of lanthanum (La) and sulfur (S) with silicon disulfide (SiS₂) in a molar ratio of 2 : 3 : 1 with an excess of potassium chloride (KCl) as flux and source of potassium ions in evacuated silica ampoules at 850 °C within seven days. The analogous reaction utilizing a melt of rubidium chloride (RbCl) instead also leads to yellow comparable single crystals of RbLa[SiS₄]. The potassium lanthanum thiosilicate crystallizes monoclinically with the space group P2₁/m (a = 653.34(6), b = 657.23(6), c = 867.02(8) pm, β = 107.496(9)°) and two formula units per unit cell, while the rubidium lanthanum thiosilicate has to be assigned orthorhombically with the space group Pnma (a = 1728.4(2), b = 667.23(6), c = 652.89(6) pm) and four formula units in its unit cell. In both compounds the La³⁺ cations are surrounded by 8+1 sulfide anions in the shape of tricapped trigonal prisms. The Rb⁺ cations in RbLa[SiS₄] show a coordination number of 9+2 relative to the S^2? anions, which form pentacapped trigonal prisms about Rb⁺. This coordination number, however, is apparently too high for the K⁺ cations in KLa[SiS₄], so that they only exhibit a bicapped trigonal prismatic environment built up by eight S^2? anions. The isolated thiosilicate tetrahedra [SiS₄]^4? of the rubidium compound are surrounded by La³⁺ both edge‐ and face‐capping, but terminal as well as edge‐ and face‐spanning by Rb⁺. In the potassium compound there is no change for the La³⁺ environment about the [SiS₄]^4? tetrahedra, but the K⁺ cations are only able to attach terminal and via edges. The whole structure is built up by anionic equation/tex2gif-stack-1.gif{La[SiS₄]}^? layers that are separated by the alkali metal cations. In direct comparison the two thiosilicate structures can be regarded as stacking variants.     

Selenostannate aus wäßriger Lösung Darstellung und Struktur von Na4Sn2Se6 · 13 H2O

Selenostannates from Aqueous Solution, Preparation and Structure of Na₄Sn₂Se₆ · 13 H₂O The dimeric anion Sn₂Se₆^4? is prepared by reaction of SnSe₂ with alkali metal selenide in a 1:1 molar ratio. The orange-red hydrated sodium salt Na₄Sn₂Se₆ · 13 H₂O is characterized by a complete X-ray structure analysis and by its vibrational spectrum. The compound is triclinic (P1 ) with a = 7.106(2), b = 10.330(2), c = 19.009(4) Å, α = 78.60(2), β = 85.66(2), γ = 72.85(2)° (?130°C), Z = 2. It contains isolated Sn₂Se₆^4? anions consisting of two edge-sharing tetrahedra [Sn? Se 2.456(1)–2.589(1) Å] which are in contact to the hydrated Na⁺ ions within an extensive hydrogen bridge system. Raman-active vibrations are observed at 260, 202, 188, 116, 93, and 78 cm^?1.     

Über Glasbildung und Eigenschaften von Chalkogenidsystemen. XIII. Über die Verbindungen Na6Ge2S6 · 4 CH3OH und Na6Ge2Se6 · 4 CH3OH

Glass Formation and Properties of Chalcogenide Systems. XIII. On the Compounds Na₆Ge₂S₆ · 4 CH₃OH and Na₆Ge₂Se₆ · 4 CH₃OH The glasses Ge₂S₃ and Ge₂Se₃ are soluble in solutions of Na₂S or Na₂Se in CH₃OH forming Na₆Ge₂S₆ · 4 CH₃OH and Na₆Ge₂Se₆ · 4 CH₃OH. On heating the CH₃OH-free substances are formed. From the i.r. and Raman spectra can de seen that the structure of the ions Ge₂S, Ge₂Se, P₂S₆^4?, and of Si₂Cl₆ is of the same type. The formation of the compounds can be regarded as a chemical proof for the existence of [Ge₂S₆] and [Ge₂Se₆] units as structural groups in the glasses Ge₂S₃ and Ge₂Se₃.