K2Ag4Se3, Darstellung und kristallstruktur

By the reaction of potassium carbonate with silver and selenium at 1000 °C, we obtained the ternary compound K₂Ag₄Se₃. Single-crystal investigations revealed the monoclinic space group C2/m; the cell constants are a = 1777.0(10)pm, b = 444.7(3)pm, c = 1185.6(3)pm and β = 108.4(1)°. The atomic arrangement is isotypic with that of K₂Ag₄S₃. The shortest distances between the silver atoms are only a little larger than those in the structure of the element and their geometrical arrangement shows a slightly distorted fragment framework of the f.c.c. lattice.     

Na3AsSe3 und K3AsSe3 – Darstellung und Kristallstruktur

Na₃AsSe₃ and K₃AsSe₃ – Synthesis and Crystal Structure The compounds Na₃AsSe₃ and K₃AsSe₃ were synthesized by heating mixtures of As₂O₃ and the respective alkalicarbonate in a stream of hydrogen saturated by selenium at 750 °C. The structures were determined from X-ray single-crystal diffractometer data. Both compounds crystallize isostructural with Na₃AsS₃, space group P2₁3, Z = 4, lattice constants a = 8,925 (1) Å for Na₃AsSe₃ and a = 9,710(1) Å for K₃AsSe₃.     

Darstellung und Kristallstruktur von Pb2(NO2)(NO3)(SeO3)

Crystals of Pb₂(NO₂)(NO₃)(SeO₃) were synthesized by partial reduction of nitrate ions with native copper under hydrothermal conditions. The crystal structure [a=5.529 (2) Å,b=10.357 (3) Å,c=6.811 (2) Å, space group Pmn2₁,Z=2] was determined from 1 707 independent X-ray data up to sin /=0.81 Å^–1 and was refined toR _w =0.028. The Pb(1) atom is ten coordinated to O atoms [Pb(1)-O from 2.51 Å to 2.96 Å], the Pb(2) atom has three nearest O atoms [Pb(2)-O=2.41 Å (1 ×) and 2.45 Å (2 ×)] and six next-nearest O atoms [Pb(2)-O from 2.80 Å to 3.22 Å].

Herrn Prof. Dr.K. Komarek zum 60. Geburtstag gewidmet.     

Darstellung und Struktur von K3(SH)TeS3

Preparation and Crystal Structure of K₃(SH)TeS₃ K₃(SH)TeS₃ has been prepared and structurally characterized. It crystallizes cubic with a = 1270(2) pm, space group 143m. The SH- Ions are surrounded by an octahedron of K⁺ ions. The TeS₃^2?. anions form flat trigonal pyramids with Te? S distances of 234.8(2) pm.     

Darstellung und Kristallstruktur von K4[SnO3]

Preparation and Crystal Structure of K₄[SnO₃] K₄[SnO₃] crystallizes with the K₄[PbO₃] structure in the orthorhombic spacegroup Pbca (No. 61) with the lattice constants a = 652.2(3) pm, b = 1 112.1(5) pm and c = 1 893.7(7) pm. In the structure isolated ψ-tetrahedral anions [Sn^IIO₃]^4? are arranged in layers perpendicular [001]. The structure of K₄[SnO₃] will be compared with those of stannates and plumbates of composition A₄[M^IIO₃] (A = Na, K, Rb, Cs) and with the known potassium stannates(II).     

Darstellung und Kristallstruktur von K3La(NH2)6

Preparation and Crystal Structure of K₃La(NH₂)₆. Single crystals of K₃La(NH₂)₆ were obtained by the reaction of the metals (3 K + 1 La) during five days at 200°C and 4000 atm NH₃ pressure. The compound crystallizes monoclinic with a = 6.74, b = 11.67, c = 7.23 Å and β = 108.1°; the space group is C2/m (No. 12). The lattice contains 2 formula units. The amide ions are arranged in a strongly distorted cubic closepacking. All cations occupy edging anion-octahedra.     

Tief-Tl3PbBr5, Darstellung und Kristallstruktur

Low-Tl₃PbBr₅, Preparation and Crystal Structure Single crystals of the low temperature modification of Tl₃PbBr₅ were prepared below the upper stability border with 239°C. X-ray investigations yield the following crystallografic data: orthorhombic system, space group P2₁2₁2₁, crystal axis a = 15.399, b = 9.063, c = 8.532 Å. The crystal structure is described in relation to the high temperature modification. Conductivity measurements aimed to demonstrate the diffusion of metal ions during phase transition.     

Darstellung und Kristallstruktur eines Kaliumimidonitridosilicats,K3Si6N5(NH)6

Preparation and Crystal Structure of a Potassium Imidenitridesilicate, K₃Si₆N₅(NH)₆ Crystals of K₃Si₆N₅(NH)₆ sufficient for an X-ray structure determination are formed when potassium and silicium react with supercritical ammonia under the following conditions K:Si = 1:1, P(NH)₃ = 6 kbar, T = 500°C within 3 days in a temperature gradient within the autoclaves used. The compound crystallizes cubic with a = 10.789(4) Å, the space group is P4₃32 (with tests for enantiomorphous pairs) and the cell contains four formula units. The positions of H-atoms are determined. The following data characterize the structure determination: N(F) = 518 with 517 ≥ 3σ(F₀²) N(Variables) = 37, R = 0.019 resp. R_w = 0.017. The conditions for the synthesis of the compound and its structure are discussed with respect to Si₃N₄ and Si₂N₂(NH).     

Darstellung,Eigenschaften und Schwingungsspektren von K[SbCl5N3], K[SbCl5NCO] und K[SbCl5CN]

Preparation, Properties and Vibrational Spectra of K[SbCl₅N₃], K[SbCl₅NCO] and K[SbCl₅CN]. KaN₃, KNCO and KCN react in liquid SO₂ with stoichiometric amounts of SbCl₅ yielding K[SbCl₅N₃] K[SbCl₅NCO], and K[SbCl₅CN], respectively. NaN₃ and SbCl₅ form Na[SbCl₅N₃] which contains impurities of Na[SbCl₆]. With more SbCl₅ (SbCl₄N₃)₂ is obtained from K[SbCl₅N₃] and (SbCl₄NCO)₂ from K[SbCl₅NCO], [BCl₂N₃]₃ is formed from K[SbCl₅N₃] and BCl₃. The vibrational spectra of the pentachloro-pseudohalo-antimonates can be assigned with a model of C_4v symmetry for the direct neighborhood of the Sb atoms.     

Darstellung und Eigenschaften einer neuen Reihe tellurhaltiger Perovskite des Typs K3MIIITe3O12

Preparation and Properties of a New Series of Tellurium Containing Perovskites of the Type K₃M^IIITe₃O₁₂ A new series of tellurium containing mixed oxides of composition K₃M^IIITe₃O₁₂ (M = Al, Ga, Cr, Fe) has been described. They crystallize in a superstructure-lattice of the PbTiO₃ type. The crystallographic data of the tetragonal unit cells have been determined from powder diffractograms. The i.r. spectra of these phases as well as the ⁵⁷Fe-Mössbauer-spectrum of K₃FeTe₃O₁₂ were recorded and discussed.     

Darstellung,thermisches Verhalten und Kristallstruktur des Calciumarsenidchlorids Ca3AsCl3

Preparation, Thermal Stability, and Crystal Structure of the Calcium Arsenide Chloride Ca₃AsCl₃ CaAsCa₃AsCl₃ was prepared as a grayish white, microcrystalline powder by the reaction of Ca, As, and CaCl₂ in the molar ratio 3:2:3 and by the reaction of “Ca₃As₂” and CaCl₂ in the molar ratio 1:3. Colourless single crystals of the compound were obtained. Ca₃AsCl₃ begins to decompose reversibly at 1 025°C by forming the phase Ca_{2? x}As_{1? x}Cl_1+x with x = 0.1₃ and CaCl₂. Single crystal investigations show that Ca₃AsCl₃ is isotypic with Mg₃NF₃; see: “Inhaltsübersicht”.     

Das Zintl-Konzept als Syntheseprinzip: Darstellung und Kristallstrukturen von K2Ba3Sb4 und KBa4Sb3O

Starting from the Zintl-Concept: Syntheses and Crystal Structures of K₂Ba₃Sb₄ and KBa₄Sb₃O The black, metallic lustrous, air sensitive compounds K₂Ba₃Sb₄ and KBa₄Sb₃O were prepared from melts of mixtures of the elements, in case of KBa₄Sb₃O with a stoichiometric amount of Sb₂O₃. K₂Ba₃Sb₄ crystallizes in the orthorhombic system, space group Pnma (a = 870.5(1) pm, b = 1770.2(2) pm, c = 923.6(1) pm, Z = 4) and is the first Sb compound with only [Sb₂]^4– dumbbells in the anionic partial structure. The compound KBa₄Sb₃O crystallizes in the tetragonal system, space group I4/mcm (a = 882.4(1) pm, c = 1659.4(2) pm, Z = 4). In this structure antimony forms [Sb₂]^4–-dumbbells and isolated ions Sb^3–. Each antimony ion of the dumbbells – in K₂Ba₃Sb₄ as well as in KBa₄Sb₃O – is coordinated in form of a bicapped skew trigonal prism. The isolated Sb^3– ions in KBa₄Sb₃O center bicapped tetragonal antiprisms, the O^2– ions occupy tetrahedral voids.     

Darstellung und Strukturbestimmung zweier Salze der Trimetaphosphimsäure,K3(PO2NH)3 und Rb3(PO2NH)3

Synthesis and Structure Determination of Two Salts of the Trimetaphosphimic Acid, K₃(PO₂NH)₃ and Rb₃(PO₂NH)₃ The reaction between P₃N₅ and the corresponding alkalimetal hydroxide monohydrate under ammonothermal conditions (6 kbar, 450 °C after 10 d) in autoclaves leads to the salts of the trimetaphosphimic acid K₃(PO₂NH)₃ resp. Rb₃(PO₂NH)₃. The structure of K₃(PO₂NH)₃ was solved by single crystals X-ray methods. The isotypic structure of Rb₃(PO₂NH)₃ was solved by X-ray powder diffraction methods. K₃(PO₂NH)₃: R3 (No. 148), a = 12.615(3) Å, c = 10.224(2) Å, Z = 6, R₁/wR₂ = 0.0276/0.0726, N(F > 2σ(F)) = 769, N(Var.) = 51.Rb₃(PO₂NH)₃: R3 (No. 148), a = 12.9971(5) Å, c = 10.5485(5), Z = 6, R_Bragg(F) = 0.0626, 289 reflections. K₃(PO₂NH)₃ and Rb₃(PO₂NH)₃ contain six-membered rings P₃N₃ substituted by oxygen which are connected to double molecules by N–H … O bridge bonds. These twinmolecules are stacked in columns which form the motive of close packed rods. K⁺ resp. Rb⁺ are between these columns. They are coordinated by 6 O which belong to 5 different rings.     

Strukturuntersuchungen an InGaSe2 und InGaTe2

Structure Investigations on InGaSe₂ and InGaTe₂ The preparation of the compounds InGaSe₂ and InGaTe₂ is reported. X-ray structure investigations at different temperatures for both compounds using their black single crystals with metallic lustre proof them to crystallize in the TlSe-type (InGaSe₂: a = 805.1(1) pm, c = 631.7(4) pm; InGaTe₂: a = 841.2(2) pm, c = 687.5(3) pm; Z = 4; I4/mcm), which is characterized by one-dimensional linear chains of edge-sharing GaSe₄-tetrahedra parallel to the c-axis of the tetragonal unit cell. The indium-indium distances within the indium chains running parallel to c are not commensurate with the tetrahedral chains in the case of InGaSe₂ giving rise to a pronounced incommensurate superstructure with complicated pattern. This is the reason why the indium positions for this compound, in contrast to InGaTe₂, do not correspond to the TlSe-type and cannot be resolved in the course of a conventional structure analysis because their electron density is nearly homogeneously smeared out along the indium chains.     

Massenspektrometrische Strukturuntersuchungen an einigen Niob- und Antimonalkoxychloriden

The 70 eV mass spectra of some niobium and antimony alkoxy chlorides are presented and fragmentation processes are discussed. Among the rearrangement reactions observed, several reactions were found providing six-coordinated niobium ions. The compounds are built up by bioctahedra; dimeric ions in addition to monomeric ones are present in the vapour state. The compounds Nb₂Cl(OC₂H₅)₉ and Nb₂Cl₃(OC₂H₅)₇ have been prepared. The association behaviour of compounds of the type MX_nY_s–n is discussed on the basis of the results of X-ray analysis and mass spectrometry.     

Niobpentachlorid-Thiazylchlorid-Addukt Darstellung,Schwingungsspektrum und Kristallstruktur

Complex of Niobium Pentachloride with Thiazyl Chloride Preparation, Vibrational Spectrum, and Crystal Structure Niobium pentachloride reacts with trithiazylchloride in CCl₄-suspension forming the complex Cl₅Nb? NSCl which forms red crystals that are very sensitive to moisture. According to the vibrational spectrum and the crystal structure determination the compound consists of monomeric units in which NbCl₅ is bonded to N?S? Cl in a relatively loose manner via the nitrogen atom. The crystal structure was determined with X-ray diffraction data and was refined to a residual index of R = 0.019 for 1879 reflexions. Cl₅NbNSCl crystallizes in the triclinic space group P1 with the lattice constants a = 636.7, b = 1215.5, c = 1266.8 pm, α = 83.32, β = 78.52 und γ = 82.26° and with four molecules per unit cell. There are two crystallographically independent molecules which differ somewhat in their geometry.     

AsPh4[ReCl4(NO)(OC(NH2)CH3)]; Darstellung,IR-Spektrum und Kristallstruktur

AsPh₄[ReCl₄(NO)(OC(NH₂)CH₃)]; Preparation, I.R. Spectrum, and Crystal Structure AsPh₄[ReCl₄(NO)(OC(NH₂)CH₃)] is obtained in the form of light green crystals from AsPh₄[ReCl₄(NO)₂] and acetonitrile in the presence of water in a dichloromethane solution. According to X-ray diffraction measurements, the complex crystallizes in the monoclinic space group P2₁/c with four formula units per unit cell (R = 4.5%, 5889 independent reflexions). There are two moles of water extra incorporated in the lattice. The structure consists of tetraphenylarsonium cations and anions [ReCl₄(NO)(OC(NH₂)CH₃)]?, in which the Re atom is coordinated octahedrally by four equatorial chlorine atoms, the N atom of the nitrosyl group, and in trans-position to it, by the O atom of the acetamide ligand. The NO group is situated in a nearly stretched arrangement (173°); it causes a trans-effect, which does not allow the chlorine atoms to form a plane with the Re atom anymore (average N? Re? Cl angle 94.3°), the i.r. spectrum is reported an assigned.     

Darstellung,Röntgen-Pulverdaten und Gitterkonstanten von K2Cd(N3)4 und Tl2Cd(N3)4

Preparation, X-Ray Powder Data, and Lattice Parameters of K₂Cd(N₃)₄ and Tl₂Cd(N₃)₄ Two monoclinic complex azides of cadmium have been crystallized from aqueous solutions containing HN₃: Dipotassium-cadmium-tetraazide, K₂Cd(N₃)₄: a = 1425.4 b = 378.5 c = 888.3 pm. β = 92.9° and dithallium-cadmium-tetraazide, Tl₂Cd(N₃)₄: a = 1066.9 b = 735.9 c = 656.3 pm, β = 104.4°.