Nitrido-silicate. III. Hochtemperatur-Synthese,Kristallstruktur und magnetische Eigenschaften von Ce3[Si6N11]

Nitrido-silicates. III [1] High-Temperature Synthesis, Crystal Structure, and Magnetic Properties of Ce₃[Si₆N₁₁] Pure Ce₃[Si₆N₁₁] was obtained as transparent yellow crystals by reaction of metallic cerium with silicon diimide (Ce:Si = 1:2) under nitrogen atmosphere in a specially developed high-frequency furnace at 1660°C. Ce₃[Si₆N₁₁] (P4bm, a = 1013.7(3), c = 483.9(5) pm, Z = 2, R = 0.034, wR = 0.024) contains Ce³⁺ ions as well as a three-dimensional covalent anionic network structure of corner-sharing SiN₄ tetrahedra. Measurements of the magnetic susceptibility gave no indications for magnetic ordering phenomena in the temperature range between 2 and 300 K. Above 100 K pure Curie-Weiss behaviour (μ_eff = 2,10 μ_B, determined at room temperature) was observed.     

Nitrido-Silicate. I. Hochtemperatur-Synthese und Kristallstruktur von Ca2Si5N8

Nitrido Silicates. I. High Temperature Synthesis and Crystal Structure of Ca₂Si₅N₈ Ca₂Si₅N₈ is obtained by reaction of silicon diimide with metallic calcium under nitrogen atmosphere performed in a specially developed high-frequency furnace at temperatures between 1 500 and 1 600°C. Ca₂Si₅N₈ (Cc, a = 1 435.2(3), b = 561.0(1), c = 968.9(2) pm, β = 112.06(3)°, Z = 4, R = 0.023, wR = 0.018) contains Ca²⁺ ions as well as a three-dimensional covalent network structure of corner-sharing SiN₄ tetrahedra. Two sorts of N occur with molar ratio 1:1 which are bonded to two and three Si, respectively.     

Synthese und Kristallstruktur von Sr2Zn(OH)6 und Ba2Zn(OH)6

Synthesis and Crystal Structure of Sr₂Zn(OH)₆ and Ba₂Zn(OH)₆ Crystallization from supersaturated sodium hydroxozincate solutions by adding solutions of alkali earth metal hydroxides yields crystals of Sr₂Zn(OH)₆ and Ba₂Zn(OH)₆. The X-ray structure determination on these crystals was successful including all hydrogen positions: Sr₂Zn(OH)₆: P2₁/n, Z = 2, a = 5.794(1) Å, b = 6.160(1) Å, c = 8.141(1) Å, b = 91.23(1)°, N(F ³° 2σ F) = 1127, N(Var.) = 53, R₁/wR₂ = 0.047/0.081Ba₂Zn(OH)₆: P2₁/n, Z = 2, a = 6.043(1) Å, b = 6.336(1) Å, c = 8.451(2) Å, b = 91.23(2)°, N(F ° 2σ F) = 1669, N(Var.) = 54, R₁/wR₂ = 0.029/0.067. Sr₂Zn(OH)₆ and Ba₂Zn(OH)₆ crystallize isotypic in a distorted Li₂O structure type. Sr²⁺ resp. Ba²⁺ form a cubic primitive arrangement. Distorted octahedra of OH^– around Zn²⁺ fill therein alternating cubic gaps in an ordered way.     

Synthese und Kristallstrukturen von NH4[Si(NH3)F5] und [Si(NH3)2F4]

Synthesis and Crystal Structures of NH₄[Si(NH₃)F₅] and [Si(NH₃)₂F₄] Single crystals of NH₄[Si(NH₃)F₅] and [Si(NH₃)₂F₄] are obtained by reaction of silicon powder with NH₄HF₂ in sealed Monel ampoules at 400°C. NH₄[Si(NH₃)F₅] crystallizes with the tetragonal space group P4/n (no. 85) with a = 614.91(7) pm, c = 721.01(8) pm, Z = 2. Characteristic for the structure is the anionic octahedron [Si(NH₃)F₅]^?. Si(NH₃)₂F₄ crystallizes with the monoclinic space group P2₁/c (no. 14) with a = 506.9(1) pm, b = 728.0(1) pm, c = 675.9(1), β = 93,21(2)°, Z = 2. Trans-[Si(NH₃)₂F₄] molecules are characteristic for this structure.     

ChemInform Abstract: First‐Principles Electronic Structure Calculations of Ba5Si2N6 with Anomalous Si2N6 Dimeric Units.

ChemInform 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.     

In-Cage Interactions in the Clathrate Superconductor Sr8Si46

The clathrate I superconductor Sr₈Si₄₆ is obtained under high-pressure high-temperature conditions, at 5 GPa and temperatures in the range of 1273 to 1373 K. At ambient pressure, the compound decomposes upon heating at T=796(5) K into Si and SrSi₂. The crystal structure of the clathrate is isotypic to that of Na₈Si₄₆. Chemical bonding analysis reveals conventional covalent bonding within the silicon network as well as additional multi-atomic interactions between Sr and Si within the framework cages. Physical measurements indicate a bulk BCS type II superconducting state below T_c=3.8(3) K.     

Synthese und Kristallstruktur von BaEu(Ba0,5Eu0,5)YbSi6N11

Synthesis and Crystal Structure of BaEu(Ba_0.5Eu_0.5)YbSi₆N₁₁ Pure BaEu(Ba_0.5Eu_0.5)YbSi₆N₁₁ was obtained by stoichiometric reaction of silicon diimide with metallic barium, europium, and ytterbium. The reaction was carried out under nitrogen atmosphere in a high-frequency furnace at 1650 °C. BaEu(Ba_0.5Eu_0.5)YbSi₆N₁₁ is cubic (space group P2₁3, a = 1043.64(5) pm, Z = 4, R1 = 0.0406, wR2 = 0.0988). The compound contains alkaline earth and rare earth ions in a three-dimensional network structure of corner-sharing SiN₄ tetrahedra.     

Synthese,Kristallstrukturen und spektroskopische Untersuchungen von 3d-Übergangsmetall-Komplexen mit Bicyclo[2.2.1]hept-5-en-2-endo,3-cis-dicarbonsäure und N,N-Donorliganden

Synthesis, Crystal Structures and Spectroscopic Investigations of 3d-Transition Metal Complexes with Bicyclo[2.2.1]hept-5-ene-2-endo,3-cis-dicarboxylic Acid and N,N-Donor Ligands The synthesis of coordination compounds of the general type [MLdam(H₂O)₃] · 2.5 H₂O with M = Mn²⁺, Co²⁺, Ni²⁺; H₂L = bicyclo[2.2.1]hept-5-ene-2-endo,3-cis-dicarboxylic acid and dam = 2,2′-dipyridyl, 1,10-phenanthroline has been described. The complexes have been characterized by elementary analysis, infrared and electronic spectra and magnetic susceptibility measurements. The results of X-ray crystal structure analyses of [MnLdipy(H₂O)₃] · 2.5 H₂O ( 1 a ) and [CoLdipy(H₂O)₃] · 2,5 H₂O ( 1 b ) show, that both compounds crystallize isotypically and prove the octahedral coordination of the metal atoms. The dicarboxylate anion is coordinated to the central atom by an O atom of only one carboxylate group, the other one is in the ionic state. One O atom of each carboxylate group makes an intramolecular hydrogen bond with a water molecule of the coordination sphere. The other crystal water molecules form a network of H bonds one with another and with the complex molecules, thus stabilizing the crystal packing.     

Nitrido-Sodalithe. I Synthese,Struktur und Eigenschaften von Zn7–xH2x[P12N24]Cl2 mit 0 ⩽ x ⩽ 3

Nitrido Sodalites. I Synthesis, Crystal Structure, and Properties of Zn_7–xH_2x [P₁₂N₂₄]Cl₂ with 0 ? x ? 3 The nitrido sodalites Zn_7–xH_2x[P₁₂N₂₄]Cl₂ with 0 ? x ? 3 are obtained by heterogeneous pressure-ammonolysis of P₃N₅ at presence of ZnCl₂ (T = 650°C). These compounds are available too by reaction of ZnCl₂, (PNCl₂)₃, and NH₄Cl at 700°C. The crystal structures of four representatives of the above mentioned compounds have been refined by the Rietveld full-profile technique using X-ray powder diffractometer data (I4 3m, a = 821.61(4) to 824.21(1) pm, Z = 1). In the solid a three-dimensional framework of corner-sharing PN₄-tetrahedra occurs (P? N: 163.6 pm, P? N? P: 125.6°, mean values) which is isosteric with the sodalite type of structure. In the center of the β-cages Cl^? ions have been found, which are tetrahedrally coordinated by Zn²⁺ ions. The Zn²⁺ ions are statistically disordered. According to the phase-width observed (0 ? x ? 3) the Zn²⁺ ions may be partially replaced each by two hydrogen atoms which on the other hand are covalently bonded to nitrogen atoms of the P? N framework. The IR-spectra of these compounds show characteristic vibrations.     

Kristallstrukturen von Kalium- und Silbercyanamidonitrat

Pseudoelement Compounds. XV Crystal Structure Analysis of Potassium and Silver Cyanamidonitrate The crystal structures of potassium and silver cyanamidonitrate are reported. In both the potassium and the silver salt metal anion contacts via the atoms cyano-N, amide-N and oxygen are observed. The structural parameters of the ion [NO₂NCN]^– are only slightly influenced by the different environments (potassium, silver). K[NO₂NCN] forms a coordination lattice in which the nearest neighbours of the potassium ion are nine N and O atoms belonging to seven different anions. Ag[NO₂NCN] has a layer structure; the silver atoms are arranged in zickzack chains running perpendicular to the layers with an Ag–Ag distance of 3.169(1) Å.     

Zur Polymorphie von SrNi2P2 sowie zur Kristallstruktur von BaNi2P2

About Polymorphism of SrNi₂P₂ and Crystal Structure of BaNi₂P₂ SrNi₂P₂ and BaNi₂P₂ were prepared by heating mixtures of the elements and investigated by single crystal X-ray methods. The Sr compound at room temperature crystallizes in a superstructure of the ThCr₂Si₂ type (NT-phase; Immm; Z = 6; a = 3.951(2), b = 11.853(2), c = 10.432(2) Å), which is caused by displacements of the atoms from the ideal positions; the P? P distances are 2.45 and 3.28 Å. With increasing temperature at 45°C (ambient pressure) and increasing pressure at 4 kbar (room temperature) respectively the compound undergoes first order phase transitions and crystallizes after that in the undistorted ThCr₂Si₂ type (I4/mmm; Z = 2). While the P atoms of the high temperature phase (HT-SrNi₂P₂: a = 3.948(1), c = 10.677(3) Å; 100°C) are isolated from each other (d_{p p}: 3.12 Å) they most probably form pairs in the high pressure phase (HD-SrNi₂P₂: a = 4.003(1), c = 9.761(2) Å; ca. 4 kbar). This will be discussed on the basis of band structure calculations. BaNi₂P₂ (a = 3.947(1), c = 11.820(1) Å) also crystallizes in the ThCr₂Si₂ type structure, the P? P distance is extended to 3.71 Å.     

Mesityltrifluorogallate. Die Kristallstrukturen von Cs[MesGaF3] und K[MesInBr3]

Mesityltrifluoro Gallates. The Crystal Structures of Cs[MesGaF₃] and K[MesInBr₃] Mes₃Ga reacts with GaBr₃ in the ratio 1:2 in a commutation reaction to MesGaBr₂ ( 1 ). 1 can be reacted with KF and CsF in MeCN to K[MesGaF₃] ( 2 ) and Cs[MesGaF₃] ( 3 ), respectively. K[MesInBr₃] ( 4 ) was isolated when MesInBr₂ was treated with KF in MeCN. The use of 15-crown-5 was leading to [K(15-crown-5)₂][Mes₂InBr₂] ( 5 ) in a substituent exchange reaction. 1-5 were characterized by NMR-, IR- and MS-techniques. The solid state structures of 3 and 4 could be established by X-ray structure determinations. According to these determinations, a layer-type arrangement of the molecules is both structures in common. In the center of the layers, ionic interactions were formed, while the separation of the layers is caused by the bulky mesityl substituents.     

Ternäre Nickelphosphide und -arsenide mit einem Metall: Nichtmetall-Verhältnis von 2:1

Ternary Phosphides and Arsenides of Nickel with a Metal: Non-Metal Ratio of 2:1 Several new ternary phosphides and arsenides of nickel were prepared by reaction of the elements. SrNi₅P₃, SrNi₅As₃, and EuNi₅As₃ crystallize in the LaCo₅P₃ structure with the following lattice constants [Å]: BaNi₉P₅ (a = 6.534(1) Å, c = 10.847(2) Å) and BaNi₉As₅ (a = 6.760(1) Å, c = 11.226(2) Å) crystallize in a new type of structure (P6₃/mmc, Z = 2). The characteristic polyhedra are trigonal Ni-antiprisms centered by P or As atoms and trigonal Ni-prisms with vacant centres and sides capped by non-metal atoms. U₂Ni₁₂P₇ (a = 9.077(2) Å, c = 3.694(1) Å) has a Zr₂Fe₁₂P₇ structure (P6 , Z = 1).     

Schichtanionen in den Kristallstrukturen der isotypen Verbindungen Sr2[Ga2S5], Ba2[In2S5] und Ba2[In2Se5]

Layer-Anions in the Crystal Structures of the Isotypic Compounds Sr₂[Ga₂S₅], Ba₂[In₂S₃], and Ba₂[In₂Se₅] The compounds Sr₂[Ga₂S₅], Ba₂[In₂S₅], and Ba₂[In₂Se₅] have been prepared from stoichiometric mixtures of the elements at temperatures between 1150°C and 1250°C. They are isotypic (space group Pbca, Z = 8) with the lattice constants see ?Inhaltsübersicht”?. In the anionic part of the structure GaS₄-(InS₄-/InSe₄)-tetrahedra share three common vertices to form layers with rings built by four and eight tetrahedra. The cations are placed between the sheets and have the coordination number seven.     

Pseudoelementverbindungen. VII [1]. Kristall- und Molekülstruktur von Tris(ethylendiamin)nickel(II)-bis(2-methyl-4-chlorphenoxycyanamidoacetat)

Pseudoelement Compounds VII. [1] Crystal and Molecular Structure of Tris(ethylenediamine)nickel(II)-bis(2-methyl-4-chlorophenoxy-cyanamidoacetate) Surprisingly, in the presence of ethylenediamine 2-methyl-4-chlorphenoxy-cyanamidoactetate reacts with nickel(II) and copper(II) ions preferentially under formation of complexes of the type [M(en)₃]X₂. The IR spectra and the X-ray diffraction investigations corresponding to [Ni(en)₃][2-Me-ClC₆H₃OCH₂C(O)NCN]₂ show that two cyanamidocarboxylate ions [RC(O)NCN]^? are bonded to the complex cation through, in each case, two N? H …? O?C hydrogen bonds between NH protons of ethylenediamine ligands and the carbonyl oxygen atoms. Additionally, in the crystal weak N? H …? N?C bridges were found between the nitrile nitrogen atoms of the anions and NH protons of neighbouring complex cations.     

配合物[Mn(C13H8N2OBr)2(C5H5N)2]·3C5H5N的结构与磁性研究

The complex [Mn(C₁₃H₈N₂OBr)₂(C₅H₅N)₂]·3C₅H₅N has been synthesized and characterized by X-Ray diffraction, IR and variable temperature (～10 to ～278K) magnetic susceptibility. X-Ray diffraction result for the single crystal shows that the crystal belongs to monoclinic, space group P2₁/c, a=1.0969(3)nm, b=2.0903(5)nm, c=2.0481(6)nm, β=97.366(6), V=4.657(2)nm³, Z=4, D_c=1.47g·cm^-3。     

Synthese,Kristallstruktur und Eigenschaften eines neuen Sialons – SrSiAl2O3N2

Synthesis, Crystal Structure, and Properties of a New Sialon – SrSiAl₂O₃N₂ The sialon SrSiAl₂O₃N₂ was obtained as a coarsly crystalline solid by reaction of silicon diimide, aluminum nitride, and strontium carbonate under N₂ atmosphere in a high-frequency furnace at 1650 °C. According to the single-crystal structure determination the title compound is isotypic with LnSi₃N₅ (Ln = La, Ce, Nd, Pr). SrSiAl₂O₃N₂ (P2₁2₁2₁, a = 491.98(6), b = 789.73(7), c = 1134.94(18) pm, Z = 4, R1 = 0.0439, wR2 = 0.0939). In the solid a three-dimensional network structure of corner sharing SiON₃, AlO₃N, and AlO₂N₂ tetrahedra occurs. Lattice energetic calculations using the MAPLE concept confirm an unequivocally correct crystallographic differentiation between N and O as well as Al and Si atoms, respectively (Al–O: 167.4(5)–170.6(6); Al–N: 175.4(6)–179.4(6); Si–O: 171.2(6); SiN: 176.7(6)–179.6(6) pm). The Sr²⁺ ions are located in the voids of the (SiAl₂O₃N₂)^2– framework (Sr–O: 250.4(6)–304.2(6); Sr–N: 287.4(6) 318.2(6) pm).     

Synthesis and Structure of Ba[ZrN2] and Ba2[NbN3]

Ba₃N₂ reacts at 950°C under pure N₂ with Zr to yield dark red, air-sensitive Ba[ZrN₂]. This new compound crystallizes in the tetragonal space group P4/nmm with a = 416.10(2), c = 839.2(1) pm and Z = 2. The crystal structure was solved and refined using X-ray and neutron powder diffraction data. In the nitrido zirconate [ZrN₂]^2? the Zr atoms exhibit a square-pyramidal coordination by five N atoms at distances of 201(3) and 220.2(2) pm. The pyramids share all the edges in the basal plane to form layers parallel to (001) with their apices alternately pointing up and down. The Ba²⁺ cations are integrated into these layers at the levels of the pyramidal apices. The structure can be interpreted as a stuffed PbFCl type. Ba₂[NbN₃] is formed by the reaction of Ba₃N₂ and NbN or of Ba and Nb at 1 000°C under N₂. Isostructural to Ba₂[TaN₃] it crystallizes in the monoclinic space group C2/c with a = 613.2(3), b = 1 176.8(3), c = 1 322.9(4) pm, β = 91.65(2)°, Z = 8. The nitrido niobate anions form chains of corner sharing NbN₄ tetrahedra with distances Nb? N between 188(1) and 199.9(9) pm.     

Zur Kristallstruktur von KGaO2 und NaGaO2(II) [1]

The Crystal Structure of KGaO₂ and NaGaO₂(II) By annealing intimate mixtures of K₂O, Na₂O and β-Ga₂O₃ (K : Na : Ga = 2.2 : 1.1 : 1) we obtained single crystals of K₂Na₄[(GaO₃)₂] and KGaO₂ (Ag-cylinder; 600°C, 26 d). Structure refinement for KGaO₂ (four-circle diffractometer data, Mo-Kα , 1 390 or 1 390 I_o(hkl); R = 5.55%, R_w = 3.05%) confirms the space group Pbca; a = 552.1 pm, b = 1 107.5 pm, c = 1 580.7 pm, Z = 16. According to K[GaO_4/2] we have a stuffed cristobalite-related structure. Single crystals of NaGaO₂(II) were grown by annealing intimate mixtures of Na₂O₂ and GaAs (Na₂O₂ : GaAs 4.1 : 1) in Ag-cylinders that were not completely closed (570°C, 6 weeks). Structure refinement for NaGaO₂(II) (four-circle diffractometer data, Mo-Kα , 588 of 616 I_o(hkl); R = 4.54%, R_w = 4.06%) confirms the spacegroup Pna2₁; a = 549.8(1) pm, b = 720.6(1) pm, c = 529.8(1) pm, Z = 4. In NaGaO₂(II) we have a wurtzite-related structure.