Über die Zerfallsstruktur des Ni-Katalysators und die Ni(C)-Phase des Diamanten bei der Diamantsynthese

The nature of intermediate phases in the Ni C system is discussed and the concentration dependence of the specific atomic volume is determined. Decomposition structures of Ni C samples exposed to high pressures and temperatures are studied metallographically and by X-ray diffraction. The specific atomic volume of Ni(C) decomposition phase and of Ni(C) satellite phase of Diamond is measured by the asymmetric powder method and from this the concentration of carbon is ascertained. It is stated that the Ni(C_y) satellite phase of diamond — the terminal solid solution of carbon in nickel approximately contains 3 at.% of carbon. It is concluded from this that this phase is the result of the last stage of decomposition of carbon supersaturated catalyst. Thus, the intermediate phase is playing no important role in diamond nucleation.     

Über die Co(C)-Begleitphase des synthetischen Diamanten

The concentration dependence of the specific atomic volume on the carbon side of the Co—C system is constructed. By means of this the carbon content of the satellite phase is determined equal to ∼ 3.7 at.% Therefore the satellite is considered as the terminal Co:0,03 C solid solution, and seems to be the product of decomposition of the basic catalyst supersaturated in carbon.     

Die Konzentrationsabhängigkeit des Brechungsindex von Ga(PAs)- und (GaIn)P-Mischkristallen

In the two systems of mixed crystals Ga_xPAs_1–x and Ga_xIn_1–xP the refraction index — using the wavelength of the green Hg line (λ = 5461 Å) — is determined ellipsometrically in dependence on the mole fraction x. The nonlinearity parameter c_n of this dependence is compared with that estimated theoretically by the use of PENNS model.     

Synthesis,Crystal Structures and Fluorescence Properties of Ni (II) and Cu (II) Complexes with 1-(Furan-2-ylmethylene)-4-phenylthiosemicarbazone

Abstract  

Two coordination complexes, NiL ₂ and CuL ₂ {L = bis[1-(furan-2-ylmethylene)-4-phenylthiosemicarbazone]}, were synthesized and determined by X-ray crystallography. Both crystallize in the Orthorhombic system, space group Pbcn, with lattice parameters: a = 11.935 (2) Å, b = 15.314(3) Å, c = 12.952(3) Å and Z = 4 for Ni (II); a = 20.850(4) Å, b = 15.049(3) Å, c = 7.5633(5) Å and Z = 4 for Cu (II). In both complexes, the central metal atom is coordinated in a distorted square-planar with two ligands through two S and N atoms, respectively. The EA, UV, IR and TG-DTG were studied and the possible structures of the complexes were speculated. Moreover, the fluorescence of the complexes were studied. The results reveal that copper complex can emit purple fluorescence in solvents.     

Die Änderung der Molekül- und Kristallstruktur des N-Methyl-piperidinum-acet-meta-chlor-anilid-jodid durch Einlagerung von Wasser

N-Methyl-piperidinium-acet-meta-chloro-anilide-iodide crystallizes from water in the space group Pna2₁ with 4 formula units C₁₄H₂₀N₂OClJ and 4 H₂O molecules in the unit cell. The lattice constants are a = 12.413 Å, b = 19.798 Å and c = 6.919 Å. The change of the molecular conformation caused by water molecules was investigated by X-ray structure analysis.     

Self-Assembly of Two Isomorphous Thiocyanate Complexes of Co(II) and Ni(II) with 3-Hydroxypicolinamide

Abstract  

The synthesis, thermal and spectral characterization, and crystal structure of isomorphous thiocyanate cobalt(II) and nickel(II) complexes with 3-hydroxypicolinamide (3-OHpia), [M(C₆H₆N₂O₂)₂(NCS)₂]·2H₂O, are reported. The metal(II) ions are chelated by two cis-oriented 3-OHpia and two thiocyanate ligands in distorted octahedral geometry. The distortion within the coordination sphere is mainly imposed by formation of the chelate rings. The compounds crystallize in monoclinic space group P2/c with two symmetrically independent molecules and a = 14.4945(2) ?, b = 8.5906(1) ?, c = 16.3865(3) ?, β = 105.987(2)°, Z = 4 (1) and a = 14.4927(5) ?, b = 8.5912(3) ?, c = 16.2712(6) ?, β = 105.740(4)°, Z = 4 (2). Commonly observed supramolecular amide synthons are not robust enough to accommodate thiocyanate ions and H₂O molecules. But instead, neutral complexes are linked through hydrogen bonds leading to two different hydrogen bonding ribbon motifs involving amide moieties and H₂O molecules [C(8)R ₂²(12) along c axis] and amide moieties and thiocyanate ions [C(8)R ₂²(16) along b axis] for symmetrically related molecules labelled as 1 [Co1 (1) and Ni1 (2)] and 2 [Co2 (1) and Ni2 (2)], respectively.     

Effect of Co substitution for Ni on the Ti–Zr–(Ni, Co) pseudo-ternary quasicrystal formation

A series of alloys designed along a Ti₉(Ni,Co)₄–Zr e/a-variant line in the Ti–Zr–(Ni, Co) pseudo-ternary alloy system, are investigated by XRD and TEM. Experimental results show that bulk icosahedral quasicrystals (IQC) prepared by copper mold suction casting, can be obtained in a large region from Ti₅₅Zr₂₀(Ni,Co)₂₅ to Ti_34.6Zr₅₀(Ni,Co)_15.4 with Ni/Co ratio equal to 3/1, and in a sharply diminished region from Ti₄₈Zr₃₀(Ni,Co)₂₂ to Ti₄₂Zr₄₀(Ni,Co)₁₈ with decreased Ni/Co ratio equal to 2/2 or 1/3. Ti₄₈Zr₃₀Ni_16.5Co_5.5 is the optimal quasicrystal-forming composition, where a nearly pure bulk IQC phase is achieved. The stepwise substitutions of Co for Ni in this pseudo-ternary system contribute to the formation of Ti₂Ni, fcc-Zr₂Ni, C14-type Laves and β-(Ti, Zr) solid solution phases. However, these substitutions greatly reduce the forming ability of the IQC phase. It is suggested that Co is essentially unfavorable to Ti/Zr-based quasicrystal formation.     

Influence of complex formation upon inclusion of Mn(II), Co(II), Ni(II), and Cu(II) in ZnC2O4·2H2O

The inclusion of 3d‐impurities Mn(II), Co(II), Ni(II) and Cu(II) in a crystalline precipitate of ZnC₂O₄·2H₂O is investigated. This study is a part of the systematic one deal with the mechanism of inclusion of 3d‐ions in sparingly soluble oxalate systems. The experiments are carried out in bi‐ end multi‐component systems at two different mediums – one with deficiency of oxalate ions, another with excess. The insertion of 3d‐ions upon mass crystallization of ZnC₂O₄·2H₂O does not proceed by a simple ionic substitution. The results show that the inserted amount of impurity depends on some physicochemical characteristics of the neutral monooxalato complexes [MnC₂O₄]^o, [CoC₂O₄]^o, [NiC₂O₄]^o and [CuC₂O₄]^o. Good agreement between included impurity and the concentration of its complex in the solution is established. The stability constant of monooxalato complex affects the impurity inclusion. This effect depends on the medium nature. In the deficiency of oxalate ions the factor determining the inclusion is thermodynamic one – stability of monooxalato complexes. In the excess of oxalate ions inserted amount depends on kinetic factor – the formation rate of these complexes. In the term of that the insertion of Mn(II) is definitely different in the two mediums while that of the Ni (II) does not depend on the medium. The copper shows deviation from overall dependence in the two mediums due to the Jahn‐Teller distortion. Its double decreasing insertion in the excess of oxalate ions is related with stabilization of [Cu(C₂O₄)2]^2‐. The conclusions presume that by varying the background medium and taking in view the ions present in the solution, the amount of inserted impurities can be predicted and controlled. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Two Co/Ni(II)-Based Coordination Polymers for Degradation of Dyes

Crystallography Reports - Two isostructural Co/Ni(II)-based coordination polymers, namely, {[Co1/2(bpba)(H2O)]?2H2O}n (1) and {[Ni1/2(bpba)(H2O)]?2H2O}n (2), where Hbpba = 3,5-bis...     

4-(2-Methylphenyl)-1,2,3,4,5,6,7,8-octahydroquinazoline-2,5-dione (I) and 4-(4chlorophenyl)-1,2,3,4,5,6,7,8-octahydroquinazoline-2,5-dione (II)

The crystal and molecular structures of the title compounds have been determined by x-ray structure analysis. The compounds (I) and (II) crystallize in space groups P2₁2₁2₁ and 12/a respectively. The structures were solved by direct methods and refined to R = 0.058 and R = 0.046. The saturated pyrimidine-2-one ring in both structures deviates from the planarity. There are two intermolecular hydrogen bonds in (I) and (II). The configuration at C4 in (I) is S.     

Reaction of 1,2-bis(2,6-dicarboxypyridin-4-yl)ethyne with Co(II) generates coordination monomers not polymers: Crystal structure of 4-(2,6-dicarboxypyridin-4-yl)ethynylpyridine-2,6-dicarboxylatotriaqua cobalt(II) monohydrate

Reaction and crystallization of 1,2-bis(2,6-dicarboxypyridin-4-yl)ethyne with Co(II) produces crystals containing monomers of 4-(2,6-dicarboxypyridin-4-yl)ethynylpyridine-2,6-dicarboxylatotriaqua cobalt(II) monohydrate complex (1), [Co(C₁₆H₆N₂O₈)(H₂O)₃]·H₂O, instead of a rigid 1-D metal–organic framework consisting of a linear coordination polymer. This complex crystallizes in the monoclinic space group C2/c with a=6.8028(9) ?, b=36.781(5) ?, c=7.5135(9) 2.474(2)° and Z=4. The complex sits on a symmetry axis such that the two halves of the molecule are related by two-fold rotation symmetry. The molecules form layers in which the molecules are joined by intermolecular O–H⋯O interactions involving hydrogen bonds between CO₂H⋯CO₂ ⁻, H₂O⋯CO₂ ⁻, H₂O⋯CO₂H and H₂O⋯H₂O groups.Supplementary material CCDC-289569 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data request/cif, by e-mailing data request@ccdc.cam.ac.uk or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 IEZ, UK; fax: +44(0)1223-336033.     

Thermal and magnetic behavior of a nanocrystalline Fe(Ni, Co) based alloy

A nanocrystalline alloy of Fe₅₁Co₂₀Ni₁₄Zr₆B₉, was produced by mechanical alloying. The main structural analysis was carried out via X-ray diffraction. The spectra were analyzed by Rietveld refinement using the MAUD program. The as-milled, 10, 20, 40 and 80 h alloys consisted primarily of metastable bcc-Fe(Co, Ni) nanocrystals reaching around 8 nm mean diameter, after 80 h. The morphology was examined via SEM and composition by ICP and EDX. Results show a slight (<1.5 at.%) contamination from milling tools. Differential scanning calorimetry data reveal broad hump between 100 and 450 °C associated with the relief of internal stresses. The exothermic peaks over 450 °C correspond to the crystallization related initially to the crystalline growth of the bcc-Fe(Co, Ni) phase and to the formation of fcc-(Fe, Ni, Co) and (Fe, Ni, Co)₂B phases at higher temperatures. Frequency-dependent AC-susceptibility on the 80 h alloy confirms the presence of nanoparticles displaying a wide distribution of sizes favoring the existence of disordered magnetic interactions among them through the nanoparticle boundaries.