Crystal and molecular structure of creatininium tetrachlorocuprate(II)
TL;DR: In this paper, the crystal and molecular structure of creatinininium tetrachlorocuprate (II) was described and the structure was solved by X-ray diffraction studies and was refined by least-squares methods to R = 0.041 for 1344 reflections.
About: This article is published in Inorganica Chimica Acta.The article was published on 1979-01-01. It has received 40 citations till now. The article focuses on the topics: Monoclinic crystal system.
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TL;DR: In this article, the nuclear quadrupole resonance spectra of deuterium are reported for anhydrous 2-imidazolidone (ethylene urea), its hemihydrate, phthalimide, and benzamide at 77 K.
5 citations
TL;DR: In this paper, the authors used titration potentiometry and spectrophotometry to determine stability constants for mixed complexes of Cu(II) with creatinine and EDTA.
Abstract: Titration potentiometry and spectrophotometry have both been used to determine stability constants for mixed complexes of Cu(II) with creatinine and EDTA. Stability constants of the ternary system were evaluated by a method suggested by the Irving-Rossotti procedure. Conditional constants were established as a function of pH; the maximum values of the conditional formation constants were found to be in agreement with the mixed-ligand complex formation constants in a given pH region. The mole fractions of mixed complexes were calculated using the formation constants. The stability constants of mixed-ligand complexes at 25°C are: log K| = 5.29, log K2 = 4.97, with ionic strength being kept constant at I = 0.1 with NaC104. Also, Cu(II)-I-glutamic acid-creatinine and Cu(II)-EDTA-creatinine complex formation, as examined by the spectrophotometric method, gave results that were in agreement with those of the Potentiometrie method. K e y w o r d s : creatinine, EDTA, 1-glutamic acid, copper(II) complexes, mixed complex, stability constants.
5 citations
TL;DR: The low temperature electronic spectrum of Cu(II) doped Cs2ZrCl6 is reported in this article, which shows vibronic structure with peak widths as small as 8 cm(-1), far narrower than previously seen for this ion.
4 citations
TL;DR: In this paper, the effect of atomic vibrations on the fine structure of the X-ray absorption near-edge structure (XANES) was shown to be due to atomic vibrations, which can be separated into two groups depending on whether the respective atoms belong to the same molecular block.
Abstract: Polarization-dependent damping of the fine structure in the Cu K-edge spectrum of creatinium tetrachlorocuprate [(creat)2CuCl4] in the X-ray absorption near-edge structure (XANES) region is shown to be due to atomic vibrations. These vibrations can be separated into two groups, depending on whether the respective atoms belong to the same molecular block; individual molecular blocks can be treated as semi-rigid entities while the mutual positions of these blocks are subject to large mean relative displacements. The effect of vibrations can be efficiently included in XANES calculations by using the same formula as for static systems but with a modified free-electron propagator which accounts for fluctuations in interatomic distances.
4 citations
TL;DR: Polarization-dependent damping of the fine structure in the Cu K-edge spectrum of creatinium tetrachlorocuprate in the X-ray absorption near-edge structure (XANES) region is shown to be due to atomic vibrations.
Abstract: Atomic vibrations are usually not taken into account when analyzing x-ray absorption near edge structure (XANES) spectra. One of the reasons is that including the vibrations in a formally exact way is quite complicated while the effect of vibrations is supposed to be small in the XANES region. By analyzing polarized Cu K edge x-ray absorption spectra of creatinium tetrachlorocuprate [(creat)$_{2}$CuCl$_{4}$], we demonstrate that a technically simple method, consisting in calculating the XANES via the same formula as for static systems but with a modified free-electron propagator which accounts for fluctuations of interatomic distances, may substantially help in understanding XANES of some layered systems. In particular we show that the difference in the damping of the x-ray absorption fine structure oscillations for different polarisations of the incoming x-rays cannot be reproduced by calculations which rely on a static lattice but it can be described if atomic vibrations are accounted for in such a way that individual creatinium and CuCl$_{4}$ molecular blocks are treated as semi-rigid entities while the mutual positions of these blocks are subject to large mean relative displacements.
4 citations
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TL;DR: In this paper, the x-ray form factors for a bonded hydrogen in the hydrogen molecule have been calculated for a spherical approximation to the bonded atom, and the corresponding complex scattering factors have also been calculated.
Abstract: The x‐ray form factors for a bonded hydrogen in the hydrogen molecule have been calculated for a spherical approximation to the bonded atom. These factors may be better suited for the least‐squares refinement of x‐ray diffraction data from organic molecular crystals than those for the isolated hydrogen atom. It has been shown that within the spherical approximation for the bonded hydrogens in H2, a least‐squares refinement of the atomic positions will result in a bond length (Re value) short of neutron diffraction or spectroscopic values. The spherical atoms are optimally positioned 0.07 A off each proton into the bond. A nonspherical density for the bonded hydrogen atom in the hydrogen molecule has also been defined and the corresponding complex scattering factors have been calculated. The electronic density for the hydrogen molecule in these calculations was based on a modified form of the Kolos—Roothaan wavefunction for H2. Scattering calculations were made tractable by expansion of a plane wave in spheroidal wavefunctions.
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TL;DR: The crystal structure of the yellow compound (NH4)2CuCl4 has been determined by x-ray diffraction studies as discussed by the authors, and the compound crystallizes in the orthorhombic space group Cmca with a=15.46 A, b=7.20 A, and c =7.33 A. The structure contains discrete, planar CuCl4= ions with Cu-Cl distances of 2.30 and 2.79 A.
Abstract: The crystal structure of the yellow compound (NH4)2CuCl4 has been determined by x‐ray diffraction studies. The compound crystallizes in the orthorhombic space group Cmca with a=15.46 A, b=7.20 A, and c=7.20 A. The structure contains discrete, planar CuCl4= ions with Cu–Cl distances of 2.30 and 2.33 A. These ions are then bonded together by longer Cu–Cl bonds of 2.79 A to form infinite two‐dimensional sheets. The yellow compounds (CH3NH3)2CuCl4 and (C2H5NH3)2CuCl4 probably have closely related structures.
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