Crystal Structure and Electronic Spectrum of the Distorted Tetrahedral CuCl42- Ion in Bis(2-aminopyridinium) Tetrachlorocuprate(II) and Comparison With the Tetragonally Elongated Octahedral Complex Bis(2-aminopyrimidinium)tetrachlorocopper(II)

1995 ◽  
Vol 48 (4) ◽  
pp. 771 ◽  
Author(s):  
CL Boutchard ◽  
MA Hitchman ◽  
BW Skelton ◽  
AH White

The crystal structure of bis(2-aminopyridinum) tetrachlorocuprate (II) has been determined by single-crystal X-ray diffraction. The triclinic unit cell, space group Pī, contains a single formula unit in the asymmetric unit. The CuCl42- ions occur as isolated groups having a highly flattened tetrahedral geometry. The chloride ions are hydrogen-bonded to both nitrogen atoms of the cation, and the influence of this upon the geometry of the copper(II) complex is discussed. The low-temperature single-crystal electronic spectrum of the compound is reported, and the intensities and energies of the d-d transitions are related to the degree of distortion of the CuCl42- ion. The electronic spectrum of a crystal of bis (2-aminopyrimidinium) tetrachlorocopper (II), which contains a tetragonally elongated octahedral complex in which the cation forms long axial bonds to the copper(II) ion, was also measured for comparison. Angular overlap metal-ligand bonding parameters are derived for the two compounds, and discussed in terms of the different geometries of the complexes.

1988 ◽  
Vol 43 (1) ◽  
pp. 49-52 ◽  
Author(s):  
Hubert Schmidbaur ◽  
Jan Ebenhöch

Abstract Trimethylsilylethine (1) has been prepared from C2H2, sodium and Me3SiCl in anisole. The product can be converted into a Grignard reagent Me3SiC≡CMgCl using iPrMgCl. This reagent yields the compounds Me3SiC≡CSiH3, (Me3SiC≡C)2SiH2, (Me3SiC≡C)3SiH, and (Me3SiC≡C)4Si (2-5) when treated with equivalent amounts of H3SiBr, H2SiBr2, HSiCl3, or SiCl4. respectively. The new silanes have been characterized by NMR data. The crystal structure of (Me3SiC≡C)4Si has been determined by single crystal X-ray diffraction. It shows the expected tetrahedral geometry at he central silicon atom with four linear SiC≡CSi linkages.


1997 ◽  
Vol 50 (2) ◽  
pp. 145 ◽  
Author(s):  
Timothy Astley ◽  
Michael A. Hitchman ◽  
Brian W. Skelton ◽  
Allan H. White

The crystal structure of the complex [Ni(pz2thCH)2(O(O′)NO′′)] NO3 has been determined by X-ray diffraction, where pz and th represent the pyrazolyl and thienyl groups of a potentially tripodal ligand. The thienyl groups are not bound to the metal, which is coordinated to four pyrazolyl groups and a chelating nitrate ion. The electronic ‘d–d’ transition energies are interpreted in terms of angular-overlap bonding parameters which agree well with those reported for other similar complexes.


2018 ◽  
Vol 74 (10) ◽  
pp. 1079-1087
Author(s):  
Kevin M. Knowles ◽  
Anjan Sil ◽  
Berthold Stöger ◽  
Matthias Weil

The determination of the crystal structure of theMphase, (MnxZn1–x)2V2O7(0.75 <x< 0.913), in the pseudobinary Mn2V2O7–Zn2V2O7system forx≃ 0.8 shows that the previously published triclinic unit-cell parameters for this thortveitite-related phase do not describe a true lattice for this phase. Instead, single-crystal X-ray data and Rietveld refinement of synchrotron X-ray powder data show that theMphase has a different triclinic structure in the space groupP-1 withZ= 2. As prior work has suggested, the crystal structure can be described as a distorted version of the thortveitite crystal structure of β-Mn2V2O7. A twofold superstructure in diffraction patterns of crystals of theMphase used for single-crystal X-ray diffraction work arises from twinning by reticular pseudomerohedry. This superstructure can be described as a commensurate modulation of a pseudo-monoclinic basis structure closely related to the crystal structure of β-Mn2V2O7. In comparison with the distortions introduced when β-Mn2V2O7transforms at low temperature to α-Mn2V2O7, the distortions which give rise to theMphase from the β-Mn2V2O7prototype are noticeably less pronounced.


Author(s):  
Süheyla Özbey ◽  
F. B. Kaynak ◽  
M. Toğrul ◽  
N. Demirel ◽  
H. Hoşgören

AbstractA new type of inclusion complex, S(–)-1 phenyl ethyl ammonium percholorate complex of R-(–)-2-ethyl - N - benzyl - 4, 7, 10, 13 - tetraoxa -1- azacyclopentadecane, has been prepared and studied by NMR, IR and single crystal X-ray diffraction techniques. The compound crystallizes in space group


2015 ◽  
Vol 71 (4) ◽  
pp. 330-337 ◽  
Author(s):  
Sabina Kovač ◽  
Ljiljana Karanović ◽  
Tamara Đorđević

Two isostructural diarsenates, SrZnAs2O7(strontium zinc diarsenate), (I), and BaCuAs2O7[barium copper(II) diarsenate], (II), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. The three-dimensional open-framework crystal structure consists of corner-sharingM2O5(M2 = Zn or Cu) square pyramids and diarsenate (As2O7) groups. Each As2O7group shares its five corners with five differentM2O5square pyramids. The resulting framework delimits two types of tunnels aligned parallel to the [010] and [100] directions where the large divalent nine-coordinatedM1 (M1 = Sr or Ba) cations are located. The geometrical characteristics of theM1O9,M2O5and As2O7groups of known isostructural diarsenates, adopting the general formulaM1IIM2IIAs2O7(M1II= Sr, Ba, Pb;M2II= Mg, Co, Cu, Zn) and crystallizing in the space groupP21/n, are presented and discussed.


Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 272
Author(s):  
Seungyeol Lee ◽  
Huifang Xu ◽  
Hongwu Xu ◽  
Joerg Neuefeind

The crystal structure of moganite from the Mogán formation on Gran Canaria has been re-investigated using high-resolution synchrotron X-ray diffraction (XRD) and X-ray/neutron pair distribution function (PDF) analyses. Our study for the first time reports the anisotropic atomic displacement parameters (ADPs) of a natural moganite. Rietveld analysis of synchrotron XRD data determined the crystal structure of moganite with the space group I2/a. The refined unit-cell parameters are a = 8.7363(8), b = 4.8688(5), c = 10.7203(9) Å, and β = 90.212(4)°. The ADPs of Si and O in moganite were obtained from X-ray and neutron PDF analyses. The shapes and orientations of the anisotropic ellipsoids determined from X-ray and neutron measurements are similar. The anisotropic ellipsoids for O extend along planes perpendicular to the Si-Si axis of corner-sharing SiO4 tetrahedra, suggesting precession-like movement. Neutron PDF result confirms the occurrence of OH over some of the tetrahedral sites. We postulate that moganite nanomineral is stable with respect to quartz in hypersaline water. The ADPs of moganite show a similar trend as those of quartz determined by single-crystal XRD. In short, the combined methods can provide high-quality structural parameters of moganite nanomineral, including its ADPs and extra OH position at the surface. This approach can be used as an alternative means for solving the structures of crystals that are not large enough for single-crystal XRD measurements, such as fine-grained and nanocrystalline minerals formed in various geological environments.


2020 ◽  
Vol 75 (8) ◽  
pp. 765-768
Author(s):  
Bohdana Belan ◽  
Dorota Kowalska ◽  
Mariya Dzevenko ◽  
Mykola Manyako ◽  
Roman Gladyshevskii

AbstractThe crystal structure of the phase Ce5AgxGe4−x (x = 0.1−1.08) has been determined using single-crystal X-ray diffraction data for Ce5Ag0.1Ge3.9. This phase is isotypic with Sm5Ge4: space group Pnma (No. 62), Pearson code oP36, Z = 4, a = 7.9632(2), b = 15.2693(5), c = 8.0803(2) Å; R1 = 0.0261, wR2 = 0.0460, 1428 F2 values and 48 variables. The two crystallographic positions 8d and 4c show Ge/Ag mixing, leading to a slight increase in the lattice parameters as compared to those of the pure binary compound Ce5Ge4.


2010 ◽  
Vol 95 (4) ◽  
pp. 655-658 ◽  
Author(s):  
S. Nazzareni ◽  
P. Comodi ◽  
L. Bindi ◽  
L. Dubrovinsky

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