scholarly journals Crystal structure and metallization mechanism of the π-radical metal TED

2020 ◽  
Vol 11 (43) ◽  
pp. 11699-11704
Author(s):  
Yuka Kobayashi ◽  
Kazuto Hirata ◽  
Samantha N. Hood ◽  
Hui Yang ◽  
Aron Walsh ◽  
...  

The molecular arrangement that enables metallic conduction in a single-component pure organic crystal is revealed by single-crystal X-ray diffraction.

2014 ◽  
Vol 70 (a1) ◽  
pp. C191-C191
Author(s):  
Jie Su ◽  
Yue-Biao Zhang ◽  
Yifeng Yun ◽  
Hiroyasu Furukawa ◽  
Felipe Gándara ◽  
...  

Covalent organic frameworks (COFs) represent an exciting new type of porous organic materials, which are constructed with organic building units via strong covalent bonds.[1] The structure determination of COFs is challenging, due to the difficulty in growing sufficiently large crystals suitable for single crystal X-ray diffraction, and low resolution and peak broadening for powder X-ray diffraction. Crystal structures of COFs are typically determined by modelling building with the aid of geometry principles in reticular chemistry and powder X-ray diffraction data. Here, we report the single-crystal structure of a new COF (COF-320) determined by 3D rotation electron diffraction (RED),[2] a technique applied in this context for the first time. The RED method can collect an almost complete three-dimensional electron diffraction dataset, and is a useful technique for structure determination of micron- and nanosized single crystals. To minimize electron beam damage, the RED dataset was collected at 89 K. 3D reciprocal lattice of COF-320 was reconstructed from the ED frames using the RED – data processing software[2]. As the resolution of the RED data only reached 1.6 Å, the simulated annealing parallel tempering algorithm in the FOX software package [3] was used to find a starting molecular arrangement from the 3D RED data. Finally, the crystal structure of COF-320 was solved in the space group of I-42d and refined using the SHELXL software package. The single-crystal structure of COF-320 exhibits a 3D extended framework by linking the tetrahedral organic building blocks and biphenyl linkers through imine-bonds forming a highly porous 9-fold interwoven diamond net.


2014 ◽  
Vol 59 (5-6) ◽  
pp. 497-501 ◽  
Author(s):  
Shanshan Li ◽  
Xiaoqing Wu ◽  
Qingqing Pan ◽  
Qiang Cheng ◽  
Hui Li

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

2017 ◽  
Vol 81 (4) ◽  
pp. 917-922
Author(s):  
Peter Elliott

AbstractThe crystal structure of the copper aluminium phosphate mineral sieleckiite, Cu3Al4(PO4)2 (OH)12·2H2O, from the Mt Oxide copper mine, Queensland, Australia was solved from single-crystal X-ray diffraction data utilizing synchrotron radiation. Sieleckiite has monoclinic rather than triclinic symmetry as previously reported and is space group C2/m with unit-cell parameters a = 11.711(2), b = 6.9233(14), c = 9.828(2) Å, β = 92.88(3)°, V = 795.8(3) Å3and Z = 2. The crystal structure, which has been refined to R1 = 0.0456 on the basis of 1186 unique reflections with Fo > 4σF, is a framework of corner-, edge- and face- sharing Cu and Al octahedra and PO4 tetrahedra.


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