scholarly journals Different Polyoxometalate Structures Obtained from the Na11H[H(2-x)Bi2W20O70(HWO3)x]·46H2O(x=1.4).

2018 ◽  
Vol 1 (2) ◽  
pp. 93-100
Author(s):  
Suhair Atta

In the supramolecular chemistry world, Polyoxometalates (POMs) are considered as a new family of inorganic molecular containers, construct itself by self-assembly reaction from very small units, to form a cluster with unique structural and properties. three structures reported in this paper - differ in their unit cell parameters and also differ from the well-known - as the result of reaction of the Na11H[H(2- x)Bi2W20O70(HWO3)x]·46H2O (x=1.4) with Ca ion at different pH conditions. These structures are [Ca(H2O)7]2[Na(H2O)2]2[HBi2W20O70(HWO3)].14H2O(1), H2[NH4]10[HBi2W20O70(HWO3)] (2), and [NH4]6[Na(H2O)4]2[Ca(H2O)4]2[W12O42].2H2O (3). The last one is bismuth-free and it is formed through reassembly of the precursor. Full structural characterization was made by multiple testing techniques such as single-crystal X-ray diffraction, UV-visible spectroscopy, FT-IR, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The single-crystal X-ray diffraction results for the three compounds are as follows:(1), Triclinic, space group P-1, while (2) and (3) crystallize in monoclinic space groups C2/m and P21/n respectively.


2006 ◽  
Vol 61 (10) ◽  
pp. 1217-1221 ◽  
Author(s):  
Zerrin Heren ◽  
Cem Keser ◽  
C. Cüneyt Ersanli ◽  
O. Zafer Yeşilel ◽  
Nazan Ocak

The mixed-ligand picolinato (pic) complex of Cu(II) with 4-methylimidazole (4-MeIm), [Cu(pic)2(4-MeIm)2], was synthesized and characterized by elemental analysis, magnetic susceptibility, spectroscopic methods (UV/vis and FT-IR) and X-ray diffraction. In the slightly distorted octahedral cis-bis(4-methylimidazole)bis(picolinato)copper(II) complex, the pic ligands are coordinated to the Cu(II) ion as bidentate N,O-donors forming chelate rings. The 4-MeIm ligands are N-coordinated in cis positions. The complex crystallizes in the triclinic space group p̅1 with unit cell parameters a = 9.204(5), b = 9.498(5), c = 13.095(5) Å , α = 90.395(5), β = 101.687(5), γ = 112.291(5)° and Z = 2. Hydrogen bondings and C-H ··· π interactions occur between picolinato and methylimidazole ligands of neighboring complex molecules. The thermal decomposition of the complex is described.



1994 ◽  
Vol 49 (12) ◽  
pp. 1654-1658 ◽  
Author(s):  
Markus Wieber ◽  
Stefan Lang ◽  
Stefan Rohse ◽  
Ralph Habersack ◽  
Christian Burschka

The synthesis of triphenyltelluroniumsulfide (Ph3TeS)4 is described together with a NMR-spectroscopic characterization. The structure of the title compound was determined by single crystal X-ray diffraction. Crystals of triphenyltelluroniumsulfide are triclinic (space group P1) with the cell parameters a = 1178.0(3) pm. b = 1295.8(6) pm. c = 1298.7(4) pm, α = 77.67(3)°, β = 82.18(2)°, γ = 66.00(2)° (V = 1766(1) × 106 pm3) and Z = 2. The compound appears to form a step-like structure of two [Ph3TeS]2 units and crystallizes with two molecules of CH2Cl2 per unit cell.



1988 ◽  
Vol 66 (7) ◽  
pp. 1770-1775 ◽  
Author(s):  
David J. Elliot ◽  
Sanna Haukilahti ◽  
David G. Holah ◽  
Alan N. Hughes ◽  
Stanislaw Maciaszek ◽  
...  

Reactions between Co(II), Diphos, and NaBH3CN lead to Co(BH3CN)2(Diphos)2, 1, or [Co(BH3CN)(Diphos)2]X, 2 (X = ClO4 or BPh4), and, in certain solvents, 2 reacts to produce [Co(CN)(Diphos)2](ClO4). Compound 1 can be reversibly converted to Co(BH3CN)2(DMF)4, 4, via Co(BH3CN)2(Diphos)(DMF). In addition, 1 reacts with CO to form the Co(I) and Co(III) compounds [Co(Diphos)2](CO)]X and [Co(Diphos)2(CN)2]X (X = BH3CN or BPh4). Single crystal X-ray diffraction studies of 4 show that the compound crystallizes in the triclinic space group [Formula: see text], with unit cell parameters a = 7.572(6), b = 9.695(6), c = 9.395(6) Å, α = 81.06(4), β = 68.46(5), γ = 68.19(5)°, V = 595.5 Å3, Z = 1, and dcalcd = 1.202 g cm−3. The structure converged to a conventional R factor of 0.040 for 2841 observations and showed an octahedral arrangement of four O atoms from DMF molecules and two trans N-bound BH3CN groups around the Co(II) center.



Author(s):  
Y. P. Lin ◽  
J. S. Xue ◽  
J. E. Greedan

A new family of high temperature superconductors based on Pb2Sr2YCu3O9−δ has recently been reported. One method of improving Tc has been to replace Y partially with Ca. Although the basic structure of this type of superconductors is known, the detailed structure is still unclear, and various space groups has been proposed. In our work, crystals of Pb2Sr2YCu3O9−δ with dimensions up to 1 × 1 × 0.25.mm and with Tc of 84 K have been grown and their superconducting properties described. The defects and crystal symmetry have been investigated using electron microscopy performed on crushed crystals supported on a holey carbon film.Electron diffraction confirmed x-ray diffraction results which showed that the crystals are primitive orthorhombic with a=0.5383, b=0.5423 and c=1.5765 nm. Convergent Beam Electron Diffraction (CBED) patterns for the and axes are shown in Figs. 1 and 2 respectively.



Author(s):  
P. Vojtíšek ◽  
I. Císařová ◽  
J. Podlaha ◽  
Z. Žák ◽  
S. Böhm ◽  
...  

AbstractCrystal structures of the title compounds were determined by single crystal X-ray diffraction. Absolute configuration of the barium salt of (+)-(



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.



Author(s):  
Gohil S. Thakur ◽  
Hans Reuter ◽  
Claudia Felser ◽  
Martin Jansen

The crystal structure redetermination of Sr2PdO3 (distrontium palladium trioxide) was carried out using high-quality single-crystal X-ray data. The Sr2PdO3 structure has been described previously in at least three reports [Wasel-Nielen & Hoppe (1970). Z. Anorg. Allg. Chem. 375, 209–213; Muller & Roy (1971). Adv. Chem. Ser. 98, 28–38; Nagata et al. (2002). J. Alloys Compd. 346, 50–56], all based on powder X-ray diffraction data. The current structure refinement of Sr2PdO3, as compared to previous powder data refinements, leads to more precise cell parameters and fractional coordinates, together with anisotropic displacement parameters for all sites. The compound is confirmed to have the orthorhombic Sr2CuO3 structure type (space group Immm) as reported previously. The structure consists of infinite chains of corner-sharing PdO4 plaquettes interspersed by SrII atoms. A brief comparison of Sr2PdO3 with the related K2NiF4 structure type is given.



Author(s):  
Takashi Mochiku ◽  
Yoshitaka Matsushita ◽  
Nikola Subotić ◽  
Takanari Kashiwagi ◽  
Kazuo Kadowaki

RhPb2 (rhodium dilead) is a superconductor crystallizing in the CuAl2 structure type (space group I4/mcm). The Rh and Pb atoms are located at the 4a (site symmetry 422) and 8h (m.2m) sites, respectively. The crystal structure is composed of [RhPb8] antiprisms, which share their square faces along the c axis and the edges in the direction perpendicular to the c axis. We have succeeded in growing single crystals of RhPb2 and have re-determined the crystal structure on basis of single-crystal X-ray diffraction data. In comparison with the previous structure studies using powder X-ray diffraction data [Wallbaum (1943). Z. Metallkd. 35, 218–221; Havinga et al. (1972). J. Less-Common Met. 27, 169–186], the current structure analysis of RhPb2 leads to more precise unit-cell parameters and fractional coordinates, together with anisotropic displacement parameters for the two atoms. In addition and likewise different from the previous studies, we have found a slight deficiency of Rh in RhPb2, leading to a refined formula of Rh0.950 (9)Pb2.



2011 ◽  
Vol 26 (2) ◽  
pp. 119-125 ◽  
Author(s):  
Sytle M. Antao ◽  
Ishmael Hassan

The crystal structures of marialite (Me6) from Badakhshan, Afghanistan and meionite (Me93) from Mt. Vesuvius, Italy were obtained using synchrotron high-resolution powder X-ray diffraction (HRPXRD) data and Rietveld structure refinements. Their structures were refined in space groups I4/m and P42/n, and similar results were obtained. The Me6 sample has a formula Ca0.24Na3.37K0.24[Al3.16Si8.84O24]Cl0.84(CO3)0.15, and its unit-cell parameters are a=12.047555(7), c=7.563210(6) Å, and V=1097.751(1) Å3. The average ⟨T1-O⟩ distances are 1.599(1) Å in I4/m and 1.600(2) Å in P42/n, indicating that the T1 site contains only Si atoms. In P42/n, the average distances of ⟨T2-O⟩=1.655(2) and ⟨T3-O⟩=1.664(2) Å are distinct and are not equal to each other. However, the mean ⟨T2,3-O⟩=1.659(2) Å in P42/n and is identical to the ⟨T2′-O⟩=1.659(1) Å in I4/m. The ⟨M-O⟩ [7]=2.754(1) Å (M site is coordinated to seven framework O atoms) and M-A=2.914(1) Å; these distances are identical in both space groups. The Me93 sample has a formula of Na0.29Ca3.76[Al5.54Si6.46O24]Cl0.05(SO4)0.02(CO3)0.93, and its unit-cell parameters are a=12.19882(1), c=7.576954(8) Å, and V=1127.535(2) Å3. A similar examination of the Me93 sample also shows that both space groups give similar results; however, the C–O distance is more reasonable in P42/n than in I4/m. Refining the scapolite structure near Me0 or Me100 in I4/m forces the T2 and T3 sites (both with multiplicity 8 in P42/n) to be equivalent and form the T2′ site (with multiplicity 16 in I4/m), but ⟨T2-O⟩ is not equal to ⟨T3-O⟩ in P42/n. Using different space groups for different regions across the series implies phase transitions, which do not occur in the scapolite series.



2007 ◽  
Vol 62 (10) ◽  
pp. 1271-1276 ◽  
Author(s):  
Liang Chen ◽  
Xian-Wen Wanga ◽  
Jing-Zhong Chen ◽  
Jian-Hong Liu

The complexes Mn(Cl3CCOO)2(4,4′-bpy) (1) and [Cu2(ClCH2COO)(2,2′-bpy)2(OH)(H2O)]-(NO3)2(2) (bpy = bipyridine) were generated under mild reaction conditions and characterized by IR spectra, thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), and single crystal X-ray diffraction. Compound 1 exhibits a two-dimensional network with octahedrally coordinated Mn(II) atoms linked by 4,4′-bpy ligands and Cl3COO− ligands. Compound 2 features a supramolecular structure of binuclear complexes, with edge-sharing five-coordinated square-pyramidal units bridged by the ClCH2COO− ligand, an OH− group and a water molecule. Complex 1 crystallizes in the orthorhombic space group Pbcn with cell parameters: a = 16.5390(17), b = 11.6396(17), c = 9.9181(12) Å, V = 1909.3(4) Å3, Z = 4, wR2 = 0.1576. Complex 2 crystallizes in the triclinic space group P1̅ with cell parameters: a = 7.6190(15), b = 11.151(2), c = 16.640(3) Å , α = 73.13(3), β = 80.89(3), γ = 74.51(3)°, V = 1298.73(4) Å3, Z = 2, wR2 = 0.1265.



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