◾ Monoclinic System: Sucrose

2014 ◽  
pp. 478-499
Keyword(s):  
Monoclinic System

Structural Study of a new Compound Based on Acid 1,4-Cyclohexanedicarboxylic (1,4-CDC)

2010 ◽  
Vol 6 (1) ◽  
pp. 891-896
Author(s):  
Manel Halouani ◽  
M. Dammak ◽  
N. Audebrand ◽  
L. Ktari
Keyword(s):  
Aqueous Solution ◽  
Water Molecules ◽  
Carboxyl Group ◽  
X Ray Diffraction ◽  
Compound I ◽  
Unit Cell Parameters ◽  
Monoclinic System ◽  
X Ray ◽  
Cell Parameters ◽  
Cyclohexanedicarboxylic Acid

One nickel 1,4-cyclohexanedicarboxylate coordination polymers, Ni2 [(O10C6H4)(COO)2].2H2O  (I), was hydrothermally synthesized from an aqueous solution of Ni (NO3)2.6H2O, (1,4-CDC) (1,4-CDC = 1,4-cyclohexanedicarboxylic acid) and tetramethylammonium nitrate. Compound (I) crystallizes in the monoclinic system with the C2/m space group. The unit cell parameters are a = 20.1160 (16) Å, b = 9.9387 (10) Å, c = 6.3672 (6) Å, β = 97.007 (3) (°), V= 1263.5 (2) (Å3) and Dx= 1.751g/cm3. The refinement converged into R= 0.036 and RW = 0.092. The structure, determined by single crystal X-ray diffraction, consists of two nickel atoms Ni (1) and Ni (2). Lots of ways of which is surrounded by six oxygen atoms, a carboxyl group and two water molecules.

scholarly journals Kinetic Analysis of the Thermal Decomposition of Iron(III) Phosphates: Fe(NH3)2PO4 and Fe(ND3)2PO4

2020 ◽  
Vol 21 (3) ◽  
pp. 781
Author(s):  
Isabel Iglesias ◽  
José A. Huidobro ◽  
Belén F. Alfonso ◽  
Camino Trobajo ◽  
Aránzazu Espina ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Analysis ◽  
Room Temperature ◽  
Isoconversional Methods ◽  
Iron Phosphate ◽  
Dihydrogen Phosphate ◽  
Monoclinic System ◽  
Space Group ◽  
X Ray ◽  
Group A

The hydrothermal synthesis and both the chemical and structural characterization of a diamin iron phosphate are reported. A new synthetic route, by using n-butylammonium dihydrogen phosphate as a precursor, leads to the largest crystals described thus far for this compound. Its crystal structure is determined from single-crystal X-ray diffraction data. It crystallizes in the orthorhombic system (Pnma space group, a = 10.1116(2) Å, b = 6.3652(1) Å, c = 7.5691(1) Å, Z = 4) at room temperature and, below 220 K, changes towards the monoclinic system P21/n, space group. The in situ powder X-ray thermo-diffraction monitoring for the compound, between room temperature and 1100 K, is also included. Thermal analysis shows that the solid is stable up to ca. 440 K. The kinetic analysis of thermal decomposition (hydrogenated and deuterated forms) is performed by using the isoconversional methods of Vyazovkin and a modified version of Friedman. Similar values for the kinetic parameters are achieved by both methods and they are checked by comparing experimental and calculated conversion curves.

Ab Initio Determination of a New Complex Structure (55 Non-Hydrogen Atoms) from Synchrotron Powder Data: An Uncommon Nickel Succinate, Ni7(C4H4O4)4(OH)6(H2O)3•7H2O

2004 ◽  
Vol 443-444 ◽  
pp. 333-336
Author(s):  
N. Guillou ◽  
C. Livage ◽  
W. van Beek ◽  
G. Férey
Keyword(s):  
Ab Initio ◽  
Complex Structure ◽  
Three Dimensional ◽  
Free Water ◽  
Hydrogen Atoms ◽  
Monoclinic System ◽  
Synchrotron Powder Diffraction ◽  
Chloride Hexahydrate ◽  
Autogenous Pressure

Ni7(C4H4O4)4(OH)6(H2O)3. 7H2O, a new layered nickel(II) succinate, was prepared hydrothermally (180°C, 48 h, autogenous pressure) from a 1:1.5:4.1:120 mixture of nickel (II) chloride hexahydrate, succinic acid, potassium hydroxide and water. It crystallizes in the monoclinic system (space group P21/c, Z = 4) with the following parameters a = 7.8597(1) Å, b = 18.8154(3)Å, c = 23.4377(4) Å,ϐ = 92.0288(9)°, and V = 3463.9(2) Å3. Its structure, which contains 55 non-hydrogen atoms, was solved ab initio from synchrotron powder diffraction data. It can be described from hybrid organic-inorganic layers, constructed from nickel oxide corrugated chains. These chains are built up from NiO6hexameric units connected via a seventh octahedron. Half of the succinates decorate the chains, and the others connect them to form the layers. The three dimensional arrangement is ensured by hydrogen bonds directly between two adjacent layers and via free water molecules.

Synthesis, structural and magnetic properties of macrocyclic aza-amido binuclear copper(II) complexes

1989 ◽  
Vol 67 (4) ◽  
pp. 662-670 ◽  
Author(s):  
Sanat K. Mandal ◽  
Laurence K. Thompson ◽  
Michael J. Newlands ◽  
Amal K. Biswas ◽  
Bibhutosh Adhikary ◽  
...  
Keyword(s):  
Variable Temperature ◽  
Complex Iii ◽  
Azomethine Nitrogen ◽  
X Ray Diffraction ◽  
Binuclear Copper ◽  
Magnetic Studies ◽  
Monoclinic System ◽  
Space Group ◽  
Pyramidal Geometry ◽  
Square Planar

Binuclear, antiferromagnetically coupled, macrocyclic copper(II) complexes, [Cu2(C28H32N4O4)]•H2O (II) and [Cu2(C36H32N4O4)]•CH3CN•H2O (III), involving asymmetric ligands with two deprotonated amide, two azomethine nitrogen, and two phenoxide donors at the binuclear centre, have been synthesized and characterized by single-crystal X-ray diffraction and variable temperature magnetic studies. Complex II crystallizes in the monoclinic system, space group P21/n, with a = 16.4854(9) Å, b = 7.6005(13) Å, c = 21.1617(11) Å, β = 104.090(5)°, Z = 4, Rf = 0.068 for 2062 significant reflections. The two copper(II) centres have square planar N2O2 donor sets with two phenoxide oxygen atoms bridging the copper centres with a copper–copper separation of 2.898(2) Å. A long copper–oxygen (amide) contact (2.808(10) Å) forms a weak dimer association. Complex III crystallizes in the triclinic system, space group [Formula: see text], with a = 8.7771(9) Å, b = 12.3983(16) Å, c = 15.7299(16) Å, α = 85.003(11)°, β = 84.574(8)°, γ = 76.838(10)°, Z = 2, Rf = 0.041 for 2966 significant reflections. The two copper(II) centres have distorted square-pyramidal geometry involving an N2O2 in plane donor set and two phenoxide oxygen bridges with a copper–copper separation of 3.018(1) Å. The fifth coordination site at each copper centre involves an amide oxygen from a neighbouring molecule (Cu(1)—O 2.371(4), Cu(2)—O 2.413(3) Å) in a staggered intermolecular array. Very strong antiferromagnetic exchange is observed in both cases (−2J = 689 ± 7 cm−1 (II), −2J = 816 ± 8 cm−1 (III)). Keywords: macrocycles, binuclear copper(II) complexes.

Kristallstruktur und Schwingungsspektren des Di-Blei-Hexaselenohypodiphosphates Pb2P2Se6 / Crystal Structure and Vibrational Spectra of Pb2P2Se6

1984 ◽  
Vol 39 (4) ◽  
pp. 357-361 ◽  
Author(s):  
Robert Becker ◽  
Wolfgang Brockner ◽  
Herbert Schäfer
Keyword(s):  
Crystal Structure ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
Title Compound ◽  
Far Infrared ◽  
Infrared And Raman Spectra ◽  
Monoclinic System ◽  
Space Group ◽  
Lattice Constants

Pb2P2Se6 crystallizes in the monoclinic system, space group Pn (No. 13) with the lattice constantsa = 974.2 (4) pm. b = 766.2 (3) pm. c = 689.8 (3) pm, β=91.44(5)°.The title compound is isotypic to the homologous Pb2P2S6. In the structure there are discrete P2Se4-6 anions.Far infrared, infrared and Raman spectra of this compound have been recorded. The observed frequencies are assigned on the basis of P2Se4-6 units with C2h symmetry in the crystal. DTA-data have been determined and interpreted.

scholarly journals Selective time-dependent changes of Cu(DPPE)(DMP)·PF6on photoexcitation

2014 ◽  
Vol 70 (a1) ◽  
pp. C776-C776 ◽  
Author(s):  
Elzbieta Trzop ◽  
Bertrand Fournier ◽  
Katarzyna Jarzembska ◽  
Jesse Sokolow ◽  
Radoslaw Kaminski ◽  
...  
Keyword(s):  
Structural Changes ◽  
Dye Sensitized Solar Cells ◽  
Department Of Energy ◽  
Data Sets ◽  
Monoclinic System ◽  
Time Resolved ◽  
Pump Probe ◽  
Light Emitting Devices ◽  
Potential Applications ◽  
Photon Source

Thanks to their potential applications as light-emitting devices, chemical sensors and dye-sensitized solar cells, heteroleptic copper (I) complexes have been extensively studied. Cu(DPPE)(DMP)·PF6(dppe= 1,2-bis(diphenylphosphino)ethane; dmp = 2,9-dimethyl-1,10-phenanthroline) crystallizes in the monoclinic system, P21/c, with two independent molecules in the asymmetric unit. Previous studies on this system [1,2] show strong temperature-dependent emission. The complex was studied at 90K under 355nm laser excitation. At this temperature, the luminescence decay for Cu(DPPE)(DMP)·PF6is biexponential with lifetimes of ~3μs and ~28μs. Two time-resolved X-ray diffraction techniques were applied for studies: (1) a Laue technique at BioCARS ID-14 beamline at the Advanced Photon Source, and (2) monochromatic diffraction at a newly constructed in-house pump-probe monochromatic facility at the University at Buffalo. Structural changes determined with the two methods are in qualitative agreement; discrepancies in position of the Cu and P atoms were observed. The molecular distortions were smaller than those determined at 16K in the earlier synchrotron study by Vorontsov et al. [2]. Photodeformation maps (see Figure below), in which the increase in temperature on photoexcitation has been eliminated, clearly illustrate the photoinduced atomic shifts for both data sets. Results will be compared with those obtained for other studied heteroleptic copper (I) complexes, for instance Cu[(1,10-phenanthroline-N,N′) bis(triphenylphosphine)]·BF4[3]. The in-house pump-probe facility is discussed by Radoslaw Kaminski at this meeting. Research funded by the National Science Foundation (CHE1213223). BioCARS Sector 14 at APS is supported by NIH (RR007707). The Advanced Photon Source is funded by the Office of Basic Energy Sciences, U.S. Department of Energy, (W-31-109-ENG-38). KNJ is supported by the Polish Ministry of Science and Higher Education through the "Mobility Plus" program.

Characterization of New Inorganic- Organic Hybrid Compounds: (C6H10N2).Cl2 (I), [C6H10N2]2ZnCl4 (II): Crystal Structure, Hirschfield Surface, IR and NMR spectroscopy Analysis.

2021 ◽  
Author(s):  
nejeh hannachi ◽  
faouzi hlel
Keyword(s):  
Nmr Spectroscopy ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Spectroscopy Analysis ◽  
Absorption Bands ◽  
Monoclinic System ◽  
Xrd Pattern ◽  
Organic Hybrid ◽  
C Nmr

Abstract Two new organic-inorganic hybrid materials, (C6H10N2).Cl2 (I) and [C6H10N2]2ZnCl4 (II), have been synthesized by hydrothermal method and characterized by single-crystal X-ray diffraction and XRD pattern investigations. These two compounds are crystallized in the monoclinic system; C2/c space group. In the both structures, the anionic-cationic entities are interconnected by hydrogen bonding contacts and p-p Interaction forming three-dimensional networks. Intermolecular interactions were investigated by Hirshfeld surfaces and the contacts of the four different chloride atoms in (II) were compared. The vibrational absorption bands were identified by infrared spectroscopy. These compounds were also investigated by solid state 13C NMR spectroscopy.

Structure of the Tris(diallyldithiocarbamate)cobalt(III) Complex

1992 ◽  
Vol 57 (2) ◽  
pp. 332-338 ◽  
Author(s):  
Eleonóra Kellö ◽  
Jan Lokaj ◽  
Viktor Vrábel
Keyword(s):  
Least Squares ◽  
Metal Atom ◽  
Least Squares Method ◽  
Heavy Atom ◽  
Distorted Octahedron ◽  
Monoclinic System ◽  
Space Group ◽  
Twofold Axis ◽  
Diagonal Approximation ◽  
Heavy Atom Method

The structure of [Co{S2CN(CH2-CH=CH2)2}3] was determined by the heavy atom method, all nonhydrogen atoms being refined by anisotropic diagonal approximation using the least squares method to the value of R= 0.067 for 1 024 reflections with I ≥ 1.96σ(I). The substance is isostructural with [Fe{S2CN(CH2-CH=CH2)2}3], crystallizes in the monoclinic system, space group C2/c, lattice parameters a = 1.8763(9), b = 1.0209(5), c = 1.5402(7) nm, β = 106.18(4)°, Z = 4. Cobalt is coordinated by 3 dithiocarbamate ligands in the bidentate way, the average Co-S lenght is 0.2267(2) nm. The metal atom and two ligand atoms are located on the twofold axis. The CoS6 polyhedron is a trigonally distorted octahedron.

Kinetics of nonisothermal dehydration of unirradiated and γ-ray irradiated neodymium (III) acetate hydrate

2019 ◽  
Vol 107 (2) ◽  
pp. 165-178
Author(s):  
Noura Mossaed Saleh ◽  
Ghada Adel Mahmoud ◽  
AbdelRahman AbdelMonem Dahy ◽  
Soliman Abdel-Fadeel Soliman ◽  
Refaat Mohamed Mahfouz
Keyword(s):  
Absorbed Dose ◽  
Isoconversional Methods ◽  
Gas Diffusion ◽  
Conversion Degree ◽  
Monoclinic System ◽  
Air Atmosphere ◽  
Dehydration Reactions ◽  
Γ Ray ◽  
Acetate Hydrate ◽  
Kinetics Of

Abstract Kinetics of dehydration of unirradiated and γ-ray irradiated neodymium (III) acetate hydrate with 103 kGy total γ-ray dose absorbed in air atmosphere were studied by isoconversional nonisothermal method. The dehydration proceeds in two steps with the elimination of 0.8 and 0.4 mol of H2O, respectively. This result indicates that the investigated neodymium (III) acetate hydrate contains 1.2 mol of crystalline water in its structure. The dehydration reactions are best described by nucleation (A2 model) and gas diffusion (D4 model) for unirradiated and γ-ray irradiated samples, respectively. Analysis of the kinetic data using linear and nonlinear isoconversional methods showed that the apparent activation energy, Ea (kJ/mol) is dependent on the conversion degree, α, of the dehydration process. The Ea−α plots for both unirradiated and γ-ray irradiated neodymium (III) acetate hydrate showed that the dehydration is a complex process and contains multistep reactions. The results showed that γ-ray irradiation has a significant effect on the kinetics and thermodynamic parameters of the dehydration reaction. Powder X-ray diffraction showed that neodymium (III) acetate hydrate has a monoclinic system (SG P2/m) and no phase transformation was detected by γ-ray irradiation up to 103 kGy absorbed dose. The system maintains the same crystal structure before and after dehydration.

scholarly journals The hydrocarbon-bearing clathrasil chibaite and its host–guest structure at low temperature

IUCrJ ◽  
2018 ◽  
Vol 5 (5) ◽  
pp. 595-607 ◽  
Author(s):  
K. S. Scheidl ◽  
H. S. Effenberger ◽  
T. Yagi ◽  
K. Momma ◽  
Ronald Miletich
Keyword(s):  
Room Temperature ◽  
Guest Molecule ◽  
Chemical Formula ◽  
X Ray Diffraction ◽  
Continuous Symmetry ◽  
Monoclinic System ◽  
X Ray ◽  
Anisotropic Displacement Parameters ◽  
Hydrocarbon Molecules ◽  
Silicate Framework

The natural sII-type clathrasil chibaite [chemical formula SiO2·(M 12,M 16), where M x denotes a guest molecule] was investigated using single-crystal X-ray diffraction and Raman spectroscopy in the temperature range from 273 to 83 K. The O atoms of the structure at room temperature, which globally conforms to space group Fd{\overline 3}m [V = 7348.9 (17) Å3, a = 19.4420 (15) Å], have anomalous anisotropic displacement parameters indicating a static or dynamic disorder. With decreasing temperature, the crystal structure shows a continuous symmetry-lowering transformation accompanied by twinning. The intensities of weak superstructure reflections increase as temperature decreases. A monoclinic twinned superstructure was derived at 100 K [A2/n, V = 7251.0 (17) Å3, a′ = 23.7054 (2), b′ = 13.6861 (11), c′ = 23.7051 (2) Å, β′ = 109.47°]. The transformation matrix from the cubic to the monoclinic system is ai ′ = (½ 1 ½ / ½ 0 −½ / ½ −1 ½). The A2/n host framework has Si—O bond lengths and Si—O—Si angles that are much closer to known values for stable silicate-framework structures compared with the averaged Fd{\overline 3}m model. As suggested from band splitting observed in the Raman spectra, the [512]-type cages (one crystallographically unique in Fd{\overline 3}m, four different in A2/n) entrap the hydrocarbon species (CH4, C2H6, C3H8, i-C4H10). The [51264]-type cage was found to be unique in both structure types. It contains the larger hydrocarbon molecules C2H6, C3H8 and i-C4H10.

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