scholarly journals Synthesis, crystal structure and vibrational spectra of Sr0.5Zr2(AsO4)3

2009 ◽  
Vol 24 (3) ◽  
pp. 200-204 ◽  
Author(s):  
A. Jrifi ◽  
A. El Jazouli ◽  
J. P. Chaminade ◽  
M. Couzi
Keyword(s):  
Rietveld Method ◽  
Group Analysis ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Bending Vibrations ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Dimensional Network ◽  
Good Agreement

Sr0.5Zr2(AsO4)3 arsenate was prepared and structurally characterized by powder X-ray diffraction and by Raman and infrared spectroscopies. Its structure, which belongs to the Nasicon-type family, was refined by the Rietveld method in the R-3 space group, from X-ray powder diffraction data. The hexagonal unit-cell parameters were determined to be ah=8.965(2) Å, ch=23.955(6) Å, V=1667.43(6) Å3, and Z=6. The structure is formed by an ionic three-dimensional network of AsO4 tetrahedra and ZrO6 octahedra linked by corners with Sr2+ ions occupying half of the M1 sites in an ordered manner. Raman and infrared spectra were recorded and assignments of the stretching and bending vibrations of the AsO43− tetrahedra were made. The number of the peaks observed is in good agreement with that predicted by the factor-group analysis of the R-3 space group.

Crystal Structures and Stability of Two Bipyridyl Complexes of Metal Chloroacetates

2007 ◽  
Vol 62 (10) ◽  
pp. 1271-1276 ◽  
Author(s):  
Liang Chen ◽  
Xian-Wen Wanga ◽  
Jing-Zhong Chen ◽  
Jian-Hong Liu
Keyword(s):  
Binuclear Complexes ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Reaction Conditions ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Dimensional Network

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.

Poly[[μ-(1-azaniumylethane-1,1-diyl)bis(hydrogen phosphonato)]sodium]: a powder X-ray diffraction study

2013 ◽  
Vol 69 (8) ◽  
pp. 815-818 ◽  
Author(s):  
Mwaffak Rukiah ◽  
Thaer Assaad
Keyword(s):  
Hydrogen Bonding ◽  
Rietveld Method ◽  
Three Dimensional ◽  
Coordination Geometry ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dimensional Network ◽  
Distorted Octahedral Coordination Geometry ◽  
Distorted Octahedral

The title two-dimensional coordination polymer, [Na(C2H8NO6P2)]n, was characterized using powder X-ray diffraction data and its structure refined using the Rietveld method. The asymmetric unit contains one Na+cation and one (1-azaniumylethane-1,1-diyl)bis(hydrogen phosphonate) anion. The central Na+cation exhibits distorted octahedral coordination geometry involving two deprotonated O atoms, two hydroxy O atoms and two double-bonded O atoms of the bisphosphonate anion. Pairs of sodium-centred octahedra share edges and the pairs are in turn connected to each other by the biphosphonate anion to form a two-dimensional network parallel to the (001) plane. The polymeric layers are connected by strong O—H...O hydrogen bonding between the hydroxy group and one of the free O atoms of the bisphosphonate anion to generate a three-dimensional network. Further stabilization of the crystal structure is achived by N—H...O and O—H...O hydrogen bonding.<!?tpb=18.7pt>

scholarly journals On the crystal structure of the ordered vacancy compound Cu3In5Te9

2019 ◽  
Vol 65 (4 Jul-Aug) ◽  
pp. 360 ◽  
Author(s):  
G. E. Delgado ◽  
C. Rincón ◽  
G. Marroquin
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Structural Models ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

The crystal structure of the ordered vacancy compound (OVC) Cu3In5Te9 was analyzed using powder X-ray diffraction data. Several structural models were derived from the structure of the Cu-poor Cu-In-Se compound b-Cu0.39In1.2Se2 by permuting the cations in the available site positions. The refinement of the best model by the Rietveld method in the tetragonal space group P2c (Nº 112), with unit cell parameters a = 6.1852(2) Å, c = 12.3633(9) Å, V = 472.98(4) Å3, led to Rp = 7.1 %, Rwp = 8.5 %, Rexp = 6.4 %, S = 1.3 for 162 independent reflections. This model has the following Wyckoff site atomic distribution: Cu1 in 2e (0,0,0); In1 in 2f (½,½,0), In2 in 2d (0,½,¼); Cu2-In3 in 2b (½,0,¼); in 2a (0,0,¼); Te in 8n (x,y,z).

Powder-Pattern: A System of Programs for Processing and Interpreting Powder Diffraction Data

1982 ◽  
Vol 26 ◽  
pp. 63-72 ◽  
Author(s):  
Nikos P. Pyrros ◽  
Camden R. Hubbard
Keyword(s):  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Pure Phase ◽  
Diffraction Patterns ◽  
Better Than ◽  
Good Agreement

The production of standard x-ray diffraction patterns at NBS imposes special requirements in the data processing of powder patterns. The patterns should be complete and have an overall accuracy of better than 0.01 degree two theta. To ensure completeness all the observable peaks should be indexed. To make certain that the sample is a pure phase, weak peaks have to be identified as well.The indexing of all the peaks implies that the cell constants must be known and there should be a good agreement between all the calculated and observed peak positions. In practice this is achieved by a least-squares refinement of the unit cell parameters. This serves as a test of the assumed unit cell and also as an interpretation of the observed peaks. Finally, an attempt is made to identify the space group. This step also requires the identification of weak peaks. The agreement of a known space group with the observed reflections further confirms the purity of the sample.

X-ray diffraction data of C16H14O4Ru2M (M=Ge,Si)

2002 ◽  
Vol 17 (1) ◽  
pp. 44-47
Author(s):  
Yu PuLan ◽  
Ding Shuang ◽  
Qiao YuanYuan ◽  
Yao XinKan ◽  
Liu Chong ◽  
...  
Keyword(s):  
Single Crystal ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Monoclinic Cell ◽  
Good Agreement

Two compounds have been studied by means of powder diffraction and their unit cell parameters are reported. The monoclinic cell parameters for dimethylgermanyl-bridged bis cyclopentadienyl tetracarbonyl diruthenium are a=11.03(2) Å, b=13.65(2) Å, c=11.609(2) Å, β=105.81(1)°, Z=4, space group P21/n (No. 14), Dx=2.135 mg/m3. The monoclinic cell parameters for λ-dimethylsilyl-dicyclopentadienyl-π, π′-tetracarbonyl diruthenium, are a=11.113(3) Å, b=13.60(1) Å, c=11.674(7) Å, and β=106.00(3)°, Z=4, space group P21/n (No. 14), and Dx=1.946 mg/m3. The cells found for the two compounds are in good agreement with those obtained from single crystal X-ray diffractometry.

Structure Refinement and Magnetic Properties of Ce2RuAl3 and a Group-Subgroup Scheme for Ce5Ru3Al2

2011 ◽  
Vol 66 (8) ◽  
pp. 771-776 ◽  
Author(s):  
Trinath Mishra ◽  
Rolf-Dieter Hoffmann ◽  
Christian Schwickert ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Properties ◽  
Diffraction Data ◽  
Structure Refinement ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Structural Distortions ◽  
Dimensional Network ◽  
Subgroup Scheme

The hexagonal Laves phase Ce2RuAl3 (≡ CeRu0.5Al1.5) was synthesized by high-frequencemelting of the elements in a sealed tantalum tube and subsequent annealing. The structure was refined from single-crystal X-ray diffraction data: MgZn2 type, P63/mmc, Z = 2, a = 565.38(9), c = 888.3(1) pm, wR2 = 0.0231, 193 F2 values and 13 parameters. The 2a (0.824 Ru + 0.176 Al) and 6h (0.956 Al + 0.044 Ru) Wyckoff positions show mixed occupancies leading to the composition CeRu0.48Al1.52 for the investigated crystal. The aluminum atoms build up Kagomé networks at z = 1/4 and z = 3/4 which are connected to a three-dimensional network by the ruthenium atoms. The cerium atoms fill cavities of coordination number 16 (3 Ru + 9 Al + 4 Ce) within the [RuAl3] network. The Ce2RuAl3 sample orders ferromagnetically at TC = 8.0(1) K. The cerium-rich aluminide Ce5Ru3Al2 shows unusually short Ce-Ru distances of 253 and 260 pm for the Ce1 position as a result of intermediate cerium valence. The structural distortions are discussed on the basis of a group-subgroup scheme for Pr5Ru3Al2 (space group I213) and the superstructure variant Ce5Ru3Al2 (space group R3).

Bavsiite, Ba2V2O2[Si4O12], mineral data and crystal structure

2019 ◽  
Vol 83 (6) ◽  
pp. 821-827
Author(s):  
Hans-Peter Bojar ◽  
Franz Walter ◽  
Judith Baumgartner
Keyword(s):  
Crystal Structure ◽  
Structural Formula ◽  
Yukon Territory ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Dimensional Network ◽  
Quartz Monzonite ◽  
Mineral Data ◽  
Good Agreement

AbstractBavsiite from the type locality Gun Claim, Yukon Territory, Canada, occurs as millimetre-sized sky-blue platy crystals in a barium-rich low-temperature skarn related to a porphyritic quartz monzonite stock. Associated minerals are alstonite, baryte, celsian, diopside, fresnoite, mica, suzukiite, walstromite, witherite and minerals of the cerchiaraite group. Bavsiite is optical uniaxial (+), with ω = 1.725(3) and ε = 1.750(3) (589 nm) and pleochroic. Electron microprobe analyses yielded the empirical formula Na0.02Ba1.98Ti0.16Fe2+0.03V4+1.80 Al0.05Si4.00O14 based on 14 oxygen atoms, the simplified chemical formula is Ba2V2Si4O14. Bavsiite is tetragonal, space group I4/m, a = 7.043(1), c = 11.444(2) Å and Z = 2 obtained from single crystal data at 100 K, which are in good agreement with cell parameters from powder diffraction data at 293 K: a = 7.051(1) Å and c = 11.470(1) Å. The eight strongest lines of the powder X-ray diffraction pattern are [d, Å (I,%)(hkl)]: 3.76(30)(112), 3.36(44)(013), 3.004(100)(022), 2.493(43)(220), 2.486(67)(114), 2.286(24)(222), 1.785(39)(116) and 1.763(25)(040). The crystal structure was refined to R = 0.0159 based upon 312 unique reflections with I > 2σ(I). The crystal structure of bavsiite comprises unbranched single [Si4O12]8– rings connected by [VO5]6– square pyramids and BaO12 polyhedra. It can also be considered as cage–like [Si4V2O18]12– clusters built by four SiO4 tetrahedra and two VO5 square pyramids. These clusters are cross–linked to form a pseudo-two-dimensional network (2D) parallel to (001) containing empty channels along the a axis and the 2D networks held together by Ba2+ ions located in channels parallel to the c axis. The structural formula is Ba2V2O2[Si4O12]. Bavsiite is polymorphic to suzukiite, BaVSi2O7, which is orthorhombic.

The Crystal Structure of GdZn3

2013 ◽  
Vol 68 (11) ◽  
pp. 1265-1268 ◽  
Author(s):  
Inna Bigun ◽  
Yaroslav M. Kalychak
Keyword(s):  
Crystal Structure ◽  
Coordination Number ◽  
Diffraction Data ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Type Space ◽  
Dimensional Network

The crystal structure of GdZn3 was refined using singlecrystal X-ray diffraction data: YZn3 type, space group Pnma, Z = 4, a = 6:7250(13), b = 4:4620(9), c = 10:201(2) Å , R1 = 0:049, wR2 = 0:082, 303 F2 values, 25 variables. The zinc atoms build up a three-dimensional network with short Zn-Zn distances, while the Gd atoms are well separated from each other. The coordination number is 17 for Gd, and 10 and 12 for the Zn atoms.

Powder X-ray characterisation of natrolite, Na2Al2Si3O10.2H2O

1995 ◽  
Vol 10 (4) ◽  
pp. 243-247 ◽  
Author(s):  
A. A. Finch ◽  
J. G. Fletcher ◽  
A. Kindness ◽  
J. M. S. Skakle
Keyword(s):  
Water Content ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Natural Sample ◽  
X Ray Diffraction ◽  
High Quality ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Icp Ms

High-quality powder X-ray diffraction data for a well-characterised natural sample of natrolite (Na2Al2Si3O10.2H2O, space group Fdd2, Z = 8) are presented. Refined cell parameters were a = 18.2984±0.0007 Å, b = 18.6502±0.0008 Å, and c = 6.5589±0.0003 Å. The sample was characterised using thermogravimetric techniques (to determine water content), EPMA and ICP-MS (to determine composition). Available data suggest that the crystal matches the expected stoichiometry of natrolite. Our powder data show close similarity with the proposed structure of natrolite using the Rietveld method, giving R values of 8.54%, and suggest that preferred orientation is not present in the sample.

X-ray powder diffraction data of LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites

2021 ◽  
pp. 1-6
Author(s):  
Mariana M. V. M. Souza ◽  
Alex Maza ◽  
Pablo V. Tuza
Keyword(s):  
Crystal Structure ◽  
Rietveld Method ◽  
Pechini Method ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Modified Pechini Method ◽  
Scanning Electron

In the present work, LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites were synthesized by the modified Pechini method. These materials were characterized using X-ray fluorescence, scanning electron microscopy, and powder X-ray diffraction coupled to the Rietveld method. The crystal structure of these materials is orthorhombic, with space group Pbnm (No 62). The unit-cell parameters are a = 5.535(5) Å, b = 5.527(3) Å, c = 7.819(7) Å, V = 239.2(3) Å3, for the LaNi0.5Ti0.45Co0.05O3, a = 5.538(6) Å, b = 5.528(4) Å, c = 7.825(10) Å, V = 239.5(4) Å3, for the LaNi0.45Co0.05Ti0.5O3, and a = 5.540(2) Å, b = 5.5334(15) Å, c = 7.834(3) Å, V = 240.2(1) Å3, for the LaNi0.5Ti0.5O3.

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