scholarly journals Crystal Structure, Vibrational, Spectroscopic and Thermochemical Properties of Double Sulfate Crystalline Hydrate [CsEu(H2O)3(SO4)2]·H2O and Its Thermal Dehydration Product CsEu(SO4)2

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1027
Author(s):  
Yuriy G. Denisenko ◽  
Maxim S. Molokeev ◽  
Aleksandr S. Oreshonkov ◽  
Alexander S. Krylov ◽  
Aleksandr S. Aleksandrovsky ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Rietveld Method ◽  
Local Symmetry ◽  
Crystalline Hydrate ◽  
Thermal Dehydration ◽  
Luminescence Spectra ◽  
Symmetry Violation ◽  
Monoclinic System ◽  
Space Group ◽  
Sulfate Hydrate

Crystalline hydrate of double cesium europium sulfate [CsEu(H2O)3(SO4)2]·H2O was synthesized by the crystallization from an aqueous solution containing equimolar amounts of 1Cs+:1Eu3+:2SO42− ions. Anhydrous salt CsEu(SO4)2 was formed as a result of the thermal dehydration of the crystallohydrate. The unusual effects observed during the thermal dehydration were attributed to the specific coordination of water molecules in the [CsEu(H2O)3(SO4)2]·H2O structure. The crystal structure of [CsEu(H2O)3(SO4)2]·H2O was determined by a single crystal X-ray diffraction analysis, and the crystal structure of CsEu(SO4)2 was obtained by the Rietveld method. [CsEu(H2O)3(SO4)2]·H2O crystallizes in the monoclinic system, space group P21/c (a = 6.5574(1) Å, b = 19.0733(3) Å, c = 8.8364(2) Å, β = 93.931(1)°, V = 1102.58(3) Å3). The anhydrous sulfate CsEu(SO4)2 formed as a result of the thermal destruction crystallizes in the monoclinic system, space group C2/c (a = 14.327(1) Å, b = 5.3838(4) Å, c = 9.5104(6) Å, β = 101.979(3) °, V = 717.58(9) Å3). The vibration properties of the compounds are fully consistent with the structural models and are mainly determined by the deformation of non-rigid structural elements, such as H2O and SO42−. As shown by the diffused reflection spectra measurements and DFT calculations, the structural transformation from [CsEu(H2O)3(SO4)2]·H2O to CsEu(SO4)2 induced a significant band gap reduction. A noticeable difference of the luminescence spectra between cesium europium sulfate and cesium europium sulfate hydrate is detected and explained by the variation of the extent of local symmetry violation at the crystallographic sites occupied by Eu3+ ions, namely, by the increase in inversion asymmetry in [CsEu(H2O)3(SO4)2]·H2O and the increase in mirror asymmetry in CsEu(SO4)2. The chemical shift of the 5D0 energy level in cesium europium sulfate hydrate, with respect to cesium europium sulfate, is associated with the presence of H2O molecules in the vicinity of Eu3+ ion.

Crystal structure determination of K2Zn(PO3)4

2009 ◽  
Vol 24 (1) ◽  
pp. 4-7 ◽  
Author(s):  
L. N. Ji ◽  
Y. Q. Chen ◽  
J. B. Li ◽  
J. Luo ◽  
J. K. Liang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structure Determination ◽  
Rietveld Method ◽  
Unit Cell ◽  
Formula Unit ◽  
Chemical Formula ◽  
Monoclinic System ◽  
Calculated Density ◽  
Space Group

The crystal structure of K2Zn(PO3)4 was determined and refined using the Rietveld method based on the isostructure model of K2Cu(PO3)4. This compound belongs to the monoclinic system with space group Cc and lattice parameters of a=11.0941(2) Å, b=12.5215(3) Å, c=7.6597(2) Å, and β=102.47(2)°. The chemical formula unit per unit cell is Z=4 and the calculated density is 2.938(3) g∕cm3. Zigzag [PO3]∞ chains formed along the a axis, and their period contains eight PO4 tetrahedrons.

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 Different Roles of Ce3+ Optical Centers in Oxyorthosilicate Nanocrystals at X-ray and UV Excitation

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 114 ◽  
Author(s):  
Vladyslav Seminko ◽  
Pavel Maksimchuk ◽  
Iryna Bespalova ◽  
Yuri Malyukin
Keyword(s):  
Crystal Structure ◽  
Dominant Role ◽  
Luminescence Spectra ◽  
Photoluminescence Intensity ◽  
Bulk Crystals ◽  
Space Group ◽  
X Ray ◽  
Oxygen Coordination ◽  
Cation Sites

Luminescence properties of Lu2SiO5:Ce3+ and Y2SiO5:Ce3+ nanocrystals were studied using photo- and X-ray luminescence techniques. The crystal structure of Re2SiO5 nanocrystals (P21/c space group) differs from the crystal structure of Re2SiO5 bulk crystals (C2/c space group) with 9- and 7-oxygen-coordinated cation positions instead of 6- and 7-coordinated ones observed for Re2SiO5 bulk crystals. Two optical centers (Ce1 and Ce2) were observed for Re2SiO5:Ce3+ nanocrystals originating from cerium ions substituting 9- and 7-oxygen-coordinated cation sites. Preferential substitution of larger cation sites by cerium ions leads to higher photoluminescence intensity of Ce1 centers, however, Ce2 centers are the main centers for electron-hole recombination, so only Ce2 band is observed in X-ray luminescence spectra. The features of oxygen coordination of Ce1 and Ce2 centers and high content of oxygen vacancies in Re2SiO5:Ce3+ nanocrystals can provide preferential trapping of electrons near Ce2 centers, and therefore, the dominant role of Ce2 band in X-ray luminescence spectra.

Crystal Structure of the New Compound NdFeSb3

2007 ◽  
Vol 353-358 ◽  
pp. 3043-3046 ◽  
Author(s):  
Ping Li Qin ◽  
Liang Qin Nong ◽  
Ji Liang Zhang ◽  
Hai Qing Qin ◽  
Jiang Ping Liao ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Rietveld Method ◽  
Structure Type ◽  
Lattice Parameters ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

The crystal structure of a new compound NdFeSb3 has been determined by X-ray powder diffraction using the Rietveld method. The compound crystallizes in the orthorhombic, space group Pbcm (No.57) with the CeNiSb3 structure type and lattice parameters a=1.26828(2)nm, b=0.61666(2)nm, c=1.81867(4) nm, z=12 and Dcalc=7.917g/cm3.

Crystal structure of bis(N-2-phenyl-ethyl salicylideneiminato)nickel(II)

1986 ◽  
Vol 175 (1-2) ◽  
Author(s):  
K. Ravikumar ◽  
S. S. Rajan ◽  
V. Rajaram ◽  
S. K. Ramalingam ◽  
S. Natarajan
Keyword(s):  
Crystal Structure ◽  
Monoclinic System ◽  
Space Group

AbstractBis(N-2-phenyl-ethyl salicylideneiminato)nickel(II) crystallizes in the monoclinic system, space group

Preparation and crystal structure of SbV1.50InIII0.50(PO4)3 and (SbV0.50InIII0.50)P2O7

2008 ◽  
Vol 23 (3) ◽  
pp. 232-240
Author(s):  
Abderrahim Aatiq ◽  
Rachid Bakri ◽  
Aaron Richard Sakulich
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Room Temperature ◽  
Rietveld Method ◽  
Monoclinic Space Group ◽  
Unit Cell Parameters ◽  
Orthorhombic System ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

Synthesis and structure of two phosphates belonging to the ternary Sb2O5–In2O3–P2O5 system are realized. Structures of SbV1.50InIII0.50(PO4)3 and (SbV0.50InIII0.50)P2O7 phases, obtained by solid state reaction in air at 950 °C, were determined at room temperature from X-ray powder diffraction using the Rietveld method. SbV1.50InIII0.50(PO4)3 have a monoclinic (space group P21/n) distortion of the Sc2(W O4)3-type framework. Its structure is constituted by corner-shared SbO6 or InO6 octahedra and PO4 tetrahedra. Monoclinic unit cell parameters are a=11.801(2) Å, b=8.623(1) Å, c=8.372(1) Å, and β=90.93(1)°. (Sb0.50In0.50)P2O7 is isotypic with (Sb0.50Fe0.50)P2O7 and crystallizes in orthorhombic system (space group Pna21) with a=7.9389(1) Å, b=16.0664(2) Å, and c=7.9777(1) Å. Its structure is built up from corner-shared SbO6 or InO6 octahedra and P2O7 groups (two group-types). Each P2O7 group shares its six vertices with three SbO6 and three InO6 octahedra, and each octahedron is connected to six P2O7 groups.

Crystal structure and powder X-ray diffraction data for new Tb3CuAl3Ge2 compound

2015 ◽  
Vol 30 (1) ◽  
pp. 63-66 ◽  
Author(s):  
Chao Zeng ◽  
Guoqiang Lin ◽  
Weijing Zeng ◽  
Wei He
Keyword(s):  
Crystal Structure ◽  
Rietveld Refinement ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Unit Cell ◽  
Type Structure ◽  
X Ray Diffraction ◽  
Quaternary Compound ◽  
Space Group ◽  
X Ray

The crystal structure of new Tb3CuAl3Ge2 quaternary compound was studied by the Rietveld method from powder X-ray diffraction (XRD) data. The Tb3CuAl3Ge2 compound crystallized in the hexagonal Y3NiAl3Ge2-type structure with space group P-62m (no. 189) and lattice parameters a = 7.0041(2) Å, c = 4.1775(1) Å, V = 177.48 Å3. There is only one formula in each unit cell, Z = 1, and the density of Tb3CuAl3Ge2 is ρx = 7.1696 g cm−3. The reliability factors characterizing the Rietveld refinement results are Rp = 6.43%, Rwp = 8.65%, RB = 4.81%, and RF = 4.09%, respectively. The powder XRD data of Tb3CuAl3Ge2 were presented and the reliability of indexation is F30 = 120.9(0.0073, 34).

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).

Polymere Dimethyl-und Diphenylglyoximatokomplexe des Cobalts und Eisens mit Pyrazin als Brückenligand. Die Kristallstruktur des Bis(dimethylglyoximato)pyrazin-cobalt(II) + / Polymeric Dimethyl-and Diphenylglyoximato Complexes of Cobalt and Iron with Pyrazine as a Bridging Ligand. The Crystal Structure of Bis(dimethylglyoximato)pyrazine Cobalt(II)+

1981 ◽  
Vol 36 (4) ◽  
pp. 441-446 ◽  
Author(s):  
Frank Kübel ◽  
Joachim Strähle
Keyword(s):  
Crystal Structure ◽  
Mössbauer Spectra ◽  
Local Symmetry ◽  
Space Group ◽  
Mossbauer Spectra ◽  
Bridging Ligand ◽  
Linear Chains ◽  
Square Planar ◽  
Fe Complexes

Abstract Polymeric bis(dimethyl-and diphenylglyoximato)-complexes of Fe(II) and Co(II) with pyrazine as a bridging ligand have been synthesized. The Co(II) complexes are para-magnetic with μ = 1.83 B.M., and surprisingly stable against oxidation. Bis (dimethyl-glyoximato)pyrazine-cobalt (II) crystallizes monoclinic in the space group C2/m with Z = 2. The crystal structure shows linear chains of alternating Co atoms and pyrazine ligands. Perpendicular to the chain, the Co atoms are coordinated in a square planar arrangement by two dimethylglyoximato ligands (Co-N= 189 pm), the local symmetry being C2h-The long Co-pyrazine distance of 224 pm is in agreement with the fact that the compound is a 19 electron complex. The Co complexes do not have conducting properties. The Fe(II) complexes possess the same structure but with stronger bonds in the chain. They show very low conductivity of approximately 10-10 cm -1 Ω-1 . The Mössbauer spectra of the Fe-complexes are reported.

scholarly journals Crystal structure of gluconate 5-dehydrogenase from Lentibacter algarum

2020 ◽  
Vol 76 (5) ◽  
pp. 228-234
Author(s):  
Dengke Tian ◽  
Xueqi Fu ◽  
Wenqiang Cao ◽  
Hong Yuan
Keyword(s):  
Crystal Structure ◽  
Escherichia Coli ◽  
Structural Similarity ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Monoclinic System ◽  
Space Group ◽  
Cell Parameters ◽  
High Structural Similarity

Gluconate 5-dehydrogenase (Ga5DH; EC 1.1.1.69) from Lentibacter algarum (LaGa5DH) was recombinantly expressed in Escherichia coli and purified to homogeneity. The protein was crystallized and the crystal structure was solved at 2.1 Å resolution. The crystal belonged to the monoclinic system, with space group P1 and unit-cell parameters a = 55.42, b = 55.48, c = 79.16 Å, α = 100.51, β = 105.66, γ = 97.99°. The structure revealed LaGaDH to be a tetramer, with each subunit consisting of six α-helices and three antiparallel β-hairpins. LaGa5DH has high structural similarity to other Ga5DH proteins, demonstrating that this enzyme is highly conserved.

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