scholarly journals New Quaternary Chalcogenides Tl2MIIMIV3Se8 and Tl2MIIMIVX4

Proceedings ◽  
2020 ◽  
Vol 62 (1) ◽  
pp. 3
Author(s):  
Andrii Selezen ◽  
Yuri Kogut ◽  
Lyudmyla Piskach ◽  
Lubomir Gulay
Keyword(s):  
Crystal Structure ◽  
Ternary Systems ◽  
Lattice Parameters ◽  
Tetragonal Symmetry ◽  
Orthorhombic Symmetry ◽  
Component Ratio

New quaternary thallium-containing chalcogenides Tl2MIIMIV3X8 and Tl2MIIMIVX4 were synthesized, and their crystal structure was determined by XRD. Three Tl2MIIMIV3X8 chalcogenides crystallize in orthorhombic symmetry (S.G. P212121; Tl2CdGe3Se8 lattice parameters a = 0.76023(9), b = 1.2071(2), c = 1.7474(2) nm), eight isostructural Tl2BIIDIVX4 compounds crystallize in tetragonal symmetry, S.G. I-42m. These compounds form in the quasi-ternary systems Tl2X–MIIX–MIVX2 (X–S, Se, Te) at the component ratio 1:1:1 and 1:1:3 at the sections Tl2MIVX3–BIIX and Tl2MIIMIVX4–MIVX2, respectively. The composition of the Tl2CdGe3Se8 compound was additionally confirmed by SEM and EDS.

A New Copper (II) Complex with the N,N'-Bis(antipyryl-4-methyl)-piperazine (BAMP) Ligand: [Cu(BAMP)](ClO4)2

2002 ◽  
Vol 57 (12) ◽  
pp. 1454-1460 ◽  
Author(s):  
Otilia Costișor ◽  
Ramona Tudose ◽  
Ingo Pantenburg ◽  
Gerd Meyer
Keyword(s):  
Crystal Structure ◽  
Copper Complex ◽  
Structural Parameters ◽  
Complex Molecule ◽  
Lattice Parameters ◽  
Tetragonal Symmetry ◽  
Apical Position ◽  
Space Group ◽  
Symmetry Space ◽  
Symmetry Space Group

The synthesis of the Mannich base N,N’-bis(antipyryl-4-methyl)-piperazine (BAMP) (1), its crystal structure as well as the synthesis and the crystal structure of the copper complex Cu(BAMP)(ClO4)2 (2) are reported. C28H34N6O2 ∙ 4H2O (BAMP ∙ 4H2O) crystallizes with triclinic symmetry, space group P1̄, lattice parameters: a = 704,9(2), b = 983,4(2), c = 1198,9(3) pm, α = 68,72°, β = 73,62°, γ = 78,49°. The copper-complex Cu(BAMP)(ClO4)2 crystallizes with tetragonal symmetry, space group P42/n, lattice parameters: a = 2295,1(3), c = 1412,2(2) pm. The copper(II) atom is five-coordinate by the two nitrogen atoms belonging to the piperazine ring and the oxygen atoms of the antipyrinemoieties. The geometry of the copper(II) atom can be described as a square-based pyramid with the N2O2 donor atoms of BAMP forming the basal plane and an oxygen atom of the neighbouring complex molecule occupying the apical position. BAMP acts as a tetradentate ligand, which incorporates a piperazine-fused ring. The structural parameters illustrate well the reinforcing effect exerted by the double “straps” of the piperazine molecule.

scholarly journals Derived crystal structure of martensitic materials by solid–solid phase transformation

2020 ◽  
Vol 76 (4) ◽  
pp. 521-533 ◽  
Author(s):  
Mostafa Karami ◽  
Nobumichi Tamura ◽  
Yong Yang ◽  
Xian Chen
Keyword(s):  
Crystal Structure ◽  
Phase Transformation ◽  
Orientation Relationship ◽  
Solid Phase ◽  
Lattice Parameters ◽  
Orthorhombic Symmetry ◽  
Face Centered Cubic ◽  
X Ray ◽  
Solid Phase Transformation ◽  
Martensitic Materials

A mathematical description of crystal structure is proposed consisting of two parts: the underlying translational periodicity and the distinct atomic positions up to the symmetry operations in the unit cell, consistent with the International Tables for Crystallography. By the Cauchy–Born hypothesis, such a description can be integrated with the theory of continuum mechanics to calculate a derived crystal structure produced by solid–solid phase transformation. In addition, the expressions for the orientation relationship between the parent lattice and the derived lattice are generalized. The derived structure rationalizes the lattice parameters and the general equivalent atomic positions that assist the indexing process of X-ray diffraction analysis for low-symmetry martensitic materials undergoing phase transformation. The analysis is demonstrated in a CuAlMn shape memory alloy. From its austenite phase (L21 face-centered cubic structure), it is identified that the derived martensitic structure has orthorhombic symmetry Pmmn with the derived lattice parameters a d = 4.36491, b d = 5.40865 and c d = 4.2402 Å, by which the complicated X-ray Laue diffraction pattern can be well indexed, and the orientation relationship can be verified.

scholarly journals Crystal structure of K[Hg(SCN)3] – a redetermination

2014 ◽  
Vol 70 (9) ◽  
pp. i46-i46 ◽  
Author(s):  
Matthias Weil ◽  
Thomas Häusler
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Three Dimensional ◽  
Lattice Parameters ◽  
Bond Lengths ◽  
Dimensional Network ◽  
Anisotropic Displacement Parameters ◽  
Precision And Accuracy ◽  
Standard Deviations ◽  
Atomic Coordinates

The crystal structure of the room-temperature modification of K[Hg(SCN)3], potassium trithiocyanatomercurate(II), was redetermined based on modern CCD data. In comparison with the previous report [Zhdanov & Sanadze (1952).Zh. Fiz. Khim.26, 469–478], reliability factors, standard deviations of lattice parameters and atomic coordinates, as well as anisotropic displacement parameters, were revealed for all atoms. The higher precision and accuracy of the model is, for example, reflected by the Hg—S bond lengths of 2.3954 (11), 2.4481 (8) and 2.7653 (6) Å in comparison with values of 2.24, 2.43 and 2.77 Å. All atoms in the crystal structure are located on mirror planes. The Hg2+cation is surrounded by four S atoms in a seesaw shape [S—Hg—S angles range from 94.65 (2) to 154.06 (3)°]. The HgS4polyhedra share a common S atom, building up chains extending parallel to [010]. All S atoms of the resulting1∞[HgS2/1S2/2] chains are also part of SCN−anions that link these chains with the K+cations into a three-dimensional network. The K—N bond lengths of the distorted KN7polyhedra lie between 2.926 (2) and 3.051 (3) Å.

scholarly journals Photoconductivity of the Single Crystals Pb4Ga4GeS12 and Pb4Ga4GeSe12

Proceedings ◽  
2020 ◽  
Vol 62 (1) ◽  
pp. 4
Author(s):  
Hadj Bellagra ◽  
Oksana Nyhmatullina ◽  
Yuri Kogut ◽  
Halyna Myronchuk ◽  
Lyudmyla Piskach
Keyword(s):  
Ternary Systems ◽  
Semiconductor Materials ◽  
Tetragonal Symmetry ◽  
Bandgap Energy ◽  
Experimental Measurements ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vertical Bridgman ◽  
Symmetry Space ◽  
Symmetry Space Group

Quaternary semiconductor materials of the Pb4Ga4GeS(Se)12 composition have attracted the attention of researchers due to their possible use as active elements of optoelectronics and nonlinear optics. The Pb4Ga4GeS(Se)12 phases belong to the solid solution ranges of the Pb3Ga2GeS(Se)8 compounds which form in the quasi-ternary systems PbS(Se)−Ga2S(Se)3−GeS(Se)2 at the cross of the PbGa2S(Se)4−Pb2GeS(Se)4 and PbS(Se)−PbGa2GeS(Se)6 sections. The quaternary sulfide melts congruently at 943 K. The crystallization of the Pb4Ga4GeSe12 phase is associated with the ternary peritectic process Lp + PbSe ↔ PbGa2S4 + Pb3Ga2GeSe8 at 868 K. For the single crystal studies, Pb4Ga4GeS(Se)12 were pre-synthesized by co-melting high-purity elements. The X-ray diffraction results confirm that these compounds possess non-centrosymmetric crystal structure (tetragonal symmetry, space group P–421c). The crystals were grown by the vertical Bridgman method in a two-zone furnace. The starting composition was stoichiometric for Pb4Ga4GeS12, and the solution-melt method was used for the selenide Pb4Ga4GeSe12. The obtained value of the bandgap energy for the Pb4Ga4GeS12 and Pb4Ga4GeSe12 crystals is 1.86 and 2.28 eV, respectively. Experimental measurements of the spectral distribution of photoconductivity for the Pb4Ga4GeS12 and Pb4Ga4GeSe12 crystals exhibit the presence of two spectral maxima. The first lies in the region of 570 (2.17 eV) and 680 nm (1.82 eV), respectively, and matches the optical bandgap estimates well. The locations of the admixture maxima at about 1030 (1.20 eV) and 1340 nm (0.92 eV), respectively, agree satisfactorily with the calculated energy positions of the defects vs. and VSe.

Single-crystal investigation of Ce5AgxGe4−x (x = 0.1−1.08) with Sm5Ge4 type

2020 ◽  
Vol 75 (8) ◽  
pp. 765-768
Author(s):  
Bohdana Belan ◽  
Dorota Kowalska ◽  
Mariya Dzevenko ◽  
Mykola Manyako ◽  
Roman Gladyshevskii
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Diffraction Data ◽  
Binary Compound ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray

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.

Crystal structure of KCaF3 determined by the Rietveld profile method

1997 ◽  
Vol 12 (2) ◽  
pp. 70-75 ◽  
Author(s):  
Alicja Ratuszna ◽  
Michel Rousseau ◽  
Philippe Daniel
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Lattice Parameters ◽  
Profile Method ◽  
Anisotropic Temperature ◽  
Monoclinic Distortion ◽  
Refinement Procedure ◽  
Watson Statistic ◽  
Temperature Factors ◽  
Atomic Coordinates

Using the Rietveld profile method, the atomic coordinates and anisotropic temperature factors of KCaF3 were refined. At room temperature, KCaF3 crystallizes in monoclinic B21/m symmetry, with the lattice parameters: a=8.754(2) Å, b=8.765(4) Å, c=8.760(5) Å, β=90.48(3)°, V=672.1(3) Å3, Z=8. The refinement procedure was stopped when RB=0.05 and the Durbin–Watson statistic factor=0.85 had been reached. The structure determined is related to the tilting of CaF6 octahedra of the a−b+c− type, which are responsible for the monoclinic distortion in perovskite crystals.

scholarly journals β-Y(BO2)3 – a new member of the β-Ln(BO2)3 (Ln=Nd, Sm, Gd–Lu) structure family

2017 ◽  
Vol 72 (12) ◽  
pp. 983-988 ◽  
Author(s):  
Martin K. Schmitt ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

Abstractβ-Y(BO2)3 was synthesized in a Walker-type multianvil module at 5.9 GPa/1000°C. The crystal structure has been elucidated through single-crystal X-ray diffraction. β-Y(BO2)3 crystallizes in the orthorhombic space group Pnma (no. 62) with the lattice parameters a=15.886(2), b=7.3860(6), and c=12.2119(9) Å. Its crystal structure will be discussed in the context of the isotypic lanthanide borates β-Ln(BO2)3 (Ln=Nd, Sm, Gd–Lu).

Crystal structure and lattice parameters of curium trichloride

1967 ◽  
Vol 29 (11) ◽  
pp. 2745-2751 ◽  
Author(s):  
J.C. Wallmann ◽  
J. Fuger ◽  
J.R. Peterson ◽  
J.L. Green
Keyword(s):  
Crystal Structure ◽  
Lattice Parameters

scholarly journals Redetermination of the crystal structure of ThI4

IUCrData ◽  
2018 ◽  
Vol 3 (2) ◽  
Author(s):  
H. Lars Deubner ◽  
Florian Kraus
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Coordination Number ◽  
Coordination Polyhedron ◽  
Lattice Parameters ◽  
Structure Model ◽  
Reliability Factor ◽  
Thorium Dioxide

Single crystals of ThI4, thorium(IV) tetraiodide, were grown from thorium dioxide and aluminium triiodide. In comparison with the structure model reported previously for this compound [Zalkinet al.(1964).Inorg. Chem.3, 639–644], we have determined the lattice parameters and fractional coordinates to a much higher precision, also leading to a better reliability factor (R= 0.029versus0.09). The coordination number of the ThIVatom is eight. Its coordination polyhedron has the shape of an irregular square antiprism. The I atoms each bridge two ThIVatoms, resulting in the formation of infinite layers parallel to (-101) that can be described with the Niggli formula2∞[ThI6/2I2/2].

scholarly journals Crystal structure analysis of LiN(DxH1-x)4SO4by neutron diffraction

2014 ◽  
Vol 70 (a1) ◽  
pp. C1703-C1703
Author(s):  
Shin Ae Kim ◽  
Chang-Hee Lee
Keyword(s):  
Crystal Structure ◽  
Neutron Diffraction ◽  
Diffraction Method ◽  
Crystal Structure Analysis ◽  
Ferroelectric Materials ◽  
Lattice Parameters ◽  
Least Square ◽  
Intensity Data ◽  
Hydrogen Atoms ◽  
Neutron Intensity

The crystal structure of Li(ND4)SO4 was analysed by neutron diffraction method. The crystal is a partially deuterated Li(NH4)SO4 and one of the ferroelectric materials with hydrogen atoms. The crystal is orthorhombic at room temperature with lattice parameters of a=5.2773(5) Å, b=9.124(2) Å, c=8.772(1) Å and Z=4. Neutron intensity data were collected on the Four-Circle Diffractometer (FCD) at HANARO in Korea Atomic Energy Research Institute. The structure was refined by full-matrix least-square to final R value of 0.049 for 745 observed reflections by neutron diffraction. All atomic positions of four hydrogen atoms at NH4 and the occupation factors of D and H were refined. From these results we obtained the average chemical structure of this sample, LiND3.05H0.95SO4. Five years later, neutron intensity data were collected and analysed once more with same crystal. The crystal is orthorhombic but with different lattice parameters, or hexagonal. We will report and discuss these results in this presentation.

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