Crystal chemistry of the compound Sr2Bi2CuO6

1990 ◽  
Vol 5 (1) ◽  
pp. 46-52 ◽  
Author(s):  
R. S. Roth ◽  
C. J. Rawn ◽  
L. A. Bendersky
Keyword(s):  
Electron Diffraction ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Crystal Chemistry ◽  
Superconducting Phase ◽  
X Ray Diffraction ◽  
Monoclinic Symmetry ◽  
X Ray ◽  
Symmetry Space ◽  
Symmetry Space Group

The compound Sr2Bi2CuO6 should nominally be the phase with n = 1 of the high Tc superconducting series Sr2Bi2CanO4+2n. However, the superconducting phase with n = 1 (with no CaO) occurs only with a gross deficiency in SrO content. Instead, at the composition Sr2Bi2CuO6, a different phase is formed with an x-ray diffraction pattern considerably different from that expected for the n −1 member of the series. This phase has been found, by a combination of electron diffraction and single crystal and powder x-ray diffraction, to have a commensurate lattice with monoclinic symmetry, space group C2/m or Cm, a = 24.473 (2), b = 5.4223 (5), c = 21.959 (2)A, and β = 105.40 (1)°. The actual composition of this phase may be deficient in CuO by as much as 1.0 mole %.

scholarly journals Structural properties of the alluaudite-type materials Ag2–xNaxMn3(VO4)3 (x=0.62 and 1.85)

2019 ◽  
Vol 74 (9) ◽  
pp. 677-684
Author(s):  
Hamdi Ben Yahia ◽  
Masahiro Shikano
Keyword(s):  
Solid Solution ◽  
Single Crystal ◽  
X Ray Diffraction ◽  
Monoclinic Symmetry ◽  
Reaction Route ◽  
New Members ◽  
X Ray ◽  
Crystal Structural ◽  
Symmetry Space ◽  
Symmetry Space Group

AbstractThe new members of the Ag2−xNaxMn3(VO4)3 (0 ≤ x ≤ 2) solid solution were synthesized by a solid-state reaction route. The crystal structures of Ag1.38Na0.62Mn3(VO4)3 (x = 0.62) and Ag0.15Na1.85Mn3(VO4)3 (x = 1.85) were solved using single crystal X-ray diffraction. These phases crystallize with a monoclinic symmetry (space group C2/c), and their structures are new members of the well-known alluaudite family. In both compounds, the Ag+/Na+, Mn2+/Mn3+ and V5+ cations are eight-, six-, and four-coordinated to oxygen atoms, respectively. All the atoms are perfectly ordered except for the Ag and Na atoms which are statistically disordered over a 4b and a 4e atomic position. This single-crystal structural study confirms the existence of a full solid solution Ag2−xNaxMn3(VO4)3 (0 ≤ x ≤ 1.85).

The low-temperature form of calcium gold stannide, CaAuSn

2014 ◽  
Vol 70 (8) ◽  
pp. 773-775 ◽  
Author(s):  
Qisheng Lin ◽  
John D. Corbett
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Single Crystal ◽  
Diffraction Analysis ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Symmetry Space ◽  
High Temperature Polymorph ◽  
Symmetry Space Group

The EuAuGe-type CaAuSn phase has been synthesized and single-crystal X-ray diffraction analysis reveals that it has an orthorhombic symmetry (space groupImm2), witha= 4.5261 (7) Å,b= 7.1356 (11) Å andc= 7.8147 (11) Å. The structure features puckered layers that are connected by homoatomic Au—Au and Sn—Sn interlayer bonds. This structure is one of the two parent structures of its high-temperature polymorph (ca873 K), which is an intergrowth structure of the EuAuGe- and SrMgSi-type structures in a 2:3 ratio.

Zur Synthese und Kristallstruktur von Kupferzinkpyroboratoxid Cu2Zn(B2O5)O / Synthesis and Crystal Structure of Copper Zinc Pyroborate Oxide Cu2Zn(B2O5)O

1995 ◽  
Vol 50 (12) ◽  
pp. 1854-1858 ◽  
Author(s):  
Silke Busche ◽  
Karsten Bluhm
Keyword(s):  
Crystal Structure ◽  
X Ray Diffraction ◽  
Monoclinic Symmetry ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Square Planar ◽  
Significant Difference ◽  
Copper Zinc ◽  
Symmetry Space ◽  
Symmetry Space Group

The compound Cu2Zn(B2O5)O was prepared by using a B2O3 flux technique, and single crystals were investigated by X-ray diffraction (monoclinic symmetry, space group C52h-P21/c ). The structure is isotypic to Cu2Co(B2O5)O with lattice parameters a = 327.38(2), b = 1479.4(3), c = 915.39(13), β = 95.794(11)°, Z = 4, but with the significant difference that zinc is pentacoordinated by oxygen. Copper exhibits a nearly square planar or a square pyramidal coordination, respectively. The structure contains isolated B2O5 units and oxygen which is not coordinated to boron.

Zur Kristallchemie eines Natrium-Cadmium-Oxoiridats: Na3Cd2IrO6 / On the Crystal Chemistry of a Sodium Cadmium Oxoiridate: Na3Cd2IrO6

1996 ◽  
Vol 51 (6) ◽  
pp. 822-825 ◽  
Author(s):  
S. Frenzen ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Sodium Chloride ◽  
Single Crystals ◽  
Crystal Chemistry ◽  
Monoclinic Symmetry ◽  
Space Group ◽  
X Ray ◽  
Symmetry Space ◽  
Symmetry Space Group

Abstract Single crystals of Na3Cd2IrO6 have been prepared by crystallization from melts in closed silver tubes. The crystal structure was investigated by X-ray techniques. Na3Cd2IrO6, crystallizes with monoclinic symmetry, space group C32h-C2/m; a = 5.663(2), b = 9.783(3), c = 5.689(2) Å, β = 109.95(2)°, Z = 2. It is isotypic to M+5A7+O6 (M = Li, Na; A = Re, Os) and shows relations to the sodium chloride structure in spite of an ordered distribution of Na+, Cd2+ and Ir5+

Zur Kristallchemie eines neuen Oxomolybdats: Cu2YbMo3O12/On the Crystal Chemistry of a New Molybdenum Oxide: Cu2YbMo3O12

1995 ◽  
Vol 50 (2) ◽  
pp. 257-260 ◽  
Author(s):  
H. Szillat ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Crystal Chemistry ◽  
Molybdenum Oxide ◽  
Structure Type ◽  
Oxidation States ◽  
Monoclinic Symmetry ◽  
X Ray ◽  
Symmetry Space ◽  
Symmetry Space Group

Single crystals of Cu2YbMo3O12 have been prepared by crystallization from melts and investigated by X-ray diffractometer techniques. Cu2YbMo3O12 crystallizes with monoclinic symmetry (space group C2h2 - P121/m 1, a = 5.162(2), b = 10.885(4), c = 8.699(4) Å. β = 95.73(7)°, Z = 2), forming a new structure type. Typical features are layers of CuO6 octahedra, connected via corners and edges. These layers are linked by molybdenum and ytterbium ions along [001]. The crystal structure as well as the coordination of copper, ytterbium and molybdenum and the oxidation states of copper and molybdenum are discussed with respect to the related but not isotypic compound (Cu,Zn)3,75Mo3O12.

Electron Microscopy of Shock Loaded Polycrystalline Beryllium

1974 ◽  
Vol 32 ◽  
pp. 506-507 ◽  
Author(s):  
J. M. Galbraith ◽  
L. E. Murr ◽  
A. L. Stevens
Keyword(s):  
Electron Microscopy ◽  
Wave Propagation ◽  
Structural Change ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Shock Loading ◽  
Slip Systems ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
X Ray

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.

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.

Synthese und Röntgenstrukturanalyse von KCuGd2Mo4O16 und KCuTb2Mo4O16/Synthesis and X-Ray Analysis of KCuGd2Mo4O16 and KCuTb2Mo4O16

1995 ◽  
Vol 50 (12) ◽  
pp. 1794-1798 ◽  
Author(s):  
Hk. Müller-Buschbaum ◽  
St. Gallinat
Keyword(s):  
Lattice Energy ◽  
Rare Earth Ions ◽  
Monoclinic Symmetry ◽  
X Ray ◽  
Coulomb Term ◽  
Relationship Of ◽  
The Relationship ◽  
Symmetry Space ◽  
Oxidation State Of Copper ◽  
Symmetry Space Group

Single crystals of the so far unknown compounds KCuGd2Mo4O16 (I) and KCuTb2Mo4O16 (II) have been prepared by flux technique. The compounds crystallize with monoclinic symmetry. space group C62h-C2 /c with (I): a = 5.278(2), b = 12.666(5), c = 19.604(14) Å; β = 92.76(6)°; (II): a = 5.259(13), b = 12.616(3), c = 19.556(9) Å, β = 92.93(4)°, Z = 4. Molybdenum exhibits tetrahedral coordination. The surroundings of copper can be described by distorted tetrahedra, capped by two more distant oxygen atoms, and the rare earth ions show a square antiprism. Potassium is inside an irregular polyhedron. The relationship of the structures of (I) and (II) is discussed with respect to the KLnMo2O8 type compounds. Coulomb term calculations of the lattice energy indicate an oxidation state of copper higher than CuI.

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