Superconductivity and Stoichiometry in Tl2Ca2Ba2Cu3Ox Single Crystals

1989 ◽  
Vol 169 ◽  
Author(s):  
E. L. Venturini ◽  
C. P. Tigges ◽  
R. J. Baughman ◽  
D. S. Ginley ◽  
B. Morosin
Keyword(s):  
Single Crystals ◽  
Crystal Structures ◽  
Cation Site ◽  
Resistivity Data ◽  
Site Disorder ◽  
Extreme Sensitivity ◽  
Identical Crystal ◽  
Superconducting Transitions

AbstractMagnetization and resistivity data are presented which show a substantial difference in superconducting transitions for nominal Tl2Ca2Ba2Cu3Ox plates with identical crystal structures grown from two different “melt” compositions. A Tl-O and CuO-rich flux yielded approximately stoichiometric plates which have sharp transitions beginning near 111 K, while a second Tl-O-rich flux produced plates containing more Tl and less Ba with very broad transitions starting near 96 K. These data demonstrate the extreme sensitivity of superconductivity to cation site disorder in the Tl-Ca-Ba-Cu-O system.

The Gold Sulfates MAu(S04)2 (M = Na, K, Rb)

2001 ◽  
Vol 56 (12) ◽  
pp. 1340-1343 ◽  
Author(s):  
Mathias S. Wickleder ◽  
Oliver Büchner
Keyword(s):  
Sulfuric Acid ◽  
Single Crystals ◽  
Crystal Structures ◽  
Structural Features ◽  
Monovalent Cations ◽  
Coordination Numbers ◽  
Square Planar ◽  
Oxygen Atoms

AbstractThe evaporation of a solution of Au(OH)3 and Na2So4 in conc. sulfuric acid led to yellow single crystals of NaAu(SO4)2 (monoclinic, P21/n, Z = 2, a = 469.1, b = 845.9, c = 831.2 pm, β = 95.7°). Analogous procedures with K2SO4 or Rb2SO4 instead of Na2SO4 yielded single crystals of KAu(SO4)2 (monoclinic, C2/c, Z = 4, a = 1109.8, b = 724.2, c = 941.1 pm, β = 118.4°) and RbAu(S04)2, respectively, (triclinic, P1̄, Z = 1, a = 423.6, b = 497.5, c = 889.0 pm, a = 76.4°, β = 88.4°, γ = 73.5°). Although the crystal structures of the three sulfates are not isotypic they show similar structural features: The gold atoms are coordinated by four oxygen atoms in a square planar manner. These oxygen atoms belong to four SO42- ions which link the [AUO4] units to infinite chains according to 1∞[Au(SO4)4/ 2]- . These chains are connected via the monovalent cations which show coordination numbers of 6 (Na+), 10 (K+) and 12 (Rb+), respectively.

scholarly journals Supram olekulare chloridverbrückte Metall(II)chlorid-Diazin-Komplexe: Kristallstrukturen von [Cd(pyrazin)Cl2], [Zn(pyrazin)Cl2] und [Zn(pyrimidin)C l2] / Supram olecular Chloride Bridged Metal(II) Dichloride Diazine Complexes: Crystal Structures of [Cd(pyrazine)Cl2], [Zn(pyrazine)Cl2], and [Zn(pyrimidine)Cl2]

1996 ◽  
Vol 51 (7) ◽  
pp. 947-951 ◽  
Author(s):  
Joachim Pickardt ◽  
Benedikt Staub
Keyword(s):  
Aqueous Solutions ◽  
Single Crystals ◽  
Crystal Structures ◽  
Diffusion Technique ◽  
Supramolecular Networks

Single crystals of [Cd(pyrazine)Cl2],[Zn(pyrazine)Cl2] and [Zn(pyrimidine)Cl2] were obtained by a diffusion technique from aqueous solutions of the metal dichlorides and solutions of the respective diazine.The structures consist of “supramolecular” networks of-M-Cl-M - and -M-diazine-M-chains.

Determining the Crystal Structures of Peptide Analogs of Boronic Acid in the Absence of Single Crystals: Intricate Motifs of Ixazomib Citrate Revealed by XRPD Guided by ss-NMR

2018 ◽  
Vol 18 (6) ◽  
pp. 3616-3625 ◽  
Author(s):  
Michal Hušák ◽  
Alexandr Jegorov ◽  
Jan Rohlíček ◽  
Andrew Fitch ◽  
Jiří Czernek ◽  
...  
Keyword(s):  
Single Crystals ◽  
Crystal Structures ◽  
Boronic Acid ◽  
Peptide Analogs

A Systematic Method for Indexing Spots of Single Crystals in Laue X-Ray Photographs

1963 ◽  
Vol 7 ◽  
pp. 107-116
Author(s):  
Y. A. Konnan
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Crystal Structures ◽  
Trial And Error ◽  
Systematic Method ◽  
X Ray ◽  
Computer Methods ◽  
Cubic System ◽  
Complex Crystal

AbstractThe determination of the orientation of a single crystal by Laue X-ray photographs is dependent on the identification of the indices of the spots. At the present time, the determination of indices is done by various methods, none of which is entirely systematical. A method for establishing the indices of the spots which avoids a trial-and-error approach is described here. The method is graphical, uses a specially compiled table of erystallographic angles and is not dependent on the complexity of the structure of the crystal or its symmetry. An example of the cubic system is included. With more complex crystal structures the method becomes very laborious and the help of computer methods is suggested.

Die Kristallstrukturen von MesSn(Cl)Me2 und Mes2SnCl2 / The Crystal Structures of MesSn(Cl)Me2 and Mes2SnCl2

1998 ◽  
Vol 53 (4) ◽  
pp. 503-506 ◽  
Author(s):  
Thomas Kräuter ◽  
Bernhard Neumüller
Keyword(s):  
Solid State ◽  
Single Crystals ◽  
Crystal Structures ◽  
Space Group ◽  
State 1

Single crystals of MesSn(Cl)Me2 (1) and Mes2SnCl2 (2) were obtained by the reactions of MesGaCl2 with Me3SnF and Mes3SnF, respectively. 1 and 2 are monomeric molecules in the solid state. 1: space group P21/n, Z = 4. lattice dimensions at -70°C: a = 1202,3(1), b = 739,1(1), c = 1441,3(1) pm , β = 102,71(1)°, R1 = 0,0469; 2: space group Pbcn, Z = 4, lattice dimensions at -50°C: a = 1107,0(2), b = 949,9(1), c = 1729,8(2) pm, R1= 0,049.

Structures and Photochemistry of Inclusion Compounds of 9,10-Dihydro-9,10-ethenoanthracene-11,12-bis(diphenylphosphine Oxide)

1997 ◽  
Vol 53 (2) ◽  
pp. 293-299 ◽  
Author(s):  
T. Y. Fu ◽  
Z. Liu ◽  
G. Olovsson ◽  
J. R. Scheffer ◽  
J. Trotter
Keyword(s):  
Solid State ◽  
Single Crystals ◽  
Crystal Structures ◽  
Inclusion Compounds ◽  
Enantiomeric Excess ◽  
Structural Features ◽  
Host Molecule ◽  
Diphenylphosphine Oxide ◽  
Solvent Molecules

Inclusion complexes of 9,10-dihydro-9,10-etheno-anthracene-11,12-bis(diphenylphosphine oxide) (1) as host are synthesized using a variety of guest solvent molecules and the photochemistry of the host molecule is studied in solution and in the crystalline complexes. The crystal structures of four complexes are determined and correlated with their photochemical reactivity. In each case only one dibenzosemibullvalene photoproduct is obtained in the photolysis. Since three of the complexes studied crystallize in the chiral space group P212121, irradiation of single crystals produces a chiral photoproduct in >90% enantiomeric excess. Determination of the absolute configurations of reactants and products allows elucidation of the key structural features that control the enantiospecific solid-state photorearrangements.

Hydrothermal Crystal Growth and Crystal Structures of the Mercury(II) Chromates(VI) α-HgCrO4, β-HgCrO4, and HgCrO4·H2O

2006 ◽  
Vol 61 (6) ◽  
pp. 708-714 ◽  
Author(s):  
Berthold Stöger ◽  
Matthias Weil
Keyword(s):  
Crystal Growth ◽  
Single Crystal ◽  
Single Crystals ◽  
Crystal Structures ◽  
Chromic Acid ◽  
Structure Type ◽  
Data Sets ◽  
Hydrothermal Conditions ◽  
Hydrothermal Crystal Growth ◽  
Structure Factors

Single crystals of α-HgCrO4, β -HgCrO4 and HgCrO4 ・ H2O were obtained by reacting yellow HgO in chromic acid of various concentrations under hydrothermal conditions at 200 °C (4 d). All crystal structures were solved and refined from single crystal diffractometer data sets [α-HgCrO4: P21/n, Z = 4, a = 5.5079(8), b = 8.5266(12), c = 7.3503(10) Å , β = 94.022(3)°, 955 structure factors, R[F2 > 2σ (F2)] = 0.0296; β -HgCrO4: Cmcm, Z = 4, a = 5.7187(9), b = 9.0169(14), c = 7.0114(11) Å, 361 structure factors, R[F2 > 2σ (F2)] = 0.0275; HgCrO4 ・ H2O: P1̅, Z = 2, a=5.6157(15), b =6.1115(16), c= 7.590(2) Å , α =108.850(5), β =91.666(5), γ =116.569(5)°, 1235 structure factors, R[F2 > 2σ (F2)] = 0.0316]. The previously reported structure of α-HgCrO4 has been re-determined. It contains distorted [HgO7] pentagonal bipyramids in which the short bonds are directed towards the apices. The new polymorph β -HgCrO4 adopts the CrVO4 (β -CrPO4) structure type and is composed of slightly distorted [HgO6] octahedra. The previously unknown monohydrate HgCrO4 ・ H2O crystallizes in an unique structure and is composed of one nearly regular [HgO4(H2O)2] octahedron and one considerably distorted [HgO6] octahedron. All three structures contain tetrahedral chromate anions CrO42− as the second building units with average Cr-O distances of ca. 1.65 Å

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