Adventitiously Obtained Rare-Earth Peroxide Complexes and Their Structural Characterisation

2014 ◽  
Vol 67 (12) ◽  
pp. 1860 ◽  
Author(s):  
Glen B. Deacon ◽  
Craig M. Forsyth ◽  
Dominique Freckmann ◽  
Peter C. Junk ◽  
Kristina Konstas ◽  
...  
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Bulk Sample ◽  
Structural Characterisation ◽  
Square Planar ◽  
Phenyl Mercury ◽  
Oxygen Atoms

The structures of three adventitiously obtained peroxolanthanoid complexes have been determined, namely, [Yb2(Cp)4(μ-O)2/3(μ-O2)1/3(thf)2] (1) (Cp = cyclopentadienyl; thf = tetrahydrofuran), which has disorder between the bridging oxide and peroxide, [Nd2(o-PhPhForm)4(thf)4(μ-O2)] (2) (o-PhPhForm = N,N′-bis(2-phenylphenyl)formamidinate), and [Eu4(FForm)6(μ-OH)2(μ3-O2)2(μ-diglyme)2]·2diglyme (3) (FForm = N,N′-bis(2-fluorophenyl)formamidinate, diglyme = bis(2-methoxyethyl) ether). In the first two complexes, the peroxide bridges side-on between metals, whereas in the last complex, each peroxide bridges three metals through both oxygen atoms. The first complex was a single crystal amongst a bulk sample of [Yb(Cp)2(pzPh)(thf)] (pzPh = 2-(1′-pyrazolyl)phenyl), prepared by oxidation of dicyclopentadienylytterbium(ii) by bis(2-(1′-pyrazolyl)phenyl)mercury, the structure of which was also determined and showed distorted square planar stereochemistry for mercury.

The Ternary Rare Earth Chromium Nitrides Ce2CrN3 and Ln3Cr10−xN11 with Ln = La, Ce, Pr

1995 ◽  
Vol 50 (6) ◽  
pp. 905-912 ◽  
Author(s):  
Sascha Broil ◽  
Wolfgang Jeitschko
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Chromium Nitrides ◽  
First Approximation ◽  
Structure Factors ◽  
Square Planar ◽  
Pauli Paramagnetism ◽  
Cubic Structure ◽  
Cold Pressed ◽  
N Flux

The title compounds have been prepared by annealing cold-pressed pellets of the binary nitrides LnN and CrN. Well developed crystals were obtained by recrystallization of the binary or prereacted ternary nitrides in a Li3N flux. Their structures were determined from single-crystal diffractometer data. C e2CrN3 has a U2CrN3 type structure: Immm , a = 379.0(1), b = 340.4(1), c = 1251.7(2) pm, Z = 2, R = 0.012 for 383 structure factors and 16 variables. The atomic positions of this structure are similar to those of U2IrC2 and K2NiF4. The structure may be rationalized to a first approximation with the formula (Ce+4)2[CrN3]8−. The chromium atoms are in a distorted square-planar nitrogen coordination. The CrN4-squares are linked via corner-sharing nitrogen atoms, thus forming infinite, straight - N - CrN2- N - CrN2- chains. The cubic structure of La3Cr10−xN11 (a = 1298.2(1) pm ), Ce3Cr10−xN11 (with a small homogenity range; a = 1284.3(1)-1286.1(3) pm ), and Pr3Cr10−xN11 (a = 1289.1(2) pm ) was determined for the lanthanum compound: Fm 3̄ m , Z = 8, R = 0.027 for 189 F values and 18 variables. One chromium site was found to have an occupancy of only 80.9(5)% resulting in the composition La3Cr9.24(1)N11. The nitrogen atoms occupy four atomic sites. Three of these have octahedral environments (6 La, 3 La + 3 Cr, 2 La + 4 Cr), the fourth one is surrounded by eight chromium atoms forming a cube. The chromium atoms are tetrahedrally coordinated by nitrogen atoms, and these CrN4-tetrahedra are linked via common corners and edges to form a three-dimensionally infinite polyanionic network. In addition the chromium atoms with oxidation numbers of about 2 to 3 form numerous Cr - Cr bonds, which allow to rationalize the Pauli paramagnetism of the compound.

SINGLE CRYSTAL NEUTRON DIFFRACTION STUDIES OF HCP RARE EARTH THORIUM ALLOYS

1971 ◽  
Vol 32 (C1) ◽  
pp. C1-1128-C1-1129
Author(s):  
H. R. CHILD ◽  
W. C. KOEHLER
Keyword(s):  
Rare Earth ◽  
Neutron Diffraction ◽  
Single Crystal

scholarly journals Synthesis, characterization, and single-crystal growth of a high-entropy rare-earth pyrochlore oxide

2020 ◽  
Vol 4 (10) ◽  
Author(s):  
Candice Kinsler-Fedon ◽  
Qiang Zheng ◽  
Qing Huang ◽  
Eun Sang Choi ◽  
Jiaqiang Yan ◽  
...  
Keyword(s):  
Rare Earth ◽  
Crystal Growth ◽  
Single Crystal ◽  
Single Crystal Growth ◽  
High Entropy ◽  
Pyrochlore Oxide

Critical Current of Bi-2212 Single Crystal by Doping Oxides as a Pinning Center

2014 ◽  
Vol 95 ◽  
pp. 175-180
Author(s):  
Takuya Agou ◽  
Hiroya Imao
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Single Crystals ◽  
Crystal Surface ◽  
Rare Earth Oxides ◽  
Pinning Centers ◽  
Current Path ◽  
Pinning Center ◽  
Superconducting Current ◽  
A Current

It is necessary to formpinning centers in superconductors to allow the flow of large currents throughthe specimens. To clarify the properties of pinning centers, it is preferableto investigate single crystals. In this study, heat treatment was used to dopevarious oxides into Bi2Sr2CaCu2Ox(Bi-2212) single crystals prepared by self-flux methods and the criticalcurrent (Ic) was measured. The oxides used in this study were Al2O3and the rare earth oxides Er2O3and Nd2O3. At 77K, Nd2O3and Er2O3 are magnetic, whereas Al2O3is nonmagnetic. The Ic of the samples were measured as a current per width of 1cm (Ics). The resulting Ics of the Bi-2212 single crystal was 2.8A/cm and thatof the Al2O3 doped Bi-2212 sample was 4.5A/cm. Comparedwith these samples, doping the other rare earth oxides gave Ics values inexcess 10A/cm. The results indicated that the doping oxides were effective inoperating as pinning centers in the samples. We assumed the current path in asingle crystal, and calculated the Ics by superconducting current simulation.The results indicated that the oxides permeated from a crystal surface in aporous shape. The oxides increase the current which flow in the Cu-O2planes that are parallel to the a-b plane.

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 Rare-Earth Triangular Lattice Spin Liquid: A Single-Crystal Study ofYbMgGaO4

2015 ◽  
Vol 115 (16) ◽  
Author(s):  
Yuesheng Li ◽  
Gang Chen ◽  
Wei Tong ◽  
Li Pi ◽  
Juanjuan Liu ◽  
...  
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Triangular Lattice ◽  
Spin Liquid ◽  
Lattice Spin ◽  
Single Crystal Study

Single-crystal rare-earth doped YAG fiber lasers grown by the laser-heated pedestal growth technique

2014 ◽  
Author(s):  
Craig D. Nie ◽  
James A. Harrington ◽  
Yuan Li ◽  
Eric G. Johnson ◽  
Elizabeth F. Cloos ◽  
...  
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Fiber Lasers ◽  
Growth Technique ◽  
Laser Heated ◽  
Rare Earth Doped

Structural Systematics of Rare Earth Complexes. VII. Crystal Structure of Bis(2,2'/6',2␛-Terpyridinium) Octaaquaterbium(III) Heptachloride Hydrate

1994 ◽  
Vol 47 (2) ◽  
pp. 391 ◽  
Author(s):  
CJ Kepert ◽  
BW Skeleton ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Single Crystal ◽  
Structural Characterization ◽  
Title Compound ◽  
Room Temperature ◽  
Chloride Ions ◽  
Full Matrix ◽  
X Ray

The room-temperature single-crystal X-ray structural characterization of the title compound (tpyH2)2[Tb(OH2)8]Cl7.~2⅓H2O is recorded. Crystals are triclinic, Pī , a 17.063(5), b 16.243(3), c 7.878(3) Ǻ, α 84.78(2), β 84.39(3), γ 87.81(2)°, Z = 2 formula units; 3167 'observed' diffractometer reflections were refined by full-matrix least-squares procedures to a residual of 0.057. Notable features of interest of the compound are the 'chelation' of chloride ions by the terpyridinium cations , and the existence of a free [Tb(OH2)8]2+ cation in the presence of an abundance of chloride ions.

scholarly journals Intermetallic REPtZn Compounds with TiNiSi-type Structure

2011 ◽  
Vol 66 (7) ◽  
pp. 671-676 ◽  
Author(s):  
Trinath Mishra ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Coordination Number ◽  
High Frequency ◽  
Three Dimensional ◽  
Type Structure ◽  
Rare Earth Compounds ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
X Ray

The equiatomic rare earth compounds REPtZn (RE = Y, Pr, Nd, Gd-Tm) were synthesized from the elements in sealed tantalum tubes by high-frequency melting at 1500 K followed by annealing at 1120 K and quenching. The samples were characterized by powder X-ray diffraction. The structures of four crystals were refined from single-crystal diffractometer data: TiNiSi type, Pnma, a = 707.1(1), b = 430.0(1), c = 812.4(1) pm, wR2 = 0.066, 602 F2, 21 variables for PrPt1.056Zn0.944; a = 695.2(1), b = 419.9(1), c = 804.8(1) pm, wR2 = 0.041, 522 F2, 21 variables for GdPt0.941Zn1.059; a = 688.2(1), b = 408.1(1), c = 812.5(1) pm, wR2 = 0.041, 497 F2, 22 variables for HoPt1.055Zn0.945; a = 686.9(1), b = 407.8(1), c = 810.4(1) pm, wR2 = 0.061, 779 F2, 20 variables for ErPtZn. The single-crystal data indicate small homogeneity ranges REPt1±xZn1±x. The platinum and zinc atoms build up three-dimensional [PtZn] networks (265 - 269 pm Pt-Zn in ErPtZn) in which the erbium atoms fill cages with coordination number 16 (6 Pt + 6 Zn + 4 Er). Bonding of the erbium atoms to the [PtZn] network proceeds via shorter RE-Pt distances, i. e. 288 - 293 pm in ErPtZn.

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