A New Family of Nonstoichiometric Layered Rare-Earth Tin Antimonides,RESnxSb2(RE= La, Ce, Pr, Nd, Sm):  Crystal Structure of LaSn0.75Sb2

1996 ◽  
Vol 35 (15) ◽  
pp. 4505-4512 ◽  
Author(s):  
Michael J. Ferguson ◽  
Ryan W. Hushagen ◽  
Arthur Mar
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
New Family

A New Family of Lithium Rare-Earth Oxyborates, LiLn6O5(BO3)3 (Ln=Pr–Tm): Crystal Structure of the Gadolinium Phase LiGd6O5(BO3)3

1999 ◽  
Vol 146 (1) ◽  
pp. 189-196 ◽  
Author(s):  
Jean-Pierre Chaminade ◽  
Pierre Gravereau ◽  
Veronique Jubera ◽  
Claude Fouassier
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
New Family

Synthesis and crystal structure of (Ca, R)(Mn, Ti)O3 (R, rare earth)

2006 ◽  
Vol 408-412 ◽  
pp. 1173-1176 ◽  
Author(s):  
Migaku Kobayashi ◽  
Ryouko Katsuraya ◽  
Syou Kurita ◽  
Makoto Yamaguchi ◽  
Hiroshisa Satoh ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Synthesis And Crystal Structure

Crystal structure and magnetic ordering of the rare-earth and Cu moments inRBa2Cu2NbO8(R=Nd,Pr)

1993 ◽  
Vol 47 (22) ◽  
pp. 15256-15264 ◽  
Author(s):  
N. Rosov ◽  
J. W. Lynn ◽  
H. B. Radousky ◽  
M. Bennahmias ◽  
T. J. Goodwin ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Magnetic Ordering ◽  
The Rare Earth

High-pressure Syntheses and Characterization of the Rare-earth Fluoride Borates RE2(BO3)F3 (RE=Tb, Dy, Ho)

2013 ◽  
Vol 68 (11) ◽  
pp. 1198-1206 ◽  
Author(s):  
Ernst Hinteregger ◽  
Michael Enders ◽  
Almut Pitscheider ◽  
Klaus Wurst ◽  
Gunter Heymann ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Rare Earth ◽  
Monoclinic Space Group ◽  
Rare Earth Fluoride ◽  
Earth Fluoride ◽  
Structure Determinations ◽  
New Compounds ◽  
Rare Earth Fluorides

The new rare-earth fluoride borates RE2(BO3)F3 (RE=Tb, Dy, Ho) were synthesized under highpressure/ high-temperature conditions of 1:5 GPa=1200 °C for Tb2(BO3)F3 and 3:0 GPa=900 °C for Dy2(BO3)F3 and Ho2(BO3)F3 in a Walker-type multianvil apparatus from the corresponding rareearth sesquioxides, rare-earth fluorides, and boron oxide. The single-crystal structure determinations revealed that the new compounds are isotypic to the known rare-earth fluoride borate Gd2(BO3)F3. The new rare-earth fluoride borates crystallize in the monoclinic space group P21/c (Z = 8) with the lattice parameters a=16:296(3), b=6:197(2), c=8:338(2) Å , b =93:58(3)° for Tb2(BO3)F3, a= 16:225(3), b = 6:160(2), c = 8:307(2) Å , b = 93:64(3)° for Dy2(BO3)F3, and a = 16:189(3), b = 6:124(2), c = 8:282(2) Å , β= 93:69(3)° for Ho2(BO3)F3. The four crystallographically different rare-earth cations (CN=9) are surrounded by oxygen and fluoride anions. All boron atoms form isolated trigonal-planar [BO3]3- groups. The six crystallographically different fluoride anions are in a nearly planar coordination by three rare-earth cations.

Growth, crystal structure and spectrum of a novel rare-earth orthophosphate crystal: Yb:LuPO4

2013 ◽  
Vol 48 (6) ◽  
pp. 369-373 ◽  
Author(s):  
Zhong De-gao ◽  
Teng Bing ◽  
Cao Li-feng ◽  
Chao Wang ◽  
He Lin-xiang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Orthophosphate Crystal

Kihlmanite-(Ce), Ce2TiO2[SiO4](HCO3)2(H2O), a new rare-earth mineral from the pegmatites of the Khibiny alkaline massif, Kola Peninsula, Russia

2014 ◽  
Vol 78 (3) ◽  
pp. 483-496 ◽  
Author(s):  
V. N. Yakovenchuk ◽  
S.V. Krivovichev ◽  
G. Y. Ivanyuk ◽  
Ya. A. Pakhomovsky ◽  
E.A. Selivanova ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
X Ray ◽  
Intimate Association ◽  
Mohs Hardness ◽  
Rare Earth Mineral ◽  
Alkaline Massif ◽  
Khibiny Alkaline Massif

AbstractKihlmanite-(Ce), Ce2TiO2[SiO4](HCO3)2(H2O), is a new rare-earth titanosilicate carbonate, closely related to tundrite-(Ce). It is triclinic, P, a = 4.994(2), b = 7.54(2), c = 15.48(4) Å, α = 103.5(4), β = 90.7(2), γ = 109.2(2)o , V = 533(1) Å3, Z = 2 (from powder diffraction data) or a = 5.009(5), b = 7.533(5), c = 15.407(5) Å, α = 103.061(5), β = 91.006(5), γ = 109.285(5)°, V = 531.8(7) Å3, Z = 2 (from single-crystal X-ray diffraction data). The mineral was found in the arfvedsonite-aegirine-microcline vein in fenitized metavolcanic rock at the foot of the Mt Kihlman (Chil’man), near the western contact of the Devonian Khibiny alkaline massif and the Proterozoic Imandra-Varzuga greenstone belt. It forms brown spherulites (up to 2 cm diameter) and sheaf-like aggregates of prismatic crystals, flattened on {010} and up to 0.5 mm diameter. Both spherulites and aggregates occur in interstices in arfvedsonite and microcline, in intimate association with golden-green tundrite-(Ce). Kihlmanite-(Ce) is brown, with a vitreous lustre and a pale yellowish-brown streak. The cleavage is perfect on {010}, parting is perpendicular to c and the fracture is stepped. Mohs hardness is ∼3. In transmitted light, the mineral is yellowish brown; pleochroism and dispersion were not observed. Kihlmanite-(Ce) is biaxial (+), α = 1.708(5), β = 1.76(1), γ = 1.82(1) (589 nm), 2Vcalc = 89°. The optical orientation is Y ^ c = 5°, other details are unclear. The calculated and measured densities are 3.694 and 3.66(2) g cm−3, respectively. The mean chemical composition, determined by electron microprobe, is: Na2O 0.13, Al2O3 0.24, SiO2 9.91, CaO 1.50, TiO2 11.04, MnO 0.26, Fe2O3 0.05, Nb2O5 2.79, La2O3 12.95, Ce2O3 27.33, Pr2O3 2.45, Nd2O3 8.12, Sm2O3 1.67, Gd2O3 0.49 wt.%, with CO2 15.0 and H2O 6.0 wt.% (determined by wet chemical and Penfield methods, respectively), giving a total of 99.93 wt.%. The empirical formula calculated on the basis of Si + Al = 1 atom per formula unit is (Ca0.16Na0.11Mn0.02)∑0.29[(Ce0.98La0.47Pr0.09Nd0.29Sm0.06Gd0.02)∑1.91(Ti0.82Nb0.12)∑0.94O2 (Si0.97Al0.03)∑1O4.02(HCO3)2.01](H2O)0.96. The simplified formula is Ce2TiO2(SiO4)(HCO3)2·H2O. The mineral reacts slowly in cold 10% HCl with weak effervescence and fragmentation into separate plates. The strongest X-ray powder-diffraction lines [listed as d in Å(I) (hkl)] are as follows: 15.11(100)(00), 7.508(20)(00), 6.912(12)(01), 4.993(14)(00), 3.563(15)(01), 2.896(15)(1). The crystal structure of kihlmanite-(Ce) was refined to R1 = 0.069 on the basis of 2441 unique observed reflections (MoKα, 293 K). It is closely related to the crystal structure of tundrite-(Ce) and is based upon [Ce2TiO2(SiO4)(HCO3)2] layers parallel to (001). Kihlmanite-(Ce) can be considered as a cationdeficient analogue of tundrite-(Ce). The mineral is named in honour of Alfred Oswald Kihlman (1858–1938), a remarkable Finnish geographer and botanist who participated in the Wilhelm Ramsay expeditions to the Khibiny Mountains in 1891–1892. The mineral name also reflects its occurrence at the Kihlman (Chil’man) Mountain.

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.

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