Growth and defect structure of CdF2 crystal and nonstoichiometric Cd1−x R x F2+x phases (R are rare earth elements and in): 6. Growth and ionic conductivity of Cd0.904In0.096F2.096 single crystal

The equiatomic germanides REPtGe with the heavy rare earth elements (RE) have been reinvestigated with respect to platinum-germanium ordering. The compounds were prepared by arc-melting of the elements followed by annealing for two weeks at 1070 K. The REPtGe germanides crystallize with the TiNiSi-type structure, space group Pnma. The structures of ErPtGe (a = 692.01(5), b = 432.03(4), c = 753.19(5) pm, wR2 = 0.0523, 435 F2, 20 variables) and the new germanide LuPtGe (a = 683.1(1), b = 429.2(1), c = 750.3(1) pm, wR2 = 0.0696, 358 F2, 20 variables) have been refined from single crystal diffractometer data. These structures exhibit three-dimensional [PtGe] networks with strong Pt-Ge intra- (251 - 255 pm in LuPtGe) and weaker interlayer (272 pm in LuPtGe) interactions. The crystal chemical peculiarities of the whole REPtGe series are briefly discussed.

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Nanostructured Crystals of Fluorite Phases Sr1 – xRxF2 + x (R Are Rare-Earth Elements) and Their Ordering. 15. Concentration Dependence of the Defect Structure of As Grown Nonstoichiometric Phases Sr1 – xRxF2 + x (R = Sm, Gd)

Crystallography Reports ◽

10.1134/s1063774519050225 ◽

2019 ◽

Vol 64 (6) ◽

pp. 873-878

Author(s):

E. A. Sulyanova ◽

D. N. Karimov ◽

B. P. Sobolev

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Concentration Dependence ◽

Defect Structure

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Zr-Rich Eudialyte from the Lovozero Peralkaline Massif, Kola Peninsula, Russia

Minerals ◽

10.3390/min11090982 ◽

2021 ◽

Vol 11 (9) ◽

pp. 982

Author(s):

Taras L. Panikorovskii ◽

Julia A. Mikhailova ◽

Yakov A. Pakhomovsky ◽

Ayya V. Bazai ◽

Sergey M. Aksenov ◽

...

Keyword(s):

Rare Earth ◽

Chemical Composition ◽

Rare Earth Elements ◽

Single Crystal ◽

Kola Peninsula ◽

Marginal Zone ◽

X Ray Diffraction ◽

Eudialyte Group ◽

X Ray ◽

Marginal Zones

The Lovozero peralkaline massif (Kola Peninsula, Russia) has several deposits of Zr, Nb, Ta and rare earth elements (REE) associated with eudialyte-group minerals (EGM). Eudialyte from the Alluaiv Mt. often forms zonal grains with central parts enriched in Zr (more than 3 apfu) and marginal zones enriched in REEs. The detailed study of the chemical composition (294 microprobe analyses) of EGMs from the drill cores of the Mt. Alluaiv-Mt. Kedykvyrpakhk deposits reveal more than 70% Zr-enriched samples. Single-crystal X-ray diffraction (XRD) was performed separately for the Zr-rich (4.17 Zr apfu) core and the REE-rich (0.54 REE apfu) marginal zone. It was found that extra Zr incorporates into the octahedral M1A site, where it replaces Ca, leading to the symmetry lowering from R3¯m to R32. We demonstrated that the incorporation of extra Zr into EGMs makes the calculation of the eudialyte formula on the basis of Si + Al + Zr + Ti + Hf + Nb + Ta + W = 29 apfu inappropriate.

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The quaternary arsenide oxides Ce9Au5–xAs8O6 and Pr9Au5–xAs8O6

Zeitschrift für Naturforschung B ◽

10.1515/znb-2016-0160 ◽

2016 ◽

Vol 71 (12) ◽

pp. 1245-1252

Author(s):

Timo Bartsch ◽

Rolf-Dieter Hoffmann ◽

Rainer Pöttgen

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Single Crystal ◽

Crystal Chemistry ◽

Structure Type ◽

Rare Earth Oxides ◽

Gold Powder ◽

X Ray ◽

Annealing Temperatures ◽

Oxide Crystal

AbstractThe quaternary gold arsenide oxides Ce9Au5−xAs8O6 and Pr9Au5−xAs8O6 were synthesized from the rare earth elements (RE), rare earth oxides, arsenic and gold powder at maximum annealing temperatures of 1173 K. The structures were refined from single crystal X-ray diffractometer data: Pnnm, a=1321.64(6) pm, b=4073.0(3), c=423.96(2), wR2=0.0842, 3106 F2 values, 160 variables for Ce9Au4.91(4)As8O6 and Pnnm, a=1315.01(4), b=4052.87(8), c=420.68(1) pm, wR2=0.0865, 5313 F2 values, 160 variables for Pr9Au4.75(1)As8O6. They represent a new structure type and show a further extension of pnictide oxide crystal chemistry. A complex polyanionic gold arsenide network [Au5As8]15− (with some disorder in the gold substructure) is charge compensated with polycationic strands of condensed edge-sharing O@RE4/4 and O@RE4/3 tetrahedra ([RE4O3]212+) as well as RE3+ cations in cavities.

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