Polymorphism in the Germanides REPdGe with the Heavy Rare Earth Elements

2009 ◽  
Vol 64 (6) ◽  
pp. 595-602 ◽  
Author(s):  
Ute Ch. Rodewald ◽  
Birgit Heying ◽  
Rolf-Dieter Hoffmann ◽  
Dirk Niepmann ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Crystal Chemical ◽  
Heavy Rare Earth ◽  
Space Group ◽  
Structure Space ◽  
Arc Melting ◽  
Different Temperatures ◽  
Heavy Rare Earth Elements ◽  
Interlayer Bonding

The structures of the equiatomic germanides REPdGe with the heavy rare earth elements have been reinvestigated with respect to palladium-germanium ordering. The samples were prepared by arc-melting of the elements followed by annealing procedures in sealed silica ampoules at different temperatures. The structures of YPdGe, HT-TbPdGe, LT-DyPdGe, HT-DyPdGe, LT-HoPdGe, HT-HoPdGe, ErPdGe, and TmPdGe, and of the new germanide LuPdGe, were refined from single crystal diffractometer data. LT-DyPdGe and LT-HoPdGe crystallize with the YPdSi-type structure, space group Pmmn. The other germanides crystallize with the non-centrosymmetric YbAuSn structure, space group Imm2. All structures are orthorhombically-distorted superstructure variants of AlB2, and they show strong intralayer Pd-Ge bonding within the ordered Pd3Ge3 hexagons. There is weak Pd-Ge and Pd-Pd interlayer bonding. The crystal chemical relationship between the different superstructures is discussed.

Platinum-Germanium Ordering in the Germanides REPtGe with the Heavy Rare Earth Elements

2009 ◽  
Vol 64 (4) ◽  
pp. 383-387 ◽  
Author(s):  
Ute Ch. Rodewald ◽  
Birgit Heying ◽  
Rolf-Dieter Hoffmann ◽  
Dirk Niepmann ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Single Crystal ◽  
Three Dimensional ◽  
Type Structure ◽  
Crystal Chemical ◽  
Heavy Rare Earth ◽  
Structure Space ◽  
Arc Melting ◽  
Heavy Rare Earth Elements

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.

Selective recovery of heavy rare earth elements from apatite with an adsorbent bearing immobilized tridentate amido ligands

2016 ◽  
Vol 159 ◽  
pp. 157-160 ◽  
Author(s):  
Takeshi Ogata ◽  
Hirokazu Narita ◽  
Mikiya Tanaka ◽  
Mihoko Hoshino ◽  
Yoshiaki Kon ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Heavy Rare Earth ◽  
Amido Ligands ◽  
Selective Recovery ◽  
Heavy Rare Earth Elements

scholarly journals Effect of acid mine drainage on dissolved rare earth elements geochemistry along a fluvial–estuarine system: the Tinto-Odiel Estuary (S.W. Spain)

2012 ◽  
Vol 43 (3) ◽  
pp. 262-274 ◽  
Author(s):  
J. Borrego ◽  
B. Carro ◽  
N. López-González ◽  
J. de la Rosa ◽  
J. A. Grande ◽  
...  
Keyword(s):  
Rare Earth ◽  
Acid Mine Drainage ◽  
Rare Earth Elements ◽  
Mine Drainage ◽  
Drainage System ◽  
Estuarine System ◽  
Mixing Zone ◽  
Heavy Rare Earth ◽  
Acid Mine ◽  
Heavy Rare Earth Elements

The concentration of rare earth elements together with Sc, Y, and U, as well as rare earth elements fractionation patterns, in the water of an affected acid mine drainage system were investigated. Significant dissolved concentrations of the studied elements were observed in the fluvial sector of this estuary system (Sc ∼ 31 μg L−1, Y ∼ 187 μg L−1, U ∼ 41 μg L−1, Σ rare earth elements ∼621 μg L−1), with pH values below 2.7. In the mixing zone of the estuary, concentrations are lower (Sc ∼ 2.1 μg L−1; Y ∼ 16.7 μg L−1; U ∼ 4.8 μg L−1; Σ rare earth elements ∼65.3 μg L−1) and show a strong longitudinal gradient. The largest rare earth elements removal occurs in the medium-chlorinity zone and it becomes extreme for heavy rare earth elements, as observed for Sc. Samples of the mixing zone show a North American Shale normalized pattern similar to the fluvial zone water, while the samples located in the zone with pH between 6.5 and 7.7 show a depletion of light rare earth elements relative to middle rare earth elements and heavy rare earth elements, similar to that observed in samples of the marine estuary.

scholarly journals Separation and Adsorption-Desorption Characteristics of Heavy Rare Earth Elements (Gd, Tb, Dy) using P507 Resin

2016 ◽  
Vol 25 (4) ◽  
pp. 60-67
Author(s):  
Sungeun Lee ◽  
Joung Woon Kim ◽  
Jong Hyuk Jeon ◽  
Hong Myeong Jun ◽  
Jin Young Lee ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Heavy Rare Earth ◽  
Heavy Rare Earth Elements ◽  
Adsorption Desorption

High specific surface 1-(2-pyridylazo) 2-naphthol (PAN) modified Carbon-based silicon film with cellulose nanocrystalline structure for efficient adsorption of rare earth elements

2021 ◽  
Author(s):  
Bin Wang ◽  
Yuzhe Zhang ◽  
Wen Sun ◽  
Xudong Zheng ◽  
Zhongyu Li
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Specific Surface ◽  
Cellulose Nanocrystals ◽  
Silicon Film ◽  
Nanocrystalline Structure ◽  
Heavy Rare Earth ◽  
Beneficial Result ◽  
Waste Products ◽  
Heavy Rare Earth Elements

The recovery of rare earth elements, especially heavy rare earth elements, from rare earth waste products has a high economic and environmental beneficial result. In this paper, cellulose nanocrystals used...

Petrogenesis of the Upper Cretaceous volcanism in the Kefken region, Western Pontides, NW Turkey

2021 ◽  
Author(s):  
Turgut Duzman ◽  
Ezgi Sağlam ◽  
Aral I. Okay
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Partial Melting ◽  
Upper Cretaceous ◽  
Volcanic Rocks ◽  
Early Eocene ◽  
Heavy Rare Earth ◽  
Heavy Rare Earth Elements ◽  
Cretaceous Volcanism ◽  
Oceanic Slab

<p>The Upper Cretaceous volcanic and volcaniclastic rocks crop out along the Black Sea coastline in Turkey. They are part of a magmatic arc that formed as a result of northward subduction of the Tethys ocean beneath the southern margin of Laurasia. The lower part of the Upper Cretaceous volcanism in the Kefken region, 100 km northeast of Istanbul, is represented by basaltic andesites, andesites, agglomerates and tuffs, which have yielded Late Cretaceous (Campanian, ca. 83 Ma) U-Pb zircon ages. The volcanic and volcanoclastic rocks are stratigraphically overlain by shallow to deep marine limestones, which range in age from Late Campanian to Early Eocene.  Geochemically, basaltic andesites and andesites display negative anomalies in Nb, Ta and Ti, enrichment in large ion lithophile elements (LILE) relative to high field strength elements (HFSE). Light rare earth elements (LREE) show slightly enrichment relative to heavy rare earth elements (La<sub>cn</sub>/Yb<sub>cn</sub> =2.51-3.63) and there are slight negative Eu anomalies (Eu/Eu* = 0.71-0.95) in basaltic andesite and andesite samples. The geochemical data indicate that Campanian volcanic rocks were derived from the partial melting of the mantle wedge induced by hydrous fluids released by dehydration of the subducted oceanic slab.</p><p>There is also a horizon of volcanic rocks, about 230 m thick, within the Late Campanian-Early Eocene limestone sequence.  This volcanic horizon, which consists of pillow basalts, porphyritic basalts,  andesites and dacites, is of Maastrichtian age based on paleontological data from the intra-pillow sediments and U-Pb zircon ages from the andesites and dacites (72-68 Ma).  The Maastrichtian andesites and dacites are geochemically distinct from the Campanian volcanic rocks. They show distinct adakite-like geochemical signatures with high ratios of Sr/Y (>85.5), high La<sub>cn</sub>/Yb<sub>cn </sub>(16.4-23.7) ratios, low content of Y (7.4-8.6 ppm) and low content of heavy rare-earth elements (HREE). The adakitic rocks most probably formed as a result of partial melting of the subducting oceanic slab under garnet and amphibole stable conditions.</p><p>The Upper Cretaceous arc sequence in the Kefken region shows a change from typical subduction-related magmas to adakitic ones, accompanied by decrease in the volcanism.</p><p> </p><p> </p>

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