Terahertz-infrared spectra of the rare-earth scandate DyScO3 single crystal

2013 ◽  
Vol 114 (2) ◽  
pp. 024102 ◽  
Author(s):  
G. A. Komandin ◽  
E. S. Zhukova ◽  
V. I. Torgashev ◽  
A. V. Boris ◽  
A. A. Boris ◽  
...  
2013 ◽  
Vol 68 (5-6) ◽  
pp. 625-634 ◽  
Author(s):  
Bastian Reker ◽  
Samir F. Matar ◽  
Ute Ch. Rodewald ◽  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen

Small single crystals of the Sm5Ge4-type (space group Pnma) germanides RE2Nb3Ge4 (RE = Sc, Y, Gd-Er, Lu) and Sc2Ta3Ge4 were synthesized by arc-melting of the respective elements. The samples were characterized by powder and single-crystal X-ray diffraction. In all structures, except for Sc2.04Nb2.96Ge4 and Sc2.19Ta2.81Ge4, the rare earth and niobium atoms show full ordering on the three crystallographically independent samarium sites of the Sm5Ge4 type. Two sites with coordination number 6 are occupied by niobium, while the slightly larger site with coordination number 7 is filled with the rare earth element. Small homogeneity ranges with RE=Nb and RE=Ta mixing can be expected for all compounds. The ordered substitution of two rare earth sites by niobium or tantalum has drastic effects on the coordination number and chemical bonding. This was studied for the pair Y5Ge4/Y2Nb3Ge4. Electronic structure calculations show larger charge transfer from yttrium to germanium for Y5Ge4, contrary to Y2Nb3Ge4 which shows stronger covalent bonding due to the presence of Nb replacing Y at two sites


1996 ◽  
Vol 49 (9) ◽  
pp. 997 ◽  
Author(s):  
LI Semenova ◽  
BW Skelton ◽  
AH White

Adducts [( dmso )nLn(O2NO)3], obtained by the crystallizatior , of lanthanoid (III) nitrate ( Ln (NO3)3.-xH2O) with excess dimethyl sulfoxide (' dmso ') in methanol or ethanol, have been the subject of a series of room-temperature single-crystal X-ray studies, defining more clearly the manner in which stoichiometry and structure systematically vary with change in metal ion radius. All complexes studied are mononuclear, the metal ion being complexed by three bidentate nitrate ligands and a number of dmso ligands , four for La-Sm and three beyond. The array La- Sm is monoclinic C2/c, a ≈ 14.9, b ≈ 15.5, c ≈ 15.5 Ǻ, β ≈ 108.4°, Z = 4 f.u .; the metal atom is disposed on a crystallographic 2 axis, which also passes through one of the nitrate groups. The series Eu -Tm (inclusive also of Y) is monoclinic, P21/n, a ≈ 11.5, b ≈ 12.7, c ≈ 13.6 Ǻ, β ≈ 100°, Z = 4 f.u ., while Yb and Lu are also monoclinic, P21/c, a ≈ 10.0, b ≈ 12.6, c ≈ 16 Ǻ, β ≈ 100.6°, Z = 4 f.u.


Author(s):  
T. F. Tenisheva ◽  
A. N. Lazarev ◽  
I. A. Bondar ◽  
N. V. Vinogradova

1981 ◽  
Vol 36 (4) ◽  
pp. 463-469 ◽  
Author(s):  
R. Schmelczer ◽  
D. Schwarzenbach ◽  
F. Hulliger

Abstract The structures of GdAsSe and NdAsSe were determined from single crystal data. GdAsSe crystallizes in the monoclinic CeAsS-type structure. The deviations from the parent tetragonal ZrSiS-type structure are smaller than in the corresponding sulphides. The As-As distances in the infinite arsenic chains appear to be too large to warrant non-metallic properties. The structure of NdAsSe is isopuntal with the CeAsS-type; however, only As pairs can be identified. The CeAsS-type structure was also found in the LnAsSe compounds with Ln = Pr, Sm, Tb, . . ., Tm, Lu, Y. The distortions of the ZrSiS-type substructure become more pronounced on going to smaller cations. The stoichiometry of the samples depends strongly upon the preparation.


2016 ◽  
Vol 71 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Daniel Schildhammer ◽  
Lucas L. Petschnig ◽  
Gerda Fuhrmann ◽  
Gunter Heymann ◽  
Martina Tribus ◽  
...  

AbstractThe new mixed rare earth (RE) orthophosphates Y0.5Er0.5PO4 and Y0.5Yb0.5PO4 were synthesized by a classical solid state reaction in an electrical furnace at 1200 °C. As starting materials, the corresponding rare earth oxides and diammonium hydrogen phosphate were used. The powder diffraction analyses revealed that the new compounds Y0.5Er0.5PO4 and Y0.5Yb0.5PO4 crystallize in a zircon-type structure being isostructural with the rare earth orthophosphate YPO4. Y0.5Er0.5PO4 and Y0.5Yb0.5PO4 crystallize in the tetragonal space group I41/amd (no. 141) with four formula units in the unit cell. The structural parameters based on Rietveld refinements are a = 687.27(2), c = 601.50(2) pm, V = 0.28412(1) nm3, Rp= 0.0143, and Rwp = 0.0186 (all data) for Y0.5Er0.5PO4 and a = 684.61(2), c = 599.31(2) pm, V = 0.28089(2) nm3, Rp = 0.0242, and Rwp = 0.0313 (all data) for Y0.5Yb0.5PO4. Furthermore, the structure of Y0.5Er0.5PO4 was refined from single-crystal X-ray diffraction data: a = 687.78(5), c = 601.85(4) pm, V = 0.28470(5) nm3, R1= 0.0165, and wR2 = 0.0385 (all data). In both compounds, the rare earth metal ions are eightfold coordinated by oxygen atoms, forming two unique interlocking tetrahedra with two individual RE–O distances. The tetrahedral phosphate groups [PO4]3– are slightly distorted in both compounds. The individual rare earth ions share a common position (Wyckoff site 4a). The presence of two rare earth ions in the structures of the new orthophosphates Y0.5Er0.5PO4 and Y0.5Yb0.5PO4 was additionally confirmed by single-crystal EDX spectroscopy revealing a ratio of 1:1.


1963 ◽  
Vol 4 (1) ◽  
pp. 33-37 ◽  
Author(s):  
L. P. Batsanova ◽  
G. N. Grigor'eva ◽  
S. S. Batsanov

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