Structure Maps and Phase Stability in AlTi3 Alloyed with Rare-Earth Elements

1988 ◽  
Vol 133 ◽  
Author(s):  
C. T. Liu ◽  
J. A. Horton ◽  
D. G. Petitifor
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Solubility Limit ◽  
Size Factor ◽  
X Ray Diffraction ◽  
Atomic Size ◽  
X Ray ◽  
Dependent Parameter ◽  
Rare Earth Additions

ABSTRACTRare-earth elements including Y, Er and Sc were added to AlTi3 for stabilizing the Ll2 ordered crystal structure, as predicted by the AB3 structure map. The crystal structure and phase composition in the AlTi3 alloys were studied by electron microprobe analysis, X-ray diffraction and TEM. The solubility limit of the rare-earth elements were determined and correlated with the atomic size factor. The results obtained so far indicate that rare-earth additions are unable to change the crystal structure of AlTi3 from DO19 to Ll2. The inability to stabilize the Ll2 structure demonstrates the need to characterize the structure map domains with a further period-dependent parameter.

Crystal structure characterization and electronic structure of a rare-earth-containing Zintl phase in the Yb–Al–Sb family: Yb3AlSb3

2021 ◽  
Vol 77 (6) ◽  
Author(s):  
Rongqing Shang ◽  
An T. Nguyen ◽  
Allan He ◽  
Susan M. Kauzlarich
Keyword(s):  
Crystal Structure ◽  
Electronic Structure ◽  
Rare Earth ◽  
Electronic Structure Calculations ◽  
Structure Characterization ◽  
Charge Balance ◽  
X Ray Diffraction ◽  
Zintl Phase ◽  
X Ray ◽  
Structure Calculations

A rare-earth-containing compound, ytterbium aluminium antimonide, Yb3AlSb3 (Ca3AlAs3-type structure), has been successfully synthesized within the Yb–Al–Sb system through flux methods. According to the Zintl formalism, this structure is nominally made up of (Yb2+)3[(Al1−)(1b – Sb2−)2(2b – Sb1−)], where 1b and 2b indicate 1-bonded and 2-bonded, respectively, and Al is treated as part of the covalent anionic network. The crystal structure features infinite corner-sharing AlSb4 tetrahedra, [AlSb2Sb2/2]6−, with Yb2+ cations residing between the tetrahedra to provide charge balance. Herein, the synthetic conditions, the crystal structure determined from single-crystal X-ray diffraction data, and electronic structure calculations are reported.

scholarly journals Identification of rare-earth minerals associated to K-feldspar: Capacsaya project in Peru

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
J. Ochoa ◽  
E. Monteblanco ◽  
L. Cerpa ◽  
A. Gutarra-Espinoza ◽  
L. Avilés-Félix
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Size Range ◽  
X Ray Diffraction ◽  
High Concentration ◽  
Particle Size Range ◽  
X Ray ◽  
Rare Earth Minerals ◽  
Heavy Rare Earth Elements ◽  
The Rare Earth

AbstractA recently discovered the rare-earth-rich site in Capacsaya, located at 123 km northwest of Cusco, at the south of Peru, contains significant quantities of light and heavy rare-earth elements such as neodymium, lanthanum, cerium, europium, and yttrium. This work reports the identification of rare-earth elements and their associated minerals using scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analyses. Five (5) samples extracted from different locations at the Capacsaya site were characterized and identified K-feldspar as the mineral associated with the rare-earth elements in a representative sample with a high concentration of lanthanum and cerium. The results showed rare-earth elements contained within the mineral phase monazite, being cerium the dominant element in the phase (La, Ce, Nd)PO$$_4$$ 4 . Finally, through the electrostatic separation process we demonstrate that it was possible to achieve an efficient separation of the K-feldspar phase in the particle size range 75–150 $$\upmu$$ μ m.

Plumbogummite-group minerals from Mull and Morvern

1970 ◽  
Vol 37 (292) ◽  
pp. 934-938 ◽  
Author(s):  
D. C. Bain
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Clay Minerals ◽  
Spectrochemical Analysis ◽  
X Ray Diffraction ◽  
Complex Composition ◽  
X Ray

SummarySandstones from Mull and Morvern, most of which are from the Greensand formation, have been shown by X-ray diffraction to contain minerals of the plumbogummite group in very small amounts in the < 1·4µm fraction. The minerals were concentrated by HF digestion of the clay minerals. X-ray spectrographic traces show concentrations of Sr, La, Ce, Yt, and Ba, and a semiquantitative spectrochemical analysis also shows a concentration of Ca and Pb and the presence of numerous rare-earth elements. Individual minerals, which have a complex composition and can not be assigned to any one named species, are disseminated throughout the rocks as particles with an estimated size of between 0·1 and 0·25µm.

Crystal structures of rare earth elements rich apatite analogues

1990 ◽  
Vol 191 (3-4) ◽  
Author(s):  
Nicoline Kalsbeek ◽  
Sine Larsen ◽  
Jørn G. Rønsbo
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Hexagonal System ◽  
Space Group ◽  
X Ray ◽  
Cell Dimensions

AbstractThe crystal structures have been determined for britholite-(Ce) and lessingite-(Ce) from the type localities and a third sample (‘min X’) showing chemical similarities to both britholite-(Ce) and lessingite-(Ce). This sample is from the Ilímaussaq intrusion in Greenland. They are rare earth elements (REE) rich apatite analogues. Based on the X-ray diffraction results they were assigned to the hexagonal system with cell dimensions slightly larger than those of apatite. The three structures have been refined in the space group

scholarly journals The synthesis, structure and physical properties of lanthanide(III) complexes with nicotinic acid

2014 ◽  
Vol 12 (2) ◽  
pp. 220-226 ◽  
Author(s):  
Nuša Hojnik ◽  
Matjaž Kristl ◽  
Amalija Golobič ◽  
Zvonko Jagličić ◽  
Miha Drofenik
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Nicotinic Acid ◽  
Central Atom ◽  
Coordination Complexes ◽  
X Ray Diffraction ◽  
Coordination Environment ◽  
X Ray ◽  
Rare Earth Coordination ◽  
Bidentate Mode

AbstractThis article reports the synthesis of novel, rare-earth coordination complexes with nicotinic acid. Three compounds with the general formula Ln2[(C5H4NCOO)6(H2O)4] (Ln = Yb, 1; Ln = Gd, 2; Ln = Nd, 3) were prepared from relatively cheap and readily available reactants. Their compositions and structure were characterized by IR spectroscopy and single-crystal X-ray diffraction. The magnetic and thermogravimetric properties were also studied. The complexes consist of centrosymetric, dimeric molecules having all six nicotinato ligands coordinated with the central atom in the bidentate mode. The coordination environment of the Ln3+ for all three compounds is 8. Here we describe the crystal structure of Yb and Gd complexes with nicotinic acid.

scholarly journals Crystal structure of apatite type Ca2.49Nd7.51(SiO4)6O1.75

2016 ◽  
Vol 72 (2) ◽  
pp. 209-211 ◽  
Author(s):  
Thu Hoai Le ◽  
Neil R. Brooks ◽  
Koen Binnemans ◽  
Bart Blanpain ◽  
Muxing Guo ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Room Temperature ◽  
Solubility Limit ◽  
Temperature Data ◽  
X Ray Diffraction ◽  
Slow Cooling ◽  
X Ray ◽  
Natural Apatite ◽  
Apatite Type

The title compound, Ca2+xNd8–x(SiO4)6O2–0.5x(x= 0.49), was synthesized at 1873 K and rapidly quenched to room temperature. Its structure has been determined using single-crystal X-ray diffraction and compared with results reported using neutron and X-ray powder diffraction from samples prepared by slow cooling. The single-crystal structure from room temperature data was found to belong to the space groupP63/mand has the composition Ca2.49Nd7.51(SiO4)6O1.75[dicalcium octaneodymium hexakis(orthosilicate) dioxide], being isotypic with natural apatite and the previously reported Ca2Nd8(SiO4)6O2and Ca2.2Nd7.8(SiO4)6O1.9. The solubility limit of calcium in the equilibrium state at 1873 K was found to occur at a composition of Ca2+xNd8–x(SiO4)6O2–0.5x, wherex= 0.49.

scholarly journals Investigation of the Structural and Magnetic Properties of the Light Rare Earth Elements and Their Intermetallic Compounds

1988 ◽  
Vol 41 (2) ◽  
pp. 155 ◽  
Author(s):  
DC Creagh
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Intermetallic Compounds ◽  
Light Rare Earth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Radiation Sources ◽  
Structural And Magnetic Properties ◽  
Light Rare Earth Elements

The experimental requirements for the investigation of the structural and magnetic properties of the light rare earth elements and their intermetallic compounds at synchrotron radiation sources are discussed. Experimental techniques considered include X-ray topography, energy dispersive X-ray diffraction and X-ray powder diffraction.

Crystal Structure and Luminescent Properties of Complex [Eu0.5Gd0.5(C12H9O2)2(C12H8N2)2(H2O)2]•(C12H9O2)•H2O

2012 ◽  
Vol 554-556 ◽  
pp. 691-694
Author(s):  
Hai Tao Xia ◽  
Yu Fen Liu ◽  
De Fu Rong
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Ternary Complex ◽  
Luminescent Properties ◽  
Luminescence Spectra ◽  
X Ray Diffraction ◽  
Red Emission ◽  
X Ray ◽  
Sharp Band ◽  
Complex Display

One new rare-earth ternary complex with 1-naphthylacetic acid and 1,10-phenanthroline, [Eu0.5Gd0.5(C12H9O2)2(C12H8N2)2(H2O)2]•(C12H9O2)•H2O were synthesized. The structures were established by single crystal X-ray diffraction. The europium (gadolinium) ion is eight-coordinate with four oxygen and four nitrogen atoms forming a coordination polyhedron best describable as a distorted dodecahedral. The luminescence spectra of the complex in a solution of DMF were studied. The complex display characteristic Eu(III)-originated red emission as a sharp band at 617 nm. It is concluded that the metal-centered red emission is promoted by the ligand-assisted energy transfer.

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