scholarly journals Rare-earth metal catalysts for high-pressure synthesis of rare diamonds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuri N. Palyanov ◽  
Yuri M. Borzdov ◽  
Igor N. Kupriyanov ◽  
Alexander F. Khohkhryakov ◽  
Denis V. Nechaev
Keyword(s):  
Rare Earth ◽  
Rare Earth Metals ◽  
Earth Metal ◽  
Group Iv ◽  
Rare Type ◽  
Single Crystal Diamond ◽  
Technology Applications ◽  
Diamond Crystallization ◽  
Pressure Synthesis ◽  
Group Iv Elements

AbstractThe combination of the unique properties of diamond and the prospects for its high-technology applications urges the search for new solvents–catalysts for the synthesis of diamonds with rare and unusual properties. Here we report the synthesis of diamond from melts of 15 rare-earth metals (REM) at 7.8 GPa and 1800–2100 °C. The boundary conditions for diamond crystallization and the optimal parameters for single crystal diamond synthesis are determined. Depending on the REM catalyst, diamond crystallizes in the form of cube–octahedrons, octahedrons and specific crystals bound by tetragon–trioctahedron and trigon–trioctahedron faces. The synthesized diamonds are nitrogen-free and belong to the rare type II, indicating that the rare-earth metals act as both solvent–catalysts and nitrogen getters. It is found that the REM catalysts enable synthesis of diamond doped with group IV elements with formation of impurity–vacancy color centers, promising for the emerging quantum technologies. Our study demonstrates a new field of application of rare-earth metals.

scholarly journals High-pressure synthesis of REB5O8(OH)2 (RE = Ho, Er, Tm)

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Michael Zoller ◽  
Hubert Huppertz
Keyword(s):  
High Pressure ◽  
Rare Earth ◽  
Ir Spectroscopy ◽  
Earth Metal ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Solution ◽  
Pressure Synthesis ◽  
The Rare Earth

AbstractThe rare earth oxoborates REB5O8(OH)2 (RE = Ho, Er, Tm) were synthesized in a Walker-type multianvil apparatus at a pressure of 2.5 GPa and a temperature of 673 K. Single-crystal X-ray diffraction data provided the basis for the structure solution and refinement. The compounds crystallize in the monoclinic space group C2 (no. 5) and are composed of a layer-like structure containing dreier and sechser rings of corner sharing [BO4]5− tetrahedra. The rare earth metal cations are coordinated between two adjacent sechser rings. Further characterization was performed utilizing IR spectroscopy.

FEATURES OF THE MAGNETIC STATE IN AMORPHOUS RE–TM AND RE–TM–B MAGNETS (review)

2021 ◽  
pp. 43-58
Author(s):  
R.B. Morgunov ◽  
◽  
D.V. Korolev ◽  
R.A. Valeev ◽  
V.P. Piskorskiy ◽  
...  
Keyword(s):  
Rare Earth ◽  
Amorphous Alloys ◽  
Magnetic State ◽  
Rare Earth Metals ◽  
Earth Metal ◽  
Spin Reorientation ◽  
Heavy Rare Earth ◽  
Temperature Dependences ◽  
Magnetic States ◽  
Amorphous Magnets

Provides an overview of the magnetism features of amorphous magnets of the RE–TM and RE–TM–B alloys (RE – rare earth metal, TM – transition metal, B – boron). Magnetic states in amorphous alloys, the effect of the single-ionic anisotropy of heavy rare-earth metals on local disorder and spin frustrations in an amorphous body, and some spin-reorientation transitions observed in such compounds are presented. It is shown that the identification of the spin-glass state can be achieved by detecting specific features on the field and temperature dependences of the magnetic moment and magnetic susceptibility of the sample.

scholarly journals High-pressure synthesis of rare earth metal polychalcogenides

2010 ◽  
Vol 66 (a1) ◽  
pp. s47-s47
Author(s):  
Thomas Doert ◽  
Carola J. Müller ◽  
Ulrich Schwarz ◽  
Peer Schmidt
Keyword(s):  
High Pressure ◽  
Rare Earth ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
High Pressure Synthesis ◽  
Pressure Synthesis

scholarly journals Do rare-earth metals deter spiny dogfish? A feasibility study on the use of electropositive “mischmetal” to reduce the bycatch of Squalus acanthias by hook gear in the Gulf of Maine

2009 ◽  
Vol 66 (2) ◽  
pp. 315-322 ◽  
Author(s):  
Shelly M. L. Tallack ◽  
John W. Mandelman
Keyword(s):  
Rare Earth ◽  
Food Deprivation ◽  
Feasibility Study ◽  
Feeding Behaviour ◽  
Gulf Of Maine ◽  
Rare Earth Metals ◽  
Earth Metal ◽  
Field Studies ◽  
Squalus Acanthias ◽  
Spiny Dogfish

Abstract Tallack, S. M. L., and Mandelman, J. W. 2009. Do rare-earth metals deter spiny dogfish? A feasibility study on the use of electropositive “mischmetal” to reduce the bycatch of Squalus acanthias by hook gear in the Gulf of Maine. – ICES Journal of Marine Science, 66: 315–322. Catches of spiny dogfish (Squalus acanthias) are considered by commercial and recreational fishers to be unacceptably high during summer and autumn in the Gulf of Maine off the northeast coast of the USA. Consequently, there is interest in finding a dogfish deterrent for application in various fishing gears. Field studies tested triangular slices of the rare-earth metal cerium/lanthanide alloy (“mischmetal”) incorporated into longlines and rod-and-reel gear to assess its effectiveness in reducing dogfish catches. Treatment catches (mischmetal present) were compared with control (no mischmetal) catches. Laboratory studies provided video-taped, behavioural observations on the effects of alloys under variable levels of food deprivation and dogfish density. No significant reductions in dogfish catch were recorded for either rod and reel or longline, and in situ video footage verified persistent dogfish feeding behaviour, regardless of mischmetal presence. The laboratory trials found some evidence of avoidance behaviour in dogfish approaching treatment baits, but only with dogfish fed to satiation; no aversion to the material was observed after 2 and 4 d of food deprivation. Dogfish density had no effect on feeding behaviour in the laboratory. Overall, there is little evidence to suggest that mischmetal can significantly reduce catches of dogfish in hook gears in the Gulf of Maine.

scholarly journals Highly efficient stabilisation of meta-ethynylpyridine polymers with amide side chains in water by coordination of rare-earth metals

2015 ◽  
Vol 13 (6) ◽  
pp. 1700-1707 ◽  
Author(s):  
Hiroki Makida ◽  
Hajime Abe ◽  
Masahiko Inouye
Keyword(s):  
Rare Earth ◽  
Rare Earth Metal ◽  
Rare Earth Metals ◽  
Earth Metal ◽  
Helical Structure ◽  
Metal Salts ◽  
Side Chains ◽  
Highly Efficient

An amphiphilic meta-ethynylpyridine polymer with chiral amide side chains coordinated with rare-earth metal salts, especially strongly with Sc(iii), to stabilise its helical structure with CD enhancement.

scholarly journals Stability Constant of Rare Earth Metals with Substituted Thiazoles at 298.15K

2016 ◽  
Vol 64 ◽  
pp. 106-109
Author(s):  
A.B. Naik ◽  
M.S. Poharkar
Keyword(s):  
Rare Earth ◽  
Ionic Strength ◽  
Stability Constant ◽  
Rare Earth Metal ◽  
Rare Earth Metals ◽  
Sodium Perchlorate ◽  
Earth Metal ◽  
Water Mixture ◽  
Dissociation Process ◽  
The Stability

The stability constant on complexation of rare earth metal ions Eu (III), Gd (III), Nd (III) and Tb (III) with substituted thiazole in 70% Dioxane (Dx)-water mixture have been determined by a pH and spectrophotometric method at 298.15K and ionic strength 0.1mol.dm-3(sodium perchlorate). At constant temperature, the stability constant of the formed complexes decreases in the order Tb (III), Gd (III), Eu (III), Nd (III). The dissociation process is non-spontaneous, endothermic and entrophically unfavorable while formation of metal complexes has been found to be spontaneous, endothermic and entrophically favorable.

scholarly journals Extraction of Rare Earth Metal Ions with an Undiluted Hydrophobic Pseudoprotic Ionic Liquid

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 502
Author(s):  
Michiaki Matsumoto ◽  
Takuya Yamaguchi ◽  
Yoshiro Tahara
Keyword(s):  
Ionic Liquid ◽  
Rare Earth ◽  
Permanent Magnets ◽  
Rare Earth Metals ◽  
Aqueous Media ◽  
Earth Metal ◽  
Decanoic Acid ◽  
Experimental Conditions ◽  
Low Viscosity ◽  
Metal Recycling

Recovering and concentrating rare earth metals (Nd and Dy) from waste permanent magnets rather than discarding them into the environment without pretreatment is critical for metal recycling and environmental responsibility. In this work, we used an undiluted hydrophobic pseudoprotic ionic liquid composed of trioctylamine and decanoic acid as an extractant to separate rare earth metals from aqueous media with a solvent extraction technique. This ionic liquid proved to be excellent with low viscosity and extractability reaching 100% for Nd and Dy in the presence of salts like sodium chloride and sodium nitrate. In acidic media, extractability decreased with increasing acid concentrations. Under all our experimental conditions, the rare earth metals (Nd and Dy) were found to be preferentially extracted compared to nickel with the distribution ratios of Dy higher than those of Nd.

Azopyridine-based chiral oxazolines with rare-earth metals for photoswitchable catalysis

2021 ◽  
Author(s):  
Kento Nakamura ◽  
Masaru Kondo ◽  
Chandu G Krishnan ◽  
Shinobu Takizawa ◽  
Hiroaki Sasai
Keyword(s):  
Rare Earth ◽  
Rare Earth Metal ◽  
Rare Earth Metals ◽  
Earth Metal ◽  
Group Coordination ◽  
Azo Group ◽  
Re Catalyst

An azopyridine-based oxazoline was developed for utilizing azo group coordination and isomerization as a photoswitchable ligand. The ligand coordinated to rare-earth metal (RE) catalyst underwent efficient E/Z photoisomerization, suggesting tri-...

Solid State and Electronic Structure of Rare Earth Metal Intercalated Graphite from First-principles Theory

2007 ◽  
Vol 62 (7) ◽  
pp. 971-976 ◽  
Author(s):  
Chang-Ming Fang ◽  
Joseph Bauer ◽  
Jean-Yves Saillard ◽  
Jean-Francois Halet
Keyword(s):  
Rare Earth ◽  
First Principles ◽  
Density Functional ◽  
Rare Earth Metals ◽  
Earth Metal ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Intercalated Graphite ◽  
Generalized Gradient Approximation ◽  
Cohesive Energies

Abstract The structural arrangements of the graphite intercalates LnC6 (Ln = La, Ce, Nd and Yb) were investigated using Density Functional Theory (DFT) within the Generalized Gradient Approximation (GGA). The EuC6-type structure (AαAβ AαAβ AαA stacking) is slightly energetically preferred for La and Ce, whereas with the other rare earth metals almost the same cohesive energies are found for the three different atomic arrangements AαAαAαAαAαA. . ., AαAβ AαAβ AαA. . ., and AαAβ AγAαAβ A. . . A rather important charge transfer occurs from the metals to the carbon sheets, with the electrons partially occupying the bottom of the carbon π* band. As a consequence, a lengthening of the C-C bond lengths of ca. 0.02 Å is computed with respect to the C-C bonds in graphite. Two-dimensional metallic character is expected for LaC6 according to its band structure.

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