scholarly journals Syntheses, structure determination and characterization of two novel non-centrosymmetric mixed alkali rare-earth orthoborates: K3Li3RE7(BO3)9 (RE=Dy, Tb)

2020 ◽  
Vol 108 ◽  
pp. 106442
Author(s):  
P.Y. Chen ◽  
Guirong Wang
2015 ◽  
Vol 3 (17) ◽  
pp. 4431-4437 ◽  
Author(s):  
Rihong Cong ◽  
Zhengyang Zhou ◽  
Qiaoqi Li ◽  
Junliang Sun ◽  
Jianhua Lin ◽  
...  

The structure determination of Ba6Bi9B79O138 uncovers the mystery of the crystallography of the well-known phosphors REBaB9O16 (RE = rare earth).


1999 ◽  
Vol 52 (6) ◽  
pp. 481 ◽  
Author(s):  
Cameron J. Kepert ◽  
Lioubov I. Semenova ◽  
Lu Wei-Min ◽  
Brian W. Skelton ◽  
Allan H. White

A room-temperature single-crystal X-ray structure determination of the 1 : 1 adduct of 1,10-phenanthroline (`phen") with lutetium(III) acetate (as its dihydrate) is recorded. Crystals are triclinic, P 1, a 12·430(8), b 10·681(4), c 8·134(8) Å, α 74·76(6), β 84·81(7), γ 74·29(4)°, Z = 2 f.u.; conventional R on |F| was 0·031 for No 3939 independent ‘observed’ (I > 3σ(I)) diffractometer reflections. The complex [(N,N′-phen)(O,O′-ac)Lu(O-ac-O′)4Lu(O,O′-ac)(N,N′-phen)].2H2O is binuclear, the lutetium being eight-coordinated by bidentate phen and ac (acetate) ligands and four oxygen atoms from the bridging acetate ligands. Also recorded is the structural characterization of 1 : 1 Lu(ac)2Cl/tpy (tpy = 2,2′:6′,2″-terpyridine) as its pentahydrate; this complex is triclinic, P 1, a 12·410(3), b 11·559(4), c 9·976(4) Å, α 85·19(3), β 70·30(3), γ 65·70(2)°, Z = 2, R 0·049 for No 4717. The complex is shown to be [(tpy)(H2O)2Lu(O2CCH3)2]Cl.3H2O, with the lutetium nine-coordinated by tridentate tpy, a pair of bidentate acetates and two unidentate water molecules, with the chloride uncoordinated. Structural characterizations of a number of 1 : 1 adducts of variously solvated lanthanoid(III) trichloroacetates, Ln(tca)3, with tpy are also recorded. Yb(tca)3/tpy/MeOH (1 : 1 : 1) is triclinic, P 1, a 14·016(4), b 12·951(5), c 9·604(3) Å, α 73·89(3), β 76·56(3), γ 69·20(3)°, Z = 2 f.u., R 0·057 for No 4465. The complex is mononuclear, the eight-coordinate N3YbO5 array containing tridentate tpy, unidentate methanol, and two unidentate and one bidentate chelating anions. 1 : 1 : 1 Ln(tca)3/tpy/OH2 adducts for Ln = La(-)Nd are triclinic, P 1, a ≈ 13·4, b ≈ 12·47, c ≈ 11·5 Å, α ≈ 114·5, β ≈ 89·9, γ ≈ 115·6°, Z = 1 binuclear array, R 0·061, 0·071 for No 3240, 2394. The two Ln atoms are O,O′-bridged by a pair of anions, the N3LnO6 nine-coordinate lanthanoid environment being completed by a tridentate tpy, one water, one unidentate and one bidentate anion. A 1 : 1 : 1 Lu(tca)3/tpy/OH2 array, by contrast, is triclinic, P 1, a 16·569(8), b 14·815(5), c 14·375(6) Å, α 62·05(3), β 81·35(4), γ 77·97(3)°, Z = 4 ‘mononuclear’ f.u., R 0·067 for No 6710. The array, remarkably, contains species of both of the above types in a 1 : 2 binuclear-to-mononuclear ratio, but with water replacing methanol in the mononuclear array.


2008 ◽  
pp. 3709 ◽  
Author(s):  
Dan Zhao ◽  
Wen-Dan Cheng ◽  
Hao Zhang ◽  
Shu-Ping Hang ◽  
Ming Fang

Author(s):  
G. M. Micha ◽  
L. Zhang

RENi5 (RE: rare earth) based alloys have been extensively evaluated for use as an electrode material for nickel-metal hydride batteries. A variety of alloys have been developed from the prototype intermetallic compound LaNi5. The use of mischmetal as a source of rare earth combined with transition metal and Al substitutions for Ni has caused the evolution of the alloy from a binary compound to one containing eight or more elements. This study evaluated the microstructural features of a complex commercial RENi5 based alloy using scanning and transmission electron microscopy.The alloy was evaluated in the as-cast condition. Its chemistry in at. pct. determined by bulk techniques was 12.1 La, 3.2 Ce, 1.5 Pr, 4.9 Nd, 50.2 Ni, 10.4 Co, 5.3 Mn and 2.0 Al. The as-cast material was of low strength, very brittle and contained a multitude of internal cracks. TEM foils could only be prepared by first embedding pieces of the alloy in epoxy.


2021 ◽  
Vol 7 (6) ◽  
pp. 89
Author(s):  
Valerio De Santis

Recent advances in computational electromagnetics (CEMs) have made the full characterization of complex magnetic materials possible, such as superconducting materials, composite or nanomaterials, rare-earth free permanent magnets, etc [...]


2021 ◽  
Vol 13 (9) ◽  
pp. 4840
Author(s):  
Fatai Arolu Ayanda ◽  
Mohd Firdaus Mohd Anuar ◽  
Syaharudin Zaibon ◽  
Shamshuddin Jusop

The physical, chemical and mineralogical characterization of the constituents of magnesium-rich synthetic gypsum produced in a rare earth-refining plant located in Gebeng, Pahang, Malaysia was conducted through elemental chemical analysis, scanning electron microscopy with Energy Dispersive X-ray (EDX)-analyzer, thermal analysis, X-ray fluorescence and X-ray diffraction. The crystalline nature of the by-product was studied using FTIR spectroscopy. Elemental analysis confirmed the presence of Ca and Mg, which are essential macronutrients required by plants and this Ca alongside the high pH (9.17) of MRSG may confer on the material a high acid neutralization capacity. From the result, it was observed that the studied by-product is a heterogeneous crystalline material comprising of gypsum (CaSO4.2H2O) and other major components such as calcium (magnesium) compounds (hydroxide, oxide, silicates, and carbonate) and sulfur. These aggregates may contribute to give an acid neutralization capacity to MRSG. The XRD study of MRSG indicated a high content of gypsum (45.4%), shown by the d-spacing of 7.609 Å (2-theta 11.63) in the diffractogram. The infrared absorption spectra of MRSG indicate close similarities to mined gypsum. The results of the characterization indicated that MRSG has valuable properties that can promote its use in amending soil fertility constraints on nutrient-deficient tropical acid soils.


ChemInform ◽  
2010 ◽  
Vol 33 (43) ◽  
pp. no-no
Author(s):  
Xiaohui Liu ◽  
Paul Mueller ◽  
Peter Kroll ◽  
Richard Dronskowski

1982 ◽  
Vol 37 (6) ◽  
pp. 702-706 ◽  
Author(s):  
Helmut Entires

Abstract[Ni(C2H5N4O2)2] · HCl · H2O, C4H10N8NiO4 · HCl · H2O, forms triclinic crystals, Mr = 347.36, P1̄, a = 7.219(2), b = 7.316(1), c = 11.797(3) Å, α = 73.89(2), β = 86.37(2), γ = 85.71(2)°, V = 596 Å3 , Z = 2, dc = 1.93 Mgm-3 ; final Rw = 0.028 for 1957 reflections. The planar complex molecules form equidistant stacks along b, with the molecular planes inclined at ~29° to the stacking axis. Molecules of adjacent stacks are linked along a by an intermolecular H bridge coexistins with the usual intramolecular H bridges. The analogous Pt complex, C4H10N8O4Pt · HCl · H2O, Mr = 483.74, a = 6.480(4), b = 16.115(5), c = 12.194(9) Å, β = 101.27(4)°, V = 1249 Å3 , Z = 4, dc = 2.57 Mgm-3 , P21/a, crystallizes in a columnar structure with a Pt-Pt separation of ~a/2 ≈ 3.24 Å. Due to twinning, faking orthorhombic symmetry, a complete structure determination was not possible.


2004 ◽  
Vol 43 (19) ◽  
pp. 3829 ◽  
Author(s):  
Lionel Aigouy ◽  
Yannick De Wilde ◽  
Michel Mortier ◽  
Jacques Giérak ◽  
Eric Bourhis

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