Temperature dependence of the crystal structures and phase fractions of secondary phases in a Nd-Fe-B sintered magnet

2018 ◽  
Vol 154 ◽  
pp. 25-32 ◽  
Author(s):  
Naruki Tsuji ◽  
Hiroyuki Okazaki ◽  
Wakana Ueno ◽  
Yoshinori Kotani ◽  
David Billington ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Crystal Structures ◽  
Secondary Phases ◽  
Sintered Magnet

Electrical Conductivity of Chloro(phenyl)glyoxime and Its Co(II), Ni(II) and Cu(II) Complexes

2003 ◽  
Vol 68 (7) ◽  
pp. 1233-1242 ◽  
Author(s):  
Orhan Turkoglu ◽  
Mustafa Soylak ◽  
Ibrahim Belenli
Keyword(s):  
Electrical Conductivity ◽  
Temperature Dependence ◽  
Electric Conductivity ◽  
Crystal Structures ◽  
Elemental Analysis ◽  
Analysis Data ◽  
Elemental Analysis Data ◽  
The Stability ◽  
Xrd Patterns ◽  
Metal Ligand

Chloro(phenyl)glyoxime, a vicinal dioxime, and its Ni(II), Cu(II) and Co(II) complexes were prepared. XRD patterns of the complexes point to similar crystal structures. IR and elemental analysis data revealed the 1:2 metal-ligand ratio in the complexes. The Co(II) complex is a dihydrate. Temperature dependence of electrical conductivity of the solid ligand and its complexes was measured in the temperature range 25-250 °C; it ranged between 10-14-10-6 Ω-1 cm-1 and increased with rising temperature. The activation energies were between 0.61-0.80 eV. The Co(II) complex has lower electric conductivity than the Ni(II) and Cu(II) complexes. This difference in the conductivity has been attributed to differences in the stability of the complexes.

Molecular Motion and Conformational Interconversion of Azobenzenes in Crystals as Studied by X-ray Diffraction

1997 ◽  
Vol 53 (4) ◽  
pp. 662-672 ◽  
Author(s):  
J. Harada ◽  
K. Ogawa ◽  
S. Tomoda
Keyword(s):  
Temperature Dependence ◽  
Crystal Structures ◽  
Torsional Vibration ◽  
Molecular Motion ◽  
X Ray Diffraction ◽  
Dynamic Disorder ◽  
X Ray ◽  
Conformational Interconversion ◽  
Free Molecules

Crystal structures of (E)-azobenzene (1), (E)-2,2′- dimethylazobenzene (2), (E)-3,3′-dimethylazobenzene (3) and (E)-4,4′-dimethylazobenzene (4) were determined by X-ray diffraction at various temperatures. An apparent shrinkage of the N=N bond and its temperature dependence were observed and are interpreted in terms of an artifact caused by the torsional vibration of the N—Ph bonds in crystals. In the crystal structures of (1), (3) and (4) the dynamic disorder was observed. The disorder is accounted for by the torsional vibration whose amplitude is large enough to give rise to the conformational interconversion. No disorder was observed for a crystal of (2). This is ascribed to the large difference in energy of the two conformers as free molecules. The true length of the N=N bond in azobenzenes was estimated to be 1.26–1.27 Å.

Temperature dependence of the AV3O7 (A = Ca, Sr) structure

2007 ◽  
Vol 63 (6) ◽  
pp. 836-842 ◽  
Author(s):  
Sebastian Prinz ◽  
Karine M. Sparta ◽  
Georg Roth
Keyword(s):  
Single Crystal ◽  
Temperature Dependence ◽  
Crystal Structures ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Space Groups ◽  
Temperature Ranges ◽  
First Time

The V4+ (spin ½) oxovanadates AV3O7 (A = Ca, Sr) were synthesized and studied by means of single-crystal X-ray diffraction. The room-temperature structures of both compounds are orthorhombic and their respective space groups are Pnma and Pmmn. The previously assumed structure of SrV3O7 has been revised and the temperature dependence of both crystal structures in the temperature ranges 297–100 K and 315–100 K, respectively, is discussed for the first time.

Similarities and peculiarities between the crystal structures of the hydrates of sodium sulfate and selenate

2014 ◽  
Vol 70 (4) ◽  
pp. 714-722 ◽  
Author(s):  
Stoyan Kamburov ◽  
Horst Schmidt ◽  
Wolfgang Voigt ◽  
Christo Balarew
Keyword(s):  
Temperature Dependence ◽  
Crystal Structures ◽  
Sodium Sulfate ◽  
Room Temperature ◽  
Site Occupancy ◽  
Monoclinic Space Group ◽  
Chemical Compositions ◽  
Crystal Nucleus ◽  
Space Group ◽  
First Time

The crystal structures of the two hydrates Na2SeO4·10H2O and Na2SeO4·7.5H2O are studied for the first time. The structures of Na2SO4·10H2O and Na2SO4·7H2O are reinvestigated as a function of temperature with respect to the degree of disorder of the O atoms of {\rm SO}_{4}^{2-} in the decahydrate and the O atom of water in the heptahydrate. For Na2SO4·10H2O, the unit site occupancy factor (SOF) of O atoms of {\rm SO}_{4}^{2-} was determined at 120 K. After the temperature dependence of the lattice parameters was studied from 120 to 260 K, it was shown that SOF decreased from 1.0 at 120 K to 0.247 at room temperature. The interesting fact that two salts with different chemical compositions and different crystal structures (Na2SO4·7H2O, tetragonal, space groupP41212 and Na2SeO4·7.5H2O, monoclinic, space groupC2/c) can act mutually as a crystal nucleus is accounted for by similarities in certain fragments of their crystal structures. This phenomenon is attributed to similarities between particular elements of their structures.

scholarly journals Interpretation of the Temperature Dependence of the EPR Spectrum of Cu2+-Doped (NH4)2[Cd(NH3)2(CrO4)2] and Crystal Structures of the High- and Low-Temperature Forms of the Host Lattice

1995 ◽  
Vol 34 (22) ◽  
pp. 5516-5523 ◽  
Author(s):  
Henrietta Headlam ◽  
Michael A. Hitchman ◽  
Horst Stratemeier ◽  
Jan M. M. Smits ◽  
Paul T. Beurskens ◽  
...  
Keyword(s):  
Low Temperature ◽  
Temperature Dependence ◽  
Crystal Structures ◽  
Host Lattice ◽  
Epr Spectrum

Torsional vibration and central bond length of N-benzylideneanilines

2004 ◽  
Vol 60 (5) ◽  
pp. 578-588 ◽  
Author(s):  
Jun Harada ◽  
Mayuko Harakawa ◽  
Keiichiro Ogawa
Keyword(s):  
Temperature Dependence ◽  
Bond Length ◽  
Crystal Structures ◽  
Torsional Vibration ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Static Disorder ◽  
X Ray ◽  
Bond Lengths ◽  
Central Bond

The crystal structures of N-benzylideneaniline (1), N-benzylidene-4-carboxyaniline (2), N-(4-methylbenzylidene)-4-nitroaniline (3), N-(4-nitrobenzylidene)-4-methoxyaniline (4), N-(4-nitrobenzylidene)-4-methylaniline (5), N-(4-methoxybenzylidene)aniline (6) and N-(4-methoxybenzylidene)-4-methylaniline (7) were determined by X-ray diffraction analyses at various temperatures. In the crystal structures of all the compounds, an apparent shortening of the central C=N bond was observed at room temperature. As the temperature was lowered, the observed bond lengths increased to approximately 1.28 Å at 90 K, irrespective of substituents in the molecules. The shortening and the temperature dependence of the C=N bond length are interpreted in terms of an artifact caused by the torsional vibration of the C—Ph and N—Ph bonds in the crystals. In the crystal structures of (1) and (7), a static disorder around the C=N bond was observed, which is also responsible for the apparent shortening of the C=N bond.

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