Structure analysis of the high-temperature phases of [NH3(C3H7)]2CuCl4. II. The modulated phase

1990 ◽  
Vol 46 (2) ◽  
pp. 180-186 ◽  
Author(s):  
B. Doudin ◽  
G. Chapuis
Keyword(s):  
High Temperature ◽  
Structure Analysis ◽  
Modulated Phase

scholarly journals Quasicrystals: What do we know? What do we want to know? What can we know?

2018 ◽  
Vol 74 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Walter Steurer
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Structure Analysis ◽  
Self Assembly ◽  
State Of The Art ◽  
The State ◽  
Growth Mechanisms ◽  
Dan Shechtman ◽  
Big Picture ◽  
Quasicrystal Structure

More than 35 years and 11 000 publications after the discovery of quasicrystals by Dan Shechtman, quite a bit is known about their occurrence, formation, stability, structures and physical properties. It has also been discovered that quasiperiodic self-assembly is not restricted to intermetallics, but can take place in systems on the meso- and macroscales. However, there are some blank areas, even in the centre of the big picture. For instance, it has still not been fully clarified whether quasicrystals are just entropy-stabilized high-temperature phases or whether they can be thermodynamically stable at 0 K as well. More studies are needed for developing a generally accepted model of quasicrystal growth. The state of the art of quasicrystal research is briefly reviewed and the main as-yet unanswered questions are addressed, as well as the experimental limitations to finding answers to them. The focus of this discussion is on quasicrystal structure analysis as well as on quasicrystal stability and growth mechanisms.

scholarly journals The structure of the aluminium-abundant γ-brass-type Al8.6Mn4.4

IUCrData ◽  
2021 ◽  
Vol 6 (9) ◽  
Author(s):  
Qifa Hu ◽  
Bin Wen ◽  
Changzeng Fan
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Structure Analysis ◽  
Site Occupancy ◽  
Initial Composition ◽  
Special Position ◽  
Space Group ◽  
Type Phase ◽  
Centrosymmetric Space Group ◽  
Acta Mater

An aluminium-abundant Al8Mn5/γ-brass-type intermetallic with formula Al8.6Mn4.4, which is isotypic with γ-Al8Cr5 and γ-Al8V5, was discovered by high-temperature sintering of an Al/Mn mixture with initial composition Al2Mn. Structure analysis revealed that one special position (Wyckoff site 18h in space group R\overline{3}m) is shared by Al and Mn, with refined site occupancy factors of 0.7 and 0.3, respectively. The present low-temperature Al8Mn5-type phase crystallizes in the centrosymmetric space group R\overline{3}m (No. 166), rather than R3m (No. 160) as previously reported for the same intermetallic characterized by TEM measurements [Zeng et al. (2018). Acta Mater. 153, 364–376].

New Iron(II) Complexes [Fe(HC(Pz)3)2]A2 with Spin-Crossover

2015 ◽  
Vol 233-234 ◽  
pp. 534-537 ◽  
Author(s):  
Оlga G. Shakirova ◽  
Natalia V. Kuratieva ◽  
Evgeny V. Korotaev ◽  
Ludmila G. Lavrenova
Keyword(s):  
Magnetic Susceptibility ◽  
High Temperature ◽  
Ir Spectroscopy ◽  
Structure Analysis ◽  
Coordination Compounds ◽  
Spin Crossover ◽  
Color Change ◽  
Static Magnetic Susceptibility ◽  
X Ray ◽  
Magnetochemical Study

Three new coordination compounds of iron (II), [Fe (HC(Pz)3)2](C8H5O4)2.C8H6O4(I), [Fe (HC(Pz)3)2](C10H7SO3)2.2H2O (II) and Fe (HC(Pz)3)2](C12H25SO4)2(III), where HC(Pz)3is the tridentate chelatortris(pyrazol-1-yl) methane, have been synthesized and investigated by X-ray structure analysis, electronic and IR spectroscopy, static magnetic susceptibility method. The magnetochemical study of complexes I–III in the interval from 300 to 500 K showed that they possessed the high-temperature spin crossover1A1↔5T2accompanied by thermochromism (the pink ↔ white color change).

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