Isolated versus Condensed Anion Structure VI: X-ray Structure Analysis and 81Br NQR of Guanidinium Pentabromodicadmate(II), [C(NH2)3]Cd2 Br5 , tris-Hydrazinium Pentabromocadmate(II), [H2NNH3]3 CdBr5 , and bis-Hydrazinium Tetrabromocadmate(II)-Tetra Hydrate, [H2NNH3]2CdBr4-4H20

2000 ◽  
Vol 55 (3-4) ◽  
pp. 390-396 ◽  
Author(s):  
Hideta Ishihara ◽  
Keizo Horiuchi ◽  
V. G. Krishnan ◽  
Ingrid Svoboda ◽  
Hartmut Fuess
Keyword(s):  
Transition Point ◽  
Thermal Hysteresis ◽  
Structural Phase ◽  
Chain Structure ◽  
Positive Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order Phase Transition ◽  
81Br Nqr ◽  
First Order Phase

The structure of the condensed bromocadmate anions in [C(NH2)3]Cd2Br5 (1) and [H2NNH3]3CdBr5 (2) were studied at room temperature by X-ray diffraction. (1) crystallizes with double-chains bridged by Br atoms (orthorhombic, Pmmn, Z= 2, a = 1394.0(5), b = 394.5(1), c = 1086.9(5) pm). This chain structure was not described previously. (1) shows three 81Br NQR lines at temperatures between 77 and 323 K. Structural phase transitions take place at 283 K and at 535 K. (2) crystallizes with Br bridged zigzag-chains (monoclinic, P21, Z=2,a = 943.1(1), b = 778.8(2), c = 942.0(2) pm, β = 102.10(2)°) and shows a first-order phase transition around 304 K with a large thermal hysteresis. Below the transition point five 81Br NQR lines are observed at temperatures between 122 and 304 K, and above the transition point four 81 Br NQR lines at tem-peratures between 288 and 353 K. Two 81Br NQR lines are observed in [H2NNH3]2CdBr4 -4H20 (3) at temperatures between 77 and around 320 K with positive temperature coefficients

Inorganic mixed phase templated by a fatty acid monolayer at the air–water interface: the Mn and Mg case

2018 ◽  
Vol 20 (9) ◽  
pp. 6629-6637 ◽  
Author(s):  
Alae El Haitami ◽  
Michel Goldmann ◽  
Philippe Fontaine ◽  
Marie-Claude Fauré ◽  
Sophie Cantin
Keyword(s):  
Grazing Incidence ◽  
Water Interface ◽  
X Ray Diffraction ◽  
Inorganic Layer ◽  
X Ray ◽  
First Order ◽  
First Order Phase Transition ◽  
Air Water Interface ◽  
First Order Phase

A first-order phase transition with a peculiar feature is evidenced by means of in situ grazing incidence X-ray diffraction in the 2D organic phase-mediated nucleation of an inorganic layer.

Structure and Phase Transition in (C2H5NH3)3Sb2Cl9 · (C2H5NH3)SbCl4 ; X-ray, DSC and Dielectric Studies

2000 ◽  
Vol 55 (5) ◽  
pp. 526-532 ◽  
Author(s):  
Maciej Bujak ◽  
Jacek Zaleski
Keyword(s):  
Phase Transition ◽  
The Other ◽  
Dielectric Studies ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase ◽  
Disorder Type

Abstract The structure of (C2H5NH3)3Sb2Cl9 • (C2H5NH3)SbCl4 at 295 K has been determined. The crystals are orthorhombic, space group Pna21 (a -16.925(3), b = 24.703(5), c = 7.956(2) Å, V = 3326.4(12) Å3 , Z = 4, dc= 2.018, dm= 2.01(1) Mg m-3). They consist of an anionic sublattice composed of two different polymeric zig-zag chains. One is built of Sb2Cl93- units (corner sharing octahedra) and the other one is made of corner sharing SbCl52-square pyramids. In the cavites between the polyanionic chains four non-equivalent ethylammonium cations are located. Three of them are disordered. The cations are connected to the anions by weak N-H...Cl hydrogen bonds. A first order phase transition of the order-disorder type was found at 274 K. It was studied by DSC, dielectric and X-ray diffraction methods. The mechanism of the phase transition is attributed to the ordering of at least one of the ethylammonium cations

An investigation of the properties of large crystals of the zeolites dodecasil-3C and ferrierite by high-temperature birefringence microscopy and X-ray diffraction

2010 ◽  
Vol 43 (1) ◽  
pp. 168-175 ◽  
Author(s):  
Zoe A. D. Lethbridge ◽  
Dean S. Keeble ◽  
David Walker ◽  
Pamela A. Thomas ◽  
Richard I. Walton
Keyword(s):  
Functional Form ◽  
Bulk Sample ◽  
Organic Template ◽  
X Ray Diffraction ◽  
Optical Birefringence ◽  
X Ray ◽  
First Order ◽  
First Order Phase Transition ◽  
Apparent Loss ◽  
First Order Phase

Optical birefringence has been measured as a function of temperature for two types of siliceous zeolite crystals that contain organic template molecules. The specimens were prepared using modified solvothermal synthesis to produce large (∼1 mm dimension) crystals. In the case of the clathrasil dodecasil-3C the material undergoes a first-order phase transition at ∼433 K that is reversible after heating to 873 K and cooling to room temperature. Comparison with powder X-ray diffraction data from a bulk sample shows that this is a ferroelastic tetragonal (I\overline 42d) to cubic (Fd\overline 3m) transition, which is supported by the functional form of temperature variation of the birefringence. There is apparently no loss of the organic template involved in this transition. For the zeolite ferrierite, the plate-like crystals show a pronounced domain-like structure, which, although not due to twinning, shows a distinctive optical birefringence change on heating, suggesting that variable concentrations of organic template might be present in different domain-like regions. In this material there is no evidence for a change in crystal symmetry up to 873 K (Pnnm), despite apparent loss of some organic template from the material which, in turn, gives rise to strain birefringence at the edges parallel to the [010] direction.

Stress Analysis of Thin-Film SmS Using a Seemann- Bohlin Diffractometer

1989 ◽  
Vol 33 ◽  
pp. 153-159 ◽  
Author(s):  
Fergus E. Moore
Keyword(s):  
Thin Film ◽  
Phase Transition ◽  
Biaxial Stress ◽  
X Ray Diffraction ◽  
Crystalline Film ◽  
X Ray ◽  
First Order ◽  
First Order Phase Transition ◽  
Samarium Monosulfide ◽  
First Order Phase

AbstractX-ray diffraction is especially useful in analyzing the phase-transition response of thin-film SmS to strain impressed by the two-dimensional constraints of the substrate. A biaxial-stress model is applied and extended to a randomly-oriented crystalline film. The changes in macrostress, the compliance tensor and effective Poisson's ratio are evaluated near the hulk phase transition. An analysis of crystallite size and microstrain broadening is also presented including broadening effects due to biaxial macrostrain on the randomly-oriented crystallites. These results illustrate the effect of a constraining, biaxial-stress field on the unusual elastic character of samarium monosulfide. It is demonstrated that the thin-film geometry suppresses the first-order phase transition allowing only linear changes between the semiconducting and metallic states.

Temperature-induced structural phase transitions in RERhSn (RE = Y, Gd-Tm, Lu)

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Simon Engelbert ◽  
Rolf-Dieter Hoffmann ◽  
Jutta Kösters ◽  
Steffen Klenner ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Phase Transitions ◽  
Driving Force ◽  
Room Temperature ◽  
Structural Phase ◽  
Structural Phase Transitions ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray

Abstract The structures of the equiatomic stannides RERhSn with the smaller rare earth elements Y, Gd-Tm and Lu were reinvestigated on the basis of temperature-dependent single crystal X-ray diffraction data. GdRhSn crystallizes with the aristotype ZrNiAl at 293 and 90 K. For RE = Y, Tb, Ho and Er the HP-CeRuSn type (approximant with space group R3m) is already formed at room temperature, while DyRhSn adopts the HP-CeRuSn type below 280 K. TmRhSn and LuRhSn show incommensurate modulated variants with superspace groups P31m(1/3; 1/3; γ) 000 (No. 157.1.23.1) (γ = 3/8 for TmRhSn and γ = 2/5 for LuRhSn). The driving force for superstructure formation (modulation) is a strengthening of Rh–Sn bonding. The modulation is expressed in a 119Sn Mössbauer spectrum of DyRhSn at 78 K through line broadening.

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