(H2dabco)[Na(BF4)3]: an ABX3-type inorganic–organic hybrid perovskite compound exhibiting dielectric switching above room-temperature

CrystEngComm ◽  
2019 ◽  
Vol 21 (46) ◽  
pp. 7043-7047 ◽  
Author(s):  
Le Ye ◽  
Zhi-Xin Gong ◽  
Chao Shi ◽  
Jia-Jun Ma ◽  
Hao Liang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Structure Analysis ◽  
Room Temperature ◽  
Crystal Structure Analysis ◽  
Organic Hybrid ◽  
Dynamic Phase ◽  
Hybrid Perovskite ◽  
Dynamic Phase Transition

The (H2dabco)[Na(BF4)3] undergoes a static-to-dynamic phase transition at 403/386 K. Crystal structure analysis reveals that H2dabco2+ and/or BF4− undergo disordering.

scholarly journals Some New Luminescent Compounds Based on 4-Methylbenzylamine and Lead Halides

2000 ◽  
Vol 55 (6) ◽  
pp. 536-540 ◽  
Author(s):  
G. C. Papavassiliou ◽  
G. A. Mousdis ◽  
C. P. Raptopoulou ◽  
A. Terzis
Keyword(s):  
Crystal Structure ◽  
Optical Absorption ◽  
General Formula ◽  
Structure Analysis ◽  
Room Temperature ◽  
Crystal Structure Analysis ◽  
Photoluminescence Spectra ◽  
X Ray

Compounds of the general formula (CH3NH3)n-1(CH3C6H4CH2NH3)2PbnX3n+1, where X = I, Br, Cl and n= 1,2, 3,..., were prepared and characterized analytically and spectroscopically. Moreover, (CH3C6H4CH2NH3)2PbX4 and (CH3NH3C6H4CH2NH3)2Pb2I7 were characterized by X-ray crystal structure analysis. Their optical absorption and photoluminescence spectra exhibit excitonic bands, even at room temperature.

Investigation of the Cs x Rb1−x TiOAsO4 Series. I. Crystal Structure Analysis and Pseudo-symmetry

1998 ◽  
Vol 54 (5) ◽  
pp. 635-644 ◽  
Author(s):  
M. N. Womersley ◽  
P. A. Thomas ◽  
D. L. Corker
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Low Temperature ◽  
Room Temperature ◽  
Structural Changes ◽  
Crystal Structure Analysis ◽  
Orthorhombic Space Group ◽  
Acta Cryst ◽  
Space Group ◽  
Structural Framework

Refinements of five crystals in the Cs2x Rb2−2x Ti2O2As2O8 series, caesium rubidium titanyl arsenate, with x = 0.07, 0.31, 0.58, 0.71 and 0.86, which are compositional analogues of KTiOPO4 (KTP), have been completed at 293 K and two (x = 0.71, 0.86) at low temperature. All the structures are found to be orthorhombic (space group Pna21) and are isostructural with KTP, although there is evidence of some Cs disorder over additional sites in the framework, particularly at the Cs-rich end of the series, as discussed in Part II [Thomas & Womersley (1998). Acta Cryst. B54, 645–651]. Unusually large U 33 parameters for shared Cs/Rb sites are observed and are shown to be the result of the existence of separate sites for Cs and Rb within the structural framework, although the coordinates of these sites cannot be resolved convincingly. The structural changes in the TiO6/AsO4 framework required to accommodate an increasing fraction of the larger Cs cation across the series and under cooling to 120 K are elucidated. Finally, the deviations of the room-temperature and low-temperature structures from the high-temperature prototypic structure (space group Pnan) are examined and suggest that the phase-transition temperature should increase linearly from CsTiOAsO4 to RbTiOAsO4.

Crystal Structure Analysis and Phase Transition in Lead Orthovanadate Pb3(VO4)2

1992 ◽  
Vol 61 (7) ◽  
pp. 2309-2316 ◽  
Author(s):  
Hirofumi Kasatani ◽  
Takashi Umeki ◽  
Hikaru Terauchi
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Structure Analysis ◽  
Crystal Structure Analysis

Isolated versus Condensed Anion Structure III: The Influence of the Cations 1,3-propanediammonium, 1,4-butanediammonium, /n-propylammonium, /n-butylammonium and /n-pentylammonium on Structures and Phase Transitions of ZnBr42- Salts. A81 Br NQR and X-ray Structure Analysis

1997 ◽  
Vol 52 (6-7) ◽  
pp. 550-560 ◽  
Author(s):  
Hideta Ishihara ◽  
Shi-qi Dou ◽  
Keizo Horiuchi ◽  
Helmut Paulus ◽  
Hartmut Fuess ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Phase Transitions ◽  
Hydrogen Bonds ◽  
Structure Analysis ◽  
Phase Ii ◽  
Crystal Structure Analysis ◽  
X Ray ◽  
Dsc Measurements

Abstract The influence of the cations on the condensation of the anions in the salts (A´)Zn(II) Br4 and (A) 2 Zn(II)Br4 is studied by 81Br NQR and X-ray crystal structure analysis. (A´)Zn(II)Br4 (A´ = [H3N(CH2)3NH3]2+) (1) shows a phase transition at 474 K. The phase II of (1) crystallizes with isolated [ZnBr4]2- tetrahedra: monoclinic P21 /n, Z = 4, a = 1108.4 (5), b = 1096.8 (2), c = 1118.5 (6) pm, and β= 117.07(4)° at 296 K. A quartet was observed in the 81Br NQR spectrum of phase II: 61.634,58062, 56.675, and 53.673 MHz (77K); 59.193, 57.448, 56.015, and 52.515 MHz (301 K).(A)2 ZnBr4 (A = [n-H3C(CH2)2NH3 ]+ (2) and [n-H3C(CH2)3NH3 ]+ (3)) also show structures with isolated [ZnBr4]2- tetrahedra. The compound (2) crystallizes with P21/c, Z = 4, a = 771.8(3), b = 1061.9(4), c = 2054.2 (7) pm, and β = 106.75(1)° at 291 K. The compound (3) crystallizes with P21/c, Z = 4, a = 768.9(4), b = 2229.6(10), c = 1071.6(5) pm, and β = 91.70(3)° at 295 K. 81Br NQR and DSC measurements on [H3N(CH2)4 NH3]ZnBr4 (4), and [n-H3 C(CH2)4NH3]2ZnBr4 (5) were also performed. The compound (4) shows several phase transitions at 349 K and higher temperatures, and a quartet in the 81r NQR spectrum could be observed between 77 and 330 K: 65.992,65.544, 59.900, and 50.162 MHz (77 K); 63.787, 62.963, 59.928, and 50.364 MHz (320 K). The compound (5) shows also a phase transition at 244 K, and a quartet of 81Br lines could be observed in the NQR spectrum between 77 and 244 K: 61.279, 58.933, 57.869, and 56.485 MHz (77 K); 59.712, 56.936, 57.409, and 54.793 MHz (240 K). The various influences of the cations, such as size and hydrogen bonds on the condensation of [MX4]2-(M = Zn, Cd; X = C1, Br) are discussed.

Phase transition of tetrakis(octylthio)tetrathiafulvalene (TTC8–TTF) and crystal structure analysis

1991 ◽  
Vol 1 (1) ◽  
pp. 37-41 ◽  
Author(s):  
Chikako Nakano ◽  
Kenichi Imaeda ◽  
Takehiko Mori ◽  
Yusei Maruyama ◽  
Hiroo Inokuchi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Structure Analysis ◽  
Crystal Structure Analysis
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