Crystal Structure of Trimethylammonium Tetrafluoroborate in Three Solid Phases

2000 ◽  
Vol 55 (9-10) ◽  
pp. 765-768 ◽  
Author(s):  
Hiroyuki Ishida ◽  
Setsuo Kashino ◽  
Ryuichi Ikeda
Keyword(s):  
Crystal Structure ◽  
Phase Iii ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cscl Type ◽  
Lattice Space ◽  
Plastic Phase ◽  
Solid Phases ◽  
Phase Phase

Abstract The crystal structure of (CH3)3 NHBF 4 was studied in three solid phases by X-ray diffraction techniques. The structures of the ionic plastic phase (Phase I) stable above 453 K and Phase II between 384 and 453 K are CsCl-type cubic (a = 5.772(4) Å) and tetragonal (a = 9.815(5) and c = 6.895(5) Å), respectively. The room temperature phase (Phase III) forms a monoclinic lattice (space group P21/m, a = 5.7017(8), b = 8.5724(9), c = 7.444(1) Å, and ß = 102.76(1)°). BF4− ions in this phase were shown to be disordered in four orientations.

Crystal Structure of Trimethylammonium Perchlorate in Three Solid Phases Including the Ionic Plastic Phase Obtainable above 480 K

1994 ◽  
Vol 49 (6) ◽  
pp. 723-726 ◽  
Author(s):  
Hiroyuki Ishida ◽  
Yoshihiro Kubozono ◽  
Setsuo Kashino ◽  
Ryuichi Ikeda
Keyword(s):  
Phase Iii ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Cscl Type ◽  
Thermal Measurements ◽  
Plastic Phase ◽  
Solid Phases ◽  
Phase Phase

Abstract The crystal structures of (CH3)3NHClO4 in three solid phases were studied by X-ray diffraction techniques. X-ray powder patterns taken at ca. 500 and 445 K revealed that the plastic phase (Phase I) attainable above 480 K crystallizes in a CsCl-type cubic structure with a = 5.845 (1) Å, Z = 1, V = 199.7 (2) Å3, and Dx = 1.327 g cm -3, while Phase II, stable between 480 and 396 K, forms a tetragonal structure with a = 9.912 (4), c = 7.01 (2) Å, Z = 4, V = 689 (3) Å3, and Dx = 1.54 gem -3. The room temperature phase (Phase III) was studied by single crystal X-ray diffraction and found to form a monoclinic lattice with space group P21 , a = 5.749(1), b = 8.670(1), c = 7.5585 (9) Å, ß = 102.66 (1)°, Z = 2, V = 367.6 (2) Å3 , and Dx= 1.441 g cm -3. Thermal measurements, differential thermal analysis and differential scanning calorimetry, were carried out on these solid phases, and the obtained results were compared with those observed for (CH3)3NHBF4.

Crystal Structure of the High-temperature Solid Phases of Choline Tetrafluoroborate and Iodide

1997 ◽  
Vol 52 (8-9) ◽  
pp. 679-680 ◽  
Author(s):  
Hiroyuki Ishida ◽  
Hiroshi Ono ◽  
Ryuichi Ikeda
Keyword(s):  
Crystal Structure ◽  
Phase Transitions ◽  
High Temperature ◽  
Solid Phase ◽  
Temperature Phase ◽  
X Ray ◽  
Cscl Type ◽  
Enthalpy And Entropy Changes ◽  
Enthalpy And Entropy ◽  
Solid Phases

Abstract The crystal structure of the highest-and second highest-temperature solid phases of choline tetrafluoroborate and iodide was determined by X-ray powder diffraction. The structure in the highest-temperature phase of both salts is NaCl-type cubic (a = 10.16(2) Å, Z = 4 for tetrafluorobo-rate; a = 10.08(2) Å, Z = 4 for iodide). The second highest-temperature phase of tetrafluoroborate and iodide is CsCl-type cubic (a = 6.198(6) Å and Z = 1) and tetragonal (a = 8.706(2) Å, c = 6.144(6) Å, and Z = 2), respectively. DSC was carried out for the iodide, where the presence of three solid-solid phase transitions was confirmed. Enthalpy and entropy changes of these transitions were evaluated.

scholarly journals Structural Study of Ferroelectric Phase Transition of Sn-doped SrTiO3

2014 ◽  
Vol 70 (a1) ◽  
pp. C61-C61 ◽  
Author(s):  
Hirofumi Kasatani ◽  
Shoichiro Suzuki ◽  
Akira Ando ◽  
Eisuke Magome ◽  
Chikako Moriyoshi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Local Structure ◽  
Ferroelectric Phase Transition ◽  
Nearest Neighbor ◽  
Ferroelectric Phase ◽  
Rietveld Analysis ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray

Recently, ferroelectricity was discovered in Sn-doped SrTiO3 (abbreviated by SSTO), in which Sr-atom was substituted by a few percent Sn-atom[1]. The ferroelctricity of SSTO was confirmed by means of the appearance of the dielectric anomaly, that reached several thousands and the clear D-E hysteresis loop in low temperature phase. In order to clarify the mechanism of ferroelectric phase transition of SSTO from the viewpoint of the crystal structure, we investigated the average crystal structure and the local structure around the substitutional Sn-atom of SSTO10 (10% Sn concentration, ferroelectric phase transition temperature 180K) by means of synchrotron-radiation powder X-ray diffraction and transmission XAFS spectrum of Sn:K-edge, respectively. From the results of MEM/Rietveld analysis of powder X-ray diffraction data, it was obtained that crystal structure of paraelectric phase of SSTO10 was cubic perovskite structure with the disorder state of Sn-atom. In ferroelectric phase, the crystal system was tetragonal, which was similar in structure to tetragonal ferroelectric structure of BaTiO3, and Sn-atom was order state. XAFS study revealed that the valence of Sn-ion was +2 charge and the local structure of Sn-atom was seemed as being the self-insistent state of SnO crystal structure. However, strangely, the coordination number of the nearest neighbor atom, that is O-atom, was 2 instead of 4. This is a mystery result and we have been analyzing. We have considered that the ferroelectricity of SSTO is induced by the distortion around the subsitituional Sn-atom. At the meeting, we are planning to discuss the precise crystal structure and the mechanism of the ferroelectric phase transition of SSTO.

Crystal structure of a high-pressure/high-temperature phase of alumina by in situ X-ray diffraction

2004 ◽  
Vol 3 (6) ◽  
pp. 389-393 ◽  
Author(s):  
Jung-Fu Lin ◽  
Olga Degtyareva ◽  
Charles T. Prewitt ◽  
Przemyslaw Dera ◽  
Nagayoshi Sata ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Pressure High Temperature

scholarly journals NQR and Phase Transitions in Hexachlorocyclopropane Crystal

1990 ◽  
Vol 45 (3-4) ◽  
pp. 339-342 ◽  
Author(s):  
Masahiko Suhara ◽  
Koichi Mano
Keyword(s):  
Phase Transitions ◽  
Slow Rate ◽  
Metastable Phase ◽  
Phase Iii ◽  
Temperature Phase ◽  
Dsc Studies ◽  
Disordered Phase ◽  
Solid Phases ◽  
Low Temperature Phase ◽  
Phase Phase

Abstract35Cl NQR and DSC studies on phase transitions in hexachlorocyclopropane (HCCP), C3Cl6 , are reported. It is found that HCCP has three solid phases: A high temperature disordered phase (Phase I) above 301 K (no NQR spectrum was observed); a metastable phase (Phase II), which exhibited 6 NQR lines from 77 to 270 K; a low temperature phase (Phase III) in which a 24-multiplet of 35Cl NQR lines at 77 K, the most complex multiplet spectrum ever reported was observed. DSC measurement shows a A-type transition at 301 K and a broad transition of very slow rate at 285 K. The structure and mechanism of phase transitions in HCCP crystal are discussed.

Structural and thermal properties of Cu1.75−xMxTe crystals

2020 ◽  
Vol 34 (19) ◽  
pp. 2050180
Author(s):  
Y. I. Aliyev ◽  
Y. G. Asadov ◽  
L. B. Rustamova ◽  
A. O. Dashdemirov ◽  
N. A. Ismayilova ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thermal Expansion ◽  
Room Temperature ◽  
Lattice Parameters ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cubic Phases ◽  
Temperature Dependences ◽  
Cubic Structure

Single crystals of Cu[Formula: see text]Te, Cu[Formula: see text]Zn[Formula: see text]Te and Cu[Formula: see text]Cd[Formula: see text]Te compounds were synthesized by Brijmen method and their crystal structure was studied by X-ray diffraction. The hexagonal, orthorhombic aand cubic structure phases of these compounds have been determined at room-temperature. Phase transitions at high-temperatures were observed. Lattice parameters for hexagonal, orthorhombic and cubic phases have been determined in the temperature range of [Formula: see text]–1073 K. From the temperature dependences of the lattice parameters, the coefficients of thermal expansion of the existing modifications in the main crystallographic directions were calculated.

NQR View of Solid Phases of NOCl

1998 ◽  
Vol 53 (6-7) ◽  
pp. 537-541 ◽  
Author(s):  
J. Pirnat ◽  
Z. Trontelj ◽  
H. Borrmann
Keyword(s):  
Phase Transition ◽  
Temperature Phase ◽  
Measured Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Disorder Phase Transition ◽  
Upper Limit ◽  
Temperature Phase Transition ◽  
Solid Phases ◽  
Low Temperature Phase

Abstract Chlorine NQR studies of solid nitrosyl chloride NOC1 between 110 and 212 K are reported. In the temperature dependence an order-disorder phase transition near 145 K, found by X-ray diffraction, is confirmed. Unusual hysteretic NQR signal behaviour indirectly proves also the low temperature phase transition below 100 K. In the measured temperature region fast relaxing mechanisms are present. The upper limit of the expected 14N NQR frequency is estimated using the Townes-Dailey approach.

Die Kristallstruktur der orientierungsfehlgeordneten kubischen Hochtemperaturphase des Natriumperchlorats NaClO4 / The Crystal Structure of the Orientationally Disordered, Cubic High-temperature Phase of Sodium Perchlorate NaClO4

1979 ◽  
Vol 34 (3) ◽  
pp. 522-523 ◽  
Author(s):  
Hans Joachim Berthold ◽  
Brigitte Gabriele Kruska ◽  
Rudolf Wartchow
Keyword(s):  
Crystal Structure ◽  
High Temperature ◽  
Single Crystal ◽  
Diffraction Data ◽  
Sodium Perchlorate ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Data Space

Abstract The crystal structure of the orientationally disordered, cubic high-temperature phase of NaC104 has been investigated using single crystal X-ray diffraction data. Space group Fm3m-O5h, Z = 4, sodium and chlorine as in NaCl, oxygen in position 96 j (occupation factor 1/6).

Electron Microscope study of commensurate-incommensurate phase transition in BaZnGeO4

1990 ◽  
Vol 48 (4) ◽  
pp. 172-173
Author(s):  
Naoki Yamamoto ◽  
Makoto Kikuchi ◽  
Tooru Atake ◽  
Akihiro Hamano ◽  
Yasutoshi Saito
Keyword(s):  
Phase Transition ◽  
Electron Microscope Study ◽  
Room Temperature ◽  
Hexagonal Lattice ◽  
Ferroelectric Materials ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Periodic Arrays ◽  
Modulation Wave Vector

BaZnGeO4 undergoes many phase transitions from I to V phase. The highest temperature phase I has a BaAl2O4 type structure with a hexagonal lattice. Recent X-ray diffraction study showed that the incommensurate (IC) lattice modulation appears along the c axis in the III and IV phases with a period of about 4c, and a commensurate (C) phase with a modulated period of 4c exists between the III and IV phases in the narrow temperature region (—58°C to —47°C on cooling), called the III' phase. The modulations in the IC phases are considered displacive type, but the detailed structures have not been studied. It is also not clear whether the modulation changes into periodic arrays of discommensurations (DC’s) near the III-III' and IV-V phase transition temperature as found in the ferroelectric materials such as Rb2ZnCl4.At room temperature (III phase) satellite reflections were seen around the fundamental reflections in a diffraction pattern (Fig.1) and they aligned along a certain direction deviated from the c* direction, which indicates that the modulation wave vector q tilts from the c* axis. The tilt angle is about 2 degree at room temperature and depends on temperature.

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