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 ◽  
...  

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.

1988 ◽  
Vol 32 ◽  
pp. 609-616 ◽  
Author(s):  
D. Chandra ◽  
C. S. Barrett ◽  
D. K. Benson

AbstractAn array of molecules that is anisotropic in the extreme has been discovered in certain thermal-energy storage materials and is reported here: neopentylglycol (NPG) and NPG-rich solid solutions with pentaglycerine (PG) have a crystal structure, stable at room temperature, that consists of bimolecular chains of molecules that are all unidirectionally aligned throughout a crystal. There are hydrogen bonds between every molecule in one chain and its neighbors in that chain, but none between molecules of one chain and any molecules of the neighboring parallel chains. Thus there are strong intermolecular bonds along each chain and only weaker bonds between the chains. The structure has been determined by using modern single crystal techniques with 529 independent reflections from a crystal of NPG (C5H12O2). The structure is monoclinic with space group P21/c - C2h5. This anisotropic structure transforms to a cubic structure at higher temperatures.


1999 ◽  
Vol 77 (7) ◽  
pp. 515-520
Author(s):  
AAI Al-Bassam

Thin film polycrystalline solar cells based on CuIn1–xGaxSe2 have been fabricated and studied with x values from 0 to 1.0. The lattice parameters, grain size, and band gap were measured. Crystal structure and X-ray data of CuIn1–xGaxSe2 were determined using X-ray diffractometry. These materials had a cubic structure with x ≥ 0.5 and a tetragonal structure with x ≤ 0.5. The lattice constants vary linearly with composition. Grain size was measured using X-ray diffraction where the grain size increased linearly with Ga content. A grain size of 1.83-3.52 μm was observed with x ≤ 0.5, while it increased to 4.53 μm for x = 0.58.PACS No.: 70.73


2007 ◽  
Vol 63 (2) ◽  
pp. 270-276 ◽  
Author(s):  
Thomas Reeswinkel ◽  
Sebastian Prinz ◽  
Karine M. Sparta ◽  
Georg Roth

The new spin ½ V4+ barium oxovanadate BaV4O9 was synthesized and studied by means of single-crystal X-ray diffraction. Its room-temperature structure is monoclinic, space group P2/c. We discuss the temperature evolution of the crystal structure and thermal expansion tensor of the material between 293 and 100 K.


1971 ◽  
Vol 4 (4) ◽  
pp. 293-297 ◽  
Author(s):  
C. J. Toussaint

A crystallographic study of the system Ni2+ 1−2x Ni3+ x Li+ x O has been carried out. The crystal structure of the material in the range 0≤x≤0.4 at room temperature and up to 1000°C has been studied. The principal coefficients of thermal expansion and the phase diagram are given. The structural rhombohedral → face-centred cubic transition temperature of NiO has been determined.


2011 ◽  
Vol 170 ◽  
pp. 131-134 ◽  
Author(s):  
Shintaro Otsuka ◽  
Manami Onizawa ◽  
Koma Kato ◽  
Shozo Hiramoto ◽  
Fumiko Yoshida ◽  
...  

We have investigated the precise crystal structure and their temperature dependences of oxyarsenides (LaO)TAs; T = Mn, Fe, Co, as the Fe based superconductor’s parent material family using high energy synchrotron radiation x-ray powder diffraction. Lattice constants a and c decrease with decreasing temperature. Focusing the ratios of the changes normalized by room temperature lattice constants, we have found anisotropic shrinks for the superconductor’s parent material of (LaO)FeAs and the ferromagnetic metal (LaO)CoAs. The shrinkage of the lattice constant c along the stacking direction will be discussed by the temperature dependence of the divided three components of the LaO layer, TAs layer, and the interlayer distance.


2008 ◽  
Vol 23 (4) ◽  
pp. 317-322 ◽  
Author(s):  
L. N. Ji ◽  
G. M. Cai ◽  
J. B. Li ◽  
J. Luo ◽  
J. K. Liang ◽  
...  

K2Zn3(P2O7)2 was synthesized by solid state reaction and its crystal structure was determined by ab initio method from powder X-ray diffraction (XRD) data. The title compound was determined to be orthorhombic with space group P212121, Z=4, and lattice parameters a=12.901(8) Å, b=10.102(6) Å, and c=9.958(1) Å. Values of lattice parameters from 303 to 573 K were measured by temperature-dependent XRD. Thermal expansion coefficients α0, lattice parameters, and cell volume at 0 K were determined to be α0(a)=1.62327×10−4/K, a0=12.855(4) Å, α0(b)=1.17921×10−4/K, b0=10.070(8) Å, α0(c)=2.62364×10−4/K, c0=9.880(4) Å, and α0(V)=6.599×10−2/K, V0=1278.967(0) Å3. The specific heat equation as a function of temperature was determined to be Cp=0.77115+0.00231T−1241.60027T−2−1.4133×10−6T2 (J/K g), for temperatures from 198 to 710 K. The melting point estimated from the μ-DTA heating curve is 795 °C.


2017 ◽  
Vol 46 (9) ◽  
pp. 2974-2980 ◽  
Author(s):  
Paula Kayser ◽  
Sean Injac ◽  
Brendan J. Kennedy ◽  
Andre L. Menezes de Oliveira ◽  
Yuichi Shirako ◽  
...  

The temperature dependences of the structures of three polytypes of BaRuO3 have been investigated between room temperature and 1000 °C using high resolution synchrotron X-ray diffraction.


Author(s):  
Naoki Yamamoto ◽  
Makoto Kikuchi ◽  
Tooru Atake ◽  
Akihiro Hamano ◽  
Yasutoshi Saito

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.


Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 149-163
Author(s):  
Duncan Micallef ◽  
Liana Vella-Zarb ◽  
Ulrich Baisch

N,N′,N″,N‴-Tetraisopropylpyrophosphoramide 1 is a pyrophosphoramide with documented butyrylcholinesterase inhibition, a property shared with the more widely studied octamethylphosphoramide (Schradan). Unlike Schradan, 1 is a solid at room temperature making it one of a few known pyrophosphoramide solids. The crystal structure of 1 was determined by single-crystal X-ray diffraction and compared with that of other previously described solid pyrophosphoramides. The pyrophosphoramide discussed in this study was synthesised by reacting iso-propyl amine with pyrophosphoryl tetrachloride under anhydrous conditions. A unique supramolecular motif was observed when compared with previously published pyrophosphoramide structures having two different intermolecular hydrogen bonding synthons. Furthermore, the potential of a wider variety of supramolecular structures in which similar pyrophosphoramides can crystallise was recognised. Proton (1H) and Phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy, mass spectrometry (MS) were carried out to complete the analysis of the compound.


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