Phase transition in metal–organic complex trans-PtCl2(PEt3)2 under pressure: insights into the molecular and crystal structure

CrystEngComm ◽  
2018 ◽  
Vol 20 (26) ◽  
pp. 3728-3740 ◽  
Author(s):  
Naini Bajaj ◽  
Himal Bhatt ◽  
K. K. Pandey ◽  
H. K. Poswal ◽  
A. Arya ◽  
...  

Molecular reorientations result in structural phase transition in trans-PtCl2(PEt3)2 under pressure, leading to a hydrogen bond assisted supramolecular architecture.

2018 ◽  
Vol 73 (9) ◽  
pp. 611-616
Author(s):  
Hideta Ishihara ◽  
Hisashi Honda ◽  
Ingrid Svoboda ◽  
Hartmut Fuess

AbstractThe crystal structure of [4-C2H5-C6H4NH3]2ZnBr4 (1) has been determined at 150(2) K: triclinic, P1̅, a=724.82(2), b=1194.20(4), c=1322.26(4) pm, α=74.151(3), β=80.887(3), γ=80.434(3)°, and Z=2. There are two crystallographically independent cations in the unit cell of 1: one has its benzene ring perpendicular to the crystallographic a axis of the unit cell and the other one has its benzene ring perpendicular to the c axis. These cations are alternatingly located along the c axis and form organic layers, and the ZnBr4 anions form inorganic layers in between. Zn–Br···H–N hydrogen bonds are formed between cations and anions. In accordance with the crystal structure, four nuclear quadrupole resonance (NQR) lines of 81Br were observed. The temperature dependence of the 81Br NQR frequencies between 77 and 320 K shows a peculiar feature which is not due to a structural phase transition. The measurement of 13C nuclear magnetic resonance spectra at around T=340 K indicates a redistribution of cations. The temperature dependence of 81Br NQR frequencies and differential thermal analysis measurements show that [4-C2H5-C6H4NH3]2CdBr4 (2) undergoes a structural phase transition at around 190 K.


2018 ◽  
Vol 42 (11) ◽  
pp. 575-578 ◽  
Author(s):  
Di Cheng ◽  
Ya-Ping Zhang ◽  
Ke Wang ◽  
Xiang-Ru Meng ◽  
Xiao-Fei Li

The metal–organic complex {[Zn(immb)(suc)]·H2O}n [immb = 2-[(1H-imidazol-1-yl)methyl]-6-methyl-1H-benzimidazole, H2suc = succinic acid] has been prepared and its crystal structure determined. Its fluorescence and thermogravimetric data have also been obtained.


CrystEngComm ◽  
2020 ◽  
Vol 22 (26) ◽  
pp. 4353-4358
Author(s):  
Breogán Pato-Doldán ◽  
Mali H. Rosnes ◽  
Dmitry Chernyshov ◽  
Pascal D. C. Dietzel

The framework of CO2 saturated CPO-27 is deformed below 110 K into a superstructure of the original honeycomb structure.


2013 ◽  
Vol 634-638 ◽  
pp. 2592-2595
Author(s):  
Qing Wei Wang ◽  
Ting Feng Lu ◽  
Jia Guo ◽  
Xiu Mei Li

A new metal-organic complex FeII2FeIII2(cbba)4(L)6 (Hcbba = 2-(4΄-chlorine-benzoyl) benzoic acid, L = 3-(2-pyridyl)pyrazole) 1 has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analyses, TG and IR spectroscopy. The compound crystallizes in monoclinic, space group Cc with a = 17.729(5), b = 15.919(5), c = 33.650(5) Å, β = 92.058(5)°, V = 9491(4) Å3, C104H68Cl4Fe4N18O12, Mr = 2126.96, Dc = 1.489 g/cm3, μ(MoKα) = 0.786 mm1, F(000) = 4344, Z = 4, the final R = 0.0559 and wR = 0.1122 for 12093 observed reflections (I > 2(I)).


2000 ◽  
Vol 64 (2) ◽  
pp. 291-300 ◽  
Author(s):  
K. S. Knight

AbstractHigh-resolution, neutron time-of-flight, powder diffraction data have been collected on natural crocoite between 873 and 1073 K. Thermal analysis carried out in the 1920s had suggested that chemically pure PbCrO4 exhibited two structural phase transitions, at 964 K, to the β phase, and at 1056 K, to the γ phase. In this study, no evidence was found for the α-β structural phase transition, however a high-temperature phase transition was found at ∼1068 K from the ambient-temperature monazite structure type to the baryte structure type. The phase transition, close to the temperatures reported for the β to γ phase modifications, is first order and is accompanied by a change in volume of −1.6%. The crystal structure of this phase has been refined using the Rietveld method to agreement factors of Rp = 0.018, Rwp = 0.019, Rp = 0.011. No evidence for premonitory behaviour was found in the temperature dependence of the monoclinic lattice constants rom 873 K to 1063 K and these have been used to determine the thermal expansion tensor of crocoite just below the phase transition. At 1000 K the magnitudes of the tensor coefficients are α11, 2.66(1) × 10−5 K−1; α22, 2.04(1) × 10−5 K−1; α33, 4.67(4) × 10−5 K−1; and α13, −1.80(2) × 10−5 K−1 using the IRE convention for the orientation of the tensor basis. The orientation of the principal axes of the thermal expansion tensor are very close to those reported previously for the temperature range 50–300 K.


2015 ◽  
Vol 119 (43) ◽  
pp. 24522-24528 ◽  
Author(s):  
Mantas Šimėnas ◽  
Aneta Ciupa ◽  
Mirosław Ma̧czka ◽  
Andreas Pöppl ◽  
Ju̅ras Banys

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1016
Author(s):  
Xiao-Cun Liu ◽  
Ming-Yan Pan

AgBiSe2, which exhibits complex structural phase transition behavior, has recently been considered as a potential thermoelectric material due to its intrinsically low thermal conductivity. In this work, we investigate the crystal structure of Sn-doped AgBiSe2 through powder X-ray diffraction and differential scanning calorimetry measurements. A stable cubic Ag1−x/2Bi1−x/2SnxSe2 phase can be obtained at room temperature when the value of x is larger than 0.2. In addition, the thermoelectric properties of Ag1−x/2Bi1−x/2SnxSe2 (x = 0.2, 0.25, 0.3, 0.35) are investigated, revealing that Ag1−x/2Bi1−x/2SnxSe2 compounds are intrinsic semiconductors with a low lattice thermal conductivity. This work provides new insights into the crystal structure adjustment of AgBiSe2 and shows that Ag1−x/2Bi1−x/2SnxSe2 is a potentially lead-free thermoelectric material candidate.


CrystEngComm ◽  
2018 ◽  
Vol 20 (39) ◽  
pp. 5949-5954 ◽  
Author(s):  
Chun-Mei Hao ◽  
Yunguo Li ◽  
Qiang Zhu ◽  
Xin-Yi Chen ◽  
Zhan-Xin Wang ◽  
...  

The structural, dynamic, elastic, and electronic properties of Li4Ge were investigated by means of evolutionary crystal structure prediction in conjunction with first-principles calculations.


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