scholarly journals Phase Transitions and Crystal Structures of Ni(II) Complexes Determined with X-ray Powder Diffraction Data

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 106 ◽  
Author(s):  
Hisashi Konaka ◽  
Akito Sasaki
Keyword(s):  
Differential Scanning Calorimetry ◽  
Crystal Structures ◽  
Structural Changes ◽  
Original Form ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Hydrate Form ◽  
X Ray ◽  
Dsc Measurements ◽  
Crystalline Forms

Structural changes of chloride and bromide complexes, [Ni(Et2en)2(H2O)2]Cl2 (designated as 1a) and [Ni(Et2en)2]Br2 (2a), have been investigated by using simultaneous measurements of powder X-ray diffraction (XRD) and differential scanning calorimetry data under the temperature and humidity controls. The hydrate form of chloride complex 1a was transformed into an anhydrate form (1b) by heating at a temperature of 361 K. Then the 1b was reversibly returned to the original 1a by humidification at 25% relative humidity (RH) and temperature of 300 K. On the other hand, the anhydrate form of the bromide complex 2a was first transformed into a hydrate form (2b) at 30% RH and 300 K. On heating, the 2b turned to a new anhydrate form (2c) at 344 K, and then it returned to the original form 2a on further heating. In the present experiments, a series of reactions of 2a proceeded via 2c, which was newly found with the benefit of differential scanning calorimetry (DSC) measurements performed in parallel to the XRD measurements. Crystal structures of new crystalline forms of 1b, 2b, and 2c were determined from the powder XRD data.

scholarly journals X-Ray Diffraction and Differential Scanning Calorimetry of BaTiO3/ Polyvinyl Chloride Nanocomposites

2015 ◽  
Vol 1 (10) ◽  
pp. 359
Author(s):  
Mohamed Yousef Farag El Zayat
Keyword(s):  
Differential Scanning Calorimetry ◽  
Polyvinyl Chloride ◽  
Structural Changes ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
The Core ◽  
Dsc Measurements ◽  
Scherrer Formula ◽  
Composite Samples

AbstractAiming to improve the inferior properties of polyvinyl chloride polymer, (BaTiO3)x(PVC)100-x composite samples were prepared and investigated. The structural changes of the composite (BaTiO3)x(PVC)100-x were studied as a function of BT content using FTIR, XRD and DSC measurements. Attention is paid to the tetragonality changes during composition changes.It was found that the hindrance to the PVC crystallization becomes less and less serious with the increase of BT ratio in the composite. This behavior could be attributed to the interaction between Ba+2 ions and Chlorine in the polymer. The FTIR spectra indicate a clear interaction between PVC and BaTiO3 particles as is concluded from XRD results.The Scherrer formula was used to estimate the grain size for the included BT in the (BT)x (PVC)100x composite samples. The composite samples show abnormally small tetragonality for its BT content less than unity (?/a < 1). It seems that in (BaTiO3)x(PVC)100-x composite samples, the stress that stabilized the tetragonal phase of the core regions of BT decreased, leading to lower tetragonality (c/a ratio). It seems that Tg of the composite samples increases with the increase of its BT content. Also DSC results reveal the increase of crystallization with the increase of BT content in the composite.

The Crystal Structures at 10 K of the Trigonal Salts KMIII(NH3)6(ClO4)2Cl2, MIII = Os and Cr, and the Possibility of Phase Transitions

1999 ◽  
Vol 52 (3) ◽  
pp. 219 ◽  
Author(s):  
Philip A. Reynolds ◽  
Brian N. Figgis ◽  
Alexander N. Sobolev
Keyword(s):  
Differential Scanning Calorimetry ◽  
Transition Temperature ◽  
Crystal Structures ◽  
Low Temperatures ◽  
Simple Structure ◽  
Alkali Metal Cations ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Threefold Axis ◽  
X Ray

The crystal structures of KOs(NH3)3(ClO4)2Cl2 and KCr(NH3)6(ClO4)2Cl2 were determined at 10 K by X-ray diffraction, and for the osmium salt also at 293 K. At 293 K the osmium salt is trigonal, space group R 3m, with the same simple structure as others of this class of double salt. At 10 K, in agreement with previous radius ratio predictions, both crystals are best described as remaining R 3m. All previously studied members, with larger alkali metal cations, are twinned R 3 at low temperatures, with small, symmetry-breaking rotations of the hexaamminemetal(III) and perchlorate ions about the threefold axis. Differential scanning calorimetry on CsRu(NH3)6(ClO4)2Cl2 suggests that the R 3m to R 3 change is very extended in temperature with only a small discontinuity at the transition temperature.

New crystal structures in the realm of 5,5′-azotetrazolates

2015 ◽  
Vol 70 (2) ◽  
pp. 125-134 ◽  
Author(s):  
Martin Lampl ◽  
Gerhard Laus ◽  
Doris E. Braun ◽  
Volker Kahlenberg ◽  
Klaus Wurst ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Single Crystal ◽  
Crystal Structures ◽  
Organic Cations ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Diffraction Patterns

AbstractThe preparation of six new 5,5′-azotetrazolates with organic cations is reported. Differential scanning calorimetry of all compounds showed exothermic decompositions. The crystal structures of the six 5,5′-azotetrazolates were determined by single-crystal X-ray diffraction analyses. The phase purities of the bulk samples were confirmed by Pawley fits of the experimental and calculated powder X-ray diffraction patterns.

Multiple dielectric anomalies in xBiLaO3–(1 − x)PbTiO3 piezoelectrics

2008 ◽  
Vol 23 (2) ◽  
pp. 565-569 ◽  
Author(s):  
Runrun Duan ◽  
Michael S. Haluska ◽  
Robert F. Speyer
Keyword(s):  
Differential Scanning Calorimetry ◽  
Dielectric Constant ◽  
Excellent Agreement ◽  
Structural Changes ◽  
Dielectric Anomaly ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thermally Induced ◽  
X Ray ◽  
Higher Temperature

Compositions of xBiLaO3–(1 − x) PbTiO3 over the range 0 ≤ x ≤ 0.225 were calcined and sintered. The dielectric constant with temperature and differential scanning calorimetry measurements were in excellent agreement with respect to Curie-like tetragonal to cubic transformations starting at 495 °C for pure PbTiO3, shifting to lower temperatures with increasing x. For compositions of x ≥ 0.05, a second higher-temperature (∼600 °C) endotherm, and matching dielectric anomaly, were consistently observed, for which there were no structural changes indicated by hot-stage x-ray diffraction. This transformation was speculated to be based on a thermally induced desegregation of B-site cations.

Mechanical alloying studies in the Γ(Fe3Zn10) and Γ1(Fe5Zn21) single and mixed phase compositions

1998 ◽  
Vol 13 (5) ◽  
pp. 1177-1185 ◽  
Author(s):  
Aszetta Jordan ◽  
Zhentong Liu ◽  
Oswald N. C. Uwakweh
Keyword(s):  
Differential Scanning Calorimetry ◽  
Stable Equilibrium ◽  
Mixed Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Crystalline Materials ◽  
X Ray ◽  
Dsc Measurements ◽  
Fe Sites

Homogeneous or uniform crystalline materials are obtained following the ball milling of pure elemental powders of Fe and Zn in proportions to yield single phases Γ(Fe3Zn10), Γ1(Fe5Zn21), and Γ + Γ1 mixed phase (Fe25Zn75). Differential scanning calorimetry (DSC) measurements of the as-milled materials show characteristic stages in the temperature range of 50–600 °C prior to establishing stable equilibrium. The activation energies determined from kinetic analyses range from 49 to 189 kJ/mole in these materials. A characteristic stage at 130 °C marking the distinct evolution of the Γ and Γ1 phases from the intermediate or mixed phase composition is identified from XRD measurements. The identification of a unique Fe site with a quadrupole splitting (QS) of 1.5 mm/s in corroboration with x-ray diffraction (XRD) shows that this stage marks the onset of an in situ transformation prior to the distinct evolution of the homogeneous phases. The Mössbauer effect measurement of the as-milled materials are resolved in terms of four unique Fe sites with QS of 1.1, 0.241, 0.073, and 0.0772 mm/s.

Research on compatibility and surface of high impact bio-based polyamide

2021 ◽  
pp. 095400832110055
Author(s):  
Yang Wang ◽  
Yuhui Zhang ◽  
Yuhan Xu ◽  
Xiucai Liu ◽  
Weihong Guo
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Crystallization Behavior ◽  
High Impact ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Scanning Electron

The super-tough bio-based nylon was prepared by melt extrusion. In order to improve the compatibility between bio-based nylon and elastomer, the elastomer POE was grafted with maleic anhydride. Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA) were used to study the compatibility and micro-distribution between super-tough bio-based nylon and toughened elastomers. The results of mechanical strength experiments show that the 20% content of POE-g-MAH has the best toughening effect. After toughening, the toughness of the super-tough nylon was significantly improved. The notched impact strength was 88 kJ/m2 increasing by 1700%, which was in line with the industrial super-tough nylon. X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) were used to study the crystallization behavior of bio-based PA56, and the effect of bio-based PA56 with high crystallinity on mechanical properties was analyzed from the microstructure.

scholarly journals Synthesis and mesomorphic properties of calamitic malonates and cyanoacetates tethered to 4-cyanobiphenyls

2012 ◽  
Vol 8 ◽  
pp. 371-378 ◽  
Author(s):  
Katharina C Kress ◽  
Martin Kaller ◽  
Kirill V Axenov ◽  
Stefan Tussetschläger ◽  
Sabine Laschat
Keyword(s):  
Differential Scanning Calorimetry ◽  
Ambient Temperature ◽  
Liquid Crystalline ◽  
X Ray Diffraction ◽  
Cyanoacetic Acid ◽  
Scanning Calorimetry ◽  
Isotropic Liquid ◽  
X Ray ◽  
Nematic Phases ◽  
Mesomorphic Properties

4-Cyano-1,1'-biphenyl derivatives bearing ω-hydroxyalkyl substituents were reacted with methyl 3-chloro-3-oxopropionate or cyanoacetic acid, giving liquid-crystalline linear malonates and cyanoacetates. These compounds formed monotropic nematic phases at 62 °C down to ambient temperature upon cooling from the isotropic liquid. The mesomorphic properties were investigated by differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction (WAXS).

Inosose-Flüssigkristalle / Inosose Liquid Crystals

1990 ◽  
Vol 45 (7) ◽  
pp. 1084-1090 ◽  
Author(s):  
Klaus Praefcke ◽  
Bernd Kohne ◽  
Andreas Eckert ◽  
Joachim Hempel
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
High Temperature ◽  
Liquid Crystalline ◽  
Structural Features ◽  
Lyotropic Liquid Crystal ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Alkyl Chains

Six S,S-dialkyl acetals 2a-f of inosose (1), tripodal in structure, have been synthesized, characterized and investigated by optical microscopy and differential scanning calorimetry (d.s.c.). The four S,S-acetals 2c-f with sufficiently long alkyl chains are thermotropic liquid crystalline; 2 e and 2 f are even dithermomesomorphic. Each of these four inosose derivatives 2c-f exhibits monotropically a most likely cubic mesophase (MI); in addition 2e and 2f show enantiotropically a hexagonal mesophase (Hx) with a non-covalent, supramolecular H-bridge architecture. Whereas the nature of the optically isotropic mesophase MI needs further clarification the stable high temperature mesophase Hx of 2 e and 2 f has been established by a miscibility test using a sugar S,S-dialkyl acetal also tripodal in structure and with a Hx phase proved by X-ray diffraction, but in contrast to 2 with an acyclic hydrophilic part. Similarities of structural features between the Hx-phases of 2e and 2f as well as of other thermotropic and lyotropic liquid crystal systems are discussed briefly.

scholarly journals Formation of Pharmaceutical Salts and Cocrystals via Vapour-Assisted Tumbling (VAT) – A Solvent Efficient Process with Potential Industrial Applications

2021 ◽  
Author(s):  
Alexander J. Stirk ◽  
Fabio E. S. Souza ◽  
Jenny Gerster ◽  
Fatemeh M. Mir ◽  
Avedis Karadeolian ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Environmental Impact ◽  
Industrial Applications ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
New Techniques ◽  
X Ray ◽  
Industry Standard ◽  
Pharmaceutical Salts ◽  
Solid Form

Crystallisations on both the academic and industrial scale often use large volumes of solvent. In order decrease the environmental impact of such processes, new techniques must be discovered that increase the efficiency of the solvents used. Introduced here is a process that combines repurposed industry standard hardware and aspects of mechanochemistry to produce a technique we call “Vapour Assisted Tumbling” (VAT). Pharmaceutical and well-known cocrystals and salts were formed by tumbling the coformers in an atmosphere of vaporised solvent, in this study, methanol (MeOH). This was done inside a custom built analogue of an industrial rotary cone dryer (RCD). It was found that a desired solid form could be obtained as monitored by powder X-ray diffraction and differential scanning calorimetry. By repurposing industrial RCDs, it is feasible that solid forms can be crystallised with both minimal and reusable/recyclable solvent – drastically lowering the environmental impact of such transformations.

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