scholarly journals Polymorphism of 1,3-X-adamantanes (X = Br, OH, CH3) and the crystal plastic phase formation ability

CrystEngComm ◽  
2020 ◽  
Vol 22 (7) ◽  
pp. 1230-1238 ◽  
Author(s):  
Philippe Negrier ◽  
Bacem Ben Hassine ◽  
Maria Barrio ◽  
Michela Romanini ◽  
Denise Mondieig ◽  
...  

The polymorphism of 1,3-dimethyladamantane (13DMA), 1,3-adamantanediol (13DOHA) and 1,3-dibromoadamantane (13DBrA) has been studied by X-ray powder diffraction, density measurements and differential scanning calorimetry at normal and high-pressure.

2000 ◽  
Vol 644 ◽  
Author(s):  
Y.X. Zhuang ◽  
L. Gerward ◽  
J.Z. Jiang ◽  
J.S. Olsen ◽  
Y. Zhang ◽  
...  

AbstractThe crystallization of bulk Zr48Nb8Cu14Ni12Be18metallic glass has been investigated by differential scanning calorimetry (DSC) and X-ray powder diffraction. The activation energies of glass transition and crystallization for the glass obtained using Kissinger analysis from the shift of the peak temperature in the DSC curve are 470 and 235 kJ/mol, respectively. The effect of applied pressure on crystallization is studied by in situ high-pressure and high-temperature X-ray powder diffraction using synchrotron radiation. It is found that the crystallization temperature increases with pressure having a slope of 9.5 K/GPa in the range of 0-4.4 GPa.


1998 ◽  
Vol 76 (11) ◽  
pp. 1520-1523
Author(s):  
Jennifer F Caplan ◽  
Christopher A Murphy ◽  
Susan Swansburg ◽  
Robert P Lemieux ◽  
T Stanley Cameron ◽  
...  

The synthesis of Ru2(μ-O2CR)4(μ´-O2CR) (1), R = -CH2(CH2)6CH=CH(CH2)5CH3, has been achieved and characterization using elemental analysis and FTIR and UV-Vis spectroscopies undertaken. Strong evidence for a hexagonal discotic mesophase has been found using differential scanning calorimetry, variable-temperature polarizing optical microscopy, and X-ray powder diffraction. A solid to liquid crystal transition was found upon heating at 128°C and the mesophase is found to persist to room temperature upon cooling from 150°C. This is the first report of room temperature mesomorphism in a mixed-valent metallomesogen. Key words: ruthenium carboxylate, liquid crystal, metallomesogen, mixed valence, polymer.


Author(s):  
Peter Zietlow ◽  
Tobias Beirau ◽  
Boriana Mihailova ◽  
Lee A. Groat ◽  
Thomas Chudy ◽  
...  

AbstractRadiation damage in minerals is caused by the α-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400–1000 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia [6.4 wt% Th, 23.1·10


2011 ◽  
Vol 172-174 ◽  
pp. 646-651 ◽  
Author(s):  
Gamra Tellouche ◽  
Khalid Hoummada ◽  
Dominique Mangelinck ◽  
Ivan Blum

The phase formation sequence of Ni silicide for different thicknesses is studied by in situ X ray diffraction and differential scanning calorimetry measurements. The formation of a transient phase is observed during the formation of δ-Ni2Si; transient phases grow and disappear during the growth of another phase. A possible mechanism is proposed for the transient phase formation and consumption. It is applied to the growth and consumption of θ-Ni2Si. A good accordance is found between the proposed model and in situ measurement of the kinetics of phase formation obtained by x-ray diffraction and differential scanning calorimetry for higher thickness.


2014 ◽  
Vol 70 (a1) ◽  
pp. C53-C53
Author(s):  
Yan Suffren ◽  
Isabelle Gautier-Luneau ◽  
Céline Darie ◽  
Céline Goujon ◽  
Murielle Legendre ◽  
...  

In the 1970s, a large number of metal iodates compounds were extensively investigated for their nonlinear optics (NLO) properties as well as for their ferroelectric, piezoelectric, and pyroelectric properties. Interest in these compounds resumed in the early 2000s. We have shown that metal iodates are particularly interesting for for quadratic NLO in mid IR, as they possess a large domain of transparency from the visible region to the beginning of the far IR region (12.5 μm), thus covering the three atmospheric transparency windows. The synthesis of metal iodates has so far been mainly investigated by solution chemistry, under hydrothermal conditions or by the flux method. The solid state synthesis of these compounds at high pressure has never been explored. To date, only the structural evolution of α-LiIO3 with pressure has been studied by X-ray powder diffraction [1]. It was shown that, at room temperature, α-LiIO3 is stable up to 75 GPa; only compression of the lattice parameters with pressure was observed. In this work, we present a new phase of silver iodate obtained at high pressure from α-AgIO3 and characterized by X-ray powder diffraction. The α-AgIO3 to β-AgIO3 transition was characterized by differential thermal analysis (DTA) at high pressure [2-3]. The thermal behaviors of α-AgIO3 and β-AgIO3 were studied by differential scanning calorimetry (DSC) at ambient pressure and in situ temperature-dependent X-ray powder diffraction. Structural studies of these two phases were carried out to understand the formation of β-AgIO3.


Author(s):  
R. Hübner ◽  
A. Belger ◽  
D. C. Meyer ◽  
P. Paufler ◽  
I. G. Polyakova

AbstractCrystallisation and annealing behaviour of two caesium borosilicate glass samples with approximate boroleucite composition were characterised by means of differential scanning calorimetry measurements as well as X-ray powder diffraction investigations with subsequent profile fitting of the observed patterns according to the Rietveld and/or Pawley method. While one sample crystallised primarily in an orthorhombic phase (


Author(s):  
Christoph Krebs ◽  
Inke Jess ◽  
Christian Näther

The reaction of Co(NCS)2 with 3-(aminomethyl)pyridine as coligand leads to the formation of crystals of the title compound, [Co(NCS)2(C6H8N2)2] n , that were characterized by single-crystal X-ray analysis. In the crystal structure, the CoII cations are octahedrally coordinated by two terminal N-bonded thiocyanate anions as well as two pyridine and two amino N atoms of four symmetry-equivalent 3-(aminomethyl)pyridine coligands with all pairs of equivalent atoms in a trans position. The CoII cations are linked by the 3-(aminomethyl)pyridine coligands into layers parallel to the ac plane. These layers are further linked by intermolecular N—H...S hydrogen bonding into a three-dimensional network. The purity of the title compound was determined by X-ray powder diffraction and its thermal behavior was investigated by differential scanning calorimetry and thermogravimetry.


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