The thermal properties of cyanatocopper complexes with pyridine, bipyridine and phenanthroline are described in this paper. It was found that the thermal stabilities of the complexes were found to increase in the order py≪bipy<phen ligands. The significantly higher thermal stability of the complexes with bipyridine and phenanthroline is caused by the presence of dimeric structural units in the crystal structure and intermolecular interactions of the cyanate and heterocyclic ligands.
Authors:M. Batista, M. Ginani, D. Melo, and A. Oliveira
ZnS(1-x)MSx(x=0.01 and M=Mn2+, Cu2+ and Eu2+) compounds have been obtained by precipitation from homogeneous solutions of zinc, copper, manganese and europium salts,
with S2- as the precipitating anion, formed by the decomposition of thioacetamide. The thermal study of the milled zinc acetate, thioacetamide,
copper acetate, manganese acetate and europium nitrate, respectively, was studied for thermal analyis TG/DSC. XRD respect
exhibits a zinc blend crystal structure.
Authors:C. Beauger, P. Grosseau, B. Guilhot, D. Huguenin, and P. Iacconi
The dependence of the firing conditions on the crystal structure formation of ZnGa2 O4 has been investigated. The effects of temperature and atmosphere were examined and gave evidence of the instability of the
zinc gallate under a reducing atmosphere at temperatures above 600C. A new preparation route has allowed to synthesize ZnGa2 O4 at low-temperature, right from 300C, avoiding the decomposition of the matrix during the annealing.
The results of theoretical analysis of the properties of crystal structure and bonding in relation to thermal decomposition
process in chosen anhydrous metal oxalates (Cd, Co, Zn) are presented. The methods used in this analysis — the Bader’s quantum
theory of atoms in molecules and bond order model (as defined by Cioslowski and Mixon), applied to topological properties
of the electron density, obtained from DFT calculations performed by Wien2k package (full potential linearized augmented plane
wave method), as well as Brown’s bond valence model (bonds valences and strengths, and bond and crystal strains, calculated
from crystal structure and bonds lengths data) are described.
Presented results allow us to state, that these methods, when used simultaneously, make possible the description and analysis
of the crystal structure and bonding properties and give us the additional insight into its behavior during thermal decomposition
process. The proposed theoretical approach can be considered as promising and reliable tool for theoretical analysis, allowing
explanation and prediction of the properties of the structure and bonding and hence the most probable way of thermal decomposition
process to take place in such structure.
Sol-gel-derived titania films were analyzed by temperature programmed desorption (TPD) and X-ray diffraction (XRD) techniques.
The relationship between the TPD curves measured for two types of titania gel films and their crystal structures was investigated.
On the basis of the analyses, a preparation process for a titania sol solution containing anatase nanocrystals was designed
and developed. Using this process, a colloidal anatase titania sol solution was prepared by heating aqueous titanium hydroxide
containing HCl at 60�C for 2 h. The nanocrystal structure of the titania films obtained by coating the sol on glass substrates
was confirmed by TPD and XRD measurements.
Authors:M. Navarro, M. Lagarrigue, J. De Paoli, R. Carbonio, and M. Gómez
In order to investigate the formation of the multiferroic BiFeO3, the thermal decomposition of the inorganic complex Bismuth hexacyanoferrate (III) tetrahydrate, Bi[Fe(CN)6]·4H2O has been studied. The starting material and the decomposition products were characterized by IR spectroscopy, thermal analysis,
laboratory powder X-ray diffraction, and microscopic electron scanning. The crystal structures of these compounds were refined
by Rietveld analysis. BiFeO3 were synthesized by the decomposition thermal method at temperature as low as 600 °C. There is a clear dependence of the
type and amount of impurities that are present in the samples with the time and temperature of preparation.
A scientometric analysis of the publications and of the information flow on all phosphides shows that: the bulk of the publications on semiconducting phosphides relates to gallium phosphide. For non-semiconducting phosphides, most of the articles are connected with phosphides of transition metals. The bulk of the studies feature crystal structure, phase equilibria, diagrams of state and electrophysical and magnetic properties. Most of the articles on phosphides are published in English (53,4%) and in Russian (24.4%). There is a tendency for research to be carried out by groups of researchers of two, three, four or more persons. The present sceintometric analysis helps establish the trend of investigations on phosphides.
Authors:T. Sakuma, Xianglian, S. Siagian, K. Basar, H. Takahashi, N. Igawa, and O. Kamishima
Neutron diffraction measurements have been performed on powder VSe at 294 K. The diffuse scattering theory including correlation
effects among thermal displacements of atoms is applied to background function in the Rietveld analysis. The oscillatory scheme
of the diffuse scattering intensity from hexagonal VSe is explained by the correlation effects among far-neighboring Se–Se
atoms. The values of the correlation effects depend on the inter-atomic distance and not on the crystal structure. The relation
between correlation effects and force constants is discussed.
Authors:M. Vasilchenko, T. Shakhtshneider, D. Naumov, and V. Boldyrev
Topochemistry of the initial stages of evaporation and dissolution of monoclinic single crystals of paracetamol and phenacetin was studied. Thermal treatment of these crystals showed that the morphology of etch pits depicts the symmetry of etched planes. The shapes of pits formed during chemical etching of the cleavage plane of a paracetamol crystal by different etchants were not similar to each other. The chemical etching of the cleavage plane of a phenacetin crystal resulted in the formation of pits stretched along the same direction, independently of the chosen solvent. An interpretation of this result is suggested, based on the analysis of the anisotropy of the crystal structure and presence of steric hindrance.
Authors:M. Ganzerli-Valentini, S. Meloni, V. Caramella-Crespi, and P. Borroni
The adsorption of about 50 ions on molybdenum dibromide, (Mo6Br8)Br4·2H2O, in nitric acid was investigated. The preparation of the adsorber and its characterization is presented and discussed. Adsorption
mechanism studies were carried out for some noble metals and chromium. Sorption cannot be ascribed to ion exchange mechanism
but to formation of insoluble species, and to settlement of few ions into surface sorption sites or into a limited number
of cavities in the cluster crystal structure of the adsorber.