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Timezgana, Morocco

Azrour M.,Equipe science des Materiaux | Elouadi B.,University of La Rochelle | El Ammari L.,Mohammed V University
Acta Crystallographica Section E: Structure Reports Online

Single crystals of lithium zinc vanadate, LiZnVO4, were grown by the flux method. The structural type of this vanadate is characterized by a three-dimensional arrangement of tetrahedra sharing apices in an LiZnVO 4 network. This arrangement contains three different tetrahedra, namely one [VO4,] and two disordered mixed-site [Li/ZnO4,] tetrahedra. The resulting lattice gives rise to hexa-gonal channels running along the [0001] direction. Both sites in the mixed-site [Li/ZnO4,] tetrahedra are occupied by a statistical mixture of lithium and zinc with a 1:1 ratio. Therefore, LiZnVO4, appears to be the first vanadate known to crystallize with a disordered phenacite structure. Moreover, the resulting values of calculated bond valences (Li = 1.083, Zn = 2.062 and V = 5.185) tend to confirm the structural model. © 2010. Source

Sinouh H.,Equipe science des Materiaux | Sinouh H.,Hassan II University | Bih L.,Equipe science des Materiaux | Azrour M.,Equipe science des Materiaux | And 8 more authors.
Journal of Thermal Analysis and Calorimetry

By means of the conventional quenching route, the glass series 33Na 2O-xSrO-xTiO2-(50 - 2x)B2O3-17P 2O5 (x = 0-12.5 mol%) were prepared. The amorphous state of samples was verified by X-ray diffraction (XRD). Density, molar volume, micro-hardness, glass transition temperature (T g), and crystallization temperature (T c) parameters are determined for each glass. The results show that they depend strongly on the chemical compositions. The structure approach of the glasses is determined by Infrared spectroscopy (IR). This investigation highlights that the glassy-matrix contains various phosphate and borate structural units. The crystallization of the high-TiO 2 glasses by heat-treatments favors the formation of titanate phosphate Na4TiO(PO4)2 or Sr 0.5Ti2(PO4)3 along with Sr 3(PO4)2 inside the glass-matrix. © 2012 Akadémiai Kiadó, Budapest, Hungary. Source

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