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Metathetic Reaction (metathetic + reaction)
Selected AbstractsMetathetic Reaction in Reverse Micelles: Synthesis of Nanostructured Alkaline-Earth Metal PhosphatesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2007Purnendu Parhi For the past few years, hydroxyapatite (HAp) has been identified as a potential biomaterial due to its excellent biocompatibility and bioactivity. The preparation of nanostructured HAp with controlled powder characteristics is a pre-requisite for processing it into useful biocomposites. Here, the synthesis of nanorods of calcium hydroxyapatite (Ca-HAp), strontium hydroxyapatite (Sr-HAp), and barium hydroxyapatite (Ba-HAp) by exploiting the metathetic reaction taking place in reverse micelles in the presence of cetyltrimethylammonium bromide has been reported. Powder X-ray diffraction analysis and thermogravimetric measurements confirm the formation of monophasic Ca-HAp and Sr-HAp. The growth of nanorods was further confirmed using transmission electron microscopy studies. The average lengths of Ca-HAp and Sr-HAp were ,60 and 30 nm, respectively. However, the preparation of Ba-HAp invariably yielded a multiphasic mixture with other competitive phases like BaHPO4 and Ba(H2PO4)2. [source] Preparation of PbZrO3/ASO4 Composites (A: Ca, Sr, Ba) and PbZrO3 by Metathetic Reactions in the Solid State: Metathetic Exchange of Divalent Species.CHEMINFORM, Issue 27 2003Monalisa Panda Abstract For Abstract see ChemInform Abstract in Full Text. [source] Hexagonal and cubic TiOF2JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 4 2010Samuel Shian The chemical, electrochemical, optical and electro-optical properties of titanium oxyfluoride, TiOF2, have led to interest in this compound for a number of applications. Prior analyses have indicated that TiOF2 possesses a simple cubic structure (space group Pmm) at room temperature. Three-dimensional nanostructured assemblies of polycrystalline TiOF2 have recently been synthesized via chemical conversion of intricate SiO2 structures by metathetic reaction with TiF4(g). Rietveld analysis has been used to evaluate the structure of the TiOF2 product formed by such reaction at 623,K. Unlike prior reports, this TiOF2 product possessed a hexagonal structure (space group Rc) at room temperature. Upon heating through 333,338 K, the hexagonal TiOF2 polymorph converted into cubic (Pmm) TiOF2. Differential scanning calorimetry and X-ray diffraction analyses have been used to evaluate this thermally induced phase transformation. [source] Metathetic Reaction in Reverse Micelles: Synthesis of Nanostructured Alkaline-Earth Metal PhosphatesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2007Purnendu Parhi For the past few years, hydroxyapatite (HAp) has been identified as a potential biomaterial due to its excellent biocompatibility and bioactivity. The preparation of nanostructured HAp with controlled powder characteristics is a pre-requisite for processing it into useful biocomposites. Here, the synthesis of nanorods of calcium hydroxyapatite (Ca-HAp), strontium hydroxyapatite (Sr-HAp), and barium hydroxyapatite (Ba-HAp) by exploiting the metathetic reaction taking place in reverse micelles in the presence of cetyltrimethylammonium bromide has been reported. Powder X-ray diffraction analysis and thermogravimetric measurements confirm the formation of monophasic Ca-HAp and Sr-HAp. The growth of nanorods was further confirmed using transmission electron microscopy studies. The average lengths of Ca-HAp and Sr-HAp were ,60 and 30 nm, respectively. However, the preparation of Ba-HAp invariably yielded a multiphasic mixture with other competitive phases like BaHPO4 and Ba(H2PO4)2. [source] | ||||||||||