Synthesis And Characterization Of Novel Tungsten Phosphates,Sodium Titanium Oxide,Sodium Tin Oxide

Hydrothermal synthesis and solid state synthesis are two important methods of crystal material synthesis. In comparison with method in normal temperature and pressure, the physical and chemical properties change much under hydrothermal conditions. Under such conditions, new kinds of reactions could be found and the speed of reaction could be improved perhaps. In this way, hydrothermal synthesis has become a powerful method on preparation of advanced materials, and has been widely used in area of advanced ceramic, crystals, complex oxide and new structure materials. The solid state synthesis method on crystal synthesis was the earliest use way because of its easy control on conditions and its stable results under high temperature conditions.In this thesis, tungsten phosphates were researched in hydrothermal synthesis way, sodium titanium oxide and sodium tin oxide were researched in solid state synthesis method. By using X-ray powder diffraction and X-ray single crystal diffraction together with EDX and IR method, the chemical structure and composition were confirmed. The appearances of the compounds were observed by SEM., Five compounds were synthensized.1,Novel compound Rb₃PO₄W₁₂O₃₆ it is a novel 12-tugstun phosphate with typical Keggin structure, it is cubic with the space group Pn-3m(224), a = 11.6608(1) (?), V= 1585.56(2) (?)³ã€‚The compound has the features of the Keggin structure, the PO₄ tetrahedron in the middle is surrounded by 12 WO₆ octahedra, every three metal clusters in the 12 octahedra connected by sharing edges, the four clusters connect the PO₄ tetrahedron in the middle by sharing atoms. The hole is constructed in the three-dimensional structure and Rb atoms stay in it. The structure was determined from powder X-ray diffraction.2,Novel compound M₁₂W₈O₂₀PO₄(HPO₄)₈Cl·H₂O(M=NH₄⁺,Cs⁺), it was a novel tungsten phosphate. It is tetragonal with the space group P 4/m(83), The structure of compound can be best described as made of novel sandwich like layers. The P(1)O₄ tetrahedra and the WO₆ octahedra form a circle, and each W atom of WO₆ units has two terminal oxygen on one side of the layers which are considered as the reason for the low dimensinality of the structure. In the group of P(2)O₈, it has a disordered structure, the occupancies of the O atoms are 0.5, which meas the coordination number of the P atom is 4 instead of 8. 4 Cs(N)4 atoms lie around the P(1)O₄-WO₆ circle. Cs(N)3 atoms lie between circles. The structure of (NH₄)₁₂W₈O₂₀PO₄(HPO₄)₈Cl·H₂O was determined by single crystal X-ray diffractions and the structure of Cs₁₂W₈O₂₀PO₄(HPO₄)₈Cl·H₂O was refined by Rietveld method based on the structure of (NH₄)₁₂W₈O₂₀PO₄(HPO₄)₈Cl·H₂O.3,Structure unknown compound Na₂TiO₃, it is monoclinic with space group C2/c, a=9.8853(13)(?), b=6.4133(8)(?), c=5.5048(7)(?),β=115.50(3)°, V=314.99(7)(?)³. Different with normal sodium titanium oxide, the coordination number of titanium in this compound is five and trigonal bipyramids are formed. TiO₅ trigonal bipyramids are connected by sharing edges, and the chain along c axis is formed in this way. The three-dimensional structure formed by connected with Na atoms. The structure was determined by single crystal X-ray diffractions.4,Novel compound Na₆Sn₅O₁₂, it is monoclinic with space group of C 1 2/m 1 (12), a=5.4253(11)(?), b=9.3842(19)(?), c=5.6581(11)(?),β=108.89(3)°, V=272.55(280)(?)³, the Sn atoms have two kinds of coordination atmosphere, a plane vertical to axis c is made up by two kinds of SnO₆ octahedra in different size. The Na atoms situate between the two planes formed by SnO₆ octahedra. The SnO₆ and the NaO₆ connected by O atoms constructured the structure. The structure was determined by single crystal X-ray diffraction.