【作者】 任骁侠；

【导师】 毛少瑜；

【作者基本信息】 厦门大学 ， 物理化学， 2006， 硕士

【摘要】 水热法和固相法是合成晶体材料的两类重要方法，与常温常压比较，水热条件下物质的理化性能均有很大变化，其间既可能产生新的化学反应，又可以使反应速度大为提高，因此作为制备新材料的强有力手段，水热法被广泛应用于制备超细及异型粉体、新型陶瓷、晶体、复合氧化物、新型结构材料等方面。而固相法由于实验条件易于控制，且可得到高温条件下稳定相等优点是较早应用在晶体合成的方法。本文通过水热法对钨磷酸盐体系，高温固相法对钛酸钠、锡酸钠进行了合成的研究，并利用X射线粉末和单晶衍射法，结合EDX能谱和红外吸收光谱等方法确定了合成产物的结构和化学组成，使用SEM扫描电子显微镜和光学显微镜对晶体形貌进行了观察。共合成和表征了五个化合物：1、新化合物Rb₃PO₄W₁2O₃6，该化合物由水热法制得，为典型的Keggin型结构，为立方晶系，空间群为Pn-3m（224），a=11．6608（1）（?），V=1585．56（2） （?）³。该化合物结构上具备Keggin结构的典型特征，中心原子为PO₄四面体，被12个WO₆八面体包围，WO₆八面体之间每三个形成三金属簇共边相连，四个三金属簇与中心四面体共顶角相连，形成空间孔洞结构，Rb原子位于孔洞中。此结构是在化合物K_2．4（H₃O）_0．6PO₄W₁₂O₃₆单晶结构模型基础上通过X射线粉末衍射法，由Rietveld方法精修而得。2、新化合物M₁₂W₈O₂₀PO₄（HPO₄）₈Cl·H₂O（M=NH4_<sup>+、Cs⁺），该化合物由水热法制得。为新型的钨磷酸盐，四方晶系，空间群为P 4／m（83），该化合物结构属于层状结构，P原子存在两种配位环境，其中P（1）O₄四面体与WO₆八面体交替相连形成八元环，P（2）O（1）8基团为局部无序配位，处于垂直于c轴的ab平面，该平面与八元环平行，沿c轴方向上，该基团处垂直于八元环的中心轴向上。P（2）O（1）8中与P（2）配位的O原子在结构中的占有率仅为0．5。即P（2）实际配位数为4而不是8。一个Cs（N）2原子位于八元环的平面中心，4个Cs（N）4原子分布在环外侧，八元环构成在垂直于c轴方向的平面结构，两个八元环之间为Cs（N）3原子。晶体结构在空间上沿c轴方向形成孔洞，在垂直于c轴方向为八元环构成的夹层结构。其中的WO₆基团在同一侧有两个最终键连O原子，从而空间上形成低维的层状结构。（NH₄）₁2W₈O₂0PO₄（HPO₄）₈Cl·H₂O的结构由X射线单晶衍射法测得，化合物Cs₁2W₈O₂0PO₄（HPO₄）₈Cl·H₂O的结构是在同构型化合物（NH₄）₁2W₈O₂0PO₄（HPO₄）₈Cl·H₂O单晶结构模型的基础上通过X射线粉末衍射法由Rietveld方法精修而得。3、化合物Na₂TiO₃的结构，该化合物由高温固相法制得，为单斜晶系，空间群为C 2／c，a=9．8853（13）（?），b=6．4133（8）（?），c=5．5048（7）（?），β=115．50（3）°，V=314．99（7）（?）³，与一般的钛酸钠中钨氧基团为6配位的八面体不同，该化合物形成5配位的双三角锥对面体，TiO₅多面体通过共边相连，且沿c轴方向形成链状，整个结构通过Na原子的连接形成空间网络结构。此结构通过X射线单晶衍射法测得。4、新化合物Na₆Sn₅O₁2，该化合物由高温固相法制得，为单斜晶系，空间群为C12／ml（12），a=5．4253（11）（?），b=9．3842（19）（?），c=5．6581（11）（?），β=108．89（3）°，V=272．55（280）（?）³，其中的Sn原子存在二价和四价两种价态，有两种配位环境，通过两种大小不同的SnO₆八面体连接，构成了垂直于c轴的平面，而Na原子则处在上下两个平面之间，通过NaO₆与SnO₆共顶角O相连形成空间网络结构。此结构通过X射线单晶衍射法测得。更多还原

【Abstract】 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） （?）³。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.更多还原