【作者】 张莉；

【导师】 陈学安；

【作者基本信息】 北京工业大学 ， 材料学， 2006， 硕士

【摘要】 本论文报道了采用水热合成法在170°C下制备新型碘酸盐非线性光学晶体的研究,作者主要合成了四种新型化合物:Ce(MoO2)(OH)(IO3)4、LiMoO3(IO3)、NH4MoO3(IO3)和LiVO2(IO3)2。在Rigaku AFC7R X-射线四圆衍射仪上进行了X-射线衍射数据收集,运用SHELX-97软件解析出了晶体结构,并对它们的性能进行了分析和研究。Ce(MoO2)(OH)(IO3)4以极性空间群P21结晶,晶体学参数为:a = 7.0144(8) ,b = 14.1554(7) ,c = 7.0969(6) ,β= 115.318(7)°,Z = 2。Ce(MoO2)(OH)(IO3)4的晶体结构是由八配位的Ce3+阳离子、高度畸变的MoO6八面体和三角锥型的IO3-组成的复杂三维网所构成。LiMoO3(IO3)以极性空间群P21结晶,晶体学参数为:a = 5.4104(4) ,b = 5.3158(3) ,c = 9.0025(7) ,β= 106.863(6)°,Z = 2。晶体结构分析表明,LiMoO3(IO3)是一种新的层状化合物,其结构中包含被Li+隔开的∞2 [MoO3(IO3)]-阴离子层。从热重-差热分析曲线中可以看出,LiMoO3(IO3)在低于430°C时能稳定存在。UV漫反射光谱表明该物质在1.1 - 2.8 eV之间有很好的透光性,能带隙约为2.8 eV。粉末倍频测试表明LiMoO3(IO3)的倍频强度为KDP(KH2PO4)的4倍,证实了该化合物具有非对称心结构。NH4MoO3(IO3)以极性空间群Pna21结晶,晶体学参数为:a = 7.8167(6) , b = 10.2280(7) ,c = 7.3466(4) ,Z = 4。NH4MoO3(IO3)的结构是由畸变的MoO6八面体和三角锥型的IO3-连接在一起形成的三维网状结构所组成。LiVO2(IO3)2以空间群P21/c结晶,所有的原子都处在一般位置。晶体学参数为:a = 9.994(2) ,b = 5.2020(10) ,c = 13.798(3) ,β= 118.23°,Z = 4。LiVO2(IO3)2的结构是一种新型结构类型,IO3-基团把VO6八面体连接起来形成了二维无限延伸的[VO2(IO3)2]-层,Li+填充在层与层之间的空隙中来平衡电荷。其中Ce(MoO2)(OH)(IO3)4、LiMoO3(IO3)、NH4MoO3(IO3)以非心空间群结晶,是潜在的非线性光学材料。更多还原

【Abstract】 Four novel nonlinear optical (NLO) compounds have been prepared by hydrothermal reactions at 170°C,including Ce(MoO2)(OH)(IO3)4、LiMoO3(IO3)、NH4MoO3(IO3) and LiVO2(IO3)2. Single-crystal X-ray intensity data were collected on an automated Rigaku AFC7R four-circle diffractometer using monochromatized Mo Kαradiation. The crystal structures were solved by the SHELX-97 software, and physical properties of these compounds were investigated.A novel NLO compound, Ce(MoO2)(OH)(IO3)4 crystallizes in the polar space group P21 with a = 7.0144(8) , b = 14.1554(10) , c = 7.0969(6) ,β= 115.318(7)°, , Z = 2. The crystal structure of Ce(MoO2)(OH)(IO3)4 consists of a complex three-dimensional network formed by eight-coordinated Ce3+ cations, strongly distorted MoO66- octahedra, and bridging iodate anions.LiMoO3(IO3) crystallizes in the space group P21 with a = 5.4104(4) , b = 5.3158(3) , c = 9.0025(7) ,β= 106.863(6)°, Z = 2. LiMoO3(IO3) is a new layered material containing∞2 [MoO3(IO3)]- anionic layers separated by Li+ cations. DTA measurements demonstrate that LiMoO3(IO3) is stable up to at least 430oC. UV-vis diffuse reflectance spectrum of this compound shows a high degree of transparency from 1.1 to 2.8 eV and a band gap of about 2.8 eV. Second-harmonic-generation measurements on LiMoO3(IO3) display a response of about 4×KH2PO4, supporting the assignment of this structure in a noncentrosymmetric setting.NH4MoO3(IO3) crystallizes in a orthorhombic group Pna21 with a = 7.8167(6) , b = 10.2280(7) , c = 7.3466(4) , Z = 4. NH4MoO3(IO3) is isostructural with AMoO3(IO3) (A = Rb, Cs) and it has a three-dimensional (3D) framework in which strongly distorted octahedral Mo(VI) centers are connected to pyramidal IO3- groups.Li[VO2(IO3)2] crystallizes in space group P21/c, with all atoms occupying general positions, a = 9.994 (2) , b = 5.2020 (10) , c = 13.798 (3) ,β= 118.23°, Z = 4. The compound represents a new structure type in which distorted VO6更多还原