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题名	碱金属硼酸盐新化合物的合成、结构与性能研究
作者	白春燕
学位类别	博士
答辩日期	2015-05-20
授予单位	中国科学院大学
授予地点	北京
导师	潘世烈
关键词	碱金属硼酸盐 类钙钛矿 XNa6 八面体 离子盐 复合碱金属
学位专业	材料物理与化学
中文摘要	本论文主要以设计合成新型硼酸盐化合物为目标，基于碱金属硼酸盐体系，引入卤素原子、采用高温熔液法获得了一系列新化合物。这些化合物主要分为四类：三种具有类钙钛矿结构的化合物Na3B6O10Cl, RbNa2B6O10Cl 和RbNa2B6O10Br；两种具有由XNa6 (X = Cl，Br)八面体共面形成一维[Na3X]链的碱金属卤素硼酸盐化合物Na3B4O7X (X = Cl, Br)；两种复合碱金属硼酸盐化合物MNa8B21O36 (M = Rb, Cs)；其它化合物如: Mg5(BO3)3F, Rb3Na(MO4)2 (M = Mo, W)，并对这些化合物的合成、结构与物化性能进行了研究。1、将卤素与碱金属硼酸盐结合，采用高温熔液法合成了三种具有类钙钛矿结构的化合物：Na3B6O10Cl, RbNa2B6O10Cl 和RbNa2B6O10Br，并对这三种化合物的结构进行了解析。其中，Na3B6O10Cl 和RbNa2B6O10Cl 同构，结晶在非中心对称的空间群P212121 (No. 19)，而RbNa2B6O10Br 却结晶于中心对称的空间群Pnma (No. 62)。此类含Cl 硼酸盐和与之相对应的含Br 硼酸盐不同构的现象在碱金属硼酸盐中属首次报道。详细的结构分析表明这主要是由于卤素原子半径的差异使得具有柔韧性的类钙钛矿框架结构发生了变化。同时，测试了这三种化合物的红外光谱、漫反射光谱和差热/热重等性质，并对电子结构进行了计算；2、将卤素与碱金属硼酸盐结合，采用高温熔液法合成了两种具有XNa6 八面体的化合物Na3B4O7X (X = Cl, Br)，并对这两种化合物的结构进行了解析。这两种化合物同构，同属于六方晶系，点群为622，空间群是P6522 (No. 179)。它们的基本构筑基元为B4O9 基团和XNa6 八面体 (X = Cl, Br), B4O9 基团通过共用O 原子形成一个具有平行于c轴方向孔道的三维共价晶格框架，而离子链[Na3X]填隙到孔道中形成了完整的三维网状结构。它们的结构特点为包含了由XNa6 八面体共面组成的一维螺旋链[Na3X]，此类链状结构在碱金属硼酸盐中属首次报道。从另外的角度看，这两个化合物可以被看成为NaX (X = Cl, Br) 型离子盐。同时，测试了这两个化合物的红外光谱、漫反射光谱和差热/热重等性质，并对电子结构进行了计算；3、将复合碱金属与硼酸盐结合，采用高温熔液法合成了两种化合物MNa8B21O36 (M = Rb, Cs)，并对这两种化合物的结构进行了解析。这两种化合物同构，均结晶于四方晶系，空间群为I (No. 82)。晶体结构解析结果及红外光谱证实，结构中既含有BO3 又含有BO4 基团。化合物MNa8B21O36 (M = Rb, Cs)包含由B5O11 和BO4 构成的三维B-O 网络结构，阳离子填隙在B-O 网络结构的空隙中。同时测试了这两个化合物的红外光谱、漫反射光谱和差热/热重等性质。4、在前几章实验实施的过程中一些结构有趣的新化合物也被获得，如Mg5(BO3)3F， 并对其晶体结构进行了解析，该化合物结晶于正交晶系，空间群为Pnma (No. 62)，结构特征为由MgO5F 和MgO6 多面体组成的Mg-O-F 三维网络结构，孤立的BO3 基团填隙在三维网络结构的空隙中，UV-Vis-NIR 漫反射实验表明该化合物在190-2600 nm 范围内具有较好的透过性，电子结构的理论计算表明该化合物为间接带隙结构，带隙为5.27 eV；另外，获得了两种复合碱金属钼酸盐和钨酸盐Rb3Na(MO4)2 (M = Mo, W)，并解析了这两种化合物的晶体结构。这两种化合物同构，均结晶于三方晶系，空间群为Pm1 (NO.164)，这两个化合物的结构为由孤立的MO4 (M = Mo, W)四面体, Rb(1)O12, Rb(2)O10 多面体和NaO6 八面体组成的三维网络结构，同时测试了Rb3Na(MoO4)2 的红外光谱、漫反射光谱和差热/热重等性质，并对这两种化合物的电子结构进行了计算。
英文摘要	The main objective of this dissertation is to design and synthesize new borate materials. In the research, on the basis of the alkali metal borates, by introducing halogen atoms into borate, a series of crystals have been successfully synthesized by high-temperature solution method for the first time. The compounds can be divided into four types: three new perovskite-related crystals Na3B6O10Cl, RbNa2B6O10Cl and RbNa2B6O10Br; two new alkali metal borate halides Na3B4O7X (X = Cl, Br) containing 1D helical [Na3X] chains of face-sharing XNa6 octahedra; two new mixed alkali metal compounds MNa8B21O36 (M = Rb, Cs); other compounds, such as Mg5(BO3)3F, RbNa2(MO4)2 (M = Mo, W). The syntheses, crystal structures and properties of the compounds have been studied. 1、On the basis of the combination of alkali metal and halogen atoms, three new perovskite-related crystals Na3B6O10Cl, RbNa2B6O10Cl and RbNa2B6O10Br have been synthesized by high-temperature solution method for the first time. The structures have been resolved by single crystal diffraction. Na3B6O10Cl and RbNa2B6O10Cl are isostructural and crystallize in the noncentrosymmetric (NCS) space group P212121 (No. 19), while RbNa2B6O10Br belongs to the centrosymmetric (CS) space group Pnma (No. 62). The phenomenon that Cl-containing borates are not isostructural with corresponding Br-containing borates is extremely rare among borates. Detailed structure analysis suggests that the difference is owing to the effect of the halogen (Cl, Br) on the symmetry of the flexible perovskite-related framework. In addition, The infrared (IR) spectra, the UV-Vis-NIR diffuse reflectance spectra, thermal analyses and first-principles theoretical studies have also been performed on the three compounds. 2、On the basis of the combination of alkali metal borates and halogen atoms, two new sodium borate halides, Na3B4O7X (X = Cl, Br), have been successfully synthesized through high-temperature solution method for the first time. The structures have been resolved by single crystal diffraction. Single-crystal X-ray diffraction analysis reveals that both of them crystallize in the same space group P6522 (No. 179) of the hexagonal system. In their crystal structures, the fundmental building units are B4O9 groups and XNa6 (X = Cl, Br) octahedra, the B4O9 groups link with each other by oxygen-sharing to form a three dimensional (3D) framework containing channels viewing along the [001] direction, in which the one dimensional (1D) helical [Na3X] chain formed by the facesharing XNa6 octahedra resides. To the best of our knowledge, the 1D helical [Na3X] chain has not been found in other alkali metal borate halides. From another perspective, the two compounds can also be regarded as NaX salt inclusion borates. In addition, IR spectroscopy, the UV-Vis-NIR diffuse reflectance spectra, thermal analyses and first-principles theoretical studies have also been performed on the two compounds. 3、On the basis of the combination of mixed alkali metal and borates, two new mixed borate alkali borates MNa8B21O36 (M = Rb，Cs) have been successfully synthesized through high-temperature solution method for the first time. The structures have been resolved by single crystal diffraction. Single-crystal X-ray diffraction analysis reveals that both of them crystallize in the same space group (No. 82) of the tetragonal system. The IR spectra confirm the existence of the BO3 triangles and BO4 tetrahedra, which is consistent with the results obtained from the single crystal X-ray structural analyses. In their crystal structures, the B5O11 and BO4 groups link with each other by oxygen-sharing to form a 3D B-O framework, the cations filling in the space of the 3D network. In addition, IR spectroscopy, the UV-Vis-NIR diffuse reflectance spectra and thermal analyses have also been performed on the two compounds. 4、During our research, we have also found several new compounds with interesting crystal structures. A magnesium borate fluoride,
公开日期	2015-06-15
内容类型	学位论文
源URL	[http://ir.xjipc.cas.cn/handle/365002/4236]
专题	新疆理化技术研究所_材料物理与化学研究室
作者单位	中国科学院新疆理化技术研究所
推荐引用方式 GB/T 7714	白春燕. 碱金属硼酸盐新化合物的合成、结构与性能研究[D]. 北京. 中国科学院大学. 2015.

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