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词根 phot(o)，phos = light 光这二个词根phot(o),phos 分别来源于希腊语 phos和phot 意思都是“光”(词根来源于phÖt,phÖs ——英文字根字典)，由这二个词根派生出来的同源单词比较多，也是重要词根之一。
它们相应的拉丁语词根为：-lumin-，-luc- 光，分别来源于拉丁语 luminis / lux。
1.photograph [photo 光，影，graph写一记录；“把实物的影子录下来”→]n.照相，拍照，摄影；像片2.photographer [见上，-er 者]n.摄影师；摄影者3.photochrome [photo 光，影→像片,chrom 色]n.彩色照片4.photochromy [见上，-y 名词后缀]n.彩色照相术5.photochemitry [photo 光，chemistry 化学]n.光化学6.photic [phot 光，-ic...的]adj.光的；发光的7.photism [phot 光，-ism (n.) 名词后缀，表示疾病；“与光有关的病症”→]n.光幻觉8.photoprint [photo 光→影，print 印]v./n. 影印；影印画9.photogenic [photo 光，gen 产生，-ic ...的]adj.[生物]发光的；发磷光的10.photoelectric [photo 光，electric 电的]adj.光电的11.photoelectron [photo 光，electron 电子]n.光电子12.photometer [photo 光，meter 测量器 / 计；“用来测量光的仪器”→]n. 光度计13.photon [phot 光，-on (n.) 名词后缀，表示物质；“物理学中，带光字的微粒元素”→]n. ( 物理 ) 光子14.photophobia [photo 光，phobia 怕]n.畏光，羞明15.photosensitive [photo 光，sensitive 敏感的]adj.感光性的，光敏的16.photosynthesis [photo 光，synthesis 综合，合作]n.光合作用词根seism ，seismo = seism 地震词根radi-,-ray-,-rad-,-radio-词根ac,acr,acid = sour （酸的词根paleo,pale,palae = old 老17.phototube [photo 光，tube 管；“会发光的电管”→]n. 光电管光，phor 带，具有；“带光的物体”→]n. 黄磷,磷光体19.holophote [holo 全、phos 光，-e (n.) 名词后缀；“能反射全部光线的镜子”→] n. 全光反射装置,( 灯塔等的 ) 全射镜20.phototherapy [photo 光，therapy 疗法]n.光线疗法21.phototoxis [photo 光，tox 毒害]n. 光线损害；放射线损害22.photocurrent [photo 光，current 电流]n.光电流23.photoconduction [photo 光，conduct 导体，-ion 名词后缀]n.光电导专业英语词根、词缀、词源以及词汇相关知识 ！英语词源词根词缀记忆法，是最科学背单词方法！英语词根大全。
Na2TiO3晶型及其相变的高温原位拉曼光谱与X射线衍射联合研究徐磊;尤静林;王建;王敏;周灿栋【摘要】本文设计了α、β和γ三种晶型的Na2 TiO3晶体的制备方法,采用固相烧结技术成功制备了该晶体的上述三种晶型,并对其常温拉曼光谱进行了比较研究.对其中已知晶型结构的γ-Na2 TiO3的拉曼光谱进行密度泛函理论的模拟计算,基于计算对其拉曼光谱高频区主要振动模式进行归属.运用高温原位拉曼光谱技术和X射线衍射技术对无序型亚稳态α-Na2 TiO3晶体升温过程的相变及其结构变化进行了原位追踪与研究,为不同晶型的Na2 TiO3晶体的温致结构演变及晶型的鉴定提供重要的实验依据.【期刊名称】《光散射学报》【年(卷),期】2018(030)002【总页数】7页(P126-132)【关键词】Na2TiO3晶体;晶型转变;高温原位拉曼光谱;高温原位X射线衍射【作者】徐磊;尤静林;王建;王敏;周灿栋【作者单位】省部共建高品质特殊钢冶金与制备国家重点实验室、上海市钢铁冶金新技术开发应用重点实验室和上海大学材料科学与工程学院,上海200072;省部共建高品质特殊钢冶金与制备国家重点实验室、上海市钢铁冶金新技术开发应用重点实验室和上海大学材料科学与工程学院,上海200072;省部共建高品质特殊钢冶金与制备国家重点实验室、上海市钢铁冶金新技术开发应用重点实验室和上海大学材料科学与工程学院,上海200072;省部共建高品质特殊钢冶金与制备国家重点实验室、上海市钢铁冶金新技术开发应用重点实验室和上海大学材料科学与工程学院,上海200072;宝山钢铁股份有限公司,上海201900【正文语种】中文【中图分类】O7921 引言碱金属钛酸盐作为一种基础的离子交换材料,被广泛应用于热稳定陶瓷电容器;此外,在微波介质谐振器、增强型塑料、绝热材料以及电位传感器等领域也有重要应用[1-2];碱金属钛酸盐也是n型半导体材料,具有良好的光催化活性[3-4]。
前沿讲座 Seminar专业英语 Professional English现代分析化学 Modern analytical che mistry生物分析技术 Bioanalytical techniques高分子进展 Advances in polymers功能高分子进展 Advances in function al polymers有机硅高分子研究进展 Progresses in organosilicon polymers高分子科学实验方法 Scientific experimental methods of polymers 高分子设计与合成 The design and sy nthesis of polymers反应性高分子专论 Instructions to re active polymers网络化学与化工信息检索 Internet Se arching for Chemistry & Chemical E ngineeringinformation有序分子组合体概论 Introduction to Organized Molecular Assembilies两亲分子聚集体化学 Chemistry of am phiphilic aggregates表面活性剂体系研究新方法 New Meth od for studying Surfactant System 微纳米材料化学 Chemistry of Micro-NanoMaterials分散体系研究新方法 New Method for studying dispersion分散体系相行为 The Phase Behavior of Aqueous Dispersions 溶液-凝胶材料 Sol-Gel Materials高等量子化学 Advanced Quantum Chemistry分子反应动力学 Molecular Reaction Dynamic计算量子化学 Computational QuantumChemistry群论 Group Theory分子模拟理论及软件应用 Theory andSoftware of Molecular Modelling &Application价键理论方法 Valence Bond Theory量子化学软件及其应用Software of Quantum 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Supramolecular Chemistry分子设计与组合化学 Molecular Designand Combinatorial Chemistry纳米材料化学前沿领域导论 Introduction to Nano-materials Chemistry纳米材料控制合成与自组装 Controlled-synthesis and Self-assembly of Nan o-materials前沿讲座 Leading Front Forum专业英语 Professional English超分子化学基础 Basics of Supramolec ular Chemistry液晶材料基础 Basics of Liquid Crysta l Materials现代实验技术 Modern analytical testi ng techniques色谱及联用技术 Chromatography and Technology of tandem发光分析及其研究法 Luminescence an alysis and Research methods胶束酶学 Micellar Enzymology分析化学中的配位化合物 Complex in Analytical Chemistry电分析化学 Electroanalytical chemist ry生物分析化学 Bioanalytical chemistry分析化学 Analytical chemistry仪器分析 Instrument analysis高分子合成化学 Polymers synthetic c hemistry高聚物结构与性能 Structures and pr operties of polymers有机硅化学 Organosilicon chemistry 功能高分子Functional polymers有机硅高分子 Organosilicon polymers 高分子现代实验技术 Advanced experimental technology of polymers高分子合成新方法 New synthetic methods of polymers液晶与液晶高分子 Liquid crystals andliquid crystal polymers大分子反应 Macromolecules 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Calculation ofProcess Devices石油化工典型设备 Common Equipmentof Petrochemical Industry化工流态化工程 Fluidization in Chemical Industry化工装置模拟与优化 Analogue and Optimization of Chemical Devices化工分离工程 Separation Engineering化工系统与优化 Chemical System andOptimization高等化工热力学 Advanced Chemical Engineering and Thermodynamics超临界流体技术及应用 Super CraticalLiguid Technegues and Applications膜分离技术 Membrane Separation T echnegues溶剂萃取原理和应用 Theory and Appli cation of Solvent Extraction树脂吸附理论 Theory of Resin Adso rption中药材化学 Chemistry of Chinese Me dicine生物资源有效成分分析与鉴定 Analysis and Detection of Bio-materials相平衡理论与应用 Theory and Applic ation of Phase Equilibrium计算机在化学工程中的应用 Application of Computer in Chemical Engineerin g微乳液和高分子溶液 Micro-emulsion a nd High Molecular Solution传递过程 Transmision Process反应工程分析 Reaction Engineering A nalysis腐蚀电化学原理与应用 Principle and A pplication of Corrosion Electrochem istry腐蚀电化学测试方法与应用 Measureme nt Method and Application of Corro sion Electrochemistry耐蚀表面工程 Surface Techniques of Anti-corrosion缓蚀剂技术 Inhabitor Techniques 腐蚀失效分析 Analysis of Corrosion Destroy材料表面研究方法 Method of Studyin g Material Surfacc分离与纯化技术 Separation and Purification Technology现代精细有机合成 Modern Fine Organic Synthesis化学工艺与设备 Chemical Technologyand Apparatuas功能材料概论 Functional Materials Conspectus油田化学 Oilfield Chemistry精细化学品研究 Study of Fine Chemicals催化剂合成与应用 Synthesis and Application of Catalyzer低维材料制备 Preparation of Low-Dimension Materials手性药物化学 Symmetrical Pharmaceutical Chemistry光敏高分子材料化学 Photosensitive Polymer Materials Chemistry纳米材料制备与表征 Preparation andCharacterization of Nanostructuredmaterials溶胶凝胶化学 Sol-gel Chemistry纳米材料化学进展 Proceeding of Nano-materials Chemistry●化学常用词汇汉英对照表1●氨ammonia氨基酸amino acid铵盐ammonium salt饱和链烃saturated aliphatichydrocarbon苯benzene变性denaturation不饱和烃unsaturatedhydrocarbon超导材料superconductivematerial臭氧ozone醇alcohol次氯酸钾potassiumhypochlorite醋酸钠sodium acetate蛋白质protein氮族元素nitrogen groupelement碘化钾potassium iodide碘化钠sodium iodide电化学腐蚀electrochemicalcorrosion电解质electrolyte电离平衡ionizationequilibrium电子云electron cloud淀粉starch淀粉碘化钾试纸starchpotassium iodide paper二氧化氮nitrogen dioxide二氧化硅silicon dioxide二氧化硫sulphur dioxide二氧化锰manganese dioxide芳香烃arene放热反应exothermic reaction非极性分子non-polar molecule非极性键non-polar bond肥皂soap分馏fractional distillation酚phenol复合材料composite干电池dry cell干馏dry distillation甘油glycerol高分子化合物polymer共价键covalent bond官能团functional group光化学烟雾photochemical fog过氧化氢hydrogen peroxide合成材料synthetic material合成纤维synthetic fiber合成橡胶synthetic rubber核电荷数nuclear charge number核素nuclide化学电源chemical powersource化学反应速率chemical reactionrate化学键chemical bond化学平衡chemical equilibrium 还原剂reducing agent磺化反应sulfonation reaction 霍尔槽 Hull Cell极性分子polar molecule极性键polar bond加成反应addition reaction加聚反应addition polymerization甲烷methane碱金属alkali metal碱石灰soda lime结构式structural formula聚合反应po1ymerization可逆反应reversible reaction空气污染指数air pollution index勒夏特列原理Le Chatelier's principle离子反应ionic reaction离子方程式ionic equation离子键ionic bond锂电池lithium cell两性氢氧化物amphoteric hydroxide两性氧化物amphoteric oxide裂化cracking裂解pyrolysis硫氰化钾potassium thiocyanate硫酸钠sodium sulphide氯化铵ammonium chloride氯化钡barium chloride氯化钾potassium chloride氯化铝aluminium chloride氯化镁magnesium chloride氯化氢hydrogen chloride氯化铁iron (III) chloride氯水chlorine water麦芽糖maltose煤coal酶enzyme摩尔mole摩尔质量molar mass品红magenta或fuchsine葡萄糖glucose气体摩尔体积molar volume of gas铅蓄电池lead storage battery强电解质strong electrolyte氢氟酸hydrogen chloride氢氧化铝aluminium hydroxide取代反应substitutionreaction醛aldehyde炔烃alkyne燃料电池fuel cell弱电解质weak electrolyte石油Petroleum水解反应hydrolysis reaction四氯化碳carbontetrachloride塑料plastic塑料的降解plasticdegradation塑料的老化plastic ageing酸碱中和滴定acid-baseneutralization titration酸雨acid rain羧酸carboxylic acid碳酸钠 sodium carbonate碳酸氢铵 ammonium bicarbonate碳酸氢钠 sodium bicarbonate糖类 carbohydrate烃 hydrocarbon烃的衍生物 derivative ofhydrocarbon烃基 hydrocarbonyl同分异构体 isomer同素异形体 allotrope同位素 isotope同系物 homo1og涂料 coating烷烃 alkane物质的量amount of substance物质的量浓度 amount-of-substanceconcentration of B烯烃 alkene洗涤剂 detergent纤维素 cellulose相对分子质量 relative molecularmass相对原子质量relative atomic mass消去反应 elimination reaction硝化反应 nitratlon reaction硝酸钡 barium nitrate硝酸银silver nitrate溴的四氯化碳溶液 solution ofbromine in carbon tetrachloride溴化钠 sodium bromide溴水bromine water溴水 bromine water盐类的水解hydrolysis of salts盐析salting-out焰色反应 flame test氧化剂oxidizing agent氧化铝 aluminium oxide氧化铁iron (III) oxide乙醇ethanol乙醛 ethana1乙炔 ethyne乙酸ethanoic acid乙酸乙酯 ethyl acetate乙烯ethene银镜反应silver mirror reaction硬脂酸stearic acid油脂oils and fats有机化合物 organic compound元素周期表 periodic table ofelements元素周期律 periodic law ofelements原电池 primary battery原子序数 atomic number皂化反应 saponification粘合剂 adhesive蔗糖 sucrose指示剂 Indicator酯 ester酯化反应 esterification周期period族group（主族：main group）Bunsen burner 本生灯product 化学反应产物flask 烧瓶apparatus 设备PH indicator PH值指示剂,氢离子(浓度的)负指数指示剂matrass 卵形瓶litmus 石蕊litmus paper 石蕊试纸graduate, graduated flask 量筒,量杯reagent 试剂test tube 试管burette 滴定管retort 曲颈甑still 蒸馏釜cupel 烤钵crucible pot, melting pot 坩埚pipette 吸液管filter 滤管stirring rod 搅拌棒element 元素body 物体compound 化合物atom 原子gram atom 克原子atomic weight 原子量atomic number 原子数atomic mass 原子质量molecule 分子electrolyte 电解质ion 离子anion 阴离子cation 阳离子electron 电子isotope 同位素isomer 同分异物现象polymer 聚合物symbol 复合radical 基structural formula 分子式valence, valency 价monovalent 单价bivalent 二价halogen 成盐元素bond 原子的聚合mixture 混合combination 合成作用compound 合成物alloy 合金organic chemistry 有机化学inorganic chemistry 无机化学derivative 衍生物series 系列acid 酸hydrochloric acid 盐酸sulphuric acid 硫酸nitric acid 硝酸aqua fortis 王水fatty acid 脂肪酸organic acid 有机酸 hydrosulphuric acid 氢硫酸hydrogen sulfide 氢化硫alkali 碱,强碱ammonia 氨base 碱hydrate 水合物hydroxide 氢氧化物,羟化物hydracid 氢酸hydrocarbon 碳氢化合物,羟anhydride 酐alkaloid 生物碱aldehyde 醛oxide 氧化物phosphate 磷酸盐acetate 醋酸盐methane 甲烷,沼气butane 丁烷salt 盐potassium carbonate 碳酸钾soda 苏打sodium carbonate 碳酸钠caustic potash 苛性钾caustic soda 苛性钠ester 酯gel 凝胶体analysis 分解fractionation 分馏endothermic reaction 吸热反应exothermic reaction 放热反应precipitation 沉淀to precipitate 沉淀to distil, to distill 蒸馏distillation 蒸馏to calcine 煅烧to oxidize 氧化alkalinization 碱化to oxygenate, to oxidize 脱氧,氧化to neutralize 中和to hydrogenate 氢化to hydrate 水合,水化to dehydrate 脱水fermentation 发酵solution 溶解combustion 燃烧fusion, melting 熔解alkalinity 碱性isomerism, isomery 同分异物现象hydrolysis 水解electrolysis 电解electrode 电极anode 阳极,正极cathode 阴极,负极catalyst 催化剂catalysis 催化作用oxidization, oxidation 氧化reducer 还原剂dissolution 分解synthesis 合成reversible 可逆的1. The Ideal-Gas Equation 理想气体状态方程2. Partial Pressures 分压3. Real Gases: Deviation from IdealBehavior 真实气体：对理想气体行为的偏离4. The van der Waals Equation 范德华方程5. System and Surroundings 系统与环境6. State and State Functions 状态与状态函数7. Process 过程8. Phase 相9. The First Law of Thermodynamics热力学第一定律10. Heat and Work 热与功11. Endothermic and ExothermicProcesses 吸热与发热过程12. Enthalpies of Reactions 反应热13. Hess’s Law 盖斯定律14. Enthalpies of Formation 生成焓15. Reaction Rates 反应速率16. Reaction Order 反应级数17. Rate Constants 速率常数18. Activation Energy 活化能19. The Arrhenius Equation 阿累尼乌斯方程20. Reaction Mechanisms 反应机理21. Homogeneous Catalysis 均相催化剂22. Heterogeneous Catalysis 非均相催化剂23. Enzymes 酶24. The Equilibrium Constant 平衡常数25. the Direction of Reaction 反应方向26. Le Chatelier’s Principle 列·沙特列原理27. Effects of Volume, Pressure, Temperature Changes and Catalysts i. 体积，压力，温度变化以及催化剂的影响28. Spontaneous Processes 自发过程29. Entropy (Standard Entropy) 熵（标准熵）30. The Second Law of Thermodynamics 热力学第二定律31. Entropy Changes 熵变32. Standard Free-Energy Changes 标准自由能变33. Acid-Bases 酸碱34. The Dissociation of Water 水离解35. The Proton in Water 水合质子36. The pH Scales pH值37. Bronsted-Lowry Acids and Bases Bronsted-Lowry 酸和碱38. Proton-Transfer Reactions 质子转移反应39. Conjugate Acid-Base Pairs 共轭酸碱对40. Relative Strength of Acids and Bases 酸碱的相对强度41. Lewis Acids and Bases 路易斯酸碱42. Hydrolysis of Metal Ions 金属离子的水解43. Buffer Solutions 缓冲溶液44. The Common-Ion Effects 同离子效应45. Buffer Capacity 缓冲容量46. Formation of Complex Ions 配离子的形成47. Solubility 溶解度48. The Solubility-Product ConstantKsp 溶度积常数49. Precipitation and separation ofIons 离子的沉淀与分离50. Selective Precipitation of Ions 离子的选择沉淀51. Oxidation-Reduction Reactions 氧化还原反应52. Oxidation Number 氧化数53. Balancing Oxidation-ReductionEquations 氧化还原反应方程的配平54. Half-Reaction 半反应55. Galvani Cell 原电池56. Voltaic Cell 伏特电池57. Cell EMF 电池电动势58. Standard Electrode Potentials 标准电极电势59. Oxidizing and Reducing Agents 氧化剂和还原剂60. The Nernst Equation 能斯特方程61. Electrolysis 电解62. The Wave Behavior of Electrons电子的波动性63. Bohr’s Model of The HydrogenAtom 氢原子的波尔模型64. Line Spectra 线光谱65. Quantum Numbers 量子数66. Electron Spin 电子自旋67. Atomic Orbital 原子轨道68. The s (p, d, f) Orbital s（p，d，f）轨道69. Many-Electron Atoms 多电子原子70. Energies of Orbital 轨道能量71. The Pauli Exclusion Principle 泡林不相容原理72. Electron Configurations 电子构型73. The Periodic Table 周期表74. Row 行75. Group 族76. Isotopes, Atomic Numbers, andMass Numbers 同位素，原子数，质量数77. Periodic Properties of theElements 元素的周期律78. Radius of Atoms 原子半径79. Ionization Energy 电离能80. Electronegativity 电负性81. Effective Nuclear Charge 有效核电荷82. Electron Affinities 亲电性83. Metals 金属84. Nonmetals 非金属85. Valence Bond Theory 价键理论86. Covalence Bond 共价键87. Orbital Overlap 轨道重叠88. Multiple Bonds 重键89. Hybrid Orbital 杂化轨道90. The VSEPR Model 价层电子对互斥理论91. Molecular Geometries 分子空间构型92. Molecular Orbital 分子轨道93. Diatomic Molecules 双原子分子94. Bond Length 键长95. Bond Order 键级96. Bond Angles 键角97. Bond Enthalpies 键能98. Bond Polarity 键矩99. Dipole Moments 偶极矩100. Polarity Molecules 极性分子101. Polyatomic Molecules 多原子分子102. Crystal Structure 晶体结构103. Non-Crystal 非晶体104. Close Packing of Spheres 球密堆积105. Metallic Solids 金属晶体106. Metallic Bond 金属键107. Alloys 合金108. Ionic Solids 离子晶体109. Ion-Dipole Forces 离子偶极力110. Molecular Forces 分子间力111. Intermolecular Forces 分子间作用力112. Hydrogen Bonding 氢键113. Covalent-Network Solids 原子晶体114. Compounds 化合物115. The Nomenclature, Composition and Structure of Complexes 配合物的命名，组成和结构116. Charges, Coordination Numbers,and Geometries 电荷数、配位数、及几何构型117. Chelates 螯合物118. Isomerism 异构现象119. Structural Isomerism 结构异构120. Stereoisomerism 立体异构121. Magnetism 磁性122. Electron Configurations inOctahedral Complexes 八面体构型配合物的电子分布123. Tetrahedral and Square-planarComplexes 四面体和平面四边形配合物124. General Characteristics 共性125. s-Block Elements s区元素126. Alkali Metals 碱金属127. Alkaline Earth Metals 碱土金属128. Hydrides 氢化物129. Oxides 氧化物130. Peroxides and Superoxides 过氧化物和超氧化物131. Hydroxides 氢氧化物132. Salts 盐133. p-Block Elements p区元素134. Boron Group (Boron, Aluminium,Gallium, Indium, Thallium) 硼族（硼，铝，镓，铟，铊）135. Borane 硼烷136. Carbon Group (Carbon, Silicon,Germanium, Tin, Lead) 碳族（碳，硅，锗，锡，铅）137. Graphite, Carbon Monoxide,Carbon Dioxide 石墨，一氧化碳，二氧化碳138. Carbonic Acid, Carbonates andCarbides 碳酸，碳酸盐，碳化物139. Occurrence and Preparation ofSilicon 硅的存在和制备140. Silicic Acid，Silicates 硅酸，硅酸盐141. Nitrogen Group (Phosphorus,Arsenic, Antimony, and Bismuth) 氮族（磷，砷，锑，铋）142. Ammonia, Nitric Acid, PhosphoricAcid 氨，硝酸，磷酸143. Phosphorates, phosphorusHalides 磷酸盐，卤化磷144. Oxygen Group (Oxygen, Sulfur,Selenium, and Tellurium) 氧族元素（氧，硫，硒，碲）145. Ozone, Hydrogen Peroxide 臭氧，过氧化氢146. Sulfides 硫化物147. Halogens (Fluorine, Chlorine,Bromine, Iodine) 卤素（氟，氯，溴，碘）148. Halides, Chloride 卤化物，氯化物149. The Noble Gases 稀有气体150. Noble-Gas Compounds 稀有气体化合物151. d-Block elements d区元素152. Transition Metals 过渡金属153. Potassium Dichromate 重铬酸钾154. Potassium Permanganate 高锰酸钾155. Iron Copper Zinc Mercury 铁，铜，锌，汞156. f-Block Elements f区元素157. Lanthanides 镧系元素158. Radioactivity 放射性159. Nuclear Chemistry 核化学160. Nuclear Fission 核裂变161. Nuclear Fusion 核聚变162. analytical chemistry 分析化学163. qualitative analysis 定性分析164. quantitative analysis 定量分析165. chemical analysis 化学分析166. instrumental analysis 仪器分析167. titrimetry 滴定分析168. gravimetric analysis 重量分析法169. regent 试剂170. chromatographic analysis 色谱分析171. product 产物172. electrochemical analysis 电化学分析173. on-line analysis 在线分析174. macro analysis 常量分析175. characteristic 表征176. micro analysis 微量分析177. deformation analysis 形态分析178. semimicro analysis 半微量分析179. systematical error 系统误差180. routine analysis 常规分析181. random error 偶然误差182. arbitration analysis 仲裁分析183. gross error 过失误差184. normal distribution 正态分布185. accuracy 准确度186. deviation 偏差187. precision精密度188. relative standard deviation相对标准偏差（RSD）189. coefficient variation变异系数（CV）190. confidence level置信水平191. confidence interval置信区间192. significant test显著性检验193. significant figure有效数字194. standard solution标准溶液195. titration滴定196. stoichiometric point化学计量点197. end point滴定终点198. titration error滴定误差199. primary standard基准物质200. amount of substance物质的量201. standardization标定202. chemical reaction化学反应203. concentration浓度204. chemical equilibrium化学平衡205. titer滴定度206. general equation for a chemicalreaction化学反应的通式207. proton theory of acid-base酸碱质子理论208. acid-base titration酸碱滴定法209. dissociation constant解离常数210. conjugate acid-base pair共轭酸碱对211. acetic acid乙酸212. hydronium ion水合氢离子213. electrolyte电解质214. ion-product constant of water水的离子积215. ionization电离216. proton condition质子平衡217. zero level零水准218. buffer solution缓冲溶液219. methyl orange甲基橙220. acid-base indicator酸碱指示剂221. phenolphthalein酚酞222. coordination compound配位化合物223. center ion中心离子224. cumulative stability constant累积稳定常数225. alpha coefficient酸效应系数226. overall stability constant总稳定常数227. ligand配位体228. ethylenediamine tetraacetic acid 乙二胺四乙酸229. side reaction coefficient副反应系数230. coordination atom配位原子231. coordination number配位数232. lone pair electron孤对电子233. chelate compound螯合物234. metal indicator金属指示剂235. chelating agent螯合剂236. masking 掩蔽237. demasking解蔽238. electron电子239. catalysis催化240. oxidation氧化241. catalyst催化剂242. reduction还原243. catalytic reaction催化反应244. reaction rate反应速率245. electrode potential电极电势246. activation energy 反应的活化能247. redox couple 氧化还原电对248. potassium permanganate 高锰酸钾249. iodimetry碘量法250. potassium dichromate 重铬酸钾251. cerimetry 铈量法252. redox indicator 氧化还原指示253. oxygen consuming 耗氧量（OC）254. chemical oxygen demanded 化学需氧量(COD)255. dissolved oxygen 溶解氧(DO)256. precipitation 沉淀反应257. argentimetry 银量法258. heterogeneous equilibrium of ions多相离子平衡259. aging 陈化260. postprecipitation 继沉淀261. coprecipitation 共沉淀262. ignition 灼烧263. fitration 过滤264. decantation 倾泻法265. chemical factor 化学因数266. spectrophotometry 分光光度法267. colorimetry 比色分析268. transmittance 透光率269. absorptivity 吸光率270. calibration curve 校正曲线271. standard curve 标准曲线272. monochromator 单色器273. source 光源274. wavelength dispersion 色散275. absorption cell吸收池276. detector 检测系统277. bathochromic shift 红移278. Molar absorptivity 摩尔吸光系数279. hypochromic shift 紫移280. acetylene 乙炔281. ethylene 乙烯282. acetylating agent 乙酰化剂283. acetic acid 乙酸284. adiethyl ether 乙醚285. ethyl alcohol 乙醇286. acetaldehtde 乙醛287. β-dicarbontl compound β–二羰基化合物288. bimolecular elimination 双分子消除反应289. bimolecular nucleophilic substitution 双分子亲核取代反应290. open chain compound 开链族化合物291. molecular orbital theory 分子轨道理论292. chiral molecule 手性分子293. tautomerism 互变异构现象294. reaction mechanism 反应历程295. chemical shift 化学位移296. Walden inversio 瓦尔登反转n 297. Enantiomorph 对映体298. addition rea ction 加成反应299. dextro- 右旋300. levo- 左旋301. stereochemistry 立体化学302. stereo isomer 立体异构体303. Lucas reagent 卢卡斯试剂304. covalent bond 共价键305. conjugated diene 共轭二烯烃306. conjugated double bond 共轭双键307. conjugated system 共轭体系308. conjugated effect 共轭效应309. isomer 同分异构体310. isomerism 同分异构现象311. organic chemistry 有机化学312. hybridization 杂化313. hybrid orbital 杂化轨道314. heterocyclic compound 杂环化合物315. peroxide effect 过氧化物效应t316. valence bond theory 价键理论317. sequence rule 次序规则318. electron-attracting grou p 吸电子基319. Huckel rule 休克尔规则320. Hinsberg test 兴斯堡试验321. infrared spectrum 红外光谱322. Michael reacton 麦克尔反应323. halogenated hydrocarbon 卤代烃324. haloform reaction 卤仿反应325. systematic nomenclatur 系统命名法e326. Newman projection 纽曼投影式327. aromatic compound 芳香族化合物328. aromatic character 芳香性r329. Claisen condensation reaction克莱森酯缩合反应330. Claisen rearrangement 克莱森重排331. Diels-Alder reation 狄尔斯-阿尔得反应332. Clemmensen reduction 克莱门森还原333. Cannizzaro reaction 坎尼扎罗反应334. positional isomers 位置异构体335. unimolecular elimination reaction单分子消除反应336. unimolecular nucleophilicsubstitution 单分子亲核取代反应337. benzene 苯338. functional grou 官能团p339. configuration 构型340. conformation 构象341. confomational isome 构象异构体342. electrophilic addition 亲电加成343. electrophilic reagent 亲电试剂344. nucleophilic addition 亲核加成345. nucleophilic reagent 亲核试剂346. nucleophilic substitution reaction亲核取代反应347. active intermediate 活性中间体348. Saytzeff rule 查依采夫规则349. cis-trans isomerism 顺反异构350. inductive effect 诱导效应 t351. Fehling’s reagent 费林试剂352. phase transfer catalysis 相转移催化作用353. aliphatic compound 脂肪族化合物354. elimination reaction 消除反应355. Grignard reagent 格利雅试剂 356. nuclear magnetic resonance 核磁共振357. alkene 烯烃358. allyl cation 烯丙基正离子359. leaving group 离去基团360. optical activity 旋光性361. boat confomation 船型构象 362. silver mirror reaction 银镜反应363. Fischer projection 菲舍尔投影式 364. Kekule structure 凯库勒结构式365. Friedel-Crafts reaction 傅列德尔-克拉夫茨反应366. Ketone 酮367. carboxylic acid 羧酸368. carboxylic acid derivative 羧酸衍生物369. hydroboration 硼氢化反应 370. bond oength 键长371. bond energy 键能372. bond angle 键角373. carbohydrate 碳水化合物374. carbocation 碳正离子375. carbanion 碳负离子376. alcohol 醇377. Gofmann rule 霍夫曼规则 378. Aldehyde 醛379. Ether 醚380. Polymer 聚合物ace- 乙（酰基）acet- 醋；醋酸；乙酸acetamido- 乙酰胺基acetenyl- 乙炔基acetoxy- 醋酸基；乙酰氧基acetyl- 乙酰（基）aetio- 初allo- 别allyl- 烯丙（基）；CH2=CH-CH2-amido- 酰胺（基）amino- 氨基amyl- ①淀粉②戊（基）amylo- 淀粉andr- 雄andro- 雄anilino- 苯胺基anisoyl- 茴香酰；甲氧苯酰anti- 抗apo- 阿朴；去水aryl- 芳（香）基aspartyl- 门冬氨酰auri- 金（基）；（三价）金基aza- 氮（杂）azido- 叠氮azo- 偶氮basi- 碱baso- 碱benxoyl- 苯酰；苯甲酰benzyl- 苄（基）；苯甲酰bi- 二；双；重biphenyl- 联苯基biphenylyl- 联苯基bis- 双；二bor- 硼boro- 硼bromo- 溴butenyl- 丁烯基（有1、2、3位三种）butoxyl- 丁氧基butyl- 丁基butyryl- 丁酰caprinoyl- 癸酰caproyl- 己酰calc- 钙calci- 钙calco- 钙capryl- 癸酰capryloyl- 辛酰caprylyl- 辛酰cef- 头孢（头孢菌素族抗生素词首）chlor- ①氯②绿chloro- ①氯②绿ciclo- 环cis- 顺clo- 氯crypto- 隐cycl- 环cyclo- 环de- 去；脱dec- 十；癸deca- 十；癸dehydro- 去氢；去水demethoxy- 去甲氧（基）demethyl- 去甲（基）deoxy- 去氧des- 去；脱desmethyl- 去甲（基）desoxy- 去氧dex- 右旋dextro- 右旋di- 二diamino- 二氨基diazo- 重氮dihydro- 二氢；双氢endo- 桥epi- 表；差向epoxy- 环氧erythro- 红；赤estr- 雌ethinyl- 乙炔（基）ethoxyl- 乙氧（基）ethyl- 乙基etio- 初eu- 优fluor- ①氟②荧光fluoro- ①氟②荧光formyl- 甲酰（基）guanyl- 脒基hepta- 七；庚hetero- 杂hexa- 六；己homo- 高(比原化合物多一个-CH2-)hypo- 次io- 碘indo- 碘iso- 异keto- 酮laevo- 左旋leuco- 白levo- 左旋。
拉曼光谱测量钙钛矿电声耦合强度1.拉曼光谱是一种用于分析晶体材料结构和性质的强大技术。
Raman spectroscopy is a powerful technique for analyzing the structure and properties of crystalline materials.2.钙钛矿是一类具有重要电声耦合特性的材料。
Perovskite is a type of material with important electroacoustic coupling properties.3.通过拉曼光谱，可以了解钙钛矿中电声耦合的强度和机制。
Raman spectroscopy can be used to understand the strength and mechanism of electroacoustic coupling in perovskite.4.钙钛矿的电声耦合特性对于光伏和光电器件的性能至关重要。
The electroacoustic coupling properties of perovskite are crucial for the performance of photovoltaic and optoelectronic devices.5.拉曼光谱可以提供关于晶体结构、相变和电子结构的丰富信息。
Raman spectroscopy can provide rich information about crystal structure, phase transitions, and electronic structure.6.钙钛矿材料的电声耦合性质直接影响着其光电器件的效率和稳定性。
The electroacoustic coupling properties of perovskite materials directly affect the efficiency and stability oftheir optoelectronic devices.7.拉曼光谱测量可以帮助科学家们深入了解钙钛矿材料的微观特性。
第21卷第4期化学研究中国科技核心期刊2010年7月CH EMICAL R ESEARCH hxyj@三核铁簇硫酸盐K2(H3O)3[Fe3(H2O)3O(SO4)6]#6H2O的合成与晶体结构陈利娟,史岽瑛,王玉龙,马鹏涛,赵俊伟*(河南大学化学化工学院分子与晶体工程研究所,河南开封475004)摘要:在室温条件下合成了含三核铁簇的硫酸盐配合物K2(H3O)3[Fe3(H2O)3O(SO4)6]#6H2O,借助IR光谱、紫外2可见吸收光谱、X射线光电子能谱(XP S)和X射线单晶衍射等测试手段对其结构进行了表征.结果表明,标题化合物属于六方晶系,P6(3)/m空间群,晶胞参数为:a=b=0.9637(2)nm,c= 1.8851(9)nm,V= 1.5163(9)nm3,Z=2,D c= 2.316g/cm3,GOOF= 1.089,R1=0.0628,wR2=0.1651.其分子由1个三核铁簇阴离子[F e3(H2O)3O(SO4)6]5-、2个K+离子、3个水合质子H3O+和6个结晶水分子组成.关键词:硫酸盐;铁簇;配合物;合成;结构表征中图分类号:O614.61文献标识码:A文章编号:1008-1011(2010)04-0001-05 Synthesis and Crystal Structure of Sulfate CoordinationCompound K2(H3O)3[Fe3(H2O)3O(SO4)6]#6H2OCH EN Li2juan,SH I Dong2ying,WANG Yu2long,MA Peng2tao,ZH AO Jun2wei*(Institute of Molecular an d Cry stal E ngineer in g,College of Ch emistry and Chemical E ngineer ing,H enan Univer s ity,K aif eng475004,H enan,China)Abstract:A sulfate K2(H3O)3[Fe3(H2O)3O(SO4)6]#6H2O containing one trinuclear ir on clus2ter was successfully synthesized at room temperature.Its structure was char acterized by meansof infrared spectrometry,ultraviolet2visible light spectrophotometry,X2ray photoelectr on spec2tr oscopy(XPS)and single2cr ystal X2ray diffraction.Results indicate that the title compoundcr ystallizes in hexagonal space gr oup P6(3)/m,with cell par ameters being a=b=0.9637(2)nm,c= 1.8851(9)nm,V= 1.5163(9)nm3,Z=2,D c= 2.316g/cm3,GOOF=1.089,R1=0.0628,a nd wR2=0.1651.It consists of1trinuclear iron cluster anion[Fe3(H2O)3O(SO4)6]5-,2K+cations,3hydrated protons H3O+and6lattice water mole2cules.Keywords:sulfate;iron cluster;coor dination compound;synthesis;structur al characterization过渡金属硫酸盐是开放式框架材料领域的一个重要研究分支,因其化学组成和结构的多样性以及独特的光学、电学和磁学性质,使这类化合物在催化技术、分离技术、离子交换、气体吸附、医药和农药等领域存在重要的应用[1-4].迄今为止,已有很多过渡金属硫酸盐被人们合成出来,但大部分的研究工作主要集中在有机2无机复合的金属硫酸盐上[5-10],印度的Rao课题组在这方面做了大量的研究工作.如Rao课题组在2002年借助有机模板方法首次合成了一系列开放框架结构的硫酸镉[H3N(CH2)2NH3]2[CdCl2(SO4)] [SO4]#H2O,[H3N(CH2)3NH3][Cd2(H2O)2(SO4)3],[H3N(CH2)6NH3][CdCl2(SO4)]和[H3N(CH2)6 NH3][CdBr2(SO4)][5].2004年,他们报道了两例以哌嗪作为结构导向剂的开放框架的硫酸镍[C4N2H12]收稿日期:2010-03-29.基金项目:河南省基础与前沿技术研究计划项目(092300410119)和河南大学自然科学基金资助项目(2008YBZR010).作者简介:陈利娟(1977-),女,博士,主要从事分子基功能材料研究.*通讯联系人,E2m ail:zh aojunwei@.2化学研究2010年[Ni3F2(SO4)3(H2O)2]和[C4N2H12][Ni2F4(SO4)H2O],并对其磁性进行了详细的研究[6].同年,他们又在水热条件下合成了一系列三维或层状结构的稀土硫酸盐[Nd2(SO4)4(H2O)2][C4N2H12],[Ln2(H2O)2 (SO4)5][C2N2H10]2(Ln=LaÓ,PrÓ,NdÓ),[La2(SO4)4][C3N2H12],[Ln2(SO4)4(H2O)4][C6N2H14]2 [C2N2H8][SO4][H2O]3(Ln=LaÓ,PrÓ,NdÓ)和[Ln2(SO4)4][C2N2H10](Ln=LaÓ,NdÓ)[7].然而,关于纯无机的硫酸盐的报道却非常稀少[11-12].Casey等在2005年报道了一例羟基桥连的硫酸铝[A l8 (OH)14(H2O)18](SO4)5#16H2O[11].2007年,Genceli等人在低温条件下得到了硫酸镁MgSO4#11H2O[12].作者报道一例包含三核铁簇的硫酸盐K2(H3O)3[Fe3(H2O)3O(SO4)6]#6H2O(CSD:421600),并借助IR 光谱、紫外2可见吸收光谱、XPS和X射线单晶衍射等测试手段对其结构进行了表征.1实验部分1.1仪器与试剂Nicolet AVAT AR360型傅里叶红外光谱仪,KBr压片,测定范围4000~400cm-1;H itachi U24100型紫外2可见分光光度计,测定范围800~190nm;Axis U ltra型X射线光电子能谱仪.K8[C2GeW10O36]# 6H2O根据文献[13]方法合成.其余试剂均为分析纯.1.2化合物的合成将K8[C2GeW10O36]#6H2O(1.483g,0.510mmol)溶于5mL蒸馏水中,搅拌下加入Fe2(SO4)3 (2.009g, 5.024mmol)固体,继续搅拌1.5h后,过滤,室温条件下将滤液静置挥发,45d左右得到黄褐色六棱柱状晶体,产率30%.实验结果表明,K8[C2GeW10O36]#6H2O起提供K+离子的作用,而[C2GeW10 O36]8-离子没有参与标题化合物结构的构建.1.3化合物的晶体学分析选取合适的单晶,在Bruker Smart APEX2II衍射仪上,采用石墨单色化的MoK A射线(K=0.071073 nm)于296(2)K下收集衍射数据,共收集8176个衍射点,其中可观测的独立衍射点[I>2R(I)]为1010个.用直接法得到全部非氢原子坐标,由全矩阵最小二乘法精修所有非氢原子坐标,均采用各向异性热参数修正,所有数据经L p因子和经验吸收校正.权重表达式为:w=1/[R2(F2o)+(0.0887P)2+8.2024P] (P=(F2o+2F2c)/3).所有计算均使用SH ELXL97程序包进行[14].标题化合物的晶体学数据和结构精修列于表1.标题化合物的主要键长列在表2中.表1标题化合物的晶体学数据和结构精修T able1Crystallographic data and str uctur al r ef inements of the tit le compound第4期陈利娟等:三核铁簇硫酸盐K 2(H 3O)3[F e 3(H 2O)3O(SO 4)6]#6H 2O 的合成与晶体结构3表2 标题化合物的主要键长数据Table 2 Select ed bond lengths of the title compoundBondLength/nm Bond Length/nm F e(1)-O(5)0.19089(10)Fe(1)-O(1W)0.2097(7)F e(1)-O(1)#10.1948(5)S(1)-O(2)0.1389(6)F e(1)-O(1)#20.1948(5)S(1)-O(3)0.1430(5)F e(1)-O(4)#30.1952(5)S(1)-O(1)0.1433(5)F e(1)-O(4)0.1952(5)S(1)-O(4)0.1443(5) Symm etry trans formations used to generate equ ivalent atom s:#1:x +2,y,z +1;#2:x +1,y +1,z;#3:x +1,y +1,z2 结果与讨论2.1 晶体结构描述图1 标题化合物的阴离子结构Fig.1 The anion structure of the tit le compound 晶体结构解析结果表明,标题化合物分子由1个三核铁簇阴离子[Fe 3(H 2O)3O (SO 4)6]5-、2个K +离子、3个水合质子H 3O +和6个结晶水分子组成.键价计算表明[15],标题化合物中铁和硫元素的价态分别为+3和+6,与XPS 测试结果相吻合.标题化合物阴离子结构如图1所示,该阴离子[Fe 3(H 2O)3O(SO 4)6]5-由3个Fe 3+离子[Fe(1),Fe(1A)(A:2-x +y,1-x ,z ),Fe(1B)(B:1-y,-1+x -y,z )]、6个SO 2-4离子、3个配位水和1个中心三桥氧O(5)组成.由于标题化合物属于六方晶系的P 6(3)/m 空间群,所以3个Fe 3+离子处在特殊位点上,其原子坐标分别为Fe (1)(0.82593,0.04143,0.25000),Fe (1A )(1.21550,0.17407,0.25000),Fe(1B)(0.95857,-0.21550,0.25000),并且3个Fe 3+离子具有C 3对称性,中心三桥氧O(5)处在C 3轴上,其原子坐标为(1.00000, 1.00000,0.25000).在该阴离子[Fe 3(H 2O)3O(SO 4)6]5-中,3个Fe 3+离子被6个SO 2-1离子和1个中心三桥氧连接在一起构成一个具有C 3对称性的环状结构,其中每两个相邻的Fe 3+离子被两个SO 2-4离子连接在一起.每个Fe 3+离子都采取了八面体的几何构型:赤道平面由来自4个SO 2-4离子的4个O 原子组成,对应的Fe-O 键长在0.1948(5)~0.1952(5)nm 之间,极位分别被1个配位水和1个中心桥氧所占据,对应的Fe-O 键长分别为0.2097(7)和0.19089(10)nm.这些Fe-O 键长数据与文献值基本吻合[16].标题化合物阴离子沿c 轴X 射线方向呈六方堆积(图2a).在bc 平面内(图2b),化合物阴离子沿c 轴X 射线方向呈ABAB 堆积模式,沿b 轴方向呈AA A 堆积模式.图2 (a)标题化合物沿c 轴X 射线的堆积图,(b)标题化合物沿a 轴的堆积图F ig.2 (a)The packing alignment of the title compound viewed along c axis,(b)The packing alignment of the title compound viewed along a axis4化学研究2010年2.2红外光谱标题化合物红外光谱如图3(a)所示,在3400cm-1处的宽峰和1636cm-1处的尖峰分别归属为水分子的伸缩振动吸收峰和弯曲振动吸收峰[17].在1221、1151、1065和995cm-1处的强吸收峰对应于SO2-4阴离子的不对称伸缩振动,而在666cm-1处中等强度的吸收峰是由于SO2-4阴离子的面外弯曲振动造成的[18-19].另外,588和487cm-1处的吸收峰为Fe-O键伸缩振动的特征吸收峰[20].该红外光谱的特征吸收峰与晶体结构分析结果一致.2.3紫外2可见吸收光谱硫酸钠、硫酸铁和标题化合物的紫外2可见光谱如图3b所示,硫酸钠在190-800nm之间几乎没有吸收带,而硫酸铁和标题化合物分别在205和295nm附近出现了明显的吸收带,由此可知,这两个吸收带是由于O y Fe的p P2d P电子荷移跃迁造成的,205nm附近的吸收带可以指认为O t y Fe(O t代表端氧)的p P2d P电子荷移跃迁,而295nm附近的吸收带可以归属为O b y Fe(O b代表桥氧)的p P2d P电子荷移跃迁.图3(a)标题化合物的红外光谱,(b)硫酸钠(Ñ)、硫酸铁(Ò)和标题化合物(Ó)的紫外2可见光谱F ig.3(a)The infrar ed spectr um of the title compound,(b)The ultraviolet2visible spectra ofNa2SO4(Ñ),Fe2(SO4)3(Ò)and the title compound(Ó)2.4X射线光电子能谱分析图4(a)铁元素的X射线光电子能谱(b)硫元素的X射线光电子能谱Fig.4(a)The XPS of the iron element(b)The XPS of the sulfur element 图4a为标题化合物中铁元素的X射线光电子能谱图,分析结果表明,在710.8和724.5eV处分别出现了Fe2p3/2和Fe2p1/2的结合能信号,这证明了Fe3+离子的存在[21].图4b为标题化合物中硫元素的X射线光电子能谱图,分析结果表明,结合能为167.5eV处的峰对应于SO2-4阴离子中正六价硫的结合能信号,这证明了SO2-4离子的存在[22].实验结果与键价计算结果相吻合.参考文献:[1]陈文通,李淑冰,许亚平,等.一个混合硫酸盐2亚硒酸盐化合物的合成和晶体结构研究[J].井冈山学院学报,2007,28:7-9.[2]孙娜波,谭成侠,袁其亮,等.二乙胍硫酸盐的合成研究[J].浙江工业大学学报,2001,29:268-271.第4期陈利娟等:三核铁簇硫酸盐K2(H3O)3[F e3(H2O)3O(SO4)6]#6H2O的合成与晶体结构5[3]徐宁.含硫酸、亚硫酸的无机2有机杂化材料的合成及性质研究[D].东北师范大学,2009.[4]Lu J J,Schlueter J A,Geiser U.H ydrothermal synthesis and crystal str uctur e of a new inor ganic/organic hybr id of scandi2um sulfate:(H2en)Sc2(SO4)4#(H2O)0.72[J].J Solid S tate Chem,2006,179:1559-1564.[5]Paul G,Choudhur y A,Rao C N anically tem plated linear and layer ed cadmium sulfates[J].J Chem Soc Dal tonT r ans,2002:3859-3867.[6]Behera J N,Gopalkrishnan K V,R ao C N R.Synthesis,str ucture,and magnet ic pr operties of amine templated open2framewor k nickel(Ò)sulfates[J].I nor g Chem,2004,43:2636-2642.[7]Dan M,Beher a J N,Rao C N anically templated r are ear th 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PAPER /dalton |Dalton TransactionsFacile hydrothermal synthesis and photocatalytic activity of bismuth tungstate hierarchical hollow spheres with an ultrahigh surface area†Xiao-Jun Dai,a ,b Yong-Song Luo,*a ,b Wei-Dong Zhang a and Shao-Yun Fu*a ,cReceived 9th November 2009,Accepted 23rd January 2010First published as an Advance Article on the web 4th March 2010DOI:10.1039/b923443hBismuth tungstate has attracted great attention as a new photocatalyst working under visibleirradiation.In this paper,we demonstrate a facile hydrothermal route for controllable synthesis of novel Bi 2WO 6hierarchical hollow spheres with an ultrahigh specific surface area in the presence of poly(vinyl pyrrolidone)at a proper C 2H 5OH/CH 3COOH/H 2O volume ratio.The obtained products are systematically studied by X-ray powder diffraction,scanning electron microscopy,transmissionelectron microscopy,Brunauer–Emmett–Teller (BET)and UV-vis absorption spectroscopy.It is shown that the Bi 2WO 6hollow spheres are constructed of numerous nanoplates while the nanoplates consist of a great deal of nanoparticles.UV-vis spectrum is used to estimate the band gap energy (about 2.90eV)of the Bi 2WO 6hollow spheres.The ultrahigh BET specific surface area of ca.45.0m 2g -1is displayed for the Bi 2WO 6hierarchical hollow spheres,which is much higher than that for all the previously reported Bi 2WO 6products.The Bi 2WO 6hierarchical hollow spheres are displayed to possess superiorphotocatalytic activity in the photodegradation of rhodamine B (RhB)under visible light irradiation over other morphological products.IntroductionIn the past few years,many efforts have been made for fabrication of nano-/micro-sized hierarchical hollow inorganic structures owing to their potential applications as efficient catalysts,photonic building blocks,acoustic insulators,and drug delayed releasing agents,etc .1-5Generally,two methods have been frequently utilized for synthesis of these nano-/micro-sized hierarchical hollow structures:one is the use of hard templates such as monodispersed silica,reducing metal nanoparticles,polymer latex spheres and so on,6-8and the other is the use of soft templates such as micelles,surfactants,supramolecular,gas bubbles and even bacteria.9-13However,usage of templates usually suffers from disadvantages related to high cost and tedious synthetic procedures,which may prevent them from being used in large-scale applications.It is thus desirable to synthesize hierarchical hollow inorganic spheres without using any templates.As important materials in the electronic and optical areas,metal tungstates have been extensively studied over the past few years.14,15Bismuth tungstate (Bi 2WO 6),one of the simplest members of the Aurivillius oxide family,possesses excellent photocatalytic activity,besides many interesting physical properties such as ferroelectric piezoelectricity,oxide anion conducting,pyroelectricity and a nonlinear dielectric susceptibility.16-19Nowadays,photocatalytic reactions for environmental protection occurring under solar illu-aTechnical Institute of Physics and Chemistry,Chinese Academy of Sciences,Beijing,100190,China.E-mail:syfu@,ysluo@ bDepartment of Physics &Electronic Engineering,Xinyang Normal Univer-sity,Xinyang,464000,China cInternational Centre for Materials Physics,Chinese Academy of Sciences,Shenyang,110016,China†Electronic supplementary information (ESI)available:SEM images and XRD patterns of the Bi 2WO 6products synthesized under different conditions.See DOI:10.1039/b923443hmination have attracted great attention.20-22It is well known that the photocatalytic activity is closely related to the size,morphol-ogy and structure of the photocatalysts.23Generally,nanoscale photocatalysts usually have high photocatalytic activity because of their large specific surface areas and high efficiency of electron-hole separation.Hence,various nanostructures of Bi 2WO 6,such as nanoparticles,24nanorods,25nanoplates,26nanooctahedra,27spherelike superstructures,28,29flowerlike nanostructures,30,31and nanocages 32have been prepared by a variety of methods to improve its photocatalytic activity.However,there is no report yet on the synthesis of Bi 2WO 6hollow spheres with high specific areas,which should have an excellent photocatalytic activity due to its high specific area.Herein we demonstrate a facile hydrothermal route for con-trollable synthesis of Bi 2WO 6hierarchical hollow spheres at 180◦C in the presence of poly(vinyl pyrrolidone)(PVP)in a C 2H 5OH/CH 3COOH/H 2O three-phase system with the volume ratio of 1:1:3without using any templates.By adjusting exper-imental parameters,different morphologies of Bi 2WO 6can be obtained and thus the influencing factors are examined on the mor-phology of the Bi 2WO 6products in order to controllably synthesize Bi 2WO 6hierarchical hollow spheres.UV-vis spectroscopy is used to estimate the band gap energy of the Bi 2WO 6hollow spheres.The photodegradation measurement of rhodamine B (RhB)is conducted to study the photocatalytic activities of Bi 2WO 6hollow spheres under visible light (l >400nm)illumination.It is demonstrated that the Bi 2WO 6hollow spheres exhibit an excellent visible-light-driven photocatalytic performance.ExperimentalAll the reagents used were purchased from Beijing Chemical Reagent Ltd.and used without further purification.In a typicalD o w n l o a d e d b y C e n t r a l S o u t h U n i v e r s i t y o n 05 M a r c h 2011P u b l i s h e d o n 04 M a r c h 2010 o n h t t p ://p u b s .r s c .o r g | d o i :10.1039/B 923443Hprocedure,a 10mL aqueous solution which marked as so-lution A was first prepared by dissolving 0.5mmol Na 2WO 4in distilled water and then sonicating in an ultrasonic water bath for 20min.At the same time,1mmol Bi(NO 3)3·5H 2O and 1g of poly(vinyl pyrrolidone)(PVP)were dissolved in the 25mL C 2H 5OH/CH 3COOH/H 2O mixed solution with a volume ratio of 1:1:3by vigorous stirring,and the resultant solution is marked as solution B.The volume ratio (1:1:3)of the C 2H 5OH/CH 3COOH/H 2O mixed solution was the optimal condition to get the hollow spheres.Other volume ratios were also used but hollow spheres could not be obtained.While solutions A and B were clear,two solutions were mixed and the obtained mixture was stirred for 10min until it became homogeneous.Then the suspension was sealed in a Teflon-lined stainless steel autoclave.The autoclave was maintained at 180◦C for 3h and then was cooled to room temperature naturally.The precipitate was obtained by centrifuging and sequentially washing with ethanol and distilled water for several times,and then dried at 65◦C for 6h.Finally,hollow Bi 2WO 6spheres were obtained by adjusting experimental parameters.For the purpose of comparison,other morphological products were prepared under different conditions and meanwhile,irregular Bi 2WO 6powders were fabricated accord-ing to the traditional solid-state reaction (SSR)method.33The phase purity of the products was characterized by XRD using a D8Focus (Germany,Bruker)automated X-ray diffrac-tometer system with Cu-K a radiation (l =1.5418A˚).X-ray energy dispersive spectroscopy (EDS)analysis and SEM observa-tion were performed using a Hitachi S-4300microscope (Japan).Transmission electron microscopy (TEM and HRTEM)images and the corresponding selected area electron diffraction (SAED)patterns were obtained on a JEOL JEM-2010instrument in bright field and an HRTEM JEM-2010FEF instrument,respectively.The surface area was measured using a Micromeritics (NOV A 4200e)analyzer.The nitrogen adsorption and desorption isotherms were obtained at 77K.The Brunauer-Emmett-Teller (BET)surface area was calculated from the linear part of the BET plot.The room-temperature UV-Vis absorption spectrum was recorded on a U-3900spectrophotometer (HITACHI)in the wavelength range of 200-800nm.Photocatalytic activities of the samples were evaluated by the degradation of rhodamine B (RhB)under visible light irradiation using a 500W Xe lamp with a cut-off filter (l >400nm).In each experiment,0.3g of the photocatalyst was added to 600mL of RhB solution (10-5mol L -1).Before illumination,the suspensions were vigorously stirred in the dark for 1h to ensure the establishment of an adsorption–desorption equilibrium between photocatalyst and RhB.Then the solution was exposed to visible light irradiation and bubbled with an air pump to provide enough oxygen.At certain intervals,a 10mL solution was sampled and centrifuged to remove the remnant photocatalyst.Finally,the adsorption UV-vis spectrum of the filtrates was recorded using a U-3900spectrophotometer.Results and discussionSynthesis of Bi 2WO 6hollow spheresFig.1a shows a typical XRD pattern of the as-prepared hollow sphere Bi 2WO 6sample.All of the diffraction peaks can beclearly Fig.1XRD pattern and EDS pattern of the as-prepared Bi 2WO 6hollow spheres.indexed to the pure orthorhombic phase of Bi 2WO 6(space groupB2ab)with lattice constants a =5.457,b =5.436and c =16.42A˚(JPCDS 73-1126).No diffraction peaks from impurities such as WO 334are observed in Fig.1a,indicating the high purity of the product.Moreover,the strong and sharp diffraction peaks in the pattern show that the as-obtained product was well crystallized.The EDS spectrum obtained from a single nanoplate of the Bi 2WO 6hollow sphere is shown in Fig.1b.The result demonstrates that only the element of Bi,W ,and O are observed in the product and the atomic ratio of Bi to W to O is nearly 2:1:6,which indicates that the as-obtained product is Bi 2WO 6.Bismuth tungstate hollow spheres were synthesized through a hydrothermal route by the reaction of Na 2WO 4and Bi(NO 3)3·5H 2O in a C 2H 5OH/CH 3COOH/H 2O three phase sys-tem using PVP as the template at 180◦C for 3h.Fig.2a is a typical low-magnification scanning electron microscopy (SEM)image of the as-prepared product,from which numerous uniformly-sized spheres with an average diameter of ~1.5m m can be clearly observed.Moreover,no other morphologies can be detected,indicating a high yield of the product with the hollow spherical morphology.Fig.2b–d displays the higher magnification SEM images of the sample.The broken sphere as shown in Fig.2b has a bowl-like shape,indicating that the spheres have a hollow struc-ture.For further studies,the hemisphere marked by a rectangle in Fig.2b is magnified in Fig.2c.Fig.2d displays an enlarged Bi 2WO 6single sphere with an intact structure.From Fig.2c and 2d,it can be observed that the Bi 2WO 6hierarchical hollow spheres are composed of nanoplates with an average thickness of ~15nmD o w n l o a d e d b y C e n t r a l S o u t h U n i v e r s i t y o n 05 M a r c h 2011P u b l i s h e d o n 04 M a r c h 2010 o n h t t p ://p u b s .r s c .o r g | d o i :10.1039/B 923443HFig.2(a)Low-magnification SEM image of the as-prepared Bi 2WO 6hollow spheres;(b)high-magnification SEM image of the Bi 2WO 6hollow spheres;(c)enlarged SEM image of an individual Bi 2WO 6hollow sphere marked by a rectangle in (b);(d)an intact hollow sphere with a loose surface.while the nanoplates with loose surfaces consist of a great deal of nanoparticles.On the basis of the above results,the as-prepared hollow microspheres can be generally classified as hierarchical structures.It is worth mentioning that these hierarchical hollow spheres are sufficiently stable that they cannot be destroyed into dispersed nanoplates even after long periods of ultrasonication.The hollow structure of the Bi 2WO 6product was further investigated by TEM.Fig.3a and 3b show the low and high magnification transmission electron microscopy (TEM)images respectively.A clear contrast between the dark edges and the pale center can be observed (Fig.3a and 3b),this confirms that all the uniform Bi 2WO 6spheres have a hollow interior.The inset in Fig.3a is the corresponding selected area electron diffraction (SAED)pattern of the Bi 2WO 6hollow sphere,which reveals its polycrystalline structure rather than well-defined single crystal.Fig.3c shows the typical HRTEM image of the corner of an individual Bi 2WO 6nanoplate and the right angle indicates that the nanoplates have a square morphology.Fig.3d is the enlarged image of the area marked by a rectangle in Fig.3c.Fig.3d clearly reveals the resolved lattice spacing of 0.27nm,which corresponds to the (020)plane of orthorhombic Bi 2WO 6.Fig.3TEM images of the as prepared Bi 2WO 6hollow spheres.(a)Overall product morphology (inset is its corresponding SAED pattern);(b)a detailed image of an individual hollow sphere.(c)HRTEM image of the tip of a single nanoplate;(d)enlarged image of the area marked by a rectangle in (c).The nitrogen adsorption–desorption and internal pore size distribution isotherm of the as-obtained Bi 2WO 6hollow spheres were further investigated.As shown in Fig.4,the recorded adsorption and desorption isotherm of the spherical Bi 2WO 6hollow structures display a significant hysteresis.The BET surface area of the products calculated from the linear part of the BET plot is ca.45.0m 2g -1,which is much higher than that of the previously reported samples 29,31-33and the corresponding result is summarized in Table 1.This is attributed to the fact that the latter has a comparatively compact structure while the former has a loose and hollow structure.The Barrett–Joyner–Halenda (BJH)calculated result for the pore size distribution,derived from desorption data,is centralized on two areas as shown in the inset of Fig.4.Moreover,irregular Bi 2WO 6powders were fabricated according to the traditional solid-state reaction (SSR)method 33and the SEM images of Bi 2WO 6were shown in Fig.S1.†Fig.4Nitrogen adsorption–desorption and pore-size distribution isotherm of the prepared Bi 2WO 6hollow spheres.Bi 2WO 6with different morphologies have different photocat-alytic properties.The photocatalytic activities of these Bi 2WO 6products should be due to the differences in the bandgap energy depending on the size and morphology of the nanomaterials and the BET surface areas resulting from their distinct morphologies.The results for the nitrogen adsorption–desorption and internal pore size distribution isotherm of the Bi 2WO 6flowers in the absence of PVP and Bi 2WO 6flowers via the addition of NaOH are shown in Fig.S5.†The specific surface areas of the other two products calculated from the linear part of the BET plot are 22.5m 2g -1(Bi 2WO 6flowers in the absence of PVP)and 13.8m 2g -1(Bi 2WO 6flowers via the addition of NaOH),respectively.It is thus clear that the hollow spheres have the highest specific area among the three different morphological products.Influencing factors on the morphology of Bi 2WO 6products To understand the growth mechanism of the Bi 2WO 6hollow spheres in some detail,the products were first harvested at different intervals of aging time at 180◦C to study the influence of aging time on the morphology of Bi 2WO 6products.The representative SEM images of the products synthesized at certain reaction time intervals are shown in Fig.5.In the initial stage,the resultant products are irregular particles as revealed by the SEM imageD o w n l o a d e d b y C e n t r a l S o u t h U n i v e r s i t y o n 05 M a r c h 2011P u b l i s h e d o n 04 M a r c h 2010 o n h t t p ://p u b s .r s c .o r g | d o i :10.1039/B 923443HTable 1Specific surface areas of Bi 2WO 6products with different morphologies SampleSSR-Bi 2WO 6Bi 2WO 6Nanocage Flower-like Bi 2WO 6Bi 2WO 6Microsphere Bi 2WO 6Hollow Sphere Specific surface area/m 2g -10.643314.53233.73124.12945.0Fig.5Time-dependent evolution of the Bi 2WO 6morphologies at differ-ent aging time:(a)0,(b)1,(c)2,and (d)3h.(Fig.5a).After hydrothermal treatment of 1h,nano-and micro-sized particles coexist in the product (Fig.5b).The coarse surfaces of irregular particles in Fig.5a and of micro-particles in Fig.5b indicate that these particles consisted of fine nanoparticles.After another 1h,underdeveloped hollow spheres were formed as shown in Fig.5c.When the reactant was hydrothermally treated for 3h,well-defined Bi 2WO 6hollow spheres were produced.Most of the obtained products are uniform hollow spheres as presented in Fig.5d.The corresponding XRD patterns of the time-dependent evolution of Bi 2WO 6products are shown in Fig.S2,†which are the same as the XRD pattern shown in Fig.1a since all the as-synthesized products are the same (namely Bi 2WO 6crystals).Further control experiment studies indicate that the final morphologies of the samples are strongly affected by PVP and NaOH.We have repeated the experiment in the absence of PVP,the final product of Bi 2WO 6is flowerlike nanocrystals (Fig.6a and 6b).This result further demonstrates that PVP plays an important role in controlling the morphology of the product.Moreover,the concentration of NaOH in the solution also affects the morphology of the Bi 2WO 6product.Fig.6c and 6d represents the product obtained in the presence of NaOH (3mmol)and the images reveal that the morphology of the product is another kind of nanoflower rather than hollow sphere when the pH value of the solution is changed (namely the C 2H 5OH/CH 3COOH/H 2O volume ratio π1:1:3).The corresponding XRD patterns of the different morphological Bi 2WO 6products were shown in Fig.S3.†A control experiment study was also conducted as the value of w (namely the volume ratio of C 2H 5OH/CH 3COOH/H 2O)changed.The results show that the final morphology of the Bi 2WO 6product is strongly affected by the value of w .When using other volume ratios rather than 1:1:3,hollow spheres could not be obtained as shown in Fig.S4.†Therefore,it is clear that the volume ratio of C 2H 5OH/CH 3COOH/H 2O is another important factor influencing the morphology of Bi 2WO 6products.Fig.6SEM images of Bi 2WO 6products synthesized at different condi-tions:(a,b)in the absence of PVP;(c,d)adding 0.12g NaOH to solution A (see experimental section)before solution mixing.From the above results about the influencing factors on the morphology of Bi 2WO 6products,it is clear that the con-trollable synthesis of Bi 2WO 6hollow spheres can be realized only in the presence of poly(vinyl pyrrolidone)at a proper C 2H 5OH/CH 3COOH/H 2O volume ratio of 1:1:3for the aging time of 3h.Under other conditions,only other Bi 2WO 6mor-phological products rather than hollow spherical morphological products can be obtained.The process of the shape evolution is summarized in Fig.7.Based on the above results,it can be concluded that Bi 2WO 6hollow spheres can be obtained via a nucleation–dissolution–recrystallization growth process.Bi 2WO 6nanoparticles were first formed when the WO 42-was added to the solution containing Bi 3+.And these nanoparticles would agglomerate to form irregular particles as shown in Fig.5a in the initial stage or to form micro-sized particles as shown in Fig.5b during the sustaining heating process.Due to the anisotropic crystal structure,there was an intrinsic tendency for the nucleation growth along the planar direction,35partial Bi 2WO 6nanoparticles start to dissolve into solution and further grow into the platelike nanocrystals through oriented aggregation.After reaction for 2h,the nanoplates were gradually assembled into a solid sphere,followed by a process known as Ostwald ripening,36nanoplates start to dissolve intheirFig.7Schematic illustration of the formation and shape evolution of Bi 2WO 6products under different synthetic conditions.D o w n l o a d e d b y C e n t r a l S o u t h U n i v e r s i t y o n 05 M a r c h 2011P u b l i s h e d o n 04 M a r c h 2010 o n h t t p ://p u b s .r s c .o r g | d o i :10.1039/B 923443Hinner and merge into the nanoplate on the outer surface because of the high surface energy,resulting in the formation of hollow interior structure.It is well known that using a polymer-assisted reaction to control the nucleation and growth is a simple but effective way,and as we know,PVP,which has a long polymeric chain structure,is usually used as a soft template in forming nanomaterials.In this experiment,PVP plays an important role in the formation of the as-synthesized product and serves as a “soft template”.It is generally believed that the building blocks for oriented aggregation/attachment are usually nanoparticles with surfaces stabilized by organic coating,and weakly protected nanoparticles often undergo entropy-driven random aggregation.37,38In this regard,selective adsorption and subsequent removal of organic additives play important roles in rotating adjacent nanoparticles at interfaces so that they share an identical 3D crystallographic orientation.We speculate that when an amount of PVP is added to the reaction solution,many active sites will be produced around the circumference of Bi 2WO 6nuclei (the Bi 2WO 6nanoparticles formed earlier),then these active sites were selectively adsorbed on various crystallographic planes of Bi 2WO 6nanoparticles.Moreover,in this experiment,NaOH is another important factor and could also be considered to influence the growth process of Bi 2WO 6hollow spheres.When the NaOH was added to the solution,the pH value approaches 7and the growth speed along all directions is almost the same in litmusless circumstances.As a result,multilayer nanodisks constructed of the nanoplates were formed.Subsequently,these multilayer nanodisks begin to self-assemble into flowerlike nanostructures (Fig.7).Optical properties and photocatalytic performanceThe optical property of Bi 2WO 6hollow spheres was investigated by UV-vis absorption spectroscopy.The result is shown in Fig.8.It can be seen that the Bi 2WO 6hollow microsphere has a steep absorption edge in the visible range,indicating that the absorption relevant to the band gap is due to the intrinsic transition of the nanomaterials.39For a crystalline semiconductor,the optical absorption near the band edge follows the equation a E p =K (E p -E g )1/2,where a ,K ,E p and E g are the absorption coefficient,a constant,the discrete photo energy and the band gap energy,respectively.40The intercept of the tangent to the plot givesaFig.8UV-Vis absorption spectra of Bi 2WO 6hollow spheres.The inset is the corresponding (a E p )2vs .E p curve.good approximation of the band gap energy for indirect band gap materials,which is consistent with previous studies.41The band gap (E g )of Bi 2WO 6is estimated to be about 2.90eV from the onset of the absorption edge (the inset of Fig.8).This value is slightly greater than the value of SSR-Bi 2WO 6,that might be due to the quantum confinement effects in the nanostructures of the hollow spheres and the effect of the morphology of the hollow spheres.42Tetraethylated rhodamine (RhB),a widely used dye,was selected as a representative pollutant to evaluate the photocatalytic efficiency of the as-prepared Bi 2WO 6catalysts.The characteristic absorption band of RhB is at about 553nm,31which is employed to monitor the photocatalytic degradation of RhB.Fig.9a reveals the temporal evolution of the absorption spectra of an RhB aqueous solution catalysed by the Bi 2WO 6hollow spheres under visible light irradiation (l >400nm).A gradual decrease of RhB absorption under irradiation of visible light at the wavelength of 553nm is observed,accompanied with an absorption band shift to shorter wavelengths.This hypsochromic shift may be attributed to the dye’s de-ethylation,that is,from N,N,N ¢,N ¢-tetraethylated rhodamine to rhodamine.In addition,the color of the dye solution changes from initial red to a light yellow-green,then to transparent,which can be observed by the naked eye,indicating the complete photocatalytic decolorization of RhB aqueous solution during the reaction.It was reported that the mechanism of mineralization of RhB includes two competitive processes:a photocatalytic process and a photosensitized process.In the photocatalytic process,Bi 2WO6Fig.9(a)The temporal evolution of the absorption spectra of the RhB solution in the presence of Bi 2WO 6hollow spheres under exposure to visible light.(b)The effect of different catalysts on photocatalytic degradation of RhB (initial concentration 1.0¥10-5M).D o w n l o a d e d b y C e n t r a l S o u t h U n i v e r s i t y o n 05 M a r c h 2011P u b l i s h e d o n 04 M a r c h 2010 o n h t t p ://p u b s .r s c .o r g | d o i :10.1039/B 923443Hacts as an active photocatalyst,and RhB could be degraded by direct interaction with a strong oxidizing hole originating from the hybridization of the Bi 6s and O 2p orbitals.The RhB molecule was attacked and then degraded via the destruction of the conjugated structure.At the same time,in the photosensitized process,RhB dye could adsorb the visible light,which was attributed to the ground state and excited state of the dye;mineralization of the dye found its origins with the active oxygen radical species,O 2∑-,and the radical cations,dye ∑+.The photosensitized degradation of RhB was commonly accomplished via the N -demethylation process.43-45Fig.9b shows the results of the RhB degradation efficiencies using different catalysts under visible light illumination (l >400nm).The blank test revealed that the degradation of RhB was extremely slow without photocatalyst,only about 10%after 6h visible-light irradiation.Similarly,the photodegradation efficiency of RhB by SSR-Bi 2WO 6just reaches 30%after 6h of reaction.However,when the hydrothermal synthesized Bi 2WO 6samples were dispersed in RhB solutions,the photodegradation is apparently ly,75%,80%and 95%of the RhB can be degraded after 6h,respectively for the three morphologies shown in Fig.9b.The Bi 2WO 6hierarchical hollow spheres display higher photocatalytic activity for the degradation of RhB (95%within 6h)than NaOH assisted flowerlike Bi 2WO 6sample (75%within 6h)and without PVP synthesized flowerlike Bi 2WO 6sample (80%within 6h)as evidenced by curves in Fig.9b.The enhanced photocatalytic activity of Bi 2WO 6hierarchical hollow spheres can be attributed to the combined effects of several factors:first,the high surface area of Bi 2WO 6hierarchical hollow structures brings not only more surface reached by the visible light and contacted with the RhB but also more active catalytic sites;second,there are plenty of pores for this structure which can be considered as transport paths for the RhB molecules to get to the active sites on the framework walls,hence enhancing the efficiency of photocatalysis;30third,the hollow spheres allow multiple reflections of visible light within the interior cavity that facilitates more efficient use of the light source.46This hydrothermal method presented here could be extended to synthesis of other photocatalysts and it might be possible to adjust the size to the nanometre scale.This will be carried out in a further work via changing some reagents and controlling experimental parameters.Moreover,the nanoscale hollow spheres should have higher catalytic efficiency than the micro-sized ones because the surface area and surface energy of nanosized products would increase with the decrease in the size of the crystalline grains,which could benefit the enhancement of the photocatalytic activities of the catalysts.ConclusionsIn summary,the controllable synthesis of Bi 2WO 6hollow sphereshas been realized via a hydrothermal route in the presence of PVP at the temperature of 180◦C for 3h at a proper C 2H 5OH/CH 3COOH/H 2O volume ratio of 1:1:3.The hierar-chical hollow spheres were found to be constructed by numerous nanoplates while the nanoplates were observed to consist of a great deal of nanoparticles.The results show that the as-prepared hollow spheres display an ultrahigh BET surface area of ca.45.0m 2g -1,which is much higher than the previously reported Bi 2WO 6products.The photocatalytic experiment indicates that the Bi 2WO 6hollow spheres exhibit superior photocatalytic activity in the photodegradation of rhodamine B (RhB)under visible light irradiation over other morphological products.Consequently,the as-prepared Bi 2WO 6hierarchical hollow spheres are promising as photocatalysis owing to their attractive photocatalytic character-istics.AcknowledgementsWe appreciate the financial support from the National Basic Research Program of China (No.2010CB934500),the Beijing Mu-nicipal Natural Science Foundation (Nos.2091004and 2082023)and China Postdoctoral Science Foundation.References1Y .Sun,B.Mayers and Y .Xia,Adv.Mater.,2003,15,641.2W .Schartl,Adv.Mater.,2000,12,1899.3L.P .Zhu,H.M.Xiao,W .D.Zhang,G.Yang and S.Y .Fu,Cryst.Growth Des.,2008,8,957.4Z.G.An,J.J.Zhang and S.L.Pan,Dalton Trans.,2009,3664.5G.F .Lin,J.W .Zheng and R.Xu,J.Phys.Chem.C ,2008,112,7363.6S.W .Kim,M.Kim,W .Y .Lee and T.Hyeon,J.Am.Chem.Soc.,2002,124,7642.7M.Yang,J.Ma,C.Zhang,Z.Yang and Y .Lu,Angew.Chem.,Int.Ed.,2005,44,6727.8J.N.Gao,Q.S.Li,H.B.Zhao,L.S.Li,C.L.Liu,Q.H.Gong and L.M.Qi,Chem.Mater.,2008,20,6263.9Q.Peng,Y .Dong and Y 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:10.1039/B 923443H。
钙钛矿的结构英语Perovskite, a mineral with a unique crystal structure, has captivated scientists due to its remarkable properties. Its composition, often represented as ABX3, is where A and B are cations and X is an anion, creating a versatile framework for various applications.The arrangement of atoms in perovskite is what makes it stand out. The central B cation is surrounded by an octahedron of X anions, while the larger A cations occupy the interstitial spaces, forming a three-dimensional lattice.This structure's malleability allows for the substitution of different elements, which can alter the material's properties. This flexibility is particularly useful in the development of solar cells, where perovskite materials have shown impressive efficiency.Moreover, the perovskite structure is not just limited to energy applications. Its potential in catalysis, sensors, and other high-tech fields has researchers exploring newfrontiers in materials science.Despite its promise, perovskite materials also face challenges. Stability issues and environmental concerns are areas that require further research to ensure the long-term viability of perovskite-based technologies.In summary, the perovskite structure is a fascinating subject in the field of materials science, offering a wide range of possibilities for technological advancements while also presenting hurdles that must be overcome.。
Synthesis and crystal structure of a new supermolecular compound: [C12H24O6][H3PMo12O40]·22H2O(C12H24O6 18-crown-6) Wansheng You a,Enbo Wang a,*,Qinglin He a,Lin Xu a,Yan Xing b,Hengqing Jia ba Northeast Normal University,Department of Chemistry,Changchun Jilin130024,People’s Republic of Chinab Changchun Institute of Applied Chemistry,Academic Sinica,Changchun Jilin130022,People’s Republic of ChinaReceived8October1999;received in revised form9November1999;accepted9November1999AbstractThe title compound,[C12H24O6][H3PMo12O40]·22H2O,was synthesized by the self-assembly of18-crown-6(abbreviated as C12H24O6or18C6)and H3PMo12O40in the mixed solvent of CH3OH and CH3CN,and was characterized by IR,1H NMR and X-ray diffraction for thefirst time.Crystal data:Triclinic,P 1;a 13:428 3 A;b 13:557 3 A;c 14:642 3 A;a 105:39 3 Њ;b 90:06 3 Њ;g 119:56 5 Њ;V 2207:5 8 A3;Z 1;R1 0:0719;wR2 0:1990:It has a disordered a-Keggin PMo12O3Ϫ40anion,which contains the strong alternating short(mean1.844A˚)and long(mean1.958A˚)Mo–O–Mo bonds.In the unit cell,crown ethers and molybdophosphates are alternatively arranged in good order along c-axis.An oxonium ion is located at the center of a crown ether molecule.,Oxonium ion interacts with18C6by the means of hydrogen bonds(mean 2.7771A˚),which are electrostatic or resonant.The observations show the existence of[H3O(C12H24O6)]ϩ.᭧2000Elsevier Science B.V.All rights reserved.Keywords:Molybdophosphate;Crown ethers;Oxonium ion;Hydrogen bonds;X-ray crystallography1.IntroductionSupermolecular compounds of polyoxometalates, or hybrid materials,produced by combining different inorganic and organic moieties by means of molecular assemblies,are of current interest in some important areas of chemistry such as catalysis,non-linear optical materials,liquid crystals and charge-transfer salts[1–3].Crown ethers have excellent ability of molecular recognition.Furthermore,combining crown ether molecules with polyoxometalates would open up broadfields for studies on supermolecular compounds and hybrid materials[4,5].Thefirst oxonium–crown ether complexes wereobtained by Izatt et al.[6];they consisted ofH3Oϩand dicyclohexano-18-crown-6adductsassociated with ClOϪ4and PFϪ6counterions.There-after,some adducts of oxonium ion and crownether were obtained,associated with BFϪ4;CIOϪ4; PFϪ6;IϪ,BrϪ,PtCl2Ϫ6;SbFϪ6and CF3SOϪ3ions[7–9].In these studies,it was generally assumed thatH3Oϩion in the adducts is located at or near thecenter of the macrocyclic ether cavity and thiswould maximize the electrostatic interactionbetween the two units.This was also expectedon the basis of the strong hydrogen bonds asrevealed by IR spectra.To our acknowledge,thishypothesis had been confirmed by only one X-raydiffraction study on[18C6][H3OϩBF4][10].Thelimited number of the crystal structure data hasJournal of Molecular Structure524(2000)133–1390022-2860/00/$-see front matter᭧2000Elsevier Science B.V.All rights reserved.PII:S0022-2860(99)00447-0www.elsevier.nl/locate/molstruc*Corresponding author.Tel.:ϩ86-43-1562-3492;fax:ϩ86-43-1568-4009.E-mail address:huchw@(E.Wang).hampered the structural study on the interaction between the oxonium ion and crown ether.To the best of our knowledge,the adducts of oxonium ion and crown ether associated with polyox-ometalates have not been reported so far.We describe herein the synthesis and crystal structure of a new supermolecular compound of crown ether and poly-oxometalate acid:[C12H24O6][H3PMo12O40]·22H2O.It is a good example of an interaction between crown ether and the oxonium ion.2.Experimental2.1.Materials and methodsAll chemicals purchased were of reagent grade and used without further purification.Infrared spectrum was recorded as KBr pellets on a Nicolet170SX FT-IR spectrometer;1H NMR spectrum was obtained with a Bruker Am-500spectrometer operating at 500MHz using CD3OD-d4as solvent.C,H elemental analysis were performed on Perkin–Elmer240c Elemental analyzer.P and Mo elemental analysis were performed on a PLASMA SPECI(I)quant-ometer.TG analysis was performed on a Q-Derivato-graph thermal analyzer.2.2.Preparation of[C12H24O6]·[H3PMo12O40]·22H2O H3PMo12O40was prepared according to the litera-ture[11].18C6(0.1g)in20ml acetonitrile was added drop-wise to a20ml methyl alcohol solution of0.8g H3PMo12O40with stirring for1h.The yellow solution was allowed to stand for3–5days and the product, [C12H24O6][H3PMo12O40]·22H2O,was collected. Yield:25%.Anal.calc.:C,5.8;H,2.8;P,1.2;Mo, 46.3%;found:C,6.0;H,2.9;P,1.1;Mo,45.7%.Calc. total loss was28.8%;found30.1%.2.3.X-ray crystallographyThe data were collected on Siemens P4four-circle diffractometer(Mo-Ka radiation l 0:71073 A;v–2u scan mode).A yellowish-green single crystal wasW.You et al./Journal of Molecular Structure524(2000)133–139134Table1Crystal data and structure refinementEmpirical formula C12H71Mo120O68PFormula weight2485.97Temperature293(2)KWavelength0.71073A˚Crystal system TriclinicSpace group P 1Unit cell dimensions a 13:428 3 A a 105:39 3 Њb 13:557 3 A b 90:06 3 Њc 14:642 3 A g 119:56 5 ЊVolume,z2207.5(8)A˚3,1Density(calc.) 1.870Mg/m3Absorption coefficient 1.758mmϪ1F(000)1206Crystal size0:46×0:38×0:16mm3u Range for data collection 1.95–23.01Limiting indicesϪ1ՅhՅ13;Ϫ13ՅkՅ12;Ϫ16ՅlՅ16Reflections collected7071Independent reflections5937 R int 0:0184Max.and min transmission0.62097and0.51046Data/restraints/parameters5927/152/433Goodness-of-fit on F2 1.004Final R indices IϾ2s I R1 0:0719;wR2 0:1990R indices(all data)R1 0:1057;wR2 0:2271Extinction coefficient0.0008(2)Largest diff.peak and hole 1.291andϪ0.816e A˚Ϫ3mounted inside a glass capillary.A semiempirical absorption correction (PSISCAN)was applied.The hydrogen atoms of crown ether were introduced in calculated positions with fixed C–H distance andisotropic displacement parameters C–H 0:97 Afor ϾCH 2and U iso 0:08 A2 :A summary of the crystallographic data and structure parameters for [C 12H 24O 6][H 3PMo 12O 40]·22H 2O is provided in TableW.You et al./Journal of Molecular Structure 524(2000)133–139135Table 2Atomic coordinates ×104 and equivalent isotropic displacementparameters A×103 for [C 12H 24O 6][H 3PMo 12O 40]·22H 2O.U (eq)is defined as one-third of the trace of the orthogonalized U ij tensorxy z U (eq)Mo(1)2433(1)6262(1)6801(1)63(1)Mo(2)Ϫ1565(1)1869(1)3801(1)64(1)Mo(3)Ϫ2842(1)3185(1)5448(1)66(1)Mo(4)1027(1)3185(1)5447(1)67(1)Mo(5)Ϫ392(1)4215(1)7159(1)65(1)Mo(6)Ϫ1172(1)6262(1)6806(1)64(1)P 05000500046(1)O(1)Ϫ2264(4)443(4)3230(3)84(2)O(2)Ϫ4136(4)2308(5)5657(4)85(2)O(3)Ϫ559(5)3893(5)8196(3)101(2)O(4)3552(4)6808(4)7621(4)81(1)O(5)Ϫ1747(4)6818(4)7623(4)81(1)O(6)1445(4)2298(4)5665(4)86(2)O(7)2200(4)4677(4)6177(4)86(2)O(8)305(4)7519(4)6951(3)82(2)O(9)2230(4)7520(4)6971(4)84(2)O(10)1220(4)5520(4)7428(4)84(2)O(11)93(4)3237(4)6463(4)90(2)O(12)Ϫ2516(4)1981(4)4705(4)90(2)O(13)Ϫ1866(4)3235(4)6470(4)85(2)O(14)Ϫ3161(4)3394(4)4309(4)87(2)O(15)Ϫ1560(5)6629(5)5714(4)92(2)O(16)Ϫ2517(4)4678(4)6168(4)82(2)O(17)Ϫ498(4)1993(4)4698(4)89(2)O(18)125(5)3921(5)4556(5)46(2)O(19)Ϫ691(4)5532(4)7437(4)88(2)O(20)Ϫ1199(5)3920(6)4556(5)44(2)O(21)Ϫ517(5)5232(6)4229(5)43(2)O(22)749(5)5233(6)4222(5)42(2)O(23)6355(4)4122(5)9110(4)103(2)O(24)4363(4)3734(5)8075(4)106(2)O(25)2762(4)4125(5)9109(4)104(2)C(1)7533(6)4829(8)9479(6)112(4)C(2)6132(8)3866(8)8117(7)115(2)C(3)4923(6)3101(7)7767(7)112(2)C(4)3166(7)3090(7)7767(7)113(3)C(5)2739(7)3888(7)8102(7)116(3)C(6)2325(6)4882(7)9483(7)118(4)O(10W)50000500010000177(4)Table 3Selected bond lengths (A˚).Symmetry transformations used to generate equivalent atoms:#1,Ϫx ;Ϫy ϩ1;Ϫz ϩ1;#2,Ϫx ϩ1;Ϫy ϩ1;Ϫz ϩ2Mo(1)–O(4) 1.631(5)Mo(1)–O(9) 1.812(6)Mo(1)–O(10) 1.836(5)Mo(1)–O(14)#1 1.948(6)Mo(1)–O(7) 1.961(5)Mo(1)–O(20)#1 2.473(8)Mo(1)–O(21)#1 2.498(6)Mo(2)–O(1) 1.632(5)Mo(2)–O(17) 1.856(6)Mo(2)–O(12) 1.870(6)Mo(2)–O(8)#1 1.967(5)Mo(2)–O(9)#1 1.997(6)Mo(2)–O(20) 2.493(7)Mo(2)–O(18) 2.499(6)Mo(3)–O(2) 1.638(5)Mo(3)–O(16) 1.942(5)Mo(3)–O(14) 1.847(6)Mo(3)–O(12) 1.950(6)Mo(3)–O(13) 1.954(6)Mo(3)–O(20) 2.468(7)Mo(3)–O(22)#1 2.495(6)Mo(4)–O(6) 1.653(6)Mo(4)–O(7) 1.850(4)Mo(4)–O(15)#1 1.875(6)Mo(4)–O(17) 1.948(5)Mo(4)–O(11) 1.956(6)Mo(4)–O(18) 2.457(9)Mo(4)–O(21)#1 2.492(8)Mo(5)–O(3) 1.675(5)Mo(5)–O(11) 1.833(6)Mo(5)–O(13) 1.841(5)Mo(5)–O(10) 1.954(4)Mo(5)–O(19) 1.958(6)Mo(5)–O(22)#1 2.456(8)Mo(5)–O(21)#1 2.469(7)Mo(6)–O(5) 1.642(5)Mo(6)–O(8) 1.831(4)Mo(6)–O(19) 1.835(6)Mo(6)–O(15) 1.937(6)Mo(6)–O(16) 1.963(4)Mo(6)–O(18)#1 2.470(8)Mo(6)–O(22)#1 2.492(8)P–O(21)#1 1.501(8)P–O(21) 1.501(8)P–O(22) 1.513(7)P–O(22)#1 1.513(7)P–O(20)#1 1.525(5)P–O(20) 1.525(5)P–O(18)#1 1.526(7)P–O(18) 1.526(7)O(23)–C(1) 1.393(8)C(23)–C(2) 1.397(11)O(24)–C(3) 1.392(10)O(24)–C(4) 1.399(9)O(25)–C(6) 1.411(10)O(25)–C(5) 1.421(11)C(1)–C(6)#2 1.453(13C(2)–C(3) 1.424(11)C(4)–C(5)1.438(12)C(6)–C(1)#21.453(13)Fig.1.IR spectrum of [C 12H 24O 6][H 3PMo 12O 40]·22H 2O.1,the partial atomic coordinates with standard devia-tions and isotropic atomic displacement parameters are provided in Table 2and the selected bond lengths are listed in Table 3.3.Results and discussionThe title compound was prepared by mixing 18C6and H 3PMo 12O 40in a mixed solvent of CH 3CN and CH 3OH.The product was obtained as yellowish-green crystals with an yield of about 25%.Elemental analysis,IR and NMR data of the compound are consistent with the crystal structure.3.1.IR spectrumThe IR spectrum of the title compound is shown in Fig. 1.The characteristic peaks at 803,880,957,and 1062cm Ϫ1demonstrate that PMo 12O 3Ϫ40is a a -Keggin structure.The peaks at 1600–1100cm Ϫ1are characteristic of 18C6.The stretching mode of H 3O ϩis a very broad band at ϳ2900cm Ϫ1,which overlaps the sharper peaks arising from the C–H stretching motions of the crown ether.The C–O–C stretching vibration of 18C6was observed at 1250cm Ϫ1(s).W.You et al./Journal of Molecular Structure 524(2000)133–139136Fig.2.1H NMR spectrum of [C 12H 24O 6][H 3PMo 12O 40]·22H 2O.Fig.3.Structure of the PMo 12O 3Ϫ40anion.3.2.1H NMR spectrumThe1H NMR spectrum of the title compound isshown in Fig.2.The line at3.743ppm is assignedto CH2of18C6and the line at4.955ppm to H3Oϩand H2O.These data are characteristic of the structureof18C6.3.3.The crystal structureA single crystal X-ray diffraction analysis of thetitle compound showed the compound consisted of18C6,H3Oϩand PMo12O3Ϫ40:The PMo12O3Ϫ40anion shows the same type of crystallographic disorder ashas been found in many crystal structures with Kegginanions,which has been explained by several authors[5,12–14].The central atom P is located at the inver-sion center0,5000,5000(see Table2).It shows thatthe central atom P is surrounded by a cube of eightoxygen atoms,with each oxygen site half-occupied,and the Mo atoms situated at the corners of a regularcubooctahedron(Fig.3).P–O bonds range from1.501(8)–1.526(7)A˚(mean 1.516A˚).The Mo–O t(terminal)bonds are in the usual range of1.631(5)–1.675(5)A˚(mean1.645A˚).The Mo–O(P)bonds arein the range of2.456(8)–2.499(62)A˚(mean2.480A˚).All Mo–Mo distances are nearly equal,rangingfrom 3.5553(11)–3.5696(10)A˚(mean 3.5627A˚).The alternating long and short Mo–O–Mo bonds inall MoO6octahedra fall into two well-resolved cate-gories:the long pairs of Mo–O b(bridge)bonds in therange1.937(6)–1.997(6)A˚(mean1.958A˚)and theshort pairs of Mo–O b bonds in the range1.812(6)–1.875(6)A˚(mean1.844A˚).In the title compound,O10W is referred to asoxonium ion.The oxonium ion plays an importantrole in bonding18C6with PMo12O3Ϫ40:There are interactions between the oxonium ion and the crownether molecule(Fig.4).The oxonium ion is located onthe center of the plane defined by O(23),O(24),O(25),O(23A),O(24A)and O(25A)of the crownether molecule.The oxonium ion bonds with sixoxygen atoms of the crown ether in nearly identicaldistances,O(23,23A), 2.7825(69)A˚;O(24,24A),2.7569(50)A˚;O(25,25A), 2.7919(40)A˚(mean2.7771A˚),which are appreciably shorter thanexpected for the crown ether(2.95A˚)[9].It is difficultto determine which of six oxygen atoms of the crownW.You et al./Journal of Molecular Structure524(2000)133–139137Fig.4.View of the O10W and structure of18-crown-6showing the interactions between them.ether molecule bond with hydrogen atoms of the oxonium ion.This interaction or the hydrogen bonding is electrostatic or resonant,contrary to Behr’s opinion [15].The above-mentioned 1H NMR result,in which the line for ϾCH 2is not split,supports the conclusion.In the unit cell,polyoxometalates and crown ethers are alternatively arranged in good order along c -axis (Fig.5).Water molecules occupy the space left by polyoxometalates and crown ethers.Except O10W,42water molecules are disordered,each with an occu-pancy factor of 0.5.They form hydrogen bonds with each other,but almost not with polyoxometalates and crown ethers.4.ConclusionBy the self-assembly,the supermolecular compound,[C 12H 24O 6][H 3PMo 12O 40]·22H 2O,was synthesized.Itconsists of PMo 12O 3Ϫ40;18C6,oxonium ions andwater molecules.PMo 12O 3Ϫ40possesses a disordered a -Keggin structure.An oxonium ion is located at the center of a crown ether molecule.It is a good example of the interaction between the crown ether and an oxonium ion.Supplementary Data relating to this article are deposited with the B.L.L.D.as Supplementary Publi-cation No.SUP 26637.AcknowledgementsThis project was financially supported by the State Key Laboratory of Coordination Chemistry of Nanjing University of China and the National Science Council of China.We thank Dr Xu Yan for helpful discussion and revision on the crystal structure.W.You et al./Journal of Molecular Structure 524(2000)133–139138Fig.5.Packing diagram viewed down the a -axis for [C 12H 24O 6][H 3PMo 12O 40]·22H 2O.References[1]E.Coronado,C.J.Go´mez-Garcı´a,Chem.Rev.98(1998)273and references therein.[2]E.B.Wang, C.W.Hu,L.Xu,Concise Polyoxmetalates,Chemical Industry,Beijing,1997.[3]J.M.Lehn,Angew.Chem.27(1989)89.[4]X.M.Lu,R.F.Zhang,S.C.Liu,Polyhedron16(1997)3865.[5]R.Neier,C.Trojanowski,R.Mattes,J.Chem.Soc.DaltonTrans.(1995)2521.[6]R.M.Izatt,B.L.Haymore,J.J.Christensen,J.Chem.Soc.mun.(1972)1308.[7]R.Che`nevert, A.Rodrigue,M.Pigeon-Gosselin,Can.J.Chem.60(1982)853.[8]G.S.Heo,R.A.Bartsch,.Chem.47(1982)3557.[9]R.Che`nevert,A.Rodrigue,P.Beauchesne,Can.J.Chem.62(1984)2293.[10]J.P.Behr,P.Dumas,D.Moras,J.Am.Chem.Soc.104(1982)4540.[11]X.Wu,J.Bio.Chem.43(1920)189.[12]J.Peng,E.B.Wang,Y.S.Zhou,J.Chem.Soc.Dalton Trans.(1998)3865.[13]H.T.Evans,M.T.Pope,Inorg.Chem.23(1984)501.[14]P.Le 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结构化学英语Structured ChemistryChemistry is a vast and complex field of study that encompasses the understanding of the composition, structure, and properties of matter. One of the key aspects of chemistry is the concept of structure, which plays a crucial role in determining the behavior and characteristics of chemical substances. Structural chemistry, a subfield of chemistry, focuses on the spatial arrangement of atoms and molecules, and how this arrangement influences the chemical and physical properties of materials.The study of structure in chemistry involves the investigation of the three-dimensional (3D) arrangements of atoms within molecules and the intermolecular interactions that exist between them. This knowledge is essential for understanding the behavior of chemical systems, predicting their properties, and designing new materials with desired characteristics.One of the fundamental tools used in structural chemistry is X-ray crystallography. This technique involves the bombardment of a crystalline sample with X-rays, which interact with the electrons inthe atoms of the crystal. The resulting diffraction pattern can be analyzed to determine the precise arrangement of atoms within the crystal structure. This information is crucial for understanding the properties of solid-state materials, such as metals, minerals, and ceramics.Another important technique in structural chemistry is nuclear magnetic resonance (NMR) spectroscopy. This method utilizes the magnetic properties of atomic nuclei to provide information about the chemical environment and connectivity of atoms within a molecule. NMR spectroscopy is widely used in the identification and characterization of organic compounds, as well as in the study of biomolecules, such as proteins and nucleic acids.In addition to these experimental techniques, computational methods have also become increasingly important in the field of structural chemistry. Quantum mechanical calculations, such as density functional theory (DFT), allow researchers to model the behavior of atoms and molecules at the quantum level, providing insights into their electronic structure and chemical reactivity.One of the key applications of structural chemistry is in the design and development of new materials. By understanding the relationship between the structure of a material and its properties, chemists can engineer substances with specific characteristics, suchas high strength, enhanced thermal stability, or improved electrical conductivity. This knowledge is particularly valuable in fields like materials science, nanotechnology, and catalysis.Another important aspect of structural chemistry is its role in the study of biological systems. The structures of proteins, nucleic acids, and other biomolecules are crucial for understanding their functions and interactions within living organisms. This knowledge is essential for the development of new drugs and the understanding of disease processes.In conclusion, the field of structural chemistry is a fundamental and multifaceted discipline that underpins our understanding of the physical and chemical properties of matter. Through the use of advanced experimental and computational techniques, structural chemists continue to unravel the mysteries of the molecular world, paving the way for new discoveries and innovations that have the potential to transform our lives.。
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LOG+Algebra and Logic数学0.488数学1937-0652ALGEBR NUMBER THEORY A lgebra and Number Theor MATHEMATICS0.5811386-923X ALGEBR REPRESENT THALGEBRAS AND REPRESENTAT数学0.719数学0002-5240ALGEBR UNIV ALGEBRA UNIVERSALIS数学0.551数学1748-7188ALGORITHM MOL BIOL Algorithms for Molecular生物 1.857生化研究方法0178-4617ALGORITHMICA ALGORITHMICA工程技术0.567计算机：软件工0269-2813ALIMENT PHARM THER ALIMENTARY PHARMACOLOGY 医学 5.478胃肠肝病学0971-4693ALLELOPATHY J ALLELOPATHY JOURNAL农林科学0.578农艺学0301-0546ALLERGOL IMMUNOPATHALLERGOLOGIA ET IMMUNOPA医学 1.58过敏0344-5062ALLERGOLOGIE ALLERGOLOGIE医学0.297过敏0105-4538ALLERGY ALLERGY医学 5.995过敏2092-7355ALLERGY ASTHMA IMMUN T he American Academy of ALLERGY 3.084IMMUNOLOGY 1088-5412ALLERGY ASTHMA PROCALLERGY AND ASTHMA PROCE医学 3.353过敏0002-5852ALLG FORST JAGDZTG ALLGEMEINE FORST UND JAG农林科学0.705林学1664-2201ALPINE BOT Alpine Botany PLANT SCIENCES2.4171078-6791ALTERN THER HEALTH M A lternative therapies in INTEGRATIVE & C1.1431868-596X ALTEX-ALTERN ANIM EX A LTEX-ALTERNATIVES TO AN MEDICINE, RESEA3.630893-0341ALZ DIS ASSOC DIS ALZHEIMER DISEASE & ASSO医学 2.688病理学1552-5260ALZHEIMERS DEMENT Alzheimers & Dementia医学17.472临床神经学1758-9193ALZHEIMERS RES THERAlzheimer\'s Research an医学 3.5神经病学0002-7626AM BEE J AMERICAN BEE JOURNAL生物0.042昆虫学0002-7685AM BIOL TEACH The American Biology Tea BIOLOGY0.369EDUCATION, SCI 0002-7812AM CERAM SOC BULL AMERICAN CERAMIC SOCIETY工程技术0.818材料科学：硅酸0002-838X AM FAM PHYSICIAN AMERICAN FAMILY PHYSICIA医学 1.818医学：内科0002-8444AM FERN J AMERICAN FERN JOURNAL生物0.429植物科学0002-8703AM HEART J AMERICAN HEART JOURNAL医学 4.555心血管系统0002-9092AM J AGR ECON AMERICAN JOURNAL OF AGRI管理科学 1.363农业经济与政策1533-3175AM J ALZHEIMERS DISAmerican Journal of Alzh GERIATRICS & GE1.426CLINICAL NEURO 1059-0889AM J AUDIOL American Journal of Audi AUDIOLOGY & SPE1.068OTORHINOLARYNG 1526-5161AM J BIOETHICS AMERICAN JOURNAL OF BIOE社会科学 2.452科学史与科学哲0002-9122AM J BOT AMERICAN JOURNAL OF BOTA生物 2.463植物科学2156-6976AM J CANCER RES American Journal of Canc ONCOLOGY 3.9680002-9149AM J CARDIOL AMERICAN JOURNAL OF CARD医学 3.425心血管系统1175-3277AM J CARDIOVASC DRUG A merican Journal of Card医学 2.203心血管系统0192-415X AM J CHINESE MED AMERICAN JOURNAL OF CHIN医学 2.625全科医学与补充1175-0561AM J CLIN DERMATOL AMERICAN JOURNAL OF CLIN医学 2.519皮肤病学0002-9165AM J CLIN NUTR AMERICAN JOURNAL OF CLIN医学 6.918营养学0277-3732AM J CLIN ONCOL-CANC A MERICAN JOURNAL OF CLIN医学 2.611肿瘤学0002-9173AM J CLIN PATHOL AMERICAN JOURNAL OF CLIN医学 3.005病理学1062-3264AM J CRIT CARE AMERICAN JOURNAL OF CRIT医学 1.6护理0894-8275AM J DENT AMERICAN JOURNAL OF DENT医学 1.062牙科与口腔外科0193-1091AM J DERMATOPATH AMERICAN JOURNAL OF DERM医学 1.426皮肤病学0095-2990AM J DRUG ALCOHOL AB A MERICAN JOURNAL OF DRUG SUBSTANCE ABUSE1.470735-6757AM J EMERG MED AMERICAN JOURNAL OF EMER医学 1.152急救医学0002-9254AM J ENOL VITICULT AMERICAN JOURNAL OF ENOL农林科学 1.632生物工程与应用0002-9262AM J EPIDEMIOL AMERICAN JOURNAL OF EPID医学 4.975公共卫生、环境0195-7910AM J FOREN MED PATHAMERICAN JOURNAL OF FORE医学0.624病理学0002-9270AM J GASTROENTEROL AMERICAN JOURNAL OF GAST医学9.213胃肠肝病学1064-7481AM J GERIAT PSYCHIAT A MERICAN JOURNAL OF GERI医学 3.519精神病学1543-5946AM J GERIATR PHARMAC A merican Journal Geriatr GERIATRICS & GE2.651PHARMACOLOGY & 1079-2082AM J HEALTH-SYST PHAMERICAN JOURNAL OF HEAL医学 2.205药学0361-8609AM J HEMATOL AMERICAN JOURNAL OF HEMA医学 3.477血液学1049-9091AM J HOSP PALLIAT ME A merican Journal of Hosp HEALTH CARE SCI1.3471042-0533AM J HUM BIOL AMERICAN JOURNAL OF HUMA生物 1.928生物学0002-9297AM J HUM GENET AMERICAN JOURNAL OF HUMA生物10.987遗传学0895-7061AM J HYPERTENS AMERICAN JOURNAL OF HYPE医学 3.402外周血管病0271-3586AM J IND MED AMERICAN JOURNAL OF INDU医学 1.59公共卫生、环境0196-6553AM J INFECT CONTROLAMERICAN JOURNAL OF INFE医学 2.326传染病学0272-6386AM J KIDNEY DIS AMERICAN JOURNAL OF KIDN医学 5.756泌尿学与肾脏学1088-0224AM J MANAG CARE AMERICAN JOURNAL OF MANA医学 2.166卫生保健。
收稿日期：2009-12-07。
收修改稿日期：2010-04-14。
安徽省高校自然科学基金资助(No.KJ2009B104)，安徽省应用化学重点建设学科基金资助(No.200802187C)。
＊通讯联系人。
E -mail ：wugangczu@ 第一作者：吴刚，男，46岁，博士，副教授；研究方向：功能配合物。
＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊研究简报铜髤与2-吡啶酸、4，4′-联吡啶配合物的合成、结构和电化学性质吴刚＊,1王小锋2鲜华2郭学林1(1滁州学院化学和生命科学系，滁州239012)(2晓庄学院生物化工与化境工程学院，南京211171)关键词：Cu 髤配合物；4，4′-联吡啶；晶体结构；循环伏安中图分类号：O614.121文献标识码：A文章编号：1001-4861(2010)07-1315-04Synthesis,Crystal Structure and Cyclic Voltametric Property of Cu 髤Complex with 4,4′-Bipy and α-Pyridine CarboxylateWU Gang ＊,1WANG Xiao -Feng 2XIAN Hua 2GUO Xue -Lin 1(1Department of Chemistry and Life Science,Chuzhou University,Chuzhou,Anhui 239012)(2Biochemistry &Environment Engineering College,Xiao Zhuang University,Nanjing 211171)Abstract:The complex [Cu(bipy)(pc)(H 2O)(ClO 4)]·H 2O (1)(bipy:4,4′-bipyridine;Hpc:α-pyridine carboxylic acid)has been synthesized and characterized by single crystal X -ray diffraction method and elemental analysis.It crysrallizes in the Monoclinic space group P 21/n .The crystal structure reveals that Cu 髤centre adopts a pseudo octahedral geometry.Ligand 4,4′-bipyridine as a bridge coordinates to two different Cu 髤center to form a one -dimensional zigzag chain.One dimensional chains are linked by C-H …O hydrogen bonding interactions to form two -dimensional yers are connected by O …H-O hydrogen bond to generate three -dimensional structure.The cyclic voltametric behavior of complex 1is also DC:743537.Key words:copper 髤complex;4,4′-bipyridine;cyclic voltametryMetallo -supramolecular species built from transi -tion metal ions and organic ligands have been rapidly developed in recent years because of their fascinating structural diversities and potential applications in the areas of catalysis,gas storage,magnetism,nonlinear optics,electrical conductivity,and molecular recogni -tion [1-4].Over the past decades,there have been various examples of the metal -organic coordination frameworks obtained by using pyridyl -based bridging ligands,inclu -ding simple 2-connecting ligand like 4,4′-bipyridine [5-7].As a rigid linear bridging ligands,is often used in the design and constructure of multi -dimensional coordination polymers.It can connect metal cations through its distal pyridyl nitrogen donor atoms into structurally intriguing solids with potentially useful properties [8-12].For example,the paratactic layered phase [Zn (isophthalate)(4,4′-bpy)2][Zn (isophthalate)-(4,4′-bpy)]·0.25H 2O exhibits blue luminescence upon ultrav -iolet irradiation [13],and the interpenetrated 3D material [Zn(terephthalate)(4,4′-bpy)0.5]can chromatographically第26卷第7期2010年7月Vol ．26No ．71315-1318无机化学学报CHINESE JOURNAL OF INORGANIC CHEMISTRY第26卷无机化学学报separate branched and linear hydrocarbons[12].Here,a new4,4′-bipyridine coordination[Cu(bipy)(pc)(H2O) (ClO4)]·H2O is obtained and structure is determined by means of X-ray diffraction crystal structure analysis.Its cyclic voltametric property is investigated.1Experimental1.1Reagents and physical measurementsAll reagents commercially available were of reagent grade and used without further purification. Solvents were purified according to the standard methods.C,H and N elements analyses were carried out on a Perkin-Elmer240C elemental analyzer.IR spectra were recorded on a Vector22FTIR spectro-photometer by using KBr pellet in the range of4000~ 400cm-1.The electrochemical measurements were performed using a ShangHai ChenHua CHI600electro-chemical workstation.A three electrode platinum disc of2mm diameter,the reference electrode was Ag/AgCl electrode and single-compartment electrochemical cell was used.The working electrode was a platinum disc of 2mm diameter,the reference electrode was Ag/AgCl electrode and the counter electrode was a platinum wire long enough.All the measurements were carried out in N,N-dimethylformamide(DMF)solvent with0.1mol·L-1Bu4NPF6as indifferent electrolyte and all experi-ments were carried out at room temperature.The electrolyte solutions were carefully deaerated with dry N2.The bubbling was stopped during the measurements in order to obtain semi-infinite linear conditions for diffusion process of the electroactive specie complex with5mg·mL-1concentration.Voltammograms were recorded in the range from0.6to-0.8V vs Ag/AgCl and the scan rate was100mV·s-1.1.2Synthesis of the title compound(1)KOH(0.04mmol, 2.4mg)was added to the solution ofα-pyridine carboxylic acid(0.04mmol,5.0 mg)and4,4′-bipyrindine(bipy)(0.04mmol,5.0mg)in 5mL H2O.Then Cu(ClO4)2·6H2O(0.04mmol,14.8mg) and CH3CH2OH(7mL)were added with stirring.The clear solution was allowed to stand at ambient tempera-ture for about two weeks.Rod deep blue crystals were obtained(7.3mg).Anal.Calcd.for C16H14ClN3O8Cu(%): C,40.43;H,2.97;N,8.84.Found(%):C,40.38;H, 3.05;N,8.93.IR(KBr,cm-1):3450(bm),1636(s),1603 (s),1588(m),1570(w),1477(w),1405(w),1358(s),1293 (w),1217(w),991(m),807(w),810,771(w),696(w),612(w).1.3Crystal structure determinationThe crystal collection for complex1was carried out on a Bruker Smart ApexⅡCCD at room tempera-ture,using graphite-monochromated Mo Kαradiation (λ=0.07107nm).The structure was solved by direct methods and refined on F2by full-matrix least-squares techniques with SHELXL-97.All non-hydrogen atoms and hydrogen atoms were refined anisotropically and isotropically,respectively.The crystal parameters,data collection and refinement results for the compound are listed in Table1.The selected bond lengths and bond angles are listed in Table2.CCDC:743537.Table1Crystallographic data for complex1Empirical formula C16H16ClN3O8Cu D c/(g·cm-3) 1.65Formula weight477.32μ/mm-10.1326Crystal system Monoclinic Crystal dimension/mm0.24×0.22×0.20Space group P21/nθrange/(°) 1.93~26.00a/nm0.85357(8)F(000)972b/nm 1.61058(14)Goodness of fit 1.056c/nm 1.41685(13)Reflections collected10105β/(°)99.407(2)Independent reflns.(R int)3756(0.0203)V/nm3 1.9216(3)Obsd.reflns.(I>2σ(I))3345Z4Parameters refined262Temperature/K293(2)R,wR(I>2σ(I))0.0680,0.2069Crystal color Blue R,wR(all reflections)0.0724,0.2129 1316第7期吴刚等：铜髤与2-吡啶酸、4，4′-联吡啶配合物的合成、结构和电化学性质2Results and discussion2.1Crystal structure of the complex 1Complex 1crystallizes in the Monoclinic space group P 21/n .The coordination plot of the Cu 髤with the atomic numbering is shown in Fig.1.Each Cu 髤centre adopts a pseudo octahedral geometry with N 3O 3set.Three nitrogen atoms come from one α-pyridine carbox -ylate anion,which acts as a bidentate ligand chelating with Cu 髤center,and two bipy molecules,which acts as a bidentate ligand coordinating to two different Cu 髤center to generate a one -dimensional chain structure as ahown in Fig.2.In bipy molecule,two pyrindine rings are not in the same plane.The dihedral angle between two pyrindine rings is 21.99°.In addition,it is worthy to note that the O atom of perchlorate anion also partici -pate coordination with the metal atom since the distan -ces of Cu1-O4is 0.2790nm.Similar Cu -O distance of 0.2790nm has been reported in complex Ca[Cu(OAc)4]·6H 2O (OAc =acetate)[14].Selected bond lengths and angles for complex 1are listed in Table 2.The other two oxygen atoms are from ligands α-pyridine carboxy -late,water molecule,respectively.The heavily distorted octahedral geometry about Cu1is completed by loosely -bound perchlorate (O4,Cu -O is 0.2790nm)and water (O1W,0.23303(19)nm).The oxygen atoms from perc -hlorate and water molecule are localed at axial position.The angle of O4-Cu1-O1W is 175.23°.The [4+2]coor -dination is in line with that predicted for the Jahn -Teller active d 9ion Cu 2+.Bidentate ligand bipys bridge neighbour Cu 髤center to generate a zigzag one -dimensional chain (Fig.2).The [Cu(bipy)(pc)(H 2O)(ClO 4)]has an extensive capacity to hydrogen bonds through pc,coordinated water and perchlorate.Details of hydrogen bonds within 1are contained in Table 3.Firstly,the two dimensionalTable 2Selected bond lengths (nm)and angles (°)for complex 1Cu(1)-O(2)0.19444(14)Cu(1)-O(1W)0.23303(19)Cu(1)-N(2)#10.20186(16)Cu(1)-N(1)0.20072(16)Cu(1)-N(3)0.20065(16)Cu(1)-O(4)0.2790O(2)-Cu(1)-N(3)82.61(6)N(1)-Cu(1)-O(1W)91.86(7)N(3)-Cu(1)-O(1W)95.53(7)N(3)-Cu(1)-N(1)97.56(6)O(2)-Cu(1)-N(1)174.31(7)N(2)-Cu(1)-O(1W)#191.52(7)N(3)-Cu(1)-N(2)#1168.85(7)O(2)-Cu(1)-N(2)#188.34(6)O(2)-Cu(1)-O(1W)93.78(7)N(1)-Cu(1)-N(2)#190.80(6)Symmetry codes:#1:x -1/2,-y +1/2,z -1/2.Uncoordinated water molecule and hydrogen atoms omitted for clarityFig.1Coordination environment around the Cu 髤atom with 30%probability displacementSymmetry codes:#1:1-x ,-y ,-z ;#2:1+x ,-1+y ,z ;#3:x ,-1+y ,z ;#4:1/2-x ,1/2+y ,1/2-z ;#5:2-x ,1-y ,1-z ;#6:1/2+x ,-1/2-y ,1/2+z .D-H …Ad (D -H)/nm d (H …A)/nmd (D …A)/nm ∠(DHA)/(°)O(1W)-H(1WA)…O(2)#10.0960.2190.2795(4)120O(1W)-H(1WB)…O(6)#20.0960.1830.2739(17)157C(1)-H(1)…O(4)#30.0930.2550.3170(13)124C(2)-H(2)…O(1)#40.0930.2390.3316(5)173C(4)-H(4)…O(2W)#50.0930.2580.3445(10)155C(12)-H(12)…O(1)#60.0920.2320.3162(5)151Table 3Distance and angles of hydrogen bonds for the complex 11317第26卷无机化学学报nets are linked by C-H…O(C12-H12…O1#6)hydro-gen bond from uncoordinated oxygen atoms(acceptor)of pc anion and C-H(donor)of pc resulting in two dimensional layer(Fig.2).Further,O-H…O hydrogen bonding interactions between perchlorates with coordinated water moleules connects adjacent layers forming three-dimensional structure.2.2Cyclic voltammetric study of complex1Cyclic voltammetry between0.6to-0.8V permits the study of the complex1without decomposition.The sharp oxidation peak of copper is absent in this potential range(Fig.3).The oxidation peak of the complex occurs at about0.32V,and in the reverse scan it shows no obvious reduction peaks which indicates that the oxidation process of complex1is irreversible.References:[1]Leininger S,Olenyuk B,Stang P J.Chem.Rev.,2000,100:853-908[2]Westcott A,Fisher J,Harding L P,et al.J.Am.Chem.Soc.,2008,130:2950-2951[3]Coronado E,Galán-Mascarós J R,Gómez-García C J,et al.Nature,2000,408:447-449[4]Han F S,Higuchi M,Kurth D G.J.Am.Chem.Soc.,2008,130:2073-2081[5]Hagrman D,Hagrman P J,Zubieta J.Angew.Chem.Int.Ed.,1999,38:3165-3168[6]MacGillivray L R,Atwood J L.Angew.Chem.Int.Ed.,1999,38:1018-1033[7]Moulton B,Zaworotko M J.Chem.Rev.,2001,101:1629-1658[8]Lu W G,Su C Y,Lu T B,et al.J.Am.Chem.Soc.,2006,128:34-35[9]Qin C,Wang X L,Li Y G,et al.Dalton Trans.,2005:2609-2614[10]Zheng Y Q,Ying E R.Polyhedron,2005,24:397-406[11]Ghosh S K,Ribas J,Bharadwaj P K.Cryst.Growth Des.,2005,5:623-629[12]Chen B,Liang C,Yang J,et al.Angew.Chem.,Int.Ed.,2006,45:1390-1393[13]Dai Y M,Ma E,Tang E,et al.Cryst.Growth Des.,2005,5:1313-1315[14]Billing D E,Hathaway B J,Nivholls P.J.Chem.Soc.A,1970:1877-881Symmetry code:#6:1/2+x,-1/2-y,1/2+z;Perchlorate omitted for clarityFig.22D layer in1formed through hydrogen bonds indicated by dashed linesFig.3Cyclic voltammogram of complex1in DMF solution 1318。
Synthesis,Crystal Structure,and Photoluminescenceof Sr-a -SiAlON:Eu 21Kousuke Shioi wSHOWA DENKO K.K.,Midori,Chiba 267-0056,JapanNaoto Hirosaki,*Rong-Jun Xie,*Takashi Takeda,and Yuan Qiang LiNational Institute for Materials Science,Tsukuba,Ibaraki 305-0044,JapanYoshitaka MatsushitaNational Institute for Materials Science,NIMS-SPring-8,Sayo,Hyogo 679-5148,JapanSr-containing a -SiAlON (Sr m /2Si 12-m –n Al m 1n O n N 16–n :Eu 21)phosphor was obtained as a major phase in compositions hav-ing small m and n values,by firing the powder mixture of SrSi 2,SrO,a -Si 3N 4,AlN,and Eu 2O 3at 20001C for 2h under 1MPa nitrogen atmosphere.The crystal structure of Sr-a -SiAlON was refined by the Rietveld analysis of the synchrotron X-ray powder diffraction pattern.The crystal structure showed that the Sr–N2bonding distance of Sr-a -SiAlON was fairly large compared with that of Ca-a -SiAlON.The displacement of N2sites prob-ably allow the interstices in a -SiAlON to accommodate the in-troduction of the large Sr ion.Sr-a -SiAlON:Eu 21phosphor has an excitation wavelength ranging from the ultraviolet region to 500nm and emits a strong yellow light.I.IntroductionWHITE light-emitting diodes (white LEDs)are considered as next-generation solid-state lighting systems because of their promising features such as low power consumption,high efficiency,long lifetime,and the lack of mercury.The availabil-ity of white-LEDs should open up a great number of new ex-citing application fields:white light sources to replace traditional incandescent and fluorescent lamps,backlights for portable elec-tronics,automobile headlights,medical,and architecture light-ing,etc.1–5Recently,rare earth-doped (oxy)nitride phosphors are gaining considerable attention due to their nontoxicity,and promising luminescence properties that enable them to be used in white-LEDs.Typical examples are red M 2Si 5N 8:Eu 21(M 5Ca,Sr,and Ba)6,7and CaAlSiN 3:Eu 21,8,9yellow Ca-a -SiAlON:Eu 21,10–13green b -SiAlON:Eu 21,14and yellow Ce-melilite.15Among these (oxy)nitride luminescence materials,Eu 21-doped a -SiAlON has a strong absorption in the range of 280–470nm and exhibits a broad yellow emission band covering the range of 550–590nm,11which is,therefore,expected to be used in white LEDs when combined with a blue LED chip.16In addition,due to its unique crystal structure,the a -SiAlON host lattice has the following advantages:(i)better flexibility of ma-terial design without changing the crystal structure,(ii)strong absorption in the visible light spectral region and long wave-length emissions,and (iii)chemical and thermal stability,as its basic structure is based on (Si,Al)–(O,N)4tetrahedral networks.a -SiAlON ceramics have been widely studied as structural materials because of their low linear expansion coefficients,high strength and hardness,and high thermal and chemical stabili-ties.It has an overall composition given by the formulaM m =v Si 12-m -n Al m þn O n N 16-n(1)where M is the modifying cations such as Li,Mg,Ca,Y,and rare earth (excluding La,Ce,Pr,and Eu),and v is the valency of the cation M.The crystal structure of a -SiAlON is derived from a -Si 3N 4by partial replacement of Si 41by Al 31and stabilized by trapping cations M into the interstices of the (Si,Al)–(O,N)4network.17It has been generally accepted that Sr 21ion alone cannot stabilize the a -SiAlON structure due to its large ionic size,but it can if codoped with calcium or yttrium.18Hwang addressed that the reaction product from the powder mixture with the com-position of Sr alone a -SiAlON without Y and Ca was the mixture of (a 1b )-SiAlON.Similar observations were also made by Man-dal 19and Liu et al .20A common feature of these reports is that the composition of Sr single-doped a -SiAlON has large m and n values.In this work,the synthesis of Sr-a -SiAlON:Eu 21with small m and n compositions is attempted,and the crystal structure of Sr-a -SiAlON is analyzed by the Rietveld refinement and then compared with that of Ca-a -SiAlON.Finally,the luminescent properties of Sr-a -SiAlON:Eu 21phosphor are reported.II.Experimental ProcedureSr-a -SiAlON:Eu 21samples were prepared from a -Si 3N 4(SN-E10,Ube Industries Ltd.,Tokyo,Japan),SrSi 2(KojyundoChemicalSr 1.5Al 3N 4Si 3N 4Fig.1.Schematic illustration of the a -SiAlON plane with the compo-sition numbers in Table I.D.Johnson—contributing editor*Member,The American Ceramic Society.wAuthor to whom correspondence should be addressed.e-mail:shioi.kousuke@nims.go.jpManuscript No.26102.Received April 7,2009;approved August 13,2009.J ournalJ.Am.Ceram.Soc.,93[2]465–469(2010)DOI:10.1111/j.1551-2916.2009.03372.x r 2009The American Ceramic Society465Laboratory Co.Ltd.,Saitama,Japan),SrO (Kojyundo Chemical Laboratory Co.Ltd.),AlN (Type F,Tokuyama Co.Ltd.,Shunan-shi,Japan),and Eu 2O 3(Shin-Etsu Chemical Co.Ltd.,Tokyo,Japan).SrSi 2was used as the Sr 21source to investigate small n compositions with an aim to eliminate the influence of the oxidation of raw materials in air,because SrSi 2is very stable against oxidation compared with metallic Sr or Sr 3N 2.The chemical compositions of the samples are plotted and listed in Fig.1and Table I.The powder mixtures were ground in the Si 3N 4mortar and pestle.The mixed powders were loaded in h-BN crucibles and then fired in a graphite resistance furnace at 20001C for 2h under 1MPa nitrogen atmosphere.The Eu 31ion in the starting powder Eu 2O 3is reduced to Eu 21under the nitrogen atmosphere during firing,which is confirmed by the absorption and emission spectra given later.Ca-a -SiAlON and Sr-a -SiAlON samples for the Rietveld refinement with nominal compositions Ca 0.375Si 11.25Al 0.75N 16and Sr 0.375Si 11.25Al 0.75N 16were also prepared by using the same firing conditions.The phase products of synthesized powders were identified by X-ray powder diffraction (XRD),operating at 40kV and 40mA and using Cu K a radiation (RINT2000,Rigaku,Tokyo,Japan).A step size of 0.0212y was used with a scan speed of 21/min.High-resolution synchrotron powder XRD data for Rietveldrefinements were recorded using wavelength l 50.65297Aat the NIMS beamline BL15XU of SPring-8synchrotron radiation facility.21The crystal structures were refined by the Rietveld method using the computer program RIETAN-FP,22and then visualized using the software package VESTA.23The photoluminescence spectra of the powder samples were mea-sured by a fluorescent spectrophotometer (Model F-4500,Hitachi Ltd.,Tokyo,Japan)at room temperature with a 150W Ushio xenon short-arc lamp.The emission spectrum was corrected for the spectral response of a monochromater and photomultiplier tube by a light diffuser (model R928P,Hamamatsu,Bridgewater,NJ)and tungsten lamp (10V,4A;Noma Electric Corp.,New York,NY).The excitation spectrum was also corrected for the spectral distribution of the xenon lamp intensity by measuring rhodamine-B as reference.III.Results and Discussion(1)SynthesisFigure 2shows the XRD patterns of samples with different m values (m 50.40–2.00)and a constant n value (n 50.02).As seen in Fig.2,the a -SiAlON phase is obtained as a major phase and SrSi 6N 8as a minor phase in samples with the m value varying from 0.70to 0.80,indicating that Sr 21can be dissolved in the a -SiAlON structure.The b -phase (b -Si 3N 4or b -SiAlON)is ob-served to coexist with a -SiAlON when m is below 0.70,the vol-ume of which increases with decreasing m value.With m values 40.80,the volume of SrSi 6N 8increases obviously,suggesting that the solubility limit of Sr 21in a -SiAlON is o 0.80.Figure 3presents XRD patterns of the samples with different n values (n 50–0.30)and a constant m value (m 50.75)As shown,the volume of the b -phase increases when n increases.As n stands for the oxygen content in the composition,a large n indicates an oxygen-rich composition.As mentioned previously,24the incre-Table I.Starting Compositions and Chemical Formula of the SamplesNo.m n Starting composition (wt%)Chemical formulaSrSi 2SrO a -Si 3N 4AlN Eu 2O 310.400.02 4.53091.84 3.010.62Sr 0.18Eu 0.02Si 11.58Al 0.42O 0.02N 15.9820.500.02 5.77089.90 3.720.61Sr 0.23Eu 0.02Si 11.48Al 0.52O 0.02N 15.9830.600.027.00087.97 4.420.61Sr 0.28Eu 0.02Si 11.38Al 0.62O 0.02N 15.9840.700.028.22086.05 5.110.61Sr 0.33Eu 0.02Si 11.28Al 0.72O 0.02N 15.9850.750.028.83085.10 5.460.61Sr 0.355Eu 0.02Si 11.23Al 0.77O 0.02N 15.9860.800.029.44084.15 5.810.61Sr 0.38Eu 0.02Si 11.18Al 0.82O 0.02N 15.987 1.100.0213.03078.527.850.60Sr 0.53Eu 0.02Si 10.88Al 1.12O 0.02N 15.988 1.500.0217.72071.1810.510.59Sr 0.73Eu 0.02Si 10.48Al 1.52O 0.02N 15.989 2.000.0223.40062.2713.750.58Sr 0.98Eu 0.02Si 9.98Al 2.02O 0.02N 15.98100.750.058.060.5485.13 5.660.61Sr 0.355Eu 0.02Si 11.20Al 0.80O 0.05N 15.95110.750.10 6.80 1.4285.19 5.990.60Sr 0.355Eu 0.02Si 11.15Al 0.85O 0.10N 15.90120.750.20 4.29 3.1885.29 6.640.60Sr 0.355Eu 0.02Si 11.05Al 0.95O 0.20N 15.80130.750.30 1.82 4.9185.407.280.60Sr 0.355Eu 0.02Si 10.95Al 1.05O 0.30N 15.70SSN,SrSi 6N 8;a ,Sr-a -SiAlON;AN-p,SrSi 10Àn Al 181n O n N 32Àn ;X,Unknown phase;s,strong;m,medium;w,weak.20I n t (a .u . ):β:αm=1.50m=1.10m=0.80m=0.75m=0.60m=0.70m=0.40m=0.50m=2.002530354045502θ (deg): SrSi 6N 8Fig.2.X-ray powder diffraction patterns of the compositions with different m values (n 50.02),a ,a -SiAlON;b ,b -SiAlON.20I n t (a .u .):α:βn=0.10n=0.20n=0.05n=0.02n=0.302530354045502θ ( deg )Fig.3.X-ray powder diffraction patterns of the compositions with different n values (m 50.75),a ,a -SiAlON;b ,b -SiAlON.466Journal of the American Ceramic Society—Shioi et al.Vol.93,No.2ment of b -phase with increasing n values is attributable to the excess formation of liquid phase during firing,and in turn pro-motes the formation of b -phase.Therefore,we demonstrate that Sr-a -SiAlON can be formed as the major phase in compositions with small m and n values (m 50.70–0.80and n 50–0.05).As mentioned above,Sr solely doped a -SiAlON was not avail-able in previous studies.It is due to the fact that the m and n values are too large in those investigations (Hwang et al .,18m 51and n 51;Mandal,19m 51.25and n 51.15;Liu et al .,20m 51.6,n 51.6),which make Sr unable to stabilize the a -SiAlON.(2)Crystal StructureThe diffraction data obtained by synchrotron powder X-ray of Sr-a -SiAlON and Ca-a -SiAlON with the nominal compositionsSr 0.375Si 11.25Al 0.75N 16and Ca 0.375Si 11.25Al 0.75N 16were used for structural refinement.Because the Sr-a -SiAlON sample contains a small amount of SrSi 6N 8,a two-phase structural refinement was conducted on Sr-a -SiAlON.As shown in Fig.4(a),a fairly good result was obtained,and the final refinement converged with the reliability indexes:R wp 51.31%,R p 50.89%.R I and R F are 4.85%,2.66%for Sr-a -SiAlON and 4.18%,1.54%for SrSi 6N 8,respectively.The mole fraction of Sr-a -SiAlON to SrSi 6N 8is 0.96–0.04.Figure 4(b)shows the refinement result of Ca-a -SiAlON.The reliability indexes obtained are:R wp 52.39%,R p 51.43%,R I 52.39%,and R F 51.29%.The refined fractional coordinates of Sr-a -SiAlON and Ca-a -Si AlON are listed in Table II.The occupancy of each Ca and Sr were 0.1825(7)and 0.1380(7),respectively.The smaller occupancy of Sr1is due to the formation of SrSi 6N 8.The calculated occupancy of Ca-a -SiAlON is smaller than that derived from the nominal composition:0.1875.The deviation of the occupancy of Ca-a -SiAlON can be ascribed to the vol-atilization of Ca at the high firing temperature of 20001C.It is seen that Ca-a -SiAlON and Sr-a -SiAlON have similar latticeconstants,and they are a 57.79277(3)A ,c 55.65325A for Ca-a -SiAlON and a 57.79189(5)A ,and c 55.65377A forSr-a -SiAlON.As mentioned previously,the lattice constants decrease with decreasing m value,13indicating that the lattice constants of Sr-a -SiAlON are influenced by the formation of SrSi 6N 8.The crystal structure of Sr-or Ca-a -SiAlON is shown in Fig.5(a).The a -SiAlON structure has the expanded a -Si 3N 4structure built up of the (Si,Al)–(O,N)network.17The intro-duction of Ca or Sr in the sevenfold coordination sites stabi-lizes the a -SiAlON structure.The local structure of the Ca or Sr site in the a -SiAlON structure is shown in Fig.5(b).Selected bonding distances and bonding angles are listed in Table III.The first nearest Ca/Sr–N2bond is much shorter than the other six Ca/Sr–N bonds.Ca–N2and Sr–N2bondingdistances are 2.367(5)Aand 2.412(7)A ,respectively,and the difference of the bonding distances between Ca–N2and Sr–N2is large compared with the other six bonds.Si/Al1–N2–Si/Al1bond angles of Ca-a -SiAlON and Sr-a -SiAlON are 116.7(2)1and 117.5(3)1,respectively.This means that the displacement of N2sites parallel to the c axis probably allow the interstices in a -SiAlON to accommodate the introduction of the large Sr ion.(3)Photoluminescence PropertiesFigure 6shows the typical excitation and emission spectra:of (a)Sr-a -SiAlON:Eu 21,(b)Ca-a -SiAlON:Eu 21phosphors.The excitation and emission spectra of Sr-a -SiAlON:Eu 21are comparable with those of Ca-a -SiAlON:Eu 21.The exci-52015302540351060555045I n t e n s i t y (b)52015302540351060555045I n t e n s i t y(a)2θ / deg2θ / degFig.4.Observed and calculated X-ray powder diffraction patterns for nominal compositions:(a)Sr 0.375Si 11.25Al 0.75N 16,(b)Ca 0.375Si 11.25Al 0.75N 16.Solid line is the pattern calculated from the refined crystal structure.Residual errors are drawn at the bottom of the figure.Vertical short lines are the permitted peak positions satisfying the Bragg condi-tion.The first row is Sr-a -SiAlON,and the second row is SrSi 6N 8in (a).Table II.The Refined Atomic Coordinates,Occupancies,and Isotropic Atomic Displacement Parameters for Ca-and Sr-a -SiAlONAtomWykoff positionOccxyzB (A2)Ca-a -SiAlONCa 2b 0.1825(7)1/32/30.23604(4)0.460(67)Si/Al16c 0.8175/0.18250.51156(6)0.0824(6)0.21097(48)0.424(8)Si/Al26c 0.8175/0.18250.16813(5)0.2527(5)0.00271(48)0.256(7)N12a 10000.34N22b 11/32/30.65475(55)0.34N36c 10.34473(12)À0.04598(15)À0.00922(63)0.34N46c 10.31852(13)0.31533(14)0.25714(56)0.34Sr-a -SiAlON Sr 2b 0.1380(7)1/32/30.2357(9)0.77(8)Si/Al16c 0.862/0.1380.51122(10)0.08219(9)0.2110(8)0.40(1)Si/Al26c 0.862/0.1380.16817(8)0.25288(7)0.0015(8)0.21(1)N12a 10000.34N22b 11/32/30.6624(9)0.34N36c 10.3453(2)À0.0426(2)À0.0037(11)0.34N46c10.3209(2)0.3139(2)0.2582(9)0.34Space group:P 31c (no.159).Refined lattice parameters are Ca-a -SiAlON:a 57.79277(3)A,c 55.65325(1)A ,Sr-a -SiAlON:a 57.79189(5)A ,c 55.65377(2)A .February 2010Synthesis,Crystal Structure,and Photoluminescence of Sr-a -SiAlON:Eu 21467tation spectrum of Sr-a -SiAlON:Eu 21covers the spectral re-gion from the UV to the visible part.Two broad bands are observed in the excitation spectrum with the maxima at about 288and 399nm corresponding to 4f 7-4f 65d transition of Eu 21.It is consistent with previous study on Ca-a -Si AlON:Eu 21.13The emission spectrum shows a single intense broad emission band ranging from 470to 750nm,peaking at about 575nm,which is attributable to the permitted 4f 65d -4f 7transition of Eu 21.The emission intensities of Sr-a -Si AlON:Eu 21(583nm)and Ca-a -SiAlON:Eu 21(575nm)were about 122%and 116%of YAG:Ce 31(P46-Y3).The emission peak of Sr-and Ca-a -SiAlON:Eu 21were longer than that of YAG:Ce 31(560nm).It means that the Sr-and Ca-a -Si AlON:Eu 21phosphors could be good yellow phosphor can-didates for creating warm white light when combined with blue LED.A very weak emission band centered at 450nm is ascribed to the luminescence of the small amount of SrSi 6N 8:Eu 21.25The characteristic Eu 31luminescence,which ex-hibits sharp and line-shaped spectrum between 600and 630nm is not observed.This suggests that the europium ion in Sr-a -SiAlON phosphor is in the divalent state.In comparisonwith Ca-a -SiAlON:Eu 21,the positions of the excitation and emission spectra are very similar (Fig.6),because the PL spectra are fixed by the network of (Si,Al)–(O,N)in a -Si AlON and nearly independent of the local structure around Sr (Eu 21)or Ca (Eu 21)ions.IV.ConclusionsNovel Sr-a -SiAlON:Eu 21phosphors have been successfully syn-thesized by gas-pressure sintering at 20001C for 2h under 1MPa nitrogen atmosphere.Nearly single phase of Sr-a -SiAlON:Eu 21sample was obtained with small m and n values (m 50.70–0.80and n 50–0.05).The Rietveld refinements have revealed that the displacement of N2site parallel to the c -axis could be the main reason for the introduction of Sr atom into the a -SiAlON struc-ture.This phosphor shows the wide excitation spectrum cover-ing from the ultra violet region to 500nm and emits a strong yellow light.It is expected that Sr-a -SiAlON:Eu 21phosphor can also be a good wavelength-conversion yellow phosphor for use in white LEDs based on a blue (Ga,In)N chip.AcknowledgmentsWe thank Drs.M.Tanaka,H.Yoshikawa,and K.Kobayashi of the National Institute for Materials Science for their suggestions and encouragements.We thank Dr.Y.Katsuya and Ms.J.Uchida of SPring-8service for their support in the diffraction experiments.References1S.Nakamura and 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-SiAlONDistance (A )M iv –N2iv 2.367(5) 2.412(7)M iv –N3vi 2.597(3) 2.600(4)M v –N3v 2.597(3) 2.600(4)M iv –N3iv 2.597(3) 2.600(4)M iv –N4v 2.6847(7) 2.7049(12)M iv –N4vi 2.6847(7) 2.7049(11)M iv –N4iv 2.6847(11) 2.705(2)Average 2.602 2.618Angle (deg)Si/Al1ii –N2iv –Si/Al1iii 116.7(2)117.5(3)Si/Al1i –N2iv –Si/Al1ii 116.7(2)117.5(2)Si/Al1iii –N2iv –Si/Al1i116.74(13)117.5(2)Symmetry operations are (i)x ,y ,z ;(ii)Ày ,x Ày ,z ;(iii)Àx 1y ,Àx ,z ;(iv)y ,x ,z 11/2;(v)x Ày ,Ày ,z 11/2;(vi)Àx ,Àx 1y ,z 11/2.M 5Ca and Sr.P L e m / e x -I n t ( a .u )(a)ExcitationEmission 200Wavelength ( nm )P L e m / e x -I n t ( a .u )(b)ExcitationEmission λem = 575 nm λem = 583 nm λex = 400 nmλex = 400 nmCa-α-SiAlON300400500600700200Wavelength ( nm )300400500600700Sr-α-SiAlONFig.6.Excitation and emission spectra of the samples with the nominal compositions:(a)Sr 0.355Eu 0.02Si 11.23Al 0.77O 0.02N 15.98,(b)Ca 0.355Eu 0.02Si 11.23Al 0.77O 0.02N 15.98.468Journal of the American Ceramic Society—Shioi et 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